editorials; disparities; health status; heart; regional variation
Adiponectin, paradoxically reduced in obesity and with lower levels in African Americans (AA), modulates several cardiometabolic risk factors. Because abdominal visceral adipose tissue (VAT), known to be reduced in AA, and subcutaneous adipose tissue (SAT) compartments may confer differential metabolic risk profiles, we investigated the associations of VAT and SAT with serum adiponectin, separately by gender, with the hypothesis that VAT is more strongly inversely associated with adiponectin than SAT.
Participants from the Jackson Heart Study, an ongoing cohort of AA (n = 2,799; 64% women; mean age, 55 ± 11 years) underwent computer tomography assessment of SAT and VAT volumes, and had stored serum specimens analyzed for adiponectin levels. These levels were examined by gender in relation to increments of VAT and SAT.
Compared to women, men had significantly lower mean levels of adiponectin (3.9 ± 3.0 μg/mL vs. 6.0 ± 4.4 μg/mL; p < 0.01) and mean volume of SAT (1,721 ± 803 cm3 vs. 2,668 ± 968 cm3; p < 0.01) but significantly higher mean volume of VAT (884 ± 416 cm3 vs. 801 ± 363 cm3; p < 0.01). Among women, a one standard deviation increment in VAT was inversely associated with adiponectin (β = − 0.13; p < 0.0001) after controlling for age, systolic blood pressure, fasting plasma glucose, high-density lipoprotein cholesterol, triglycerides, education, pack-years of smoking and daily intake of alcohol. The statistically significant inverse association of VAT and adiponectin persisted after additionally adjusting for SAT, body mass index (BMI) and waist circumference (WC), suggesting that VAT provides significant information above and beyond BMI and WC. Among men, after the same multivariable adjustment, there was a direct association of SAT and adiponectin (β = 0.18; p = 0.002) that persisted when controlling for BMI and WC, supporting a beneficial effect of SAT. Insulin resistance mediated the association of SAT with adiponectin in women.
In African Americans, abdominal visceral adipose tissue had an inverse association with serum adiponectin concentrations only among women. Abdominal subcutaneous adipose tissue appeared as a protective fat depot in men.
Genetic studies may help explain abnormalities of fat distribution in HIV-infected patients treated with antiretroviral therapy (ARV).
Subcutaneous adipose tissue (SAT) volume measured by magnetic resonance imaging (MRI) in leg, lower trunk, upper trunk, and arm was examined in 192 HIV-infected Caucasian men, ARV-treated from the Fat Redistribution and Metabolic Change in HIV infection (FRAM) study. Single nucleotide polymorphisms (SNPs) were assayed using the Illumina HumanCNV370-quad beadchip. Multivariate and univariate genome wide association analyses of the four SAT depots were implemented in PLINK software adjusted for age and ARV duration. Functional annotation analysis (FAA) using Ingenuity Systems Pathway Analysis tool (IPA) was carried out for markers with P<10-3 near known genes identified by multivariate analysis.
Loci (rs10504906, rs13267998, rs921231) in or near the anion exchanger solute carrier family 26, member 7 isoform a (SLC26A7) were strongly associated with upper trunk and arm SAT (9.8*10-7≤P<7.8*10-6). Loci (rs193139, rs7523050, rs1761621) in and near a gene rich region including G-protein-signaling modulator 2 (GPSM2) and syntaxin binding protein 3 (STXBP3) were significantly associated with lower body SAT depots (9.9*10-7≤P<9.5*10-6). GPSM2 is associated with cell division and cancer while STXBP3 is associated with glucose metabolism in adipoctyes. IPA identified atherosclerosis, mitochondrial function and T-Cell mediated apoptosis as processes related to SAT volume in HIV-infected individuals (P<5*10-3).
Our results are limited by the small sample size and replication is needed, however this genomic scan uncovered new genes associated with metabolism and inflammatory pathways that may affect SAT volume in ARV-treated HIV-infected patients.
HIV; HAART; GWAS; Subcutaneous Fat; SAT
African Americans are a genetically diverse population with a high burden of many, common heritable diseases. However, our understanding of genetic variation in African Americans is substandard because of a lack of published population-based genetic studies. We report the distribution of copy-number variation (CNV) in African Americans collected as part of the Hypertension Genetic Epidemiology Network (HyperGEN) using the Affymetrix 6.0 array and the CNV calling algorithms Birdsuite and PennCNV. We present population estimates of CNV from 446 unrelated African-American subjects randomly selected from the 451 families collected within HyperGEN. Although the majority of CNVs discovered were individually rare, we found the frequency of CNVs to be collectively high. We identified a total of 11 070 CNVs greater than 10 kb passing quality control criteria that were called by both algorithms – leading to an average of 24.8 CNVs per person covering 2214 kb (median). We identified 1541 unique copy-number variable regions, 309 of which did not overlap with the Database of Genomic Variants. These results provide further insight into the distribution of CNV in African Americans.
