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1.  Low-Density Lipoprotein Apheresis 
Executive Summary
Objective
To assess the effectiveness and safety of low-density lipoprotein (LDL) apheresis performed with the heparin-induced extracorporeal LDL precipitation (HELP) system for the treatment of patients with refractory homozygous (HMZ) and heterozygous (HTZ) familial hypercholesterolemia (FH).
Background on Familial Hypercholesterolemia
Familial hypercholesterolemia is a genetic autosomal dominant disorder that is caused by several mutations in the LDL-receptor gene. The reduced number or absence of functional LDL receptors results in impaired hepatic clearance of circulating low-density lipoprotein cholesterol (LDL-C) particles, which results in extremely high levels of LDL-C in the bloodstream. Familial hypercholesterolemia is characterized by excess LDL-C deposits in tendons and arterial walls, early onset of atherosclerotic disease, and premature cardiac death.
Familial hypercholesterolemia occurs in both HTZ and HMZ forms.
Heterozygous FH is one of the most common monogenic metabolic disorders in the general population, occurring in approximately 1 in 500 individuals1. Nevertheless, HTZ FH is largely undiagnosed and an accurate diagnosis occurs in only about 15% of affected patients in Canada. Thus, it is estimated that there are approximately 3,800 diagnosed and 21,680 undiagnosed cases of HTZ FH in Ontario.
In HTZ FH patients, half of the LDL receptors do not work properly or are absent, resulting in plasma LDL-C levels 2- to 3-fold higher than normal (range 7-15mmol/L or 300-500mg/dL). Most HTZ FH patients are not diagnosed until middle age when either they or one of their siblings present with symptomatic coronary artery disease (CAD). Without lipid-lowering treatment, 50% of males die before the age of 50 and 25% of females die before the age of 60, from myocardial infarction or sudden death.
In contrast to the HTZ form, HMZ FH is rare (occurring in 1 case per million persons) and more severe, with a 6- to 8-fold elevation in plasma LDL-C levels (range 15-25mmol/L or 500-1000mg/dL). Homozygous FH patients are typically diagnosed in infancy, usually due to the presence of cholesterol deposits in the skin and tendons. The main complication of HMZ FH is supravalvular aortic stenosis, which is caused by cholesterol deposits on the aortic valve and in the ascending aorta. The average life expectancy of affected individuals is 23 to 25 years. In Ontario, it is estimated that there are 13 to 15 cases of HMZ FH. An Ontario clinical expert confirmed that 9 HMZ FH patients have been identified to date.
Diagnosis
There are 2 accepted clinical diagnostic criterion for the diagnosis of FH: the Simon Broome FH Register criteria from the United Kingdom and the Dutch Lipid Network criteria from the Netherlands. The criterion supplement cholesterol levels with clinical history, physical signs and family history. DNA-based-mutation-screening methods permit a definitive diagnosis of HTZ FH to be made. However, given that there are over 1000 identified mutations in the LDL receptor gene and that the detection rates of current techniques are low, genetic testing becomes problematic in countries with high genetic heterogeneity, such as Canada.
Treatment
The primary aim of treatment in both HTZ and HMZ FH is to reduce plasma LDL-C levels in order to reduce the risk of developing atherosclerosis and CAD.
The first line of treatment is dietary intervention, however it alone is rarely sufficient for the treatment of FH patients. Patients are frequently treated with lipid-lowering drugs such as resins, fibrates, niacin, statins and cholesterol absorption-inhibiting drugs (ezetimibe). Most HTZ FH patients require a combination of drugs to achieve or approach target cholesterol levels.
A small number of HTZ FH patients are refractory to treatment or intolerant to lipid-lowering medication. According to clinical experts, the prevalence of refractory HTZ FH in Ontario is between 1 to 5%. Using the mean of 3%, it is estimated that there are approximately 765 refractory HTZ FH patients in Ontario, of which 115 are diagnosed and 650 are undiagnosed.
Drug therapy is less effective in HMZ FH patients since the effects of the majority of cholesterol-lowering drugs are mediated by the upregulation of LDL receptors, which are often absent or function poorly in HMZ FH patients. Some HMZ FH patients may still benefit from drug therapy, however this rarely reduces LDL-C levels to targeted levels.
Existing Technology: Plasma Exchange
An option currently available in Ontario for FH patients who do not respond to standard diet and drug therapy is plasma exchange (PE). Patients are treated with this lifelong therapy on a weekly or biweekly basis with concomitant drug therapy.
Plasma exchange is nonspecific and eliminates virtually all plasma proteins such as albumin, immunoglobulins, coagulation factors, fibrinolytic factors and HDL-C, in addition to acutely lowering LDL-C by about 50%. Blood is removed from the patient, plasma is isolated, discarded and replaced with a substitution fluid. The substitution fluid and the remaining cellular components of the blood are then returned to the patient.
The major limitation of PE is its nonspecificity. The removal of HDL-C prevents successful vascular remodeling of the areas stenosed by atherosclerosis. In addition, there is an increased susceptibility to infections, and costs are incurred by the need for replacement fluid. Adverse events can be expected to occur in 12% of procedures.
Other Alternatives
Surgical alternatives for FH patients include portocaval shunt, ileal bypass and liver transplantation. However, these are risky procedures and are associated with a high morbidity rate. Results with gene therapy are not convincing to date.
The Technology Being Reviewed: LDL Apheresis
An alternative to PE is LDL apheresis. Unlike PE, LDL apheresis is a selective treatment that removes LDL-C and other atherogenic lipoproteins from the blood while minimally impacting other plasma components such as HDL-C, total serum protein, albumin and immunoglobulins. As with PE, FH patients require lifelong therapy with LDL apheresis on a weekly/biweekly basis with concomitant drug therapy.
Heparin-Induced Extracorporeal LDL Precipitation
Heparin-induced extracorporeal LDL precipitation (HELP) is one of the most widely used methods of LDL apheresis. It is a continuous closed-loop system that processes blood extracorporeally. It operates on the principle that at a low pH, LDL and lipoprotein (a) [Lp(a)] bind to heparin and fibrinogen to form a precipitate which is then removed by filtration. In general, the total duration of treatment is approximately 2 to 3 hours.
Results from early trials indicate that LDL-C concentration is reduced by 65% to 70% immediately following treatment in both HMZ and HTZ FH and then rapidly begins to rise. Typically patients with HTZ FH are treated every 2 weeks while patients with HMZ FH require weekly therapy. Heparin-induced extracorporeal LDL precipitation also produces small transient decreases in HDL-C, however levels generally return to baseline within 2 days. After several months of therapy, long-term reductions in LDL-C and increases in HDL-C have been reported.
In addition to having an impact on plasma cholesterol concentrations, HELP lowers plasma fibrinogen, a risk factor for atherosclerosis, and reduces concentrations of cellular adhesion molecules, which play a role in early atherogenesis.
In comparison with PE, HELP LDL apheresis does not have major effects on essential plasma proteins and does not require replacement fluid, thus decreasing susceptibility to infections. One study noted that adverse events were documented in 2.9% of LDL apheresis treatments using the HELP system compared with 12% using PE. As per the manufacturer, patients must weigh at least 30kgs to be eligible for treatment with HELP.
Regulatory Status
The H.E.L.P.® System (B.Braun Medizintechnologie GmbH, Germany) has been licensed by Health Canada since December 2000 as a Class 3 medical device (Licence # 26023) for performing LDL apheresis to acutely remove LDL from the plasma of 3 high-risk patient populations for whom diet has been ineffective and maximum drug therapy has either been ineffective or not tolerated. The 3 patient groups are as follows:
Functional hypercholesterolemic homozygotes with LDL-C >500 mg/dL (>13mmol/L);
Functional hypercholesterolemic heterozygotes with LDL-C >300 mg/dL (>7.8mmol/L);
Functional hypercholesterolemic heterozygotes with LDL-C >200 mg/dL (>5.2mmol/L) and documented CAD
No other LDL apheresis system is currently licensed in Canada.
Review Strategy
The Medical Advisory Secretariat systematically reviewed the literature to assess the effectiveness and safety of LDL apheresis performed with the HELP system for the treatment of patients with refractory HMZ and HTZ FH. A standard search methodology was used to retrieve international health technology assessments and English-language journal articles from selected databases.
The GRADE approach was used to systematically and explicitly make judgments about the quality of evidence and strength of recommendations.
Summary of Findings
The search identified 398 articles published from January 1, 1998 to May 30, 2007. Eight studies met the inclusion criteria. Five case series, 2 case series nested within comparative studies, and one retrospective review, were included in the analysis. A health technology assessment conducted by the Alberta Heritage Foundation for Medical Research, and a review by the United States Food and Drug Administration were also included.
Large heterogeneity among the studies was observed. Studies varied in inclusion criteria, baseline patient characteristics and methodology.
Overall, the mean acute1 relative decrease in LDL-C with HELP LDL apheresis ranged from 53 to 77%. The mean acute relative reductions ranged as follows: total cholesterol (TC) 47 to 64%, HDL-C +0.4 to -29%, triglycerides (TG) 33 to 62%, Lp(a) 55 to 68% and fibrinogen 56 to 65%.
The mean chronic2 relative decreases in LDL-C and TC with HELP LDL apheresis ranged from 9 to 46% and 5 to 34%, respectively. Familial hypercholesterolemia patients treated with HELP did not achieve the target LDL-C value set by international guidelines (LDL-C < 2.5mmol/L, 100mg/dL). The chronic mean relative increase in HDL-C ranged from 12 to 27%. The ratio of LDL:HDL and the ratio of TC:HDL are 2 measures that have been shown to be important risk factors for cardiac events. In high-risk patients, the recommended target LDL:HDL ratio is less than or equal to 2, and the target TC:HDL ratio is less than 4. In the studies that reported chronic lipid changes, the LDL:HDL and TC:HDL ratios exceeded targeted values.
Three studies investigated the effects of HELP on coronary outcomes and atherosclerotic changes. One noted that twice as many lesions displayed regression in comparison to those displaying progression. The second study found that there was a decrease in Agatston scores3 and in the volume of coronary calcium. The last study noted that 2 of 5 patients showed regression of coronary atherosclerosis, and 3 of the 5 patients showed no change as assessed by a global change score.
