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1.  Associations between dietary patterns and hypertension among Korean adults: the Korean National Health and Nutrition Examination Survey (2008-2010) 
Nutrition Research and Practice  2013;7(3):224-232.
The objective of this study is to identify the dietary patterns associated with the risk of hypertensions among Korean adults using data from the Korean National Health and Nutrition Examination Survey (KNHANES, 2008-2010). This study analyzes data from 11,883 subjects who participated in the health and nutrition survey, aging from 20 to 64 years. We performed factor analysis based on the weekly mean intake frequencies of 36 food groups to identify major dietary patterns. We identified three major dietary patterns in both sexes, namely "traditional", "western" and "dairy and carbohydrate" patterns. Participants in the highest quartile of western pattern scores had significantly higher blood pressure, serum total cholesterol, and triglyceride levels than those in the lowest quartile. Although not statistically significant, a trend (P for trend = 0.0732) toward a positive association between the western dietary pattern and hypertension risk was observed after adjustments for age, sex, education, income, body mass index (BMI), smoking, physical activity, and energy intake. The dairy and carbohydrate pattern was inversely related with BMI and blood pressures and positively associated with serum high-density lipoprotein (HDL)-cholesterol. After adjusting the age, sex, education, income, BMI, smoking, physical activity and energy intake, the dairy and carbohydrate pattern showed inverse associations with hypertension prevalence (OR = 0.64, 95% CI = 0.55-0.75; P for trend < 0.0001). Intakes of fiber, sodium, and antioxidant vitamins were significantly higher in the top quartile for the traditional pattern than in the lowest quartile for the traditional pattern (P for trend < 0.0001). Intakes of fiber (P for trend < 0.0001), calcium (P for trend < 0.0001), retinol (P for trend = 0.0164), vitamin B1 (P for trend = 0.001), vitamin B2 (P for trend < 0.0001), niacin (P for trend = 0.0025), and vitamin C (P for trend < 0.0001) were significantly increased across quartiles for the dairy and carbohydrate pattern whereas sodium (P for trend < 0.0001) intake was decreased for this pattern. In conclusion, the dairy and carbohydrate pattern may be associated with a reduced risk of hypertension whereas the western pattern may be associated with an increased risk of hypertension among Korean adults.
doi:10.4162/nrp.2013.7.3.224
PMCID: PMC3679332  PMID: 23766884
Dietary pattern; Korean adults; hypertension; nutrient intake; odd ratio
2.  Association of dietary pattern and body weight with blood pressure in Jiangsu Province, China 
BMC Public Health  2014;14(1):948.
Background
To identify risk factors, associations between dietary patterns, body mass index (BMI), and hypertension in a Chinese population.
Methods
Dietary intake was assessed in 2518 adults by a 3-day 24 h recall and a food frequency questionnaire. Salt and oil intake was assessed by weighing records. Four dietary patterns were identified using principal component analysis. Overweight and obesity was determined according to the Chinese cut-offs for BMI. High blood pressure was defined as systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg. Prevalence ratios (PR) were calculated using Poisson regression.
Results
Of the subjects, 26.7% had high blood pressure. Subjects with overweight and obesity were more likely to have high blood pressure than those with normal weight (PR, 95% CI: 1.60, 1.40-1.87; 2.45, 2.11-2.85, respectively). Subjects with a ‘traditional’ dietary pattern were more likely to have high blood pressure (P for trend = 0.001), whereas those with a ‘macho’ or ‘sweet tooth’ dietary pattern were less likely to have high blood pressure (P for trend = 0.004 and <0.001, respectively). More than half of the population had salt intakes > 9 g/d, and blood pressure increased with salt intake (P for trend <0.001). Subjects with a ‘traditional’ dietary pattern had the highest salt intake (12.3 g/d).
Conclusion
A traditional dietary pattern is associated with high blood pressure among the population of Jiangsu Province, which may be mainly due to high salt intake. Moreover, high BMI is an important determinant of high blood pressure. Both issues need to be addressed by lifestyle interventions.
doi:10.1186/1471-2458-14-948
PMCID: PMC4176575  PMID: 25216777
Dietary pattern; Body weight; Salt; Blood pressure; China
3.  Healthful dietary patterns and type 2 diabetes risk among women with a history of gestational diabetes 
Archives of internal medicine  2012;172(20):1566-1572.
Background
Type 2 diabetes (T2DM) has reached epidemic proportions. Women with gestational diabetes mellitus (GDM) are at high risk for T2DM after pregnancy. Adherence to healthful dietary patterns has been inversely associated with T2DM in the general population; however whether these dietary patterns are associated with progression to T2DM among a susceptible population is unknown.
Methods
4,413 participants from the Nurses’ Health Study II cohort with prior GDM were followed from 1991–2005. The alternate Mediterranean Diet (aMED), Dietary Approaches to Stop Hypertension (DASH), and alternate Healthy Eating Index (aHEI) dietary pattern adherence scores were derived from post-GDM validated food-frequency questionnaire, with cumulative average updating every 4 years. Multivariable Cox proportional hazards models estimated the relative risk (HR) and 95% confidence intervals [95% CI].
Results
491 cases of incident T2DM were observed over 52,743 person-years. All three patterns were inversely associated with T2DM risk adjusting for age, total calories, age at first birth, parity, ethnicity, parental diabetes, oral contraceptive use, menopause, and smoking. Comparing participants with highest adherence (quartile 4) versus lowest (quartile 1), the aMED pattern was associated with 40% lower risk of T2DM (HR=0.60 [95% CI: 0.44, 0.82] p-trend=0.0019), DASH with 46% lower risk (HR=0.54 [95% CI: 0.39, 0.73] p-trend=0.0002), and aHEI with 57% lower risk (HR=0.43 [95% CI: 0.31, 0.59] p-trend<0.0001). Adjustment for body mass index (BMI) moderately attenuated these findings.
Conclusions
Adherence to healthful dietary patterns is associated with lower T2DM risk among women with a history of GDM. The inverse associations were partly mediated by BMI.
doi:10.1001/archinternmed.2012.3747
PMCID: PMC3774782  PMID: 22987062
4.  Dietary Patterns of Korean Adults and the Prevalence of Metabolic Syndrome: A Cross-Sectional Study 
PLoS ONE  2014;9(11):e111593.