DNA copy-number variation; African American; calling algorithm; Birdsuite; PennCNV; HyperGEN
Background and Aims
Metabolic syndrome (MetS) is a complex condition characterized by different phenotypes, according to combinations of risk factors and is associated with cardiovascular abnormalities. Whether control of MetS components by treatment produces improvement in the associated cardiovascular abnormalities is unknown. We investigated whether partial control of components of MetS was associated with less echocardiographic abnormalities than the complete presentation of MetS based on measured components.
Methods and Results
We evaluated markers of echocardiographic preclinical cardiovascular disease in MetS (ATPIII) defined by measured components or by history of treatment, in 1,421 African- American and 1,195 Caucasian non-diabetic HyperGEN participants, without prevalent cardiovascular disease or serum creatinine>2 mg/dL. Of 2,616 subjects, 512 subjects had MetS by measured components and 328 by history. Hypertension was found in 16% of participants without MetS, 6% of those with MetS by history and 42% of those with MetS by measured components. Obesity and central fat distribution had similar prevalence in both MetS groups (both p<0.0001 vs No-MetS). Blood pressure was similar in MetS by history and No-MetS, and lower than in MetS by measured components (p<0.0001). LV mass and midwall shortening, left atrial (LA) dimension and LA systolic force were similarly abnormal in both MetS groups (all p<0.0001 vs. No-MetS) without difference between them.
There is little impact of control by treatment of single components of MetS (namely hypertension) on echocardiographic abnormalities. Lower blood pressure in participants with MetS by history was not associated with substantially reduced alterations in cardiac geometry and function.
Collapsing multiple variants into one variable and testing their collective effect is a useful strategy for rare variant association analysis. Direct collapsing, however, is not valid or may significantly lose power when a group of variants to be collapsed have heterogeneous effects on target traits (i.e. some positive and some negative). This could be especially true for quantitative traits (such as blood pressure and body mass index), regardless of whether subjects are sampled randomly from a population or selectively from two extreme tails of the trait distribution. To deal with this problem, we propose a novel, data-driven method, the P-value Weighted Sum Test (PWST), which allows each variant to be individually weighted according to the evidence of association from the data itself. Specifically, both significance and direction of individual variant effects are used to calculate a single weighted sum score based on rescaled left-tail p-values from single-variant analysis, after which a permutation test of association is performed between the score and the trait. Our simulation under different sampling strategies shows that PWST significantly increases statistical power when there are heterogeneous variant effects. The appeal of the PWST approach is illustrated in an application to sequence data by detecting the collective effect of variants in the peroxisome proliferator-activated receptor alpha (PPARα) gene on triglycerides (TG) response to fenofibrate treatment from 300 subjects in the GOLDN study.
rare variant; collapsing; heterogeneous effects; sum test; quantitative trait
African Americans (AA) have a higher prevalence of left ventricular hypertrophy than whites. Several population-based studies have reported an inverse association between adiponectin and left ventricular mass (LVM). However, the relationship between adiponectin levels and LVM has yet to be defined in AA. The Jackson Heart Study (JHS) cohort provides an opportunity to test the hypothesis that the inverse association between adiponectin and LVM may be modified by risk factors common among AA.
Methods and Results
The study population included 2,649 AA JHS participants; mean age, 51 ± 12 years, 63% women, 51% obese, 54% with hypertension and 16% with diabetes. Multiple linear and spline regression was used to assess the association adjusting for demographic, clinical and behavioral covariates. Among all the participants, there was a statistically significant but modest inverse association between adiponectin and left ventricular mass index (LVMI). Hypertension and insulin resistance emerged as statistically significant effect modifiers of this relationship. The inverse association present among the normotensive participants was explained by obesity measures such as the body mass index. Among participants with both hypertension and insulin resistance there was a significant direct association between adiponectin and LVMI after multivariable adjustment (β = 1.55, p = 0.04; per one standard deviation increments in the adiponectin log-value).