Adverse effects were typically mild and transient, and the majority of events were related to problems with vascular access. Of the 3 studies that provided quantitative information, the proportion of adverse events ranged from 2.9 to 5.1%.
GRADE Quality of Evidence
In general, studies were of low quality, i.e., case series studies (Tables 1-3). No controlled studies were identified and no studies directly compared the effectiveness of the HELP system with PE or with diet and drug therapy. Conducting trials with a sufficiently large control group would not have been feasible or acceptable given that HELP represents a last alternative in these patients who are resistant to conventional therapeutic strategies.
A major limitation is that there is limited evidence on the effectiveness and safety of HELP apheresis in HMZ FH patients. However, it is unlikely that better-quality evidence will become available, given that HMZ FH is rare and LDL apheresis is a last therapeutic option for these patients.
Lastly, there is limited data on the long-term effects of LDL apheresis in FH patients. No studies with HELP were identified that examined long-term outcomes such as survival and cardiovascular events. The absence of this data may be attributed to the rarity of the condition, and the large number of subjects and long duration of follow-up that would be needed to conduct such trials.
Homozygous Familial Hypercholesterolemia - Lipid Outcomes
Heterozygous Familial Hypercholesterolemia - Lipid Outcomes
Heterozygous Familial Hypercholesterolemia - Coronary Artery Disease Outcomes
Economic Analysis
A budget-impact analysis was conducted to forecast future costs for PE and HELP apheresis in FH patients. All costs are reported in Canadian dollars. Based on epidemiological data of 13 HMZ, 115 diagnosed HTZ and 765 cases of all HTZ patients (diagnosed + undiagnosed), the annual cost of weekly treatment was estimated to be $488,025, $4,332,227 and $24,758,556 respectively for PE. For HELP apheresis, the annual cost of weekly treatment was estimated to be $1,025,338, $9,156,209 and $60,982,579 respectively. Costs for PE and HELP apheresis were halved with a biweekly treatment schedule.
The cost per coronary artery disease death avoided over a 10-year period in HTZ FH-diagnosed patients was also calculated and estimated to be $37.5 million and $18.7 million for weekly and biweekly treatment respectively, when comparing HELP apheresis with PE and with no intervention. Although HELP apheresis costs twice as much as PE, it helped to avoid 12 deaths compared with PE and 22 deaths compared with no intervention, over a period of 10 years.
Ontario Health System Impact Analysis
Low-density lipoprotein apheresis using the HELP system is currently being funded by the provinces of Quebec and Alberta. The program in Quebec has been in operation since 2001 and is limited to the treatment of HMZ FH patients. The Alberta program is relatively new and is currently treating HMZ FH patients, but it is expanding to include refractory HTZ FH patients.
Low-density lipoprotein apheresis is a lifelong treatment and requires considerable commitment on the part of the patient, and the patient’s family and physician. In addition, the management of FH continues to evolve. With the advent of new more powerful cholesterol-lowering drugs, some HTZ patients may be able to sufficiently control their hypercholesterolemia. Nevertheless, according to clinical experts, HMZ patients will likely always require LDL apheresis.
Given the substantial costs associated with LDL apheresis, treatment has been limited to HMZ FH patients. However, LDL apheresis could be applied to a much larger population, which would include HTZ FH patients who are refractory to diet and drug therapy. HTZ FH patients are generally recruited in a more advanced state, demonstrate a longer natural survival than HMZ FH patients and are older.
Conclusions
For HMZ FH patients, the benefits of LDL apheresis clearly outweigh the risks and burdens. According to GRADE, the recommendation would be graded as strong, with low- to very low-quality evidence (Table 4).
In both HMZ and HTZ FH patients, there is evidence of overall clinical benefit of LDL apheresis from case series studies. Low-density lipoprotein apheresis has several advantages over the current treatment of PE, including decreased exposure to blood products, decreased risk of adverse events, conservation of nonatherogenic and athero-protective components, such as HDL-C and lowering of other atherogenic components, such as fibrinogen.
In contrast to HMZ FH patients, there remains a lot of uncertainty in the social/ethical acceptance of this technology for the treatment of refractory HTZ FH patients. In addition to the substantial costs, it is unknown whether the current health care system could cope with the additional demand. There is uncertainty in the estimates of benefits, risks and burdens. According to GRADE, the recommendation would be graded as weak with low- to very-low-quality evidence (Table 5).
GRADE Recommendation - Homozygous Patients
GRADE of recommendation: Strong recommendation, low-quality or very-low-quality evidence
Benefits clearly outweigh risk and burdens
Case series study designs
Strong, but may change when higher-quality evidence becomes available
GRADE Recommendation - Heterozygous Patients
GRADE of recommendation: Weak recommendation, low-quality or very-low-quality evidence
Uncertainty in the estimates of benefits, risks and burden, which these may be closely balanced
Case series study designs
Very weak; other alternatives may be equally reasonable
PMCID: PMC3377562  PMID: 23074505
2.  Short term effects of a low-carbohydrate diet in overweight and obese subjects with low HDL-C levels 
Background
The aim of this study was to evaluate short-term effects of a low-carbohydrate diet in overweight and obese subjects with low HDL-C levels.
Methods
Overweight (BMI between 25-30 kg/m2) or obese (BMI over 30 kg/m2) subjects with low HDL-C levels (men with HDL-C <1.03, women <1.29 mmol/l) were invited to the study. A 1400 kcal 75-gram carbohydrate (CHO) diet was given to women and an 1800 kcal 100-gram CHO diet was given to men for four weeks. The distribution of daily energy of the prescribed diet was 21-22% from CHO, 26-29% from protein and 49-53% from fat. Subjects completed a three-day dietary intake record before each visit. Anthropometric indices, body fat ratio, blood lipids, glucose and insulin were measured. Baseline and week-four results were compared with a Wilcoxon signed ranks test.
Results
Twenty-five women and 18 men participated. Basal median LDL-C level of men was 3.11 and basal median LDL-C level of women was 3.00 mmol/l. After four weeks of a low-carbohydrate diet, the median energy intake decreased from 1901 to 1307 kcal/day, daily energy from carbohydrate from 55% to 33%, body weight from 87.7 to 83.0 kg and HDL-C increased from 0.83 to 0.96 mmol/l in men (p < 0.002, for all). After four weeks of a low-carbohydrate diet, the median energy intake tended to decrease (from 1463 to 1243 kcal, p = 0.052), daily energy from carbohydrate decreased from 53% to 30% (p < 0.001) and body weight decreased from 73.2 to 70.8 kg (p < 0.001) in women, but HDL-C did not significantly change (from 1.03 to 1.01 mmol/l, p = 0.165). There were significant decreases in body mass index, waist circumference, body fat ratio, systolic blood pressure, total cholesterol, triglyceride and insulin levels in all subjects.
Conclusions
HDL-C levels increased significantly with energy restriction, carbohydrate restriction and weight loss in men. HDL-C levels didn't change in women in whom there was no significant energy restriction but a significant carbohydrate restriction and a relatively small but significant weight loss. Our results suggest that both energy and carbohydrate restriction should be considered in overweight and obese subjects with low HDL-C levels, especially when LDL-C levels are not elevated.
doi:10.1186/1472-6823-10-18
PMCID: PMC2994852  PMID: 21062488
3.  Hyperlipoproteinaemia in primary gout: hyperlipoproteinaemic phenotype and influence of alcohol intake and obesity in Japan. 
Annals of the Rheumatic Diseases  1986;45(4):308-313.
Serum lipoprotein profiles were investigated in 108 male patients with primary gout before treatment to elucidate the prevalence of each individual phenotype of coexisting hyperlipoproteinaemia and pathogenic factors responsible for it. The mean serum triglyceride (TG) and total cholesterol (TC) levels in the patients with gout were 2.10 +/- 0.14 mmol/l and 5.26 +/- 0.10 mmol/l (mean +/- SEM) respectively, which were significantly higher (p less than 0.01 and p less than 0.05 respectively) than the levels in age matched controls without gout (1.30 +/- 0.07 mmol/l and 4.77 +/- 0.08 mmol/l respectively). Serum high density lipoprotein cholesterol (HDL-C) values were slightly decreased in patients with gout compared with controls (1.24 +/- 0.08 mmol/l v 1.40 +/- 0.03 mmol/l, p less than 0.05). Hyperlipoproteinaemia was seen in 61 patients (56%), of whom patients with type IIa, IIb, and IV hyperlipoproteinaemia formed 13, 15, and 69% respectively. Thus the prevalence of type IV hyperlipoproteinaemia was high in primary gout as compared with primary hyperlipoproteinaemia with primary hyperlipoproteinaemia (69% v 43%, p less than 0.01). The independent and relative influences of clinical data of the patients upon the concentrations of serum lipids were assessed by stepwise multiple regression analysis. Two major predictors of serum TG level were alcohol intake (p less than 0.01) and serum uric acid level (p less than 0.05). The most significant predictive variable was alcohol intake, but its influence was judged to be small (r2 = 0.067). None of the other variables, including obesity index, had any significant influence. The relationships between any of these variables and serum TC or HDL-C levels were not significant. In addition, serum lipid levels were investigated in patients with neither obesity (defined as 120% or more of ideal body weight) nor a history of alcohol intake. Their serum TG and TC concentrations were also significantly higher than the respective control levels. Thus hyperlipoproteinaemia in primary gout its unlikely to be secondary to excess alcohol intake or obesity, or both. Instead, it may result from genetic factors such as a combined hyperlipidaemic trait.
PMCID: PMC1001874  PMID: 3707219
4.  Dairy products and plasma cholesterol levels 
Food & Nutrition Research  2010;54:10.3402/fnr.v54i0.5124.