The prevalence of metabolic syndrome has been increasing in Korea and has been associated with dietary habits. The aim of our study was to identify the relationship between dietary patterns and the prevalence of metabolic syndrome. Using a validated food frequency questionnaire, we employed a cross-sectional design to assess the dietary intake of 1257 Korean adults aged 31 to 70 years. To determine the participants’ dietary patterns, we considered 37 predefined food groups in principal components analysis. Metabolic syndrome was defined according to the National Cholesterol Education Program Adult Treatment Panel III. The abdominal obesity criterion was modified using Asian guidelines. Prevalence ratios and 95% confidence intervals for the metabolic syndrome were calculated across the quartiles of dietary pattern scores using log binomial regression models. The covariates used in the model were age, sex, total energy intake, tobacco intake, alcohol consumption, and physical activity. The prevalence of metabolic syndrome was 19.8% in men and 14.1% in women. The PCA identified three distinct dietary patterns: the ‘traditional’ pattern, the ‘meat’ pattern, and the ‘snack’ pattern. There was an association of increasing waist circumference and body mass index with increasing score in the meat dietary pattern. The multivariate-adjusted prevalence ratio of metabolic syndrome for the highest quartile of the meat pattern in comparison with the lowest quartile was 1.47 (95% CI: 1.00–2.15, p for trend = 0.016). A positive association between the prevalence of metabolic syndrome and the dietary pattern score was found only for men with the meat dietary pattern (2.15, 95% CI: 1.10–4.21, p for trend = 0.005). The traditional pattern and the snack pattern were not associated with an increased prevalence of metabolic syndrome. The meat dietary pattern was associated with a higher prevalence of metabolic syndrome in Korean male adults.
doi:10.1371/journal.pone.0111593
PMCID: PMC4218781  PMID: 25365577
5.  Serum Vitamin D Level and Prehypertension among Subjects Free of Hypertension 
Kidney & Blood Pressure Research  2011;35(2):106-113.
Background
Low serum vitamin D levels are associated with high blood pressure (BP). Prehypertension is a preclinical stage where primary prevention efforts have been recommended for delaying or preventing the onset of hypertension. However, the majority of studies examining the association between vitamin D and BP have not accounted for kidney function or systemic inflammation.
Methods
Participants of the 3rd National Health and Nutrition Examination Survey >20 years of age and free of hypertension (n = 9,215, 53.5% women) and clinical cardiovascular disease were examined. Serum vitamin D levels were analyzed as quartiles. Prehypertension (n = 3,712) was defined as systolic BP 120–139 mm Hg or diastolic BP 80–89 mm Hg.
Results
Lower serum vitamin D levels were found to be associated with prehypertension independent of potential confounders including body mass index (BMI), serum cholesterol, C-reactive protein and estimated glomerular filtration rate. Compared to the highest quartile of serum vitamin D (referent), the odds ratio (95% confidence interval) of prehypertension associated with the lowest quartile was 1.48 (1.16–1.90; p trend <0.0001). This association persisted in subgroup analyses by gender, race-ethnicity and BMI.
Conclusion
Lower serum vitamin D levels are associated with prehypertension in a representative sample of US adults.
doi:10.1159/000330716
PMCID: PMC3221248  PMID: 21934326
Vitamin D; Blood pressure; Prehypertension
6.  Association of Dietary Patterns With Albuminuria and Kidney Function Decline in Older White Women: A Subgroup Analysis From the Nurses’ Health Study 
Background
Dietary patterns have been linked to chronic diseases such as cardiovascular disease, but sparse data are currently available on associations between dietary patterns and microalbuminuria or kidney function decline.
Study Design
Subgroup analysis from a prospective observational cohort study
Setting and Participants
Female participants in the Nurses’ Health Study who had dietary patterns data from food frequency questionnaires returned in 1984, 1986, 1990, 1994, and 1998 and urinary albumin-creatinine ratios (ACR) from the year 2000 (n=3121); estimated glomerular filtration rate (eGFR) change between 1989 and 2000 was available in 3071.
Predictor
Prudent (higher intake of fruits, vegetables, legumes, fish, poultry, and whole grains), Western (higher intake of red and processed meats, saturated fats, and sweets), and Dietary Approach to Stop Hypertension (DASH) style dietary patterns (also greater intake of vegetables, fruits, and whole grains).
Outcomes and Measurements
Microalbuminuria (albumin-to-creatinine ratio 25 to 354 mcg/mg) in 2000 and change in kidney function by eGFR between 1989 and 2000.
Results
After multivariable adjustment, the highest quartile of Western pattern score compared to the lowest quartile was directly associated with microalbuminuria (OR, 2.17; 95% CI, 1.18 to 3.66; p-for trend=0.01) and rapid eGFR decline of ≥3 ml/min/1.73 m2 per year (OR, 1.77; 95% CI, 1.03 to 3.03). Women in the top quartile of the DASH score had decreased risk for rapid eGFR decline (OR, 0.55; 95% CI, 0.38 to 0.80), but had no association with microalbuminuria. These associations did not vary with diabetes status. The prudent dietary pattern was not associated with microalbuminuria or eGFR decline.
Limitations
Study cohort included primarily older white women and generalizability of results would benefit from validation in non-whites and men.
Conclusions
A Western dietary pattern is associated with a significantly elevated risk for microalbuminuria and rapid kidney function decline whereas a DASH-style dietary pattern may be protective against rapid eGFR decline.
doi:10.1053/j.ajkd.2010.09.027
PMCID: PMC3026604  PMID: 21251540
7.  Dietary glycemic index, glycemic load and incidence of type 2 diabetes in Japanese men and women: the Japan public health center-based prospective study 
Nutrition Journal  2013;12:165.
Background
Japanese diets contain a relatively high amount of carbohydrates, and its high dietary glycemic index and glycemic load may raise the risk of diabetes in the Japanese population. The current study evaluated the associations between the dietary glycemic index, glycemic load, and the risk of type 2 diabetes in a population based cohort in Japan.
Methods
We observed 27,769 men and 36,864 women (45–75 y) who participated in the second survey of the Japan Public Health Center-based Prospective Study. The dietary glycemic index and glycemic load were estimated using a food-frequency questionnaire. The development of diabetes was reported in a questionnaire administered five years later, and the associations were analyzed using logistic regression after controlling for age, area, total energy intake, smoking status, family history of diabetes, physical activity, hypertension, BMI, alcohol intake, magnesium, calcium, dietary fiber and coffee intake, and occupation.