The association between serum adiponectin and LVM among AA in the JHS cohort was dependent on hypertension and insulin resistance status. Normotensive AA exhibited an inverse adiponectin – LVM association, whereas participants with hypertension and insulin resistance had a direct association.
adiponectin; biomarkers; epidemiology; left ventricular mass; obesity
Background: High pulse pressure (PP) is associated with cardiovascular events, but subclinical abnormalities in cardiac structure and function in relation to high pulse pressure are not well described. Methods and Results: 2225 hypertensive and 1380 non-hypertensive participants with adequate echocardiographic left ventricular measurements were evaluated. Non-hypertensives in the highest PP tertile (compared to the lower tertiles) were older (44 years vs. 40 years, p<0.009), had higher systolic pressure [(SBP) 136 mmHg vs. 108 mmHg] and lower diastolic pressure [(DBP) 54 vs. 71 mmHg (p=.0001)], greater BMI (27 vs. 25 kg/m2, p<.001) and more diabetes (4% vs. 2.25%, p<.001). In the hypertensive group, subjects in the highest PP tertile were older (52 vs 42 years), had higher SBP (157 vs. 116 mmHg) but lower DBP (65 vs. 83 mmHg). In the non-hypertensive group, higher PP (>60 mmHG) was associated with a higher frequency of echocardiographic structural and functional abnormalities, specifically, greater posterior and relative wall thickness, longer isovolumic relaxation time, and concentric left ventricular (LV) hypertrophy. Conclusion: In a population-based sample of hypertensive and non-hypertensive participants, higher PP was associated with subclinical abnormalities of cardiac structure and function, which exist even in the absence of hypertension and/or the use of antihypertensive treatment.
Left ventricular hypertrophy; pulse pressure; hypertension; arterial stiffness; echocardiography
Trans fatty acids (TFA) lower HDL and increase triglyceride concentrations while polyunsaturated fatty acids (PUFA) lower triglycerides and may decrease HDL concentrations. The effect of the interaction between trans fat and PUFA on lipids is uncertain.
Men and women (n = 1032) in the Genetics of Lipid-Lowering Drugs and Diet Network (GOLDN) study were included. Fatty acids in erythrocyte membranes were measured with gas chromatography while data on potential confounders were obtained from questionnaires. To test the interaction between total erythrocyte PUFA (ePUFA) and TFA (eTFA) on lipid concentrations we distributed eTFA into tertiles and dichotomized ePUFA at the median concentration.
For the 1st, 2nd and 3rd tertiles of eTFA, multivariate-adjusted means±s.e.m for HDL were 46.2±1.1, 46.3±1.1 and 45.5±1.0 mg/dL among those with low ePUFA, respectively, while they were 50.0±1.1, 46.9±1.1 and 44.7±1.1 mg/dL among those with high ePUFA, respectively (P for interaction = 0.01). For the 1st, 2nd and 3rd tertiles of eTFA, multivariate-adjusted means±s.e.m for triglycerides were 178.6±11.3, 144.7±10.9 and 140.8±10.6, respectively, among those with low ePUFA, while they were 133.8±11.3, 145.7±10.9 and 149.3±11.5, respectively, among those with high ePUFA (P for interaction = 0.005). Results for VLDL were similar to those for triglycerides. No significant interactions were observed for LDL or total cholesterol.
The relation between trans fat and HDL, VLDL and triglycerides may depend on PUFA. The benefit of avoiding trans fat may be greater among individuals with higher PUFA intake. Supplementation with PUFA among individuals with relatively high trans fat intake may have limited benefits on lipid profiles.
Macronutrient intakes and genetic variants have been shown to interact to alter the risk of insulin resistance, but replication of gene-nutrient interactions across independent populations may be difficult to achieve. Saturated fat and carbohydrate were previously shown to interact with genotype for insulin resistance for a variant of perilipin (PLIN), the major adipocyte-associated protein and a regulator of adipocyte metabolism. We investigated the same interaction for PLIN 11482G>A (rs894160) on insulin resistance in US men(n=462) and women(n=508) (mean ±SD, 49±16 years). In multivariate linear regression models, we found a significant (P<0.05) interaction between the ratio of saturated fat to carbohydrate intake as a continuous variable and PLIN 11482G>A for HOMA-IR (homeostasis model assessment of insulin resistance) in women. For carriers of the minor allele but not for non-carriers, as the ratio of saturated fat to carbohydrate intake increased, predicted HOMA-IR increased significantly (P=0.002). By dichotomizing the ratio of saturated fat to carbohydrate intake into high and low, we found significant interaction terms for insulin and HOMA-IR (P<0.05). When the ratio of saturated fat to carbohydrate was high, insulin and HOMA-IR were higher in minor allele carriers (P=0.004 and P=0.003, respectively), but did not differ when the ratio was low. Similar patterns or trends were observed when saturated fat and carbohydrate were dichotomized into high and low as individual macronutrients. Replication of the previously reported interaction between macronutrient intakes and PLIN genotype for insulin resistance reinforces the potential usefulness of applying genotype information in the dietary management of insulin resistance.