Cholesterol synthesized in the body or ingested is an essential lipid component for human survival from our earliest life. Newborns ingest about 3–4 times the amount per body weight through mother's milk compared to the dietary intake of adults. A birth level of 1.7 mmol/L plasma total cholesterol will increase to 4–4.5 mmol/L during the nursing period and continue to increase from adulthood around 40% throughout life. Coronary artery disease and other metabolic disorders are strongly associated with low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol as well as triacylglycerol concentration. Milk fat contains a broad range of fatty acids and some have a negative impact on the cholesterol rich lipoproteins. The saturated fatty acids (SFAs), such as palmitic acid (C16:0), myristic acid (C14:0), and lauric acid (C12:0), increase total plasma cholesterol, especially LDL, and constitute 11.3 g/L of bovine milk, which is 44.8% of total fatty acid in milk fat. Replacement of dairy SFA and trans-fatty acids with polyunsaturated fatty acids decreases plasma cholesterol, especially LDL cholesterol, and is associated with a reduced risk of cardiovascular disease. Available data shows different effects on lipoproteins for different dairy products and there is uncertainty as to the impact a reasonable intake amount of dairy items has on cardiovascular risk. The aim of this review is to elucidate the effect of milk components and dairy products on total cholesterol, LDL, HDL, and the LDL/HDL quotients. Based on eight recent randomized control trials of parallel or cross-over design and recent reviews it can be concluded that replacement of saturated fat mainly (but not exclusively) derived from high-fat dairy products with low-fat dairy products lowers LDL/HDL cholesterol and total/HDL cholesterol ratios. Whey, dairy fractions enriched in polar lipids, and techniques such as fermentation, or fortification of cows feeding can be used to produce dairy products with more beneficial effects on plasma lipid profile.
doi:10.3402/fnr.v54i0.5124
PMCID: PMC2926059  PMID: 20806084
bovine milk; low-density lipoprotein; high-density lipoprotein; saturated fatty acids; LDL/HDL quotients
5.  Effects on Coronary Heart Disease of Increasing Polyunsaturated Fat in Place of Saturated Fat: A Systematic Review and Meta-Analysis of Randomized Controlled Trials 
PLoS Medicine  2010;7(3):e1000252.
Dariush Mozaffarian and colleagues conduct a systematic review and meta-analysis to investigate the effect of consuming polyunsaturated fats in place of saturated fats for lowering the risk of coronary heart disease.
Background
Reduced saturated fat (SFA) consumption is recommended to reduce coronary heart disease (CHD), but there is an absence of strong supporting evidence from randomized controlled trials (RCTs) of clinical CHD events and few guidelines focus on any specific replacement nutrient. Additionally, some public health groups recommend lowering or limiting polyunsaturated fat (PUFA) consumption, a major potential replacement for SFA.
Methods and Findings
We systematically investigated and quantified the effects of increased PUFA consumption, as a replacement for SFA, on CHD endpoints in RCTs. RCTs were identified by systematic searches of multiple online databases through June 2009, grey literature sources, hand-searching related articles and citations, and direct contacts with experts to identify potentially unpublished trials. Studies were included if they randomized participants to increased PUFA for at least 1 year without major concomitant interventions, had an appropriate control group, and reported incidence of CHD (myocardial infarction and/or cardiac death). Inclusions/exclusions were adjudicated and data were extracted independently and in duplicate by two investigators and included population characteristics, control and intervention diets, follow-up duration, types of events, risk ratios, and SEs. Pooled effects were calculated using inverse-variance-weighted random effects meta-analysis. From 346 identified abstracts, eight trials met inclusion criteria, totaling 13,614 participants with 1,042 CHD events. Average weighted PUFA consumption was 14.9% energy (range 8.0%–20.7%) in intervention groups versus 5.0% energy (range 4.0%–6.4%) in controls. The overall pooled risk reduction was 19% (RR = 0.81, 95% confidence interval [CI] 0.70–0.95, p = 0.008), corresponding to 10% reduced CHD risk (RR = 0.90, 95% CI = 0.83–0.97) for each 5% energy of increased PUFA, without evidence for statistical heterogeneity (Q-statistic p = 0.13; I2 = 37%). Meta-regression identified study duration as an independent determinant of risk reduction (p = 0.017), with studies of longer duration showing greater benefits.
Conclusions
These findings provide evidence that consuming PUFA in place of SFA reduces CHD events in RCTs. This suggests that rather than trying to lower PUFA consumption, a shift toward greater population PUFA consumption in place of SFA would significantly reduce rates of CHD.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Coronary heart disease (CHD) is the leading cause of death among adults in developed countries. It is caused by disease of the coronary arteries, the blood vessels that supply the heart with oxygen and nutrients. With age, inflammatory deposits (atherosclerotic plaques) coat the walls of these arteries and restrict the heart's blood supply, causing angina (chest pains that are usually relieved by rest), shortness of breath, and, if these plaques rupture or break, heart attacks (myocardial infarctions), which can reduce the heart's function or even be fatal. The key risk factors for CHD are smoking, physical inactivity, and poor diet. Blood cholesterol levels are altered by consuming dietary fats. There are three main types of dietary fats—“saturated” fatty acids (SFA) and unsaturated fatty acids; the latter can be “mono” unsaturated (MUFA) or “poly” unsaturated (PUFA). Eating SFA-rich foods (for example, meat, butter, and cheese) increases the amount of LDL-C in the blood but also increases HDL-C (the “good” cholesterol) and decreases triglycerides. Eating foods that are rich in unsaturated fatty acids (for example, vegetable oils and fatty fish) decreases the amount of LDL-C and triglycerides in the blood and also raises HDL-C.
Why Was This Study Done?
Because of the connection between eating SFA and high blood LDL-C levels, reduced SFA consumption is recommended as a way to avoid CHD. However, the evidence from individual randomized controlled trials that have studied CHD events (such as heart attacks and CHD-related deaths) have been mixed and could not support this recommendation. Furthermore, dietary recommendations to reduce SFA have generally not specified any replacement, i.e., whether SFA should be replaced with carbohydrate, protein, or unsaturated fats. Because of their beneficial effects on blood LDL-C and HDL-C levels, PUFA could be one important replacement for SFA, but, surprisingly, some experts argue that eating PUFA could actually increase CHD risk. Consequently, some guidelines recommend that PUFA consumption should be limited or even reduced. In this systematic review (a study that uses predefined criteria to identify all the research on a specific topic) and meta-analysis (a statistical method for combining the results of several studies) of randomized controlled trials, the researchers assess the impact of increased PUFA consumption as replacement for SFA on CHD events.
What Did the Researchers Do and Find?
The researchers' search of the published literature, “grey” literature (doctoral dissertations, technical reports, and other documents not printed in books and journals), and contacts with relevant experts identified eight trials in which participants were randomized to increase their PUFA intake for at least a year and in which CHD events were reported. 1,042 CHD events were recorded among the 13,614 participants enrolled in these trials. In their meta-analysis, the researchers found that on average the consumption of PUFA accounted for 14.9% of total energy intake in the intervention groups compared with only 5% of total energy intake in the control groups. Participants in the intervention groups had a 19% reduced risk of CHD events compared to participants in the control groups. Put another way, each 5% increase in the proportion of energy obtained from PUFA reduced the risk of CHD events by 10%. Finally, the researchers found that the benefits associated with PUFA consumption increased with longer duration of the trials.
What Do These Findings Mean?
These findings suggest that the replacement of some dietary SFA with PUFA reduces CHD events. Because the trials included in this study looked only at replacing SFA with PUFA, it is not possible from this evidence alone to distinguish between the benefits of reducing SFA and the benefits of increasing PUFA. Furthermore, the small number of trials identified in this study all had design faults, so the risk reductions reported here may be inaccurate. However, other lines of evidence (for example, observational studies that have examined associations between the fat intake of populations and their risk of CHD) also suggest that consumption of PUFA in place of SFA reduces CHD risk. Thus, in the light of these findings, future recommendations to reduce SFA in the diet should stress the importance of replacing SFA with PUFA rather than with other forms of energy, and the current advice to limit PUFA intake should be revised.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000252.
The American Heart Association provides information about all aspects of coronary heart disease for patients, caregivers, and professionals, including advice on dietary fats (in several languages)
The UK National Health Service Choices Web site provides information about coronary heart disease
Eatwell, a resource provided by the UK Food Standards Agency, gives advice on all aspects of healthy eating, including fat consumption
MedlinePlus provides links to further resources on coronary heart disease and on cholesterol (in English and Spanish)
doi:10.1371/journal.pmed.1000252
PMCID: PMC2843598  PMID: 20351774
6.  Adding monounsaturated fatty acids to a dietary portfolio of cholesterol-lowering foods in hypercholesterolemia 
Background
Higher intake of monounsaturated fat may raise high-density lipoprotein (HDL) cholesterol without raising low-density lipoprotein (LDL) cholesterol. We tested whether increasing the monounsaturated fat content of a diet proven effective for lowering LDL cholesterol (dietary portfolio) also modified other risk factors for cardiovascular disease, specifically by increasing HDL cholesterol, lowering serum triglyceride and further reducing the ratio of total to HDL cholesterol.
Methods
Twenty-four patients with hyperlipidemia consumed a therapeutic diet very low in saturated fat for one month and were then randomly assigned to a dietary portfolio low or high in monounsaturated fatty acid for another month. We supplied participants’ food for the two-month period. Calorie intake was based on Harris–Benedict estimates for energy requirements.
Results
For patients who consumed the dietary portfolio high in monounsaturated fat, HDL cholesterol rose, whereas for those consuming the dietary portfolio low in monounsaturated fat, HDL cholesterol did not change. The 12.5% treatment difference was significant (0.12 mmol/L, 95% confidence interval [CI] 0.05 to 0.21, p = 0.003). The ratio of total to HDL cholesterol was reduced by 6.5% with the diet high in monounsaturated fat relative to the diet low in monounsaturated fat (−0.28, 95% CI −0.59 to −0.04, p = 0.025). Patients consuming the diet high in monounsaturated fat also had significantly higher concentrations of apolipoprotein AI, and their C-reactive protein was significantly lower. No treatment differences were seen for triglycerides, other lipids or body weight, and mean weight loss was similar for the diets high in monounsaturated fat (−0.8 kg) and low in monounsaturated fat (−1.2 kg).