Results
The dietary glycemic load was positively associated with the risk of diabetes among women: the multivariable-adjusted odds ratio comparing the highest vs. the lowest quartile was 1.52 (95% CI, 1.13-2.04; P-trend = 0.01). The association was implied to be stronger among women with BMI < 25 than the women with BMI ≥ 25. The dietary glycemic index was positively associated with the risk of diabetes among men with a high intake of total fat: the multivariable-adjusted odds ratio comparing the highest vs. the lowest quartile was 1.46 (95% CI, 0.94-2.28; P-trend = 0.04). Among women with a high total fat intake, those in the first and second quartiles of the dietary glycemic index had a significant reduced risk of diabetes, compared with those in the first quartile who had a lower total fat level (multivariable-adjusted odds ratio = 0.59 with 95% CI, 0.37-0.94, and odds ratio = 0.63 with 95% CI, 0.40-0.998 respectively).
Conclusions
The population-based cohort study in Japan indicated that diets with a high dietary glycemic load increase the risk of type 2 diabetes among women. Total fat intake may modify the association between the dietary glycemic index and the risk of type 2 diabetes among men and women.
doi:10.1186/1475-2891-12-165
PMCID: PMC4029149  PMID: 24370346
Dietary glycemic index; Dietary glycemic load; Diabetes Mellitus; Cohort study; Japanese
8.  Serum 25-Hydroxyvitamin D Levels and Prediabetes Among Subjects Free of Diabetes 
Diabetes Care  2011;34(5):1114-1119.
OBJECTIVE
Animal studies suggest that low serum 25-hydroxyvitamin D (25[OH]D) may impair insulin synthesis and secretion and be involved in the pathogenesis of diabetes. Results in studies in humans have not been consistent, however. Prediabetes is a stage earlier in the hyperglycemia/diabetes continuum where individuals are at increased risk of developing diabetes and where prevention efforts have been shown to be effective in delaying or preventing the onset of diabetes. However, previous studies have not examined the association between low serum 25(OH)D levels and prediabetes.
RESEARCH DESIGN AND METHODS
We examined the 12,719 participants (52.5% women) in the third National Health and Nutrition Examination Survey aged >20 years who were free of diabetes. Serum 25(OH)D levels were categorized into quartiles (≤17.7, 17.8–24.5, 24.6–32.4, >32.4 ng/mL). Prediabetes was defined as a 2-h glucose concentration of 140–199 mg/dL, or a fasting glucose concentration of 110–125 mg/dL, or an A1C value of 5.7–6.4%.
RESULTS
Lower serum 25(OH)D levels were associated with prediabetes after adjusting for age, sex, race/ethnicity, season, geographic region, smoking, alcohol intake, BMI, outdoor physical activity, milk consumption, dietary vitamin D, blood pressure, serum cholesterol, C-reactive protein, and glomerular filtration rate. Compared with quartile 4 of 25(OH)D (referent), the odds ratio of prediabetes associated with quartile 1 was 1.47 (95% CI 1.16–1.85; P = 0.001 for trend). Subgroup analyses examining the relation between 25(OH)D and prediabetes by sex, BMI, and hypertension categories also showed a consistent positive association.
CONCLUSIONS
Lower serum 25(OH)D levels are associated with prediabetes in a representative sample of U.S. adults.
doi:10.2337/dc10-1203
PMCID: PMC3114501  PMID: 21430085
9.  Genome-Wide Association Study Identifies Eight Novel Loci Associated with Blood Pressure Responses to Interventions in Han Chinese 
Background
Blood pressure (BP) responses to dietary sodium and potassium intervention and cold pressor test (CPT) vary considerably among individuals. We aimed to identify novel genetic variants influencing individuals’ BP responses to dietary intervention and CPT.
Methods and Results
We conducted a genome-wide association study of BP responses in 1,881 Han Chinese and de novo genotyped top findings in 698 Han Chinese. Diet-feeding study included a 7-day low-sodium (51.3 mmol/day), a 7-day high-sodium (307.8 mmol/day), and a 7-day high-sodium plus potassium-supplementation (60 mmol/day). Nine BP measurements were obtained during baseline observation and each intervention period. The meta-analyses identified eight novel loci for BP phenotypes, which physically mapped in or near PRMT6 (P=7.29×10−9), CDCA7 (P=3.57×10−8), PIBF1 (P=1.78×10−9), ARL4C (P=1.86×10−8), IRAK1BP1 (P=1.44×10−10), SALL1 (P=7.01×10−13), TRPM8 (P=2.68×10−8), and FBXL13 (P=3.74×10−9). There was a strong dose-response relationship between the number of risk alleles of these independent SNPs and the risk of developing hypertension over 7.5-year follow-up in the study participants. Compared to those in the lowest quartile of risk alleles, odds ratios (95% confidence intervals) for those in the second, third and fourth quartiles were 1.39 (0.97, 1.99), 1.72 (1.19, 2.47), and 1.84 (1.29, 2.62), respectively (P=0.0003 for trend).
Conclusions
Our study identified 8 novel loci for BP responses to dietary sodium and potassium intervention and CPT. The effect size of these novel loci on BP phenotypes are much larger than those reported by the previously published studies. Furthermore, these variants predict the risk of developing hypertension among individuals with normal BP at baseline.
doi:10.1161/CIRCGENETICS.113.000307
PMCID: PMC3952335  PMID: 24165912
blood pressure; genomics; sodium; potassium
10.  Association between Dietary Sodium and Potassium Intake with Chronic Kidney Disease in U.S. Adults: A Cross-Sectional Study 
American journal of nephrology  2013;37(6):526-533.
Background/Aims
Clinical guidelines recommend a diet low in sodium and high in potassium to reduce blood pressure and cardiovascular events. Little is known about the relationship between dietary sodium and potassium intake and chronic kidney disease (CKD).
Methods
13,917 participants from the National Health and Nutrition Examination Survey (2001–2006) were examined. Sodium and potassium intake were calculated from 24-hour recall and evaluated in quartiles. CKD was defined as eGFR <60 mL/min, or eGFR ≥ 60mL/min with albuminuria (>30mg/g creatinine).
Results
The mean (SE) age and eGFR of participants was 45.0 ± 0.4 years and 88.0 ± 0.60 ml/min/1.73m2, respectively. 2333 (14.2%) had CKD: 1146 (7.3%) had an eGFR < 60 ml/min/1.73m2 and 1514 (8.4%) had an eGFR ≥ 60 ml/min/1.73 m2 and albuminuria. After adjustment for age, sex, race, body mass index, diabetes, hypertension, cardiovascular disease and congestive heart failure subjects in the highest quartile of sodium intake had a lower odds of CKD compared to subjects in the lowest quartile (adjusted OR 0.79, 95% CI, 0.66 to 0.96; p<0.016). Compared to the highest quartile, participants in the lowest quartile of potassium intake had a 44% increased odds of CKD (adjusted OR 1.44, 95% CI 1.16–1.79, p=0.0011).