Left ventricular (LV) mass and related phenotypes are heritable, important predictors of cardiovascular disease, particularly in hypertensive individuals.
Identify genetic predictors of echocardiographic phenotypes in hypertensive families.
Methods & Results
A multi-stage genome-wide association study (GWAS) was conducted in hypertensive-ascertained African American families (HyperGEN, Stage I; GENOA, Stage II); findings were replicated in HyperGEN Caucasian families (Stage III). Echocardiograms were collected using a common protocol, and participants were genotyped with the Affymetrix Genome-Wide Human SNP 6.0 Array. In Stages I and II, 1258 and 989 African Americans, and Stage III 1316 Caucasians, were analyzed using mixed models adjusted for ancestry. Phenotypes included LV mass, LV internal dimension (LVID), wall thicknesses (posterior (PWT) and intraventricular septum (IVST)), and relative wall thickness (RWT). In Stage I, 5 single nucleotide polymorphisms (SNP) had P≤10−6. In Stage II, one SNP (rs1436109; NCAM1 intron 1) replicated with the same phenotype (PWT, P=0.025) in addition to RWT (P=0.032). In Stage III, rs1436109 was associated with RWT (P=5.47×10−4) and LVID (P=1.86×10−4). Fisher’s combined P-value for all stages was RWT=3.80×10−9, PWT=3.12×10−7, IVST=8.69×10−7, LV mass=2.52×10−3, and LVID=4.80×10−4.
This GWAS conducted in hypertensive families identified a variant in NCAM1 associated with LV wall thickness and RWT. NCAM is upregulated during the remodeling period of hypertrophy to heart failure in Dahl salt-sensitive rats. Our initial screening in hypertensive African-Americans may have provided the context for this novel locus.
GWAS; NCAM1; hypertrophy; genomics
Background and Aims
Epidemiologic studies have suggested beneficial effects of flavonoids on cardiovascular disease. Cocoa and particularly dark chocolate are rich in flavonoids and recent studies have demonstrated blood pressure lowering effects of dark chocolate. However, limited data are available on the association of chocolate consumption and the risk of coronary heart disease (CHD). We sought to examine the association between chocolate consumption and prevalent CHD.
We studied in a cross-sectional design 4,970 participants aged 25 to 93 years who participated in the National Heart, Lung, and Blood Institute (NHLBI) Family Heart Study. Chocolate intake was assessed through a semi-quantitative food frequency questionnaire. We used generalized estimating equations to estimate adjusted odds ratios.
Compared to subjects who did not report any chocolate intake, odds ratios (95% CI) for CHD were 1.01 (0.76-1.37), 0.74 (0.56-0.98), and 0.43 (0.28-0.67) for subjects consuming 1-3 times/month, 1-4 times/week, and 5+ times/week, respectively (p for trend <0.0001) adjusting for age, sex, family CHD risk group, energy intake, education, non-chocolate candy intake, linolenic acid intake, smoking, alcohol intake, exercise, and fruit and vegetables. Consumption of non-chocolate candy was associated with a 49% higher prevalence of CHD comparing 5+/week vs. 0/week [OR=1.49 (0.96-2.32)].
These data suggest that consumption of chocolate is inversely related with prevalent CHD in a general population.