Interpretation
Monounsaturated fat increased the effectiveness of a cholesterol-lowering dietary portfolio, despite statin-like reductions in LDL cholesterol. The potential benefits for cardiovascular risk were achieved through increases in HDL cholesterol, further reductions in the ratio of total to HDL cholesterol and reductions in C-reactive protein. (ClinicalTrials.gov trial register no. NCT00430430.)
doi:10.1503/cmaj.092128
PMCID: PMC3001502  PMID: 21041432
7.  Effects of Poly-Bioactive Compounds on Lipid Profile and Body Weight in a Moderately Hypercholesterolemic Population with Low Cardiovascular Disease Risk: A Multicenter Randomized Trial 
PLoS ONE  2014;9(8):e101978.
A dietary supplement (AP, Armolipid Plus) that combines red yeast rice extract, policosanol, berberine, folic acid, coenzyme Q10 and asthaxantine can have beneficial effects on cardiovascular disease (CVD) biomarkers. The aim of this study was to assess whether the intake of AP, in combination with dietary recommendations, reduces serum low density lipoprotein cholesterol (LDL-c) concentrations and other CVD biomarkers in patients with hypercholesterolemia. Eligible patients were recruited from the outpatient clinics of six Spanish hospitals Hospital Virgen del Rocío (Sevilla); Hospital San Jorge (Huesca); Hospital San Pedro (Logroño); Hospital Gregorio Marañón (Madrid), Hospital la Fe (Valencia) and Hospital Universitari Sant Joan (Reus) as recruiting and coordinating center. 102 participants (mean age ± SD; 50.91±11.61; 32 men) with low CVD, with mild-to-moderately elevated LDL-c (between 3.35 mmol/L and 4.88 mmol/L) without hypolipemic therapy were randomized in a double-blind, parallel, controlled, multicenter trial commencing January 2012 and ending December 2012. Among the exclusion criteria were any concomitant chronic disease, triglycerides (TG) >3.97 mmol/L, pregnant or lactating, and history of CVD. At 12 weeks, compared to placebo, AP reduced LDL-c by −6.9%, apolipoprotein (Apo) B-100 by −6.6% and total cholesterol/HDL-c ratio by −5.5%, the ApoB/ApoA1 ratio by −8.6%, while increasing ApoA1 by +2.5% (p<0.05). AP consumption was associated with modest mean weight loss of −0.93 kg (95%CI: -1.74 to -0.12; P = 0.02) compared with control group while dietary composition remained unchanged in the AP group. The AP product was well tolerated. In conclusion, AP, combined with dietary recommendations, reduced LDL-c levels as well as total cholesterol/HDL-c and ApoB/ApoA1 ratios, while increasing Apo A1, all of which are improvements in CVD risk indicators. AP is a product which could benefit patients having moderate hyperlipidemia and excess body weight.
Trial Registration
ClinicalTrials.gov NCT01562080
doi:10.1371/journal.pone.0101978
PMCID: PMC4118855  PMID: 25084280
8.  A comparative study between Wuweizi seed and its post-ethanol extraction residue in normal and hypercholesterolemic mice 
Background
At the present, a shift from drug therapy, especially herbal therapy, to dietary supplementation is a trend in the management of dyslipidemia and related diseases. Therefore, the optimal utilization of herbal resource is important for a sustainable development of herbal medicine. Here, we compared the effects of dietary supplementation with Chinese medicine Schisandrae Chinensis Fructus seed (FSC-S) and the post-ethanol extraction residue of FSC-S (FSC-SpEt) on normal diet-fed (normal) and experimental hypercholesterolemic (HCL) mice.
Methods
Male ICR mice (n = 10 in each group), weighing 17–21 g, were fed with normal diet (ND) or high cholesterol/bile salt (1/0.3 %, w/w) diet (HCBD) with or without supplemented with FSC-S, FSC-SpEt), or lipid-lowering agent fenofibrate (FF). Ten days later, serum/hepatic lipid and glucose (GLU) levels, body weight, organ/epididymal fat masses, and food/water intake were measured. Lipid level measurements included those of total cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL), low density lipoprotein (LDL), HDL/LDL ratio, LDL/HDL ratio, and non-HDL (N-HDL).
Results
Supplementation with FSC-S and FSC-SpEt increased serum TC (by 64 and 25 %, respectively) and LDL (by 60 and 27 %, respectively) in normal mice. FSC-S supplementation elevated serum TC, TG, HDL, LDL, and LDL/HDL ratio (up to 64, 118, 77, 197, and 51 %, respectively) in HCL mice. FSC-SpEt supplementation reduced serum TG (by 15 %) and LDL/HDL ratio (by 18 %), as well as increased serum HDL (by 22 %) and HDL/LDL ratio (by 21 %) in HCBD-fed mice. FSC-S decreased hepatic TC (by 19 %) contents and increased hepatic TG contents by 14 % in normal mice. FSC-S reduced hepatic GLU level in both normal and HCL mice by 24 and 22 %, respectively. Hepatic TC and TG contents were lowered in FSC-SpEt-supplemented normal mice by 16 and 20 %, respectively. The body/fatty masse and food intake were lowered, but the feed efficiency index (FEI), weight gain per unit of food ingested, was increased in FSC-S-supplemented normal and HCL mice. FF supplements reduced serum/hepatic lipids, hepatic GLU contents, and epididymal fat mass, but it induced hepatomegaly and high serum alanine aminotransferase (ALT) activity in normal and/or HCL mice.
Conclusion
The ensemble of results indicated that while FSC-SpEt supplementation is beneficial for the treatment of hyperlipidemia/fatty liver, FSC-S is potentially useful for the management of overweight/obesity.
doi:10.1186/s12944-015-0097-z
PMCID: PMC4549086  PMID: 26303027
Schisandrae Chinensis Fructus seed; Fenofibrate; Hypercholesterolemic mice; Lipids; Glucose; Fecal cholesterol; Epididymal fat; Hepatomegaly
9.  Association between serum cholesterol and eating behaviours during early childhood: a cross-sectional study 
Background:
Modifiable behaviours during early childhood may provide opportunities to prevent disease processes before adverse outcomes occur. Our objective was to determine whether young children’s eating behaviours were associated with increased risk of cardiovascular disease in later life.
Methods:
In this cross-sectional study involving children aged 3–5 years recruited from 7 primary care practices in Toronto, Ontario, we assessed the relation between eating behaviours as assessed by the NutriSTEP (Nutritional Screening Tool for Every Preschooler) questionnaire (completed by parents) and serum levels of non–high-density lipoprotein (HDL) cholesterol, a surrogate marker of cardiovascular risk. We also assessed the relation between dietary intake and serum non-HDL cholesterol, and between eating behaviours and other laboratory indices of cardiovascular risk (low-density lipoprotein [LDL] cholesterol, apolipoprotein B, HDL cholesterol and apoliprotein A1).
Results:
A total of 1856 children were recruited from primary care practices in Toronto. Of these children, we included 1076 in our study for whom complete data and blood samples were available for analysis. The eating behaviours subscore of the NutriSTEP tool was significantly associated with serum non-HDL cholesterol (p = 0.03); for each unit increase in the eating behaviours subscore suggesting greater nutritional risk, we saw an increase of 0.02 mmol/L (95% confidence interval [CI] 0.002 to 0.05) in serum non-HDL cholesterol. The eating behaviours subscore was also associated with LDL cholesterol and apolipoprotein B, but not with HDL cholesterol or apolipoprotein A1. The dietary intake subscore was not associated with non-HDL cholesterol.
Interpretation:
Eating behaviours in preschool-aged children are important potentially modifiable determinants of cardiovascular risk and should be a focus for future studies of screening and behavioural interventions.
doi:10.1503/cmaj.121834
PMCID: PMC3735770  PMID: 23775611
10.  Effects of policosanol on borderline to mildly elevated serum total cholesterol levels: a prospective, double-blind, placebo-controlled, parallel-group, comparative study☆ 
Background
Hypercholesterolemia is a major risk factor for coronary heart disease. Clinical studies have shown that lowering elevated serum cholesterol levels, particularly low-density lipoprotein cholesterol (LDL-C), is beneficial for patients with borderline to mildly elevated serum total cholesterol (TC) levels (5.0–6.0 mmol/L). Policosanol is a cholesterol-lowering drug made from purified sugar cane wax. The therapeutic range of policosanol is 5 to 20 mg/d.
Objective
This study investigated the efficacy and tolerability of policosanol 5 mg/d in patients with borderline to mildly elevated serum TC levels.
Methods
This 14-week, single-center, prospective, double-blind, placebo-controlled, parallel-group, comparative study was conducted in men and women aged 25 to 75 years with a serum TC level ≥4.8 to <6.0 mmol/L. After a 6-week run-in period in which patients were placed on therapeutic lifestyle changes, in particular a cholesterol-lowering diet, patients were randomly assigned to receive policosanol 5-mg tablets or placebo tablets once daily with the evening meal for 8 weeks, and the diet was continued throughout the study. Lipid profile variables, safety indicators, adverse events (AEs), and compliance with study medications were assessed.