Conclusions
Higher intake of sodium and potassium is associated with lower odds of CKD among US adults. These results should be corroborated through longitudinal studies and clinical trials designed specifically to examine the effects of dietary sodium and potassium intake on kidney disease and its progression.
doi:10.1159/000351178
PMCID: PMC3919025  PMID: 23689685
Chronic Kidney Disease; Dietary sodium intake; Dietary potassium intake
11.  High normal levels of albuminuria and risk of hypertension in Indo-Asian population 
Nephrology Dialysis Transplantation  2011;27(Suppl 3):iii58-iii64.
Background
Urine albumin excretion in the high normal range [urine albumin to creatinine ratio (UACR) 10–29 mg/g)] predicts hypertension in European-origin populations. However, the prognostic significance of UACR in the high normal range for incident hypertension is unclear in Indo-Asians. The objective of this study was to examine the relationship of normal to high normal levels of UACR and incident hypertension.
Methods
We conducted a nested cohort study within a cluster randomized controlled trial in Pakistan on 1272 normotensive non-diabetic adults aged ≥40 years with UACR <30 mg/g. Incident hypertension was defined as new onset of systolic blood pressure (SBP) ≥140 mmHg or diastolic ≥ 90 mmHg or initiation of antihypertensive therapy.
Results
A total of 920 (72.3%) participants completed the 2-year final follow-up. During this time, 105 (11.4%) developed incident hypertension. In the multivariable model, the odds [95% confidence interval (CI)] for incident hypertension were 2.45(1.21–4.98) for those in the fourth (top) quartile (≥6.1 mg/g) and 2.12 (1.04–4.35) in the third quartile (3.8–6.1 mg/g) compared to those in the lowest quartile (<2.8 mg/g). In addition, a significant interaction between UACR and baseline SBP was observed suggesting that the odds (95% CI) of incident hypertension with UACR were greater at lower baseline SBP (interaction P = 0.044).
Conclusions
High normal levels of albuminuria as measured by UACR predict hypertension in non-diabetic Indo-Asians, and this relationship may be enhanced in individuals with low baseline SBP. Further research is needed to assess the clinical applicability of these findings.
doi:10.1093/ndt/gfr200
PMCID: PMC3634393  PMID: 21592974
albuminuria; ethnicity; hypertension
12.  Associations between dietary patterns and demographics, lifestyle, anthropometry and blood pressure in Chinese community-dwelling older men and women 
This cross-sectional study examined dietary patterns, and the associations of these patterns with demographics, lifestyle, anthropometry and blood pressure in 3707 Chinese people aged 65 years and above taking part in a population-based cohort study investigating the risk factors for osteoporosis. Baseline dietary data were collected using a validated FFQ. Dietary patterns were identified using factor analysis. Scores were calculated for each pattern. Demographics, lifestyle factors and self-reported hypertension history were collected through a questionnaire. BMI, waist circumference (WC), hip circumference (HC), waist-to-hip ratio, systolic blood pressure and diastolic blood pressure (DBP) were measured. Three dietary patterns were identified, namely ‘vegetables–fruit’, ‘snacks–drinks–milk products’ and ‘meat–fish’. Participants who were more physically active, more educated, non-smokers and non-drinkers were more likely to have higher ‘vegetables–fruit’ dietary pattern scores. Current smoking habit and alcohol use were associated with higher ‘snacks–drinks–milk products’ dietary pattern scores and ‘meat–fish’ dietary pattern scores. ‘Vegetables–fruit’ dietary pattern scores were inversely (unstandardised regression coefficient B = −0·60 mmHg, 95 % CI −1·04, −0·16) and ‘snacks–drinks–milk products’ dietary pattern scores were positively (B = 0·50 mmHg, 95 % CI 0·08, 0·92) associated with DBP in men in multiple regressions. Higher ‘meat–fish’ dietary pattern scores were associated with higher BMI (B = 0·19 kg/m2, 95 % CI 0·06, 0·33), waist-to-hip ratio (B = 0·004, 95 % CI 0·002, 0·007) and WC (B = 0·57 cm, 95 % CI 0·18, 0·97) in men, and higher BMI (B = 0·40 kg/m2, 95 % CI 0·22, 0·57), WC (B = 0·87 cm, 95 % CI 0·39, 1·36) and HC (B = 0·61 cm, 95 % CI 0·26, 0·96) in women in multiple regressions. The influence of demographic and lifestyle characteristics on dietary patterns and the health risks associated with dietary patterns provides insights for the provision of tangible dietary advice to this population.
doi:10.1017/jns.2012.19
PMCID: PMC4153085  PMID: 25191550
Dietary patterns; Factor analysis; Cross-sectional studies; Chinese elderly; DBP, diastolic blood pressure; PASE, Physical Activity Scale for the Elderly; SES, socio-economic status; WC, waist circumference
13.  A Prospective Cohort Study to Examine the Association between Dietary Patterns and Depressive Symptoms in Older Chinese People in Hong Kong 
PLoS ONE  2014;9(8):e105760.
Introduction
Dietary patterns are culturally specific and there is limited data on the association of dietary patterns with late-life depression in Chinese. This study examined the associations between dietary patterns and baseline and subsequent depressive symptoms in community-dwelling Chinese older people in Hong Kong.
Methods
Participants aged ≥65 year participating in a cohort study examining the risk factors for osteoporosis completed a validated food frequency questionnaire at baseline between 2001 and 2003. Factor analysis was used to identify three dietary patterns: “vegetables-fruits” pattern, “snacks-drinks-milk products” pattern, and “meat-fish” pattern. Depressive symptoms were measured at baseline and 4-year using the validated Geriatric Depression Scale. Multiple logistic regression was used for cross-sectional analysis (n = 2,902) to assess the associations between dietary patterns and the presence of depressive symptoms, and for longitudinal analysis (n = 2,211) on their associations with 4-year depressive symptoms, with adjustment for socio-demographic and lifestyle factors.
Results
The highest quartile of “vegetables-fruits” pattern score was associated with reduced likelihood of depressive symptoms [Adjusted OR = 0.55 (95% CI: 0.36–0.83), ptrend = 0.017] compared to the lowest quartile at baseline. Similar inverse trend was observed for the highest quartile of “snacks-drinks-milk products” pattern score [Adjusted OR = 0.41 (95% CI: 0.26–0.65), ptrend<0.001] compared to the lowest quartile. There was no association of “meat-fish” pattern with the presence of depressive symptoms at baseline. None of the dietary patterns were associated with subsequent depressive symptoms at 4-year.