epidemiology; carbohydrate; nutrition; cardiovascular disease
Nitric oxide synthase 3 (NOS3) catalyzes production of NO in the endothelium and may play a role in cardiovascular disease (CVD). We assessed the pharmacogenetic associations of three NOS3 polymorphisms and three antihypertensive drugs with CVD outcomes. Hypertensive subjects (n = 30,280) from a multi-center, double-blind clinical trial were randomized to chlorthalidone, amlodipine, or lisinopril treatment (mean follow up, 4.9 years). Outcomes included coronary heart disease (CHD: fatal CHD and nonfatal myocardial infarction); stroke; heart failure (fatal, requiring hospitalization, or outpatient treatment); all-cause mortality; and end-stage renal disease (ESRD). Main effects of NOS3 variants on outcome and genotype-treatment interactions were tested. For NOS3 −690 C>T (rs3918226), a higher hazard ratio (HR) was found in minor allele carriers for CHD (CC = 1.00, CT+TT = 1.12 (95% confidence interval (CI) = 1.00–1.26), P = 0.048). For NOS3 −922 A>G (rs1800779), a higher HR was found in minor allele carriers for heart failure (AA = 1.00, AG+GG = 1.10 (CI = 1.00–1.21), P = 0.046). Significant pharmacogenetic findings were observed for stroke and all-cause mortality. For −690 C>T, a lower HR was observed for stroke in minor allele carriers when treated with amlodipine versus lisinopril (CC = 0.85 (CI = 0.73–0.99), CT+TT = 0.49 (CI = 0.31–0.80), P = 0.04). For glu298asp G>T (rs1799983), a lower HR was observed for all-cause mortality in minor allele carriers when treated with amlodipine versus lisinopril (GG = 1.01 (CI = 0.91–1.13), GT+TT = 0.85 (CI = 0.75–0.97), P = 0.04). We observed significant associations with NOS3 variants and CHD and heart failure and significant pharmacogenetic effects for stroke and all cause mortality. This suggests that NOS3 variants may potentially provide useful clinical information with respect to treatment decisions in the future.
The LDL receptor-related protein-1 gene (LRP-1) has been associated with obesity in animal models, but no such association has yet been reported in humans. As data suggest this increase in fat mass may be mediated through a mechanism involving the clearance of plasma triglyceride-rich lipoproteins (TGRL), where the LRP interacts with apolipoprotein E (ApoE) on chylomicron remnants, we aimed to examine (1) whether there was an association between 3 single nucleotide polymorphisms (SNPs) on LRP-1 with body mass index (BMI) and (2) whether any association between LRP-1 SNPs and BMI could be modified by polymorphisms on the ApoE gene when comparing the wild type ε3/ε3 genotype against mutant ApoE allele (ε2/ε4) carriers.
We used data from 1,036 men and women (mean age±SD = 49±16 y) participating in the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) Study. Mixed linear models, which controlled for age, sex, alcohol intake and smoking, as well as family pedigree and center of data collection were calculated. Models that used LRP-1 genotype as a predictor of BMI revealed that individuals who were homozygous for the minor allele at the LRP-1 I10701 locus had BMIs, on average, 1.03 kg/m2 higher than major allele carriers (P = 0.03). In subsequent mixed linear models that included main effects of LRP-1 I10701 SNP and ApoE alleles, and an interaction term the two genotypes, there was no interaction detected between the LRP-1 I70701 genotype with either the ApoE ε2 or ε4 allele carriers (P>0.05).
This has implications for starting to understand pathways from genotype to human BMI, which may operate through TGRL uptake at the LRP-1 receptor. This may pave the way for future research into individualized dietary interventions.
Background and Aims
While a diet rich in anti-oxidant has been favorably associated with coronary disease and hypertension, limited data have evaluated the influence of such diet on subclinical disease. Thus, we sought to examine whether chocolate consumption is associated with calcified atherosclerotic plaque in the coronary arteries (CAC).
In a cross-sectional design, we studied 2,217 participants of the NHLBI Family Heart Study. Chocolate consumption was assessed by a semi-quantitative food-frequency questionnaire and CAC was measured by cardiac CT. We defined prevalent CAC using an Agatston score of at least 100 and fitted generalized estimating equations to calculate prevalence odds ratios of CAC.
There was an inverse association between frequency of chocolate consumption and prevalent CAC. Odds ratios (95% CI) for CAC were 1.0 (reference), 0.94 (0.66-1.35), 0.78 (0.53-1.13), and 0.68 (0.48-0.97) for chocolate consumption of 0, 1-3 times per month, once per week, and 2+ times per week, respectively (p for trend 0.022), adjusting for age, sex, energy intake, waist-hip ratio, education, smoking, alcohol consumption, ratio of total-to-HDL-cholesterol, non-chocolate candy, and diabetes mellitus. Controlling for additional confounders did not alter the findings. Exclusion of subjects with coronary heart disease or diabetes mellitus did not materially change the odds ratio estimates but did modestly decrease the overall significance (p = 0.07).
These data suggest that chocolate consumption might be inversely associated with prevalent CAC.