Results
One hundred patients (71 women, 29 men; mean [SD] age, 52 [10] years) entered the study after the dietary run-in period. After 8 weeks of treatment, the mean (SD) serum LDL-C level decreased significantly in the policosanol group (P<0.001 vs baseline and placebo) from 3.57 (0.30) mmol/L to 2.86 (0.41) mmol/L (change, −19.9%). Significantly more patients in the policosanol group (42 patients [84%]) achieved a ≥15% decrease in serum LDL-C than in the placebo group (2 patients [4%]) (P<0.001). Also in the policosanol group, the mean (SD) serum TC level decreased significantly, from 5.20 (0.22) mmol/L to 4.56 (0.44) mmol/L (P<0.001 vs baseline and placebo) (change, −12.3%); the mean (SD) triglyceride (TG) level decreased significantly, from 1.59 (0.57) mmol/L to 1.48 (0.57) mmol/L (P<0.01 vs baseline; P<0.05 vs placebo) (change, −6.9%); and the mean (SD) high-density lipoprotein cholesterol (HDL-C) level increased significantly from 1.05 (0.18) mmol/L to 1.16 (0.21) mmol/L (P<0.001 vs baseline and placebo) (change, +10.5%). The percentage changes were significantly different between the policosanol and placebo groups for serum LDL-C, TC, and HDL-C levels (P<0.001, P<0.001, and P<0.05, respectively), but not for TG. In the placebo group, changes in lipid profile variables from baseline were not significant. Policosanol did not significantly impair any safety indicator and was well tolerated. Three patients (3%) (1 patient [2%] in the policosanol group; 2 patients [4%] in the placebo group) withdrew from the trial, none because of AEs. Two patients (1 patient [2%] each in the policosanol and placebo groups) withdrew from the study because of an unwillingness to return for follow-up; 1 patient (2%) in the placebo group had a change of address and could not be followed up. Overall, 4 patients (4%) (1 patient [2%] in the policosanol group; 3 [6%], placebo) reported AEs; all were mild. Of the patients who received placebo and reported AEs, all 3 (6%) experienced heartburn, and 1 (2%) also experienced dry skin, while the policosanol-treated patient (2%) who reported an AE experienced headache.
Conclusions
In this study of patients with borderline to mildly elevated serum TC levels, based on the criterion that ≥70% of policosanol-treated patients reached the LDL-C goal of a decrease ≥15% from baseline whenever this proportion was different with respect to placebo, 8 weeks of treatment with policosanol 5 mg/d was effective. The decreased LDL-C, TC, and TG levels, increased HDL-C level, and good tolerability found with this treatment support its use in such patients.
doi:10.1016/j.curtheres.2003.09.002
PMCID: PMC4053045  PMID: 24944402
policosanol; hypercholesterolemia; cholesterol-lowering drugs; borderline dyslipidemia
11.  Yi-Qi-Zeng-Min-Tang, a Chinese medicine, ameliorates insulin resistance in type 2 diabetic rats 
AIM: To investigate the effects of the Chinese herbal decoction, Yi-Qi-Zeng-Min-Tang (YQZMT), on insulin resistance in type 2 diabetic rats.
METHODS: Sprague-Dawley rats were divided into two dietary regiments by feeding either normal pellet diet (NPD) or high fat diet (HFD). Four weeks later, the HFD-fed rats were injected intraperitoneally with low-dose streptozotocin (STZ). Rats with non-fasting blood glucose level ≥ 16.67 mmol/L were considered type 2 diabetic and further divided into five subgroups: the type 2 diabetes model group, low-dose, medium-dose and high-dose YQZMT groups, and rosiglitazone group. Age-matched NPD-fed rats served as controls. YQZMT or rosiglitazone were administered for 8 wk. Intraperitoneal glucose and insulin tolerance tests were performed before and after the treatment to measure the glucose tolerance and insulin sensitivity. Serum levels of biochemical parameters, adipocytokines, such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), as well as free fatty acids (FFAs), were also analyzed.
RESULTS: There was significant elevation of insulin resistance and serum levels of fasting glucose (12.82 ± 1.08 mmol/L vs 3.60 ± 0.31 mmol/L, P < 0.01), insulin (7197.36 ± 253.89 pg/mL vs 4820.49 ± 326.89 pg/mL, P < 0.01), total cholesterol (TC) (8.40 ± 0.49 mmol/L vs 2.14 ± 0.06 mmol/L, P < 0.01), triglyceride (2.24 ± 0.12 mmol/L vs 0.78 ± 0.05 mmol/L, P < 0.01), low-density lipoprotein cholesterol (LDL-c) (7.84 ± 0.51 mmol/L vs 0.72 ± 0.04 mmol/L, P < 0.01) and decrease in high-density lipoprotein cholesterol (HDL-c) (0.57 ± 0.03 mmol/L vs 1.27 ± 0.03 mmol/L, P < 0.01) in the low-dose STZ and high-fat diet induced type 2 diabetic group when compared with the control group. Administration of YQZMT induced dose- and time-dependent changes in insulin resistance, glucose and lipid profile, and reduced levels of FFA, TNF-α and IL-6 in the type 2 diabetic rats. After the treatment, compared with the diabetic group, the insulin resistance was ameliorated in the high-dose YQZMT (2.82 g/100 g per day) group, with a significant reduction in serum glucose (12.16 ± 1.00 mmol/L vs 17.65 ± 2.22 mmol/L, P < 0.01), homeostasis model assessment of basal insulin resistance (22.68 ± 2.37 vs 38.79 ± 9.02, P < 0.05), triglyceride (0.87 ± 0.15 mmol/L vs 1.99 ± 0.26 mmol/L, P < 0.01), TC (3.31 ± 0.52 mmol/L vs 6.50 ± 1.04 mmol/L, P < 0.01) and LDL-c (2.47 ± 0.50 mmol/L vs 6.00 ± 1.07 mmol/L, P < 0.01), and a significant increase in HDL-c (0.84 ± 0.08 mmol/L vs 0.50 ± 0.03 mmol/L, P < 0.01). But the body weight was not changed significantly.
CONCLUSION: YQZMT, which ameliorates insulin resistance and does not cause increase in body weight, may be a suitable therapeutic adjunct for the treatment of type 2 diabetes.
doi:10.3748/wjg.v17.i8.987
PMCID: PMC3057160  PMID: 21448349
Yi-Qi-Zeng-Min-Tang; Insulin resistance; Type 2 diabetes; Lipids; Adipocytokines; Free fatty acids
12.  Effects of Low-Carbohydrate and Low-Fat Diets 
Annals of internal medicine  2014;161(5):309-318.
Background
Low-carbohydrate diets are popular for weight loss, but their cardiovascular effects have not been well-studied, particularly in diverse populations.
Objective
To examine the effects of a low-carbohydrate diet compared with a low-fat diet on body weight and cardiovascular risk factors.
Design
A randomized, parallel-group trial. (ClinicalTrials.gov: NCT00609271)
Setting
A large academic medical center.
Participants
148 men and women without clinical cardiovascular disease and diabetes.
Intervention
A low-carbohydrate (<40 g/d) or low-fat diet (<30% fat; <7% saturated fat). Both groups received dietary counseling at regular intervals throughout the trial.
Measurements
Data on weight, cardiovascular risk factors, and dietary composition were collected at 0, 3, 6, and 12 months.
Results
Sixty participants (82%) in the low-fat group and 59 (79%) in the low-carbohydrate group completed the intervention. At 12 months, participants on the low-carbohydrate diet had greater decreases in weight (mean difference in change, −3.5 kg [95% CI, −5.6 to −1.4 kg]; P < 0.001), fat mass (mean difference in change, −1.5% [CI, −2.6% to −0.4%]; P = 0.011), ratio of total to high-density lipoprotein (HDL) cholesterol (mean difference in change, −0.44 [CI, −0.71 to −0.16]; P = 0.002), and triglyceride level (mean difference in change, −0.16 mmol/L [−14.1 mg/dL] [CI, −0.31 to −0.01 mmol/L {−27.4 to −0.8 mg/dL}]; P = 0.038) and greater increases in HDL cholesterol level (mean difference in change, 0.18 mmol/L [7.0 mg/dL] [CI, 0.08 to 0.28 mmol/L {3.0 to 11.0 mg/dL}]; P< 0.001) than those on the low-fat diet.
Limitation
Lack of clinical cardiovascular disease end points.
Conclusion
The low-carbohydrate diet was more effective for weight loss and cardiovascular risk factor reduction than the low-fat diet. Restricting carbohydrate may be an option for persons seeking to lose weight and reduce cardiovascular risk factors.
Primary Funding Source
National Institutes of Health.
doi:10.7326/M14-0180
PMCID: PMC4428290  PMID: 25178568
13.  Atherogenic Dyslipidemia and Residual Vascular Risk in Practice of Family Doctor 
Medical Archives  2015;69(5):339-341.
Objective:
Timely recognition and optimal management of atherogenic dyslipidemia (AD) and residual vascular risk (RVR) in family medicine.
Background:
The global increase of the incidence of obesity is accompanied by an increase in the incidence of many metabolic and lipoprotein disorders, in particular AD, as an typical feature of obesity, metabolic syndrome, insulin resistance and diabetes type 2. AD is an important factor in cardio metabolic risk, and is characterized by a lipoprotein profile with low levels of high-density lipoprotein (HDL), high levels of triglycerides (TG) and high levels of low-density lipoprotein (LDL) cholesterol. Standard cardiometabolic risk assessment using the Framingham risk score and standard treatment with statins is usually sufficient, but not always that effective, because it does not reduce RVR that is attributed to elevated TG and reduced HDL cholesterol. RVR is subject to reduction through lifestyle changes or by pharmacological interventions. In some studies it was concluded that dietary interventions should aim to reduce the intake of calories, simple carbohydrates and saturated fats, with the goal of reaching cardiometabolic suitability, rather than weight reduction. Other studies have found that the reduction of carbohydrates in the diet or weight loss can alleviate AD changes, while changes in intake of total or saturated fat had no significant influence. In our presented case, a lifestyle change was advised as a suitable diet with reduced intake of carbohydrates and a moderate physical activity of walking for at least 180 minutes per week, with an recommendation for daily intake of calories alignment with the total daily (24-hour) energy expenditure (24-EE), depending on the degree of physical activity, type of food and the current health condition. Such lifestyle changes together with combined medical therapy with Statins, Fibrates and Omega-3 fatty acids, resulted in significant improvement in atherogenic lipid parameters.