Conclusion
Higher “vegetables-fruits” and “snacks-drinks-milk products” pattern scores were associated with reduced likelihood of baseline depressive symptoms in Chinese older people in Hong Kong. The longitudinal analyses failed to show any causal relationship between dietary patterns and depressive symptoms in this population.
doi:10.1371/journal.pone.0105760
PMCID: PMC4141823  PMID: 25148515
14.  Vitamin C in plasma is inversely related to blood pressure and change in blood pressure during the previous year in young Black and White women 
Nutrition Journal  2008;7:35.
Background
The prevalence of hypertension and its contribution to cardiovascular disease risk makes it imperative to identify factors that may help prevent this disorder. Extensive biological and biochemical data suggest that plasma ascorbic acid may be such a factor. In this study we examined the association between plasma ascorbic acid concentration and blood pressure (BP) in young-adult women.
Methods
Participants were 242 Black and White women aged 18–21 yr from the Richmond, CA, cohort of the National Heart, Lung and Blood Institute Growth and Health Study. We examined the associations of plasma ascorbic acid with BP at follow-up year 10, and with change in BP during the previous year.
Results
In cross-sectional analysis, plasma ascorbic acid at year 10 was inversely associated with systolic BP and diastolic BP after adjusting for race, body mass index, education, and dietary intake of fat and sodium. Persons in the highest one-fourth of the plasma ascorbic acid distribution had 4.66 mmHg lower systolic BP (95% CI 1.10 to 8.22 mmHg, p = 0.005) and 6.04 mmHg lower diastolic BP (95% CI 2.70 to 9.38 mmHg, p = 0.0002) than those in the lowest one-fourth of the distribution. In analysis of the change in BP, plasma ascorbic acid was also inversely associated with change in systolic BP and diastolic BP during the previous year. While diastolic blood pressure among persons in the lowest quartile of plasma ascorbic acid increased by 5.97 mmHg (95% CI 3.82 to 8.13 mmHg) from year 9 to year 10, those in the highest quartile of plasma vitamin C increased by only 0.23 mmHg (95% CI -1.90 to +2.36 mmHg) (test for linear trend: p < 0.0001). A similar effect was seen for change in systolic BP, p = 0.005.
Conclusion
Plasma ascorbic acid was found to be inversely associated with BP and change in BP during the prior year. The findings suggest the possibility that vitamin C may influence BP in healthy young adults. Since lower BP in young adulthood may lead to lower BP and decreased incidence of age-associated vascular events in older adults, further investigation of treatment effects of vitamin C on BP regulation in young adults is warranted.
doi:10.1186/1475-2891-7-35
PMCID: PMC2621233  PMID: 19091068
15.  Relationship between serum cystatin C and hypertension among US adults without clinically recognized chronic kidney disease 
Background
Previous animal studies have suggested that mild reductions in renal function, even before the development of clinically recognized chronic kidney disease (CKD), are associated with hypertension. However, few studies have examined this hypothesis in humans. We therefore examined the association between serum cystatin C levels and hypertension among subjects without clinically recognized CKD in a large multiethnic sample of US adults.
Methods
We examined the National Health and Nutrition Examination Survey 1999–2002 participants >20 years of age (n=2583, 54.5% women) without clinically recognized CKD (defined as an estimated glomerular filtration rate<60 mL/min/1.73 m2 or microalbuminuria). Serum cystatin C levels were categorized into quartiles (<0.76 mg/L, 0.76–0.86 mg/L, 0.87–0.97 mg/L, >0.97 mg/L). Hypertension was defined as blood pressure (BP)-reducing medication use or having systolic BP ≥140 mmHg and/or diastolic BP ≥90 mmHg.
Results
Higher serum cystatin C levels were found to be associated with hypertension in women, but not men. After adjusting for age, race-ethnicity, education, smoking, alcohol intake, body mass index, diabetes, total cholesterol and C-reactive protein, the odds ratio (95% confidence interval) of hypertension comparing quartile 4 of cystatin C to quartile 1 (referent) was 2.04 (1.13–3.69); p-trend=0.02 in women and 0.86 (0.53–1.41); p-trend=0.51 in men.
Conclusion
In a representative sample of US adults, mild reductions in kidney function as measured by higher serum cystatin C levels among subjects without clinically recognized CKD are associated with hypertension in women, but not men.
doi:10.1016/j.jash.2011.03.003
PMCID: PMC3140570  PMID: 21498146
Cystatin C; Hypertension; NHANES
16.  Sodium intake in men and potassium intake in women determine the prevalence of metabolic syndrome in Japanese hypertensive patients: OMEGA Study 
Hypertension Research  2011;34(8):957-962.
Dietary intake affects hypertension and metabolic syndrome (MS) and their management. In Japanese hypertensive patients, little evidence exists regarding the relation between diet and MS. A self-administered lifestyle questionnaire was completed by each patient at the baseline. Three dietary scores were calculated for each patient: sodium intake, potassium intake and soybean/fish intake. The relationships between dietary scores and systolic blood pressure (SBP) and diastolic blood pressure (DBP) were analyzed by multiple regression analysis. The relation between dietary intake of sodium, potassium and soybean/fish, and the presence of MS was evaluated by the Mantel–Haenszel test. A total of 9585 hypertensive patients (mean age, 64.9 years; women, 51.4%) were included in this sub-analysis. High sodium intake was significantly related to increased SBP (P=0.0003) and DBP (P=0.0130). Low potassium intake was significantly related to increased SBP (P=0.0057) and DBP (P=0.0005). Low soybean/fish intake was significantly related to increased SBP (P=0.0133). A significantly higher prevalence of MS was found in men in the highest quartile of sodium intake compared with the lower quartiles (P=0.0026) and in women in the lowest quartile of potassium intake compared with the higher quartiles (P=0.0038). A clear relation between dietary habits and blood pressure was found in Japanese hypertensive patients using a patient-administered questionnaire. Sodium and potassium intake affect MS prevalence. Dietary changes are warranted within hypertension treatment strategies.
doi:10.1038/hr.2011.63
PMCID: PMC3257031  PMID: 21654751
blood pressure; diet; essential hypertension; metabolic syndrome; prospective observational study
17.  Effects of Intensive Blood Pressure Lowering on Cardiovascular and Renal Outcomes: A Systematic Review and Meta-Analysis 
PLoS Medicine  2012;9(8):e1001293.
In a systematic review and meta-analysis Vlado Perkovic and colleagues investigate whether more intensive blood pressure lowering regimens are associated with greater reductions in the risk of major cardiovascular events and end stage kidney disease.