Chocolate; diet; epidemiology; coronary calcium; subclinical disease
Biomarkers of inflammation and hemostasis have been associated with left ventricular (LV) mass. We studied relationships of C-reactive protein (CRP), interleukin-6 (IL6), D-dimer, soluble intercellular adhesion molecule-1 (sICAM-1), plasminogen activator inhibitor 1 (PAI-1), soluble thrombomodulin (sTM), soluble tumor necrosis factor type 1 receptor (sTNFR1), von Willebrand factor (vWF), soluble E-selectin (sE-selectin), factor VIII, fibrinogen, matrix metalloproteinase 3 (MMP3), and matrix metalloproteinase 9 (MMP9) with LV mass in an asymptomatic population. Multi-Ethnic Study of Atherosclerosis participants underwent magnetic resonance imaging to characterize LV mass; biomarkers were measured using standardized protocols (N = 763 to 4979). Adjusted models were used to associate each biomarker with LV mass while correcting for potential confounding.
LV mass was associated with many biomarkers after adjustment for demographic characteristics and traditional cardiovascular risk factors. Although the demographic and risk factor adjustments attenuated the association of CRP and IL6 with LV mass, further adjustment for weight changed regression coefficients from positive to negative for CRP and IL6 for LV mass. sTM, Factor VIII, and vWF were directly associated with LV mass in fully-adjusted models. For sTNFR1, sICAM-1, D-dimer, fibrinogen, and PAI-1, adjustment for risk factors and weight rendered associations with LV mass nonsignificant.
In this large cohort free of clinical cardiovascular disease, several hemostasis and inflammation markers were associated with LV mass. The unusual finding of a negative relationship of CRP and IL6 with LV mass only after adjustment for weight suggests that the effects of inflammation on LV mass are strongly influenced by obesity.
Left ventricle; biomarker; hemostasis; inflammation
In developing countries, 8 to 71% of patients initiating highly active antiretroviral therapy (HAART) die within the first year of treatment. Apart from baseline CD4 count, viral load, hemoglobin, BMI and stage of the disease, there may be other variables that contribute to AIDS-related mortality. We investigated the potential role of nutrition, lipids and insulin resistance-related phenotypes in predicting early mortality.
We recruited 210 HAART-naïve HIV/AIDS patients in Lusaka, Zambia. Dietary intake, anthropometric measurements, fasting serum insulin, glucose, and lipid profiles were assessed at baseline. Mortality was assessed after 90 days of follow-up. We used logistic regression models to identify variables associated with mortality.
The mean±SD for age, BMI and CD4 count at baseline were 34±7.4 y, 20±3 kg/m2 and 138±52 cells/μL, respectively. Sixteen patients (7.6%) died during follow-up. Triglyceride concentrations were associated with increased mortality [odds ratio (OR) for 1 mmol/L increase in triglyceride concentration=2.51; 95% CI: 1.34-4.71]. This association remained significant (OR=3.24; 95% CI: 1.51-6.95) after adjusting for age, gender, smoking, alcohol use, total cholesterol, BMI, CD4 count and n3 fatty acid intake. Apart from higher n3 fat intake which was inversely associated with mortality (survivors: 1.81±0.99% total energy/day vs. non-survivors 1.28±0.66% energy/day, P=0.04), there were no other macronutrients associated with mortality.
Triglyceride concentrations at the time of initiating HAART are independently associated with increased risk for early mortality. If this association is confirmed in larger studies, assessment of triglycerides could become part of routine care of HIV patients initiating HAART in developing countries.
Triglycerides; lipids; mortality; HIV; HAART; Africa; Zambia
While much is known about the effect of APOE alleles on fasting lipid concentrations, less is known about the effect of APOE alleles on postprandial triglyceridemia or the triglyceride response to fenofibrate.
Methods and Results
We evaluated the effects of the APOE locus on fasting and postprandial triglyceride concentrations as part of the Genetics of Lipid Lowering and Diet Network (GOLDN) study. Participants were evaluated following a high-fat meal challenge before (N=1072) and after 3 weeks of daily treatment with 160 mg of fenofibrate (N=738). Mixed models adjusted for gender, age, waist circumference and family relationship were used to examine the association of the ε4 carrier and ε2 carrier status versus ε3 homozygotes with fasting triglycerides and the area under the curve (AUC) for triglycerides during the high-fat meal challenge. Compared to the ε3/ε3 genotype, ε2 carriers had on average higher fasting triglyceride concentrations (130.5 mg/dL vs. 109.3 mg/dL, P<0.001). After fenofibrate treatment, the APOE genotype differences persisted in the fasting state (ε2 carriers: 85.1 mg/dL vs. ε3/ε3: 75.9 mg/dL, P<0.05). Carriers of the ε4 allele had significantly higher fasting triglyceride concentrations only pre-fenofibrate (120.9 mg/dL vs. 109.3 md/dL, P=0.008). APOE alleles did not have an effect on response to fenofibrate. Postprandial triglycerides were significantly higher for ε2 carriers versus ε3 homozygotes (but not ε4 carriers) both before and after fenofibrate treatment (P=0.01 and P=0.005, respectively).