Conclusion:
Unsuitable atherogenic nutrition and insufficient physical activity are the new risk factors characteristic for AD. Nutritional interventions such as diet with reduced intake of carbohydrates and calories, moderate physical activity, combined with pharmacotherapy can improve atherogenic dyslipidemic profile and lead to loss of weight. Although one gram of fat release twice more kilo calories compared to carbohydrates, carbohydrates seems to have a greater atherogenic potential, which should be explored in future.
doi:10.5455/medarh.2015.69.339-341
PMCID: PMC4639368  PMID: 26622090
atherogenic dyslipidemia; residual vascular risk; lifestyle changes; statins; fibrates; omega-3 fatty acids
14.  Positive association of tomato consumption with serum urate: support for tomato consumption as an anecdotal trigger of gout flares 
Background
Gout is a consequence of an innate immune reaction to monosodium urate crystals deposited in joints. Acute gout attacks can be triggered by dietary factors that are themselves associated with serum urate levels. Tomato consumption is an anecdotal trigger of gout flares. This study aimed to measure the frequency of tomato consumption as a self-reported trigger of gout attacks in a large New Zealand sample set, and to test the hypothesis that tomato consumption is associated with serum urate levels.
Methods
Two thousand fifty one New Zealanders (of Māori, Pacific Island, European or other ancestry) with clinically-ascertained gout were asked about gout trigger foods. European individuals from the Atherosclerosis Risk In Communities (ARIC; n = 7517) Study, Cardiovascular Health Study (CHS; n = 2151) and Framingham Heart Study (FHS; n = 3052) were used to test, in multivariate-adjusted analyses, for association between serum urate and tomato intake.
Results
Seventy one percent of people with gout reported having ≥1 gout trigger food. Of these 20 % specifically mentioned tomatoes, the 4th most commonly reported trigger food. There was association between tomato intake and serum urate levels in the ARIC, CHS and FHS combined cohort (β = 0.66 μmolL−1 increase in serum urate per additional serve per week; P = 0.006) - evident in both sexes (men: β = 0.84 μmolL−1, P = 0.035; women: β = 0.59 μmolL −1, P = 0.041).
Conclusions
While our descriptive and observational data are unable to support the claim that tomato consumption is a trigger of gout attacks, the positive association between tomato consumption and serum urate levels suggests that the self-reporting of tomatoes as a dietary trigger by people with gout has a biological basis.
Electronic supplementary material
The online version of this article (doi:10.1186/s12891-015-0661-8) contains supplementary material, which is available to authorized users.
doi:10.1186/s12891-015-0661-8
PMCID: PMC4541734  PMID: 26286027
15.  Association between Carbohydrate Intake and Serum Lipids 
Background
The effect of dietary carbohydrate on blood lipids has received considerable attention in light of the current trend in lowering carbohydrate intake for weight loss.
Objectives
To evaluate the association between carbohydrate intake and serum lipids.
Methods
Blood samples and 24-hour dietary and physical activity recall interviews were obtained from each subject at quarterly intervals for five consecutive quarters between 1994 and 1998 from 574 healthy adults in Central Massachusetts. Relationships between serum lipids and dietary carbohydrate factors were assessed using linear mixed models and adjusting for other risk factors known to be related to blood lipids. Both cross-sectional and longitudinal results were reported.
Results
Cross-sectional analysis results from this study suggest that higher total carbohydrate intake, percentage of calories from carbohydrate, glycemic index (GI) and/or glycemic load (GL) are related to lower high-density lipoprotein cholesterol (HDL-C) and higher serum triacylglycerol levels, while higher total carbohydrate intake and/or GL are related to lower total and low-density lipoprotein cholesterol (LDL-C) levels. In a one-year longitudinal analysis, GL was positively associated with total and LDL-C levels, and there was an inverse association between percentage of calories from carbohydrate and HDL-C levels.
Conclusions
Results suggest that there is a complex and predominantly unfavorable effect of increased intake of highly processed carbohydrate on lipid profile, which may have implications for metabolic syndrome, diabetes, and coronary heart disease. Further studies in the form of randomized controlled trials are required to investigate these associations and determine the implications for lipid management.
PMCID: PMC1479303  PMID: 16582033
dietary carbohydrates; LDL cholesterol; glycemic index; longitudinal studies
16.  Effects of High vs Low Glycemic Index of Dietary Carbohydrate on Cardiovascular Disease Risk Factors and Insulin Sensitivity 
JAMA  2014;312(23):2531-2541.
IMPORTANCE
Foods that have similar carbohydrate content can differ in the amount they raise blood glucose. The effects of this property, called the glycemic index, on risk factors for cardiovascular disease and diabetes are not well understood.
OBJECTIVE
To determine the effect of glycemic index and amount of total dietary carbohydrate on risk factors for cardiovascular disease and diabetes.
DESIGN, SETTING, AND PARTICIPANTS
Randomized crossover-controlled feeding trial conducted in research units in academic medical centers, in which 163 overweight adults (systolic blood pressure, 120–159 mm Hg) were given 4 complete diets that contained all of their meals, snacks, and calorie-containing beverages, each for 5 weeks, and completed at least 2 study diets. The first participant was enrolled April 1, 2008; the last participant finished December 22, 2010. For any pair of the 4 diets, there were 135 to 150 participants contributing at least 1 primary outcome measure.
INTERVENTIONS
(1) A high–glycemic index (65% on the glucose scale), high-carbohydrate diet (58% energy); (2) a low–glycemic index (40%), high-carbohydrate diet; (3) a high–glycemic index, low-carbohydrate diet (40% energy); and (4) a low–glycemic index, low-carbohydrate diet. Each diet was based on a healthful DASH-type diet.
MAIN OUTCOMES AND MEASURES
The 5 primary outcomes were insulin sensitivity, determined from the areas under the curves of glucose and insulin levels during an oral glucose tolerance test; levels of low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides; and systolic blood pressure.
RESULTS
At high dietary carbohydrate content, the low– compared with high–glycemic index level decreased insulin sensitivity from 8.9 to 7.1 units (−20%, P = .002); increased LDL cholesterol from 139 to 147 mg/dL (6%, P ≤ .001); and did not affect levels of HDL cholesterol, triglycerides, or blood pressure. At low carbohydrate content, the low– compared with high–glycemic index level did not affect the outcomes except for decreasing triglycerides from 91 to 86 mg/dL (−5%, P = .02). In the primary diet contrast, the low–glycemic index, low-carbohydrate diet, compared with the high–glycemic index, high-carbohydrate diet, did not affect insulin sensitivity, systolic blood pressure, LDL cholesterol, or HDL cholesterol but did lower triglycerides from 111 to 86 mg/dL (−23%, P ≤ .001).
CONCLUSIONS AND RELEVANCE
In this 5-week controlled feeding study, diets with low glycemic index of dietary carbohydrate, compared with high glycemic index of dietary carbohydrate, did not result in improvements in insulin sensitivity, lipid levels, or systolic blood pressure. In the context of an overall DASH-type diet, using glycemic index to select specific foods may not improve cardiovascular risk factors or insulin resistance.
TRIAL REGISTRATION
clinicaltrials.gov Identifier: NCT00608049
doi:10.1001/jama.2014.16658
PMCID: PMC4370345  PMID: 25514303
17.  Interleukin-6 Gene Polymorphisms, Dietary Fat Intake, Obesity and Serum Lipid Concentrations in Black and White South African Women 
Nutrients  2014;6(6):2436-2465.
This study investigated interactions between dietary fat intake and IL-6 polymorphisms on obesity and serum lipids in black and white South African (SA) women. Normal-weight and obese, black and white women underwent measurements of body composition, serum lipids and dietary fat intake, and were genotyped for the IL-6 −174 G>C, IVS3 +281 G>T and IVS4 +869 A>G polymorphisms. In black women the IVS4 +869 G allele was associated with greater adiposity, and with increasing dietary fat intake adiposity increased in the IVS3 +281 GT+GG and IVS4 +869 AA or AG genotypes. In white women, with increasing omega-3 (n-3) intake and decreasing n-6:n-3 ratio, body mass index (BMI) decreased in those with the −174 C allele, IVS3 +281 T allele and IVS4 +869 AG genotype. In the white women, those with the IVS3 +281 T allele had lower triglycerides. Further, with increasing n-3 polyunsaturated fatty acid (PUFA); triglyceride and total cholesterol:high-density lipoprotein cholesterol (T-C:HDL-C) ratio decreased in those with the −174 C allele. In black women, with increasing total fat intake, triglycerides and T-C:HDL-C ratio increased in those with the IVS4 +869 G allele. This study is the first to show that dietary fat intake modulates the relationship between the IL-6 −174 G>C, IVS3 +281 G>T and IVS4 +869 A>G polymorphisms on obesity and serum lipids in black and white SA women.
doi:10.3390/nu6062436
PMCID: PMC4073161  PMID: 24962479
IL-6 gene; dietary fat; obesity; serum lipids; ethnicity
18.  Effect of dietary patterns differing in carbohydrate and fat content on blood lipid and glucose profiles based on weight-loss success of breast-cancer survivors 
Introduction
Healthy body weight is an important factor for prevention of breast cancer recurrence. Yet, weight loss and weight gain are not currently included in clinical-practice guidelines for posttreatment of breast cancer. The work reported addresses one of the questions that must be considered in recommending weight loss to patients: does it matter what diet plan is used, a question of particular importance because breast cancer treatment can increase risk for cardiovascular disease.
Methods
Women who completed treatment for breast cancer were enrolled in a nonrandomized, controlled study investigating effects of weight loss achieved by using two dietary patterns at the extremes of macronutrient composition, although both diet arms were equivalent in protein: high fat, low carbohydrate versus low fat, high carbohydrate. A nonintervention group served as the control arm; women were assigned to intervention arms based on dietary preferences. During the 6-month weight-loss program, which was menu and recipe defined, participants had monthly clinical visits at which anthropometric data were collected and fasting blood was obtained for safety monitoring for plasma lipid profiles and fasting glucose. Results from 142 participants are reported.
Results
Adverse effects on fasting blood lipids or glucose were not observed in either dietary arm. A decrease in fasting glucose was observed with progressive weight loss and was greater in participants who lost more weight, but the effect was not statistically significant, even though it was observed across both diet groups (P = 0.21). Beneficial effects of weight loss on cholesterol (4.7%; P = 0.001), triglycerides (21.8%; P = 0.01), and low-density lipoprotein (LDL) cholesterol (5.8%; P = 0.06) were observed in both groups. For cholesterol (P = 0.07) and LDL cholesterol (P = 0.13), greater reduction trends were seen on the low-fat diet pattern; whereas, for triglycerides (P = 0.01) and high-density lipoprotein (HDL) cholesterol (P = 0.08), a decrease or increase, respectively, was greater on the low-carbohydrate diet pattern.