Background
Guidelines recommend intensive blood pressure (BP) lowering in patients at high risk. While placebo-controlled trials have demonstrated 22% reductions in coronary heart disease (CHD) and stroke associated with a 10-mmHg difference in systolic BP, it is unclear if more intensive BP lowering strategies are associated with greater reductions in risk of CHD and stroke. We did a systematic review to assess the effects of intensive BP lowering on vascular, eye, and renal outcomes.
Methods and Findings
We systematically searched Medline, Embase, and the Cochrane Library for trials published between 1950 and July 2011. We included trials that randomly assigned individuals to different target BP levels.
We identified 15 trials including a total of 37,348 participants. On average there was a 7.5/4.5-mmHg BP difference. Intensive BP lowering achieved relative risk (RR) reductions of 11% for major cardiovascular events (95% CI 1%–21%), 13% for myocardial infarction (0%–25%), 24% for stroke (8%–37%), and 11% for end stage kidney disease (3%–18%). Intensive BP lowering regimens also produced a 10% reduction in the risk of albuminuria (4%–16%), and a trend towards benefit for retinopathy (19%, 0%–34%, p = 0.051) in patients with diabetes. There was no clear effect on cardiovascular or noncardiovascular death. Intensive BP lowering was well tolerated; with serious adverse events uncommon and not significantly increased, except for hypotension (RR 4.16, 95% CI 2.25 to 7.70), which occurred infrequently (0.4% per 100 person-years).
Conclusions
Intensive BP lowering regimens provided greater vascular protection than standard regimens that was proportional to the achieved difference in systolic BP, but did not have any clear impact on the risk of death or serious adverse events. Further trials are required to more clearly define the risks and benefits of BP targets below those currently recommended, given the benefits suggested by the currently available data.
Please see later in the article for the Editors' Summary.
Editors' Summary
Background
About a third of US and UK adults have high blood pressure (hypertension). Although hypertension has no obvious symptoms, it can lead to heart attacks, stroke, and other forms of cardiovascular disease, to kidney failure, and to retinopathy (blindness caused by damage to the blood vessels in the back of the eye). Hypertension is diagnosed by measuring blood pressure (BP)—the force that blood moving around the body exerts on the inside of large blood vessels. BP is highest when the heart is pumping out blood (systolic BP) and lowest when it is refilling with blood (diastolic BP). A normal adult BP is defined as a systolic BP of less than 130 millimeters of mercury (mmHg) and a diastolic BP of less than 85 mmHg (a BP of 130/85). A reading of more than 140/90 indicates hypertension. Many factors affect BP, but overweight people and individuals who eat fatty or salty food are at high risk of developing hypertension. Mild hypertension can be corrected by making lifestyle changes, but people often take antihypertensive drugs to reduce their BP.
Why Was This Study Done?
Doctors usually try to reduce the BP of their hypertensive patients to 140/90 mmHg. However, some treatment guidelines now advocate a target BP of 130/80 mmHg for individuals at high risk of life-threatening cardiovascular events, such as people with diabetes or kidney impairment. But does more intensive BP lowering actually reduce the risk of heart attacks and stroke? Although placebo-controlled randomized trials of BP lowering have suggested that a 10 mmHg fall in systolic BP is associated with a 22% reduction in the risk in coronary heart disease and a 41% reduction in the risk of stroke, it is unclear whether intensive BP lowering strategies are associated with greater reductions in the risk of cardiovascular disease than standard strategies. In this systematic review (a search that uses predefined criteria to identify all the research on a given topic) and meta-analysis (a statistical method for combining the results of studies), the researchers investigate the effects of intensive BP lowering on cardiovascular, eye, and renal outcomes.
What Did the Researchers Do and Find?
The researchers identified 15 randomized controlled trials in which more than 37,000 participants were randomly assigned to antihypertensive drug-based strategies designed to achieve different target BPs. On average, the more intensive strategies reduced the BP of participants by 7.5/4.5 mmHg more than the less intensive strategies. Compared to standard BP lowering strategies, more intensive BP lowering strategies reduced the risk of major cardiovascular events (a composite endpoint comprising heart attack, stroke, heart failure, and cardiovascular death) by 11%, the risk of heart attack by 13%, the risk of stroke by 24%, the risk of end-stage kidney disease by 11%, and the risk of albuminuria (protein in the urine, a sign of kidney damage) by 10%. There was also a trend towards a reduced risk for retinopathy with more intensive BP lowering but no clear reduction in cardiovascular or noncardiovascular deaths. Finally, aiming for a lower BP target did not increase the rate of drug discontinuation or the risk of serious adverse events apart from hypotension (very low BP).
What Do These Findings Mean?
These findings suggest that, although intensive BP lowering regimens have no clear effect on the risk of death, they may provide greater protection against cardiovascular events than standard BP lowering regimens. Indeed, the researchers calculate that among every thousand hypertensive patients with a high cardiovascular risk, more intensive BP lowering could prevent two of the 20 cardiovascular events expected to happen every year. Although intensive BP lowering did not seem to increase the risk of severe adverse effects, the accuracy of this finding is limited by inconsistent reporting of adverse events in the trials included in this study. Moreover, because most of the trial participants had additional risk factors for cardiovascular events such as diabetes and chronic kidney disease, these findings may not be generalizable to people with hypertension alone. Thus, although this study suggests that a target BP of 130/80 is likely to produce an additional overall benefit compared to a target of 140/90, more trials are needed to confirm this conclusion and to determine the best way to reach the lower target.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001293.
The US National Heart Lung and Blood Institute has patient information about high blood pressure (in English and Spanish)
The American Heart Association provides information on high blood pressure and on cardiovascular diseases (in several languages); it also provides personal stories from people dealing with high blood pressure
The UK National Health Service (NHS) Choices website also provides detailed information for patients about hypertension, cardiovascular disease and kidney disease; the NHS Local website has a collection of personal stories about hypertension and a series of films that explain hypertension
MedlinePlus provides links to further information about high blood pressure, heart disease, stroke, and kidney disease (in English and Spanish)
doi:10.1371/journal.pmed.1001293
PMCID: PMC3424246  PMID: 22927798
18.  Major Dietary Patterns and Their Associations with Overweight and Obesity Among Iranian Children 
Background:
Increasing prevalence of obesity is a major health concern. Lifestyle behaviors and diet play an important role in developing childhood obesity. The aim of this study was to determine the association between major dietary patterns and overweight/obesity in a group of Iranian school-aged children.