APOE polymorphisms are important determinants of triglyceride concentrations, especially in the fasting state.
apolipoproteins; lipids; genetics
We sought to examine whether ε4 carrier status modifies the relation between body mass index (BMI) and HDL. The National Heart, Lung, and Blood Institute Family Heart Study included 657 families with high family risk scores for coronary heart disease and 588 randomly selected families of probands in the Framingham, Atherosclerosis Risk in Communities, and Utah Family Health Tree studies. We selected 1402 subjects who had ε4 carrier status available. We used generalized estimating equations to examine the interaction between BMI and ε4 allele carrier status on HDL after adjusting for age, gender, smoking, alcohol intake, mono- and poly-unsaturated fat intake, exercise, comorbidities, LDL, and family cluster.
The mean (standard deviation) age of included subjects was 56.4(11.0) years and 47% were male. Adjusted means of HDL for normal, overweight, and obese BMI categories were 51.2(± 0.97), 45.0(± 0.75), and 41.6(± 0.93), respectively, among 397 ε4 carriers (p for trend < 0.0001) and 53.6(± 0.62), 51.3(± 0.49), and 45.0(± 0.62), respectively, among 1005 non-carriers of the ε4 allele (p-value for trend < 0.0001). There was no evidence for an interaction between BMI and ε4 status on HDL(p-value 0.39).
Our findings do not support an interaction between ε4 allele status and BMI on HDL.
HDL cholesterol; body mass index; genetic epidemiology; apolipoproteins; lipid metabolism; adiposity
C-reactive protein (CRP) is positively associated with risk for cardiovascular disease and all-cause mortality. Some but not all randomized and non-randomized clinical trials found significant associations between fenofibrate therapy and CRP but the direction and magnitude of the association varied across studies. The duration of treatment, patient populations and sample sizes varied greatly, and most short-term studies (i.e., ≤ 12 weeks) had fewer than 50 patients. In this study we meta-analyzed randomized clinical trials to determine the short-term effect of fenofibrate on CRP.
Two reviewers independently searched PubMed and other online databases for short-term randomized clinical trials that reported CRP concentrations before and after fenofibrate treatment. Of the 81 studies examined, 14 studies with 540 patients were found eligible. Data for the change in CRP and corresponding measures of dispersion were extracted for use in the meta-analysis.
The weighted mean CRP concentrations before and after fenofibrate therapy were 2.15 mg/L and 1.53 mg/L (-28.8% change), respectively. Inverse-variance weighted random effects meta-analysis revealed that short-term fenofibrate treatment significantly lowers CRP by 0.58 mg/L (95% CI: 0.36-0.80). There was significant heterogeneity between studies (Q statistic = 64.5, P< 0.0001, I2 = 79.8%). There was no evidence of publication bias and sensitivity analysis revealed that omitting any of the 14 studies did not lead to a different conclusion from the overall meta-analysis result.
Short-term treatment with fenofibrate significantly lowers CRP concentration. Randomized trials that will recruit patients based with high baseline CRP concentrations and with change in CRP as a primary outcome are needed.
CRP; fenofibrate; meta-analysis; randomized; clinical trials; short-term
AHA Conference Proceedings; cardiovascular diseases; morbidity; mortality; risk factors
MMP-9 and -12 function in tissue remodeling and may play roles in cardiovascular disease (CVD). We assessed associations of four MMP polymorphisms and three antihypertensive drugs with cardiovascular outcomes.
Hypertensives (n = 42,418) from a double-blind, randomized, clinical trial were randomized to chlorthalidone, amlodipine, lisinopril, or doxazosin treatment (mean follow up, 4.9 years). The primary outcome was coronary heart disease (CHD). Secondary outcomes included combined CHD, all CVD outcomes combined, stroke, heart failure (HF), and mortality. Genotype-treatment interactions were tested.
There were 38,698 participants genotyped for at least one of the polymorphisms included here. For MMP9 R668Q (rs2274756), lower hazard ratios (HRs) were found for AA subjects for most outcomes when treated with chlorthalidone versus amlodipine (eg., CCHD: GG = 1.00, GA = 1.01, AA = 0.64; P = 0.038). For MMP9 R279Q (rs17576), modest pharmacogenetic findings were observed for combined CHD and the composite CVD outcome. For MMP12 N122S (rs652438), lower HRs were observed for CHD in subjects carrying at least one G allele and being treated with chlorthalidone versus lisinopril (CHD: AA = 1.07, AG = 0.80, GG = 0.49; P = 0.005). In the lisinopril-amlodipine comparison, higher HRs were observed for participants having at least one G allele at the MMP12 N122S locus (CHD: AA = 0.94, AG = 1.19, GG = 1.93; P = 0.041). For MMP12 −82A>G (rs2276109), no pharmacogenetic effect was found for the primary outcome, although lower HRs were observed for AA homozygotes in the chlorthalidone-amlodipine comparison for HF (P = 0.015).