Conclusions
Because an individual's dietary preferences can affect dietary adherence and weight-loss success, the lack of evidence of a negative effect of dietary pattern on biomarkers associated with cardiovascular risk is an important consideration in the development of breast cancer practice guidelines for physicians who recommend that their patients lose weight. Whether dietary pattern affects biomarkers that predict long-term survival is a primary question in this ongoing clinical trial.
doi:10.1186/bcr3082
PMCID: PMC3496116  PMID: 22225711
19.  Dietary lipids and blood cholesterol: quantitative meta-analysis of metabolic ward studies. 
BMJ : British Medical Journal  1997;314(7074):112-117.
OBJECTIVE: To determine the quantitative importance of dietary fatty acids and dietary cholesterol to blood concentrations of total, low density lipoprotein, and high density lipoprotein cholesterol. DESIGN: Meta-analysis of metabolic ward studies of solid food diets in healthy volunteers. SUBJECTS: 395 dietary experiments (median duration 1 month) among 129 groups of individuals. RESULTS: Isocaloric replacement of saturated fats by complex carbohydrates for 10% of dietary calories resulted in blood total cholesterol falling by 0.52 (SE 0.03) mmol/l and low density lipoprotein cholesterol falling by 0.36 (0.05) mmol/l. Isocaloric replacement of complex carbohydrates by polyunsaturated fats for 5% of dietary calories resulted in total cholesterol falling by a further 0.13 (0.02) mmol/l and low density lipoprotein cholesterol falling by 0.11 (0.02) mmol/l. Similar replacement of carbohydrates by monounsaturated fats produced no significant effect on total or low density lipoprotein cholesterol. Avoiding 200 mg/day dietary cholesterol further decreased blood total cholesterol by 0.13 (0.02) mmol/l and low density lipoprotein cholesterol by 0.10 (0.02) mmol/l. CONCLUSIONS: In typical British diets replacing 60% of saturated fats by other fats and avoiding 60% of dietary cholesterol would reduce blood total cholesterol by about 0.8 mmol/l (that is, by 10-15%), with four fifths of this reduction being in low density lipoprotein cholesterol.
PMCID: PMC2125600  PMID: 9006469
20.  Effects of Increasing Dietary Polyunsaturated Fatty Acids Within the Guidelines of the AHA Step 1 Diet on Plasma Lipid and Lipoprotein Levels in Normal Males 
Arteriosclerosis and Thrombosis  1994;14(6):892-901.
We attempted to ascertain the effects of polyunsaturated fatty acids by conducting two studies in normal young men, in which monounsaturated fats were replaced by polyunsaturated fats within the guidelines of the American Heart Association step 1 diet. Study A employed a randomized parallel design in which subjects first consumed an average American diet (AAD) containing 37% of calories as fat (saturated fat, 16% calories; monounsaturated fat, 14% calories; and polyunsaturated fat, 7% calories). After 3 weeks, one third of the subjects continued with the AAD, one third switched to a step 1 diet in which total fat calories were reduced to 30% by replacing saturated fat with carbohydrate, and one third switched to a polyunsaturated fat-enriched (Poly) diet with the same 30% fat calories and a reduction of monounsaturated fat from 14% to 8% and an increase of polyunsaturated fat from 7% to 13% of calories. The randomized period lasted 6 weeks. Total and low-density lipoprotein (LDL) cholesterol levels on the step 1 and Poly diets were reduced compared with levels on the AAD (P < .001). Total and LDL cholesterol did not differ between the step 1 and Poly diets, although comparison between the two diets is limited by the small study groups. Serum apolipoprotein (apo) B levels fell on the Poly diet compared with the AAD. Total high-density lipoprotein (HDL), HDL2, and HDL3 cholesterol levels were not significantly affected by the diets. Postprandial lipid and lipoprotein concentrations did not significantly differ either. In study B, a randomized crossover design was used in which all subjects ate the step 1 and Poly diets for 5 weeks each with a 4-day break between diets. In the eight subjects studied, the values for fasting plasma total, LDL, and HDL cholesterol; triglycerides; apoB; and apoA-I were essentially identical at the end of each diet period. Postprandial triglyceride areas obtained after ingestion of a large, standard fat load were also the same. Finally, LDL apoB and HDL apoA-I turnovers were unaffected by replacement of monounsaturates with polyunsaturates. In summary our results indicate that modest exchanges of monounsaturated for polyunsaturated fats do not significantly affect LDL or HDL levels or metabolism, which supports the view that reducing saturated fats is the key to lowering total and LDL cholesterol.
PMCID: PMC3275914  PMID: 8199179
plasma lipids; lipoproteins; dietary fatty acids; LDL; HDL; saturated fat; monounsaturated fat; polyunsaturated fat
21.  Gout  
BMJ Clinical Evidence  2008;2008:1120.
Introduction
Gout affects about 5% of men and 1% of women, with up to 80% of people experiencing a recurrent attack within 3 years.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments for acute gout? What are the effects of treatments to prevent gout in people with prior acute episodes? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2008 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
Results
We found 21 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
Conclusions
In this systematic review we present information relating to the effectiveness and safety of the following interventions: colchicine, corticosteroids, corticotrophin (ACTH), non-steroidal anti-inflammatory drugs (NSAIDs), sulfinpyrazone, xanthine oxidase inhibitors, advice to lose weight, advice to reduce alcohol intake, advice to reduce dietary intake of purines.
Key Points
Gout is characterised by deposition of urate crystals, causing acute monoarthritis and crystal deposits (tophi) in the skin. Gout affects about 5% of men and 1% of women, with up to 80% of people experiencing a recurrent attack within 3 years.Diagnosis is usually clinical, supported by signs of hyperuricaemia.Risk factors are those associated with increased serum urate concentrations, including: older age; non-white ethnicity; obesity; consumption of alcohol, meat, and fish; and use of diuretics.Hyperuricaemia may be associated with an increased risk of cardiovascular events; we don't know whether it is an independent risk factor.
We don't know whether NSAIDs reduce pain and tenderness in an acute attack of gout, although they are commonly used in clinical practice. They are associated with increased risks of gastrointestinal, and possible cardiovascular, adverse effects. Indometacin is widely used to treat acute gout despite the absence of RCT evidence of benefit. Etoricoxib is as effective as indometacin with reduced risks of gastrointestinal adverse effects.
Although it has been widely used for many years, we don't know whether oral colchicine improves symptoms in acute gout. Its use is limited by the high incidence of adverse effects.
We don't know whether intra-articular, parenteral or oral corticosteroids, or corticotropin (ACTH), improve symptoms in acute gout.
We don't know whether colchicine prevents attacks of gout in people with prior episodes, but it may reduce the risk of an attack in a person starting allopurinol treatment. We don't know whether advice to lose weight or reduce alcohol or dietary purine intake prevents further attacks of gout.We don't know whether allopurinol or febuxostat, orsulfinpyrazone reduce the risk of recurrent attacks compared with placebo or other treatments.
PMCID: PMC2907998  PMID: 19445790
22.  Caloric Sweetener Consumption and Dyslipidemia Among US Adults 
Context
Dietary carbohydrates have been associated with dyslipidemia, a lipid profile known to increase cardiovascular disease risk. Added sugars (caloric sweeteners used as ingredients in processed or prepared foods) are an increasing and potentially modifiable component in the US diet. No known studies have examined the association between the consumption of added sugars and lipid measures.
Objective
To assess the association between consumption of added sugars and blood lipid levels in US adults.
Design, Setting, and Participants
Cross-sectional study among US adults (n=6113) from the National Health and Nutrition Examination Survey (NHANES) 1999–2006. Respondents were grouped by intake of added sugars using limits specified in dietary recommendations (<5% [reference group], 5%–<10%, 10%–<17.5%, 17.5%–<25%, and ≥25% of total calories). Linear regression was used to estimate adjusted mean lipid levels. Logistic regression was used to determine adjusted odds ratios of dyslipidemia. Interactions between added sugars and sex were evaluated.
Main Outcome Measures
Adjusted mean high-density lipoprotein cholesterol (HDL-C), geometric mean triglycerides, and mean low-density lipoprotein cholesterol (LDL-C) levels and adjusted odds ratios of dyslipidemia, including low HDL-C levels (<40 mg/dL for men; <50 mg/dL for women), high triglyceride levels (≥150 mg/dL), high LDL-C levels (≥130 mg/dL), or high ratio of triglycerides to HDL-C (>3.8). Results were weighted to be representative of the US population.
Results
A mean of 15.8% of consumed calories was from added sugars. Among participants consuming less than 5%, 5% to less than 17.5%, 17.5% to less than 25%, and 25% or greater of total energy as added sugars, adjusted mean HDL-C levels were, respectively, 58.7, 57.5, 53.7, 51.0, and 47.7 mg/dL (P<.001 for linear trend), geometric mean triglyceride levels were 105, 102, 111, 113, and 114 mg/dL (P<.001 for linear trend), and LDL-C levels modified by sex were 116, 115, 118, 121, and 123 mg/dL among women (P=.047 for linear trend). There were no significant trends in LDL-C levels among men. Among higher consumers (≥10% added sugars) the odds of low HDL-C levels were 50% to more than 300% greater compared with the reference group (<5% added sugars).