Methods:
This cross-sectional study was conducted in Isfahan, Iran with 637 elementary school-aged children. A semi-quantitative food-frequency questionnaire was used to assess usual dietary intakes. Data on socio-demographic, physical activity and other lifestyle habits were collected using standard questionnaires. Obesity was determined based on national cut-offs. Factor analysis was used for identifying major dietary patterns.
Results:
Three major dietary patterns were extracted; “Healthy,” “Western,” and “Sweet-Dairy.” After adjusting for confounders, girls in the second quartile of healthy pattern, were more likely to be overweight (odds ratio [OR] =2.23, Confidence intervals [CI] =1.003, 4.96) compared to those in the highest quartile. Likelihood of being overweight was lower for girls in the second quartile of western dietary pattern versus the fourth quartile (OR = 0.46, CI = 0.21, 1.01). Accordingly, lower adherence to sweet and dairy pattern was associated with lower body mass index (BMI) among girls (OR = 0.42, CI = 0.21, 0.85). There was no significant relationship between western and sweet-dairy pattern with BMI among boys, however, significant association was observed between lowest and highest quartiles of healthy pattern (OR = 0.36, CI = 0.15, 0.84).
Conclusions:
We found significant associations between the three dietary patterns and obesity among girls. Only healthy pattern was related to weight status of schoolboys. Longitudinal studies will be needed to confirm these associations.
PMCID: PMC3650598  PMID: 23671778
Children; dietary patterns; factor analysis; obesity; overweight
19.  Association between Blood Pressure Responses to Cold Pressor Test and Dietary Sodium Intervention in the Chinese Population 
Archives of internal medicine  2008;168(16):1740-1746.
Background
Blood pressure (BP) responses to the cold pressor test (CPT) and to dietary sodium intake might be related to the risk of hypertension. We examined the association between BP responses to the CPT and to dietary sodium and potassium interventions.
Methods
The CPT and dietary intervention were conducted among 1,906 study participants in rural China. The dietary intervention included three 7-day periods of low-sodium-feeding (51.3 mmol/day), high-sodium-feeding (307.8 mmol/day), and high-sodium-feeding plus potassium-supplementation (60 mmol/day). A total of 9 BP measurements were obtained during the 3-day baseline observation and the last 3 days of each intervention using a random-zero sphygmomanometer.
Results
BP response to the CPT was significantly associated with BP changes during the sodium and potassium interventions (all p<0.0001). Compared to the lowest quartile of BP response to the CPT, systolic BP changes (95% confident interval) for the top 3 quartiles, respectively, were −2.02 (−2.87, −1.16), −3.17 (−4.05, −2.28), and −5.98 (−6.89, −5.08) mm Hg during the low-sodium intervention. Corresponding systolic BP changes during the high-sodium intervention were 0.40 (−0.36, 1.16), 0.44 (−0.35, 1.22), and 2.30 (1.50, 3.10) mm Hg, and during the potassium-supplementation were −0.26 (−0.99, 0.46), −0.95 (−1.70, −0.20), and −1.59 (−2.36, −0.83) mm Hg, respectively.
Conclusions
These results indicated that BP response to the CPT was associated with salt-sensitivity and potassium-sensitivity. Furthermore, a low-sodium or high-potassium diet might be more effective to lower BP among individuals with high responses to the CPT.
doi:10.1001/archinte.168.16.1740
PMCID: PMC2535851  PMID: 18779460
blood pressure; cold pressor test; dietary sodium; dietary potassium; hypertension; salt sensitivity
20.  Relationship between Blood Mercury Level and Risk of Cardiovascular Diseases: Results from the Fourth Korea National Health and Nutrition Examination Survey (KNHANES IV) 2008–2009 
Limited epidemiologic data is available regarding the cardiovascular effects of mercury exposure. The purpose of this study was to determine the relationship between mercury exposure from fish consumption and cardiovascular disease in a nationally representative sample of Korean adults using the Fourth Korea National Health and Nutrition Examination Survey (KNHANES IV 2008~2009). Survey logistic regression models accounting for the complex sampling were used to estimate the odds ratios (OR) adjusted for fish consumption frequency, age, education, individual annual income, household annual income, body mass index (BMI), waist circumference (WC), alcohol consumption status, and smoking status. The mean blood mercury level in the population was 5.44 μg/L. Trends toward increased blood mercury levels were seen for increased education level (P=0.0011), BMI (P<0.0001), WC (P<0.0001), and fish (i.e., anchovy) consumption frequency (P=0.0007). The unadjusted OR for hypertension in the highest blood mercury quartile was 1.450 [95% confidential interval (CI): 1.106~1.901] times higher than that of the lowest quartile. The fish consumption-adjusted OR for hypertension in the highest blood mercury quartile was 1.550 (95% CI: 1.131~2.123) times higher than that of the lowest quartile, and the OR for myocardial infarction or angina in the highest blood mercury quartile was 3.334 (95% CI: 1.338~8.308) times higher than that of the lowest quartile. No associations were observed between blood mercury levels and stroke. These findings suggest that mercury in the blood may be associated with an increased risk of hypertension and myocardial infarction or angina in the general Korean population.
doi:10.3746/pnf.2014.19.4.333
PMCID: PMC4287327  PMID: 25580399
blood mercury levels; cardiovascular disease; KNHANES; fish consumption
21.  No association between perfluoroalkyl chemicals and hypertension in children 
Background
Hypertension is a leading cause of cardiovascular disease worldwide. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are perfluoroalkyl chemicals (PFCs) used in the manufacture of common consumer products and detected in the blood of the majority of Americans. Emerging biological data suggest that PFC exposure may have a role in the development of hypertension. However, the association between PFCs and hypertension has not yet been explored in humans. Therefore, we examined this association in a representative sample of US children.
Methods
A cross-sectional study was performed on 1,655 children from the National Health and Nutrition Examination Survey, 1999–2000 and 2003–2008. The main outcome of interest was hypertension, defined as age, height, and sex specific systolic and/or diastolic blood pressure level at the 95th percentile.
Results
We found no association between serum levels of PFOA and PFOS and hypertension in either unadjusted or multivariable-adjusted analyses controlling for age, sex, race-ethnicity, body mass index, annual household income, moderate activity, total serum cholesterol, and serum cotinine. Compared with the lowest quartile, the multivariable-adjusted odds ratio (95% confidence interval) of hypertension in the highest quartile of exposure was 0.69 (0.41–1.17) for PFOA and 0.77 (0.37–1.61) for PFOS (all P-trend values >0.30).
Conclusion
Our findings indicate that exposure to PFOA or PFOS is not significantly associated with hypertension in children at the lower PFC exposure levels typical of the general population.
doi:10.2147/IBPC.S47660
PMCID: PMC3920456  PMID: 24520202
perfluorooctanoic acid; perfluorooctane sulfonate; perfluoroalkyl chemicals; blood pressure; children
22.  Food patterns associated with blood lipids are predictive of coronary heart disease: the Whitehall II study 
The British journal of nutrition  2009;102(4):619-624.
Analysis of the epidemiological effects of overall dietary patterns offers an alternative approach to the investigation of the role of diet in coronary heart disease (CHD).We analyzed the role of blood lipid-related dietary patterns using a two-step method to confirm the prospective association of dietary pattern with incident CHD. Analysis is based on 7314 participants of the Whitehall II study. Dietary intake was measured using a 127-item food frequency questionnaire. Reduced rank regression (RRR) was used to derive dietary pattern scores using baseline serum total and HDL cholesterol, and triglyceride levels as dependent variables. Cox proportional hazard regression was used to confirm the association between dietary patterns and incident CHD (n=243) over 15 years of follow-up. Increased CHD risk (hazard ratio for top quartile:2.01, 95%CI 1.41-2.85, adjusted for age, sex, ethnicity and energy misreporting) was observed with a diet characterised by high consumption of white bread, fried potatoes, sugar in tea and coffee, burgers & sausages, soft drinks, and low consumption of French dressing and vegetables. The diet-CHD relationship was attenuated after adjustment for employment grade and health behaviors (HR for top quartile:1.81, 95%CI 1.26-2.62), and further adjustment for blood pressure and BMI (HR for top quartile:1.57, 95% CI 1.08-2.27). Dietary patterns are associated with serum lipids and predict CHD risk after adjustment for confounders. RRR identifies dietary patterns uses prior knowledge and focuses on the pathways through which diet may influence disease. This study adds to the evidence that diet is an important risk factor for CHD.
doi:10.1017/S0007114509243030
PMCID: PMC2788758  PMID: 19327192
dietary patterns; lipids; coronary heart disease; prospective cohort study; Whitehall II study
23.  Alcohol Intake and Blood Pressure: A Systematic Review Implementing a Mendelian Randomization Approach 
PLoS Medicine  2008;5(3):e52.
Background
Alcohol has been reported to be a common and modifiable risk factor for hypertension. However, observational studies are subject to confounding by other behavioural and sociodemographic factors, while clinical trials are difficult to implement and have limited follow-up time. Mendelian randomization can provide robust evidence on the nature of this association by use of a common polymorphism in aldehyde dehydrogenase 2 (ALDH2) as a surrogate for measuring alcohol consumption. ALDH2 encodes a major enzyme involved in alcohol metabolism. Individuals homozygous for the null variant (*2*2) experience adverse symptoms when drinking alcohol and consequently drink considerably less alcohol than wild-type homozygotes (*1*1) or heterozygotes. We hypothesise that this polymorphism may influence the risk of hypertension by affecting alcohol drinking behaviour.
Methods and Findings
We carried out fixed effect meta-analyses of the ALDH2 genotype with blood pressure (five studies, n = 7,658) and hypertension (three studies, n = 4,219) using studies identified via systematic review. In males, we obtained an overall odds ratio of 2.42 (95% confidence interval [CI] 1.66–3.55, p = 4.8 × 10−6) for hypertension comparing *1*1 with *2*2 homozygotes and an odds ratio of 1.72 (95% CI 1.17–2.52, p = 0.006) comparing heterozygotes (surrogate for moderate drinkers) with *2*2 homozygotes. Systolic blood pressure was 7.44 mmHg (95% CI 5.39–9.49, p = 1.1 × 10−12) greater among *1*1 than among *2*2 homozygotes, and 4.24 mmHg (95% CI 2.18–6.31, p = 0.00005) greater among heterozygotes than among *2*2 homozygotes.
Conclusions
These findings support the hypothesis that alcohol intake has a marked effect on blood pressure and the risk of hypertension.
Using a mendelian randomization approach Sarah Lewis and colleagues find strong support for the hypothesis that alcohol intake has a marked effect on blood pressure and the risk of hypertension.
Editors' Summary
Background.
High blood pressure (hypertension) is a common medical condition that affects nearly a third of US and UK adults. Hypertension has no symptoms but can lead to heart attacks or strokes. It is diagnosed by measuring blood pressure—the force that blood moving around the body exerts on the inside of large blood vessels. Blood pressure is highest when the heart is pumping out blood (systolic pressure) and lowest when it is filling up with blood (diastolic pressure). Normal blood pressure is defined as a systolic pressure of less than 130 millimeters of mercury (mmHg) and a diastolic pressure of less than 85 mmHg (a blood pressure of 130/85). A reading of more than 140/90 indicates hypertension. Many factors affect blood pressure, but overweight people and individuals who eat too much salty or fatty foods are at high risk of developing hypertension. Mild hypertension can often be corrected by lifestyle changes, but many people also take antihypertensive drugs to reduce their blood pressure.
Why Was This Study Done?
Another modifiable lifestyle factor thought to affect blood pressure is alcohol intake. Observational studies that ask people about their drinking habits and measure their blood pressure suggest that alcohol intake correlates with blood pressure, but they cannot prove a causal link because of “confounding”—other risk factors associated with alcohol drinking, such as diet, might also affect the study participant's blood pressures. A trial that randomly assigns people to different alcohol intakes could provide this proof of causality, but such a trial is impractical. In this study, therefore, the researchers have used “Mendelian randomization” to investigate whether alcohol intake affects blood pressure. An inactive variant of aldehyde dehydrogenase 2 (ALDH2; the enzyme that removes alcohol from the body) has been identified. People who inherit the variant form of this gene from both parents have an ALDH2 *2*2 genotype (genetic makeup) and become flushed and nauseated after drinking. Consequently, they drink less than people with a *1*2 genotype and much less than those with a *1*1 genotype. Because inheritance of these genetic variants does not affect lifestyle factors other than alcohol intake, an association between ALDH2 genotypes and blood pressure would indicate that alcohol intake has an effect on blood pressure without any confounding.
What Did the Researchers Do and Find?
The researchers identified ten published studies (mainly done in Japan where the ALDH2 gene variant is common) on associations between ALDH2 genotype and blood pressure or hypertension using a detailed search protocol (a “systematic review”). A meta-analysis (a statistical method for combining the results of independent studies) of the studies that had investigated the association between ALDH2 genotype and hypertension showed that men with the *1*1 genotype (highest alcohol