We observed interactions between antihypertensive drugs and MMP9 and MMP12 for CHD and composite CVD. The data suggest that these genes may provide useful clinical information with respect to treatment decisions.
To examine the association between baseline bone mineral density (BMD) and radiographic damage at 3-year disease duration in a longitudinal cohort of African Americans (AAs) with recent-onset RA.
Participants (n=141) included AAs with < 2 years of disease duration. All patients underwent baseline BMD measurement (femoral neck and/or lumbar spine) using DXA. T-scores were calculated using AAs normative data. Patients were categorized as having osteopenia/osteoporosis (T score ≤ −1) or healthy. Hand/wrist radiographs, obtained at baseline and at 3-year disease duration, were scored using modified Sharp/van der Heijde method. The association between baseline BMD and total radiographic score at 3-year disease duration was examined using multivariable negative binomial regression.
At baseline, the mean age and disease duration were 52.4 years and 14.8 months respectively (85.1% women). Average total radiographic scores at baseline and 3-year disease duration were 2.4 and 5.7. In the final reduced multivariable model adjusting for age, gender, anti-cyclic citrullinated peptide antibody positivity, and the presence of radiographic damage at baseline, the total radiographic score at 3-years of disease duration in patients with osteopenia/osteoporosis at the femoral neck was twice that in patients with healthy bone density and the difference was statistically significant (p=0.0084). No association between lumbar spine osteopenia/osteoporosis and radiographic score was found.
These findings suggest that reduced generalized BMD may be a predictor of future radiographic damage and support the hypothesis that radiographic damage and reduced generalized BMD in RA patients may share a common pathogenic mechanism.
The metabolic syndrome represents a clustering of risk factors that has been shown to predict adverse cardiovascular outcomes. Although the precise mechanisms contributing to the cardiometabolic syndrome (CMS) remain poorly defined, accumulating evidence identifies two intersecting candidate pathways responsible for inflammation and energy homeostasis in the pathophysiology that underlie cardiometabolic traits. Although currently no pharmacologic interventions specifically target CMS, future drug development efforts should attempt to capitalize on molecular nodes at the intersections of these pathways in the CMS.
Metabolic syndrome; cardiometabolic syndrome; substrate metabolism; inflammation; obesity; insulin resistance; hypertension; dyslipidemia
A prediction model, developed in the Framingham Heart Study (FHS), has been proposed for use in estimating a given individual’s risk of hypertension. We compared this model with systolic blood pressure (SBP) alone and age-specific diastolic blood pressure (DBP) categories for the prediction of hypertension. Participants in the Multi-Ethnic Study of Atherosclerosis, without hypertension or diabetes (n=3013), were followed for the incidence of hypertension (SBP ≥ 140 mmHg and/or DBP ≥ 90 mmHg and/or the initiation of antihypertensive medication). The predicted probability of developing hypertension between four adjacent study examinations, with a median of 1.6 years between examinations, was determined. The mean (standard deviation) age of participants was 58.5 (9.7) years and 53% were women. During follow-up, 849 incident cases of hypertension occurred. The c-statistic for the FHS model was 0.788 (95% CI: 0.773, 0.804) compared with 0.768 (95% CI: 0.751, 0.785; p=0.096 compared to the FHS model) for SBP alone and 0.699 (95% CI: 0.681, 0.717; p<0.001 compared to the FHS model) for age-specific DBP categories. The relative integrated discrimination improvement index for the FHS model versus SBP alone was 10.0% (95% CI: −1.7%, 22.7%) and versus age-specific DBP categories was 146% (95% CI: 116%, 181%). Using the FHS model, there were significant differences between observed and predicted hypertension risk (Hosmer-Lemeshow goodness of fit p<0.001); re-calibrated and best-fit models produced a better model fit (p=0.064 and 0.245, respectively). In this multi-ethnic cohort of U.S. adults, the FHS model was not substantially better than SBP alone for predicting hypertension.
hypertension; epidemiology; systolic blood pressure; diastolic blood pressure; risk prediction