Conclusion
In this study, there was a statistically significant correlation between dietary added sugars and blood lipid levels among US adults.
doi:10.1001/jama.2010.449
PMCID: PMC3045262  PMID: 20407058
23.  Effects of Dietary Fat Intake on HDL Metabolism 
High-density lipoprotein (HDL) is a lipoprotein which has anti-atherogenic property by reversing cholesterol transport from the peripheral tissues to liver. Low HDL-cholesterol (HDL-C) as well as high low-density lipoprotein-cholesterol (LDL-C) is associated with the development of coronary heart diseases (CHD). Various epidemiological studies have suggested that the development of CHD increase in individuals with less than 40 mg/dL of HDL-C. In spite of accumulation of evidences suggesting a significant association between low HDL-C and CHD, effects of dietary factors on HDL metabolism remained largely unknown. We reviewed published articles about effects of dietary fat intake on HDL metabolism. The substitution of fatty acids (FA) for carbohydrates is beneficially associated with HDL metabolism. Monounsaturated FA intake may not affect HDL-C. Trans-FA is significantly associated with reduction of HDL-C, and is also adversely related with total cholesterol/HDL-C. Fish oils consumption, especially docosahexaenoic acid consumption, may be favorably associated with HDL metabolism. Although plant sterols and stanols may not affect HDL-C, policosanol intake is associated with a clinically significant decrease in the LDL/HDL ratio.
doi:10.14740/jocmr2030w
PMCID: PMC4285059  PMID: 25584098
Coronary heart diseases; Fatty acids; Fish oils; High-density lipoprotein; Plant sterols
24.  SLC2A9 Is a High-Capacity Urate Transporter in Humans 
PLoS Medicine  2008;5(10):e197.
Background
Serum uric acid levels in humans are influenced by diet, cellular breakdown, and renal elimination, and correlate with blood pressure, metabolic syndrome, diabetes, gout, and cardiovascular disease. Recent genome-wide association scans have found common genetic variants of SLC2A9 to be associated with increased serum urate level and gout. The SLC2A9 gene encodes a facilitative glucose transporter, and it has two splice variants that are highly expressed in the proximal nephron, a key site for urate handling in the kidney. We investigated whether SLC2A9 is a functional urate transporter that contributes to the longstanding association between urate and blood pressure in man.
Methods and Findings
We expressed both SLC2A9 splice variants in Xenopus laevis oocytes and found both isoforms mediate rapid urate fluxes at concentration ranges similar to physiological serum levels (200–500 μM). Because SLC2A9 is a known facilitative glucose transporter, we also tested whether glucose or fructose influenced urate transport. We found that urate is transported by SLC2A9 at rates 45- to 60-fold faster than glucose, and demonstrated that SLC2A9-mediated urate transport is facilitated by glucose and, to a lesser extent, fructose. In addition, transport is inhibited by the uricosuric benzbromarone in a dose-dependent manner (Ki = 27 μM). Furthermore, we found urate uptake was at least 2-fold greater in human embryonic kidney (HEK) cells overexpressing SLC2A9 splice variants than nontransfected kidney cells. To confirm that our findings were due to SLC2A9, and not another urate transporter, we showed that urate transport was diminished by SLC2A9-targeted siRNA in a second mammalian cell line. In a cohort of men we showed that genetic variants of SLC2A9 are associated with reduced urinary urate clearance, which fits with common variation at SLC2A9 leading to increased serum urate. We found no evidence of association with hypertension (odds ratio 0.98, 95% confidence interval [CI] 0.9 to 1.05, p > 0.33) by meta-analysis of an SLC2A9 variant in six case–control studies including 11,897 participants. In a separate meta-analysis of four population studies including 11,629 participants we found no association of SLC2A9 with systolic (effect size −0.12 mm Hg, 95% CI −0.68 to 0.43, p = 0.664) or diastolic blood pressure (effect size −0.03 mm Hg, 95% CI −0.39 to 0.31, p = 0.82).
Conclusions
This study provides evidence that SLC2A9 splice variants act as high-capacity urate transporters and is one of the first functional characterisations of findings from genome-wide association scans. We did not find an association of the SLC2A9 gene with blood pressure in this study. Our findings suggest potential pathogenic mechanisms that could offer a new drug target for gout.
Editors' Summary
Background.
Blood is continually pumped around the human body to deliver the chemicals needed to keep the body's cells alive and to take cellular waste products to the kidneys where they are filtered out of the blood and excreted in the urine. In healthy people, the levels of nutrients and waste products in serum (the liquid part of blood) fall within “normal” ranges but in ill people these levels can be very different. For example, serum uric acid (urate) levels are usually increased in people with gout. In this arthritic condition, uric acid crystallizes in the joints (often those in the big toe) and causes swelling and intense pain. Increased serum urate levels, which are also associated with high blood pressure, diabetes, and several other important conditions, can be caused by eating food that is rich in chemicals called purines (for example, liver, dried beans, and port). The body also converts its own purines into uric acid so genetic variations in the enzymes involved in purine breakdown can alter serum urate levels, as can variations in the rate of urate removal from the body by the kidneys. Urinary urate excretion is controlled by urate transporters, proteins that carry urate into and out of the kidney cells. Uricosuric drugs, which are used to treat gout, reduce serum urate levels by inhibiting a urate transporter that reabsorbs urate from urine.
Why Was This Study Done?
Several urate transporters have already been identified but recently, using an approach called genome-wide association scanning, scientists found that some genetic variants of a human gene called SLC2A9 are more common in people with high serum urate levels than in people with normal levels. SLC2A9 encodes a glucose transporter (a protein that helps to move the sugar glucose through cell membranes) and is highly expressed in the kidney's main urate handling site. Given these facts, could SLC2A9 (the protein made from SLC2A9) be a urate transporter as well as a glucose transporter? In this study, the researchers investigate this possibility and also ask whether genetic variations in SLC2A9 might be responsible for the association between serum urate levels and high blood pressure.
What Did the Researchers Do and Find?
The researchers first expressed SLC2A9 in frog eggs, a type of cell that does not have its own urate transporter. They found that urate rapidly moved into eggs expressing SLC2A9 but not into control eggs, that SLC2A9 transported urate about 50 times faster than glucose, and that glucose stimulated SLC2A9-mediated urate transport. Similarly, overexpression of SLC2A9 in human embryonic kidney cells more than doubled their urate uptake. Conversely, when the researchers used a technique called RNA interference to reduce the expression of mouse SLC2A9 in mouse cells that normally makes this protein, urate transport was reduced. Next, the researchers looked at two small parts of SLC2A9 that vary between individuals (so-called single polynucleotide polymorphisms) in nearly 900 men who had had their serum urate levels and urinary urate excretion rates measured. They found that certain genetic variations at these two sites were associated with increased serum urate levels and decreased urinary urate excretion. Finally, the researchers used a statistical technique called meta-analysis to look for an association between one of the SLC2A9 gene variants and blood pressure. In two separate meta-analyses that together involved more than 20, 000 participants in several studies, there was no association between this gene variant and blood pressure.
What Do These Findings Mean?
Overall, these findings indicate that SLCA9 is a high capacity urate transporter and suggest that this protein plays an important part in controlling serum urate levels. They provide confirmation that common genetic variants in SLC2A9 affect serum urate levels to a marked degree, although they do not show exactly which genetic variant is responsible for increasing serum urate levels. They also provide important new insights into how the kidneys normally handle urate and suggest ways in which this essential process may sometimes go wrong. Thus, these findings could eventually lead to new treatments for gout and possibly for other diseases that are associated with increased serum urate levels.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050197.
The UK National Health Service Direct health encyclopedia provides detailed information for patients about gout
MedlinePlus provides links to many sources of information about gout (in English and Spanish), including “What is gout?”, an easy-to-read guide from the US National Institutes of Arthritis and Musculoskeletal and Skin Diseases
Wikipedia also has pages on gout, uric acid, and SCL2A9 (note: Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)
The Arthritis Research Campaign also has information on gout
Mark Caulfield and colleagues show that theSLC2A9 gene, which encodes a facilitative glucose transporter, is also a high-capacity urate transporter.
doi:10.1371/journal.pmed.0050197
PMCID: PMC2561076  PMID: 18842065
25.  Trends in cardiovascular risk factor levels in Finnish children and young adults from the 1970s: The Cardiovascular Risk in Young Finns Study 
OBJECTIVES
The Cardiovascular Risk in Young Finns Study is an ongoing multicentre study of atherosclerosis precursors in Finnish children and young adults. The aim of the present report is to describe the secular trends in cardiovascular risk factors between 1980 and 2001 in children and young adults.
METHODS
Data on cardiovascular risk factors were collected in a cohort of subjects (original n=3596) that were followed with serial cross-sectional studies from childhood to adulthood. The study was initiated in 1980, and the latest follow-up (after 21 years) was performed in 2001 (with n=2285 participants). To assess secular trends up to the year 2001, selected risk variables were analyzed (ie, total cholesterol, low density lipoprotein [LDL] cholesterol, high density lipoprotein [HDL] cholesterol, triglycerides, apolipoproteins A1 and B, blood pressure, body mass index [BMI] and daily intake of energy and quality of fat) in subjects with complete data for the years 1980, 1986 and 2001 (n=1758).
RESULTS
From 1980 to 1986, LDL-cholesterol concentrations decreased 0.32 mmol/L (P<0.0001) in subjects aged 15 to 18 years. From 1986 to 2001, LDL concentrations did not change in 24-year-old subjects (delta=−0.12 mmol/L, P>0.05). HDL-cholesterol concentrations decreased 0.28 mmol/L (P<0.0001) from 1986 to 2001. Triglyceride concentrations increased 0.21 mmol/L (P<0.0001) from 1980 to 1986 and 0.26 mmol/L (P<0.0001) from 1986 to 2001. In female subjects, BMI increased both from 1980 to 1986 (delta=0.5 kg/m2, P=0.03) and from 1986 to 2001 (delta=1.7 kg/m2, P=0.0002). Systolic blood pressure levels decreased 3.7 mmHg (P<0.0001) from 1980 to 1986 and 7.0 mmHg (P<0.0001) from 1986 to 2001 in all subjects.
CONCLUSION
The authors conclude that between 1986 and 2001, the decreases in LDL-cholesterol concentrations among young adults in Finland stopped. During the same time, HDL-cholesterol concentrations started to decrease, and triglyceride concentrations continued to decrease, and in female subjects, BMI continued to increase. However, also during this time, blood pressure levels continued to decrease in all subjects.
PMCID: PMC2274851  PMID: 18651040
Blood pressure; Cardiovascular; Cholesterol; Obesity; Risk factors; Secular trend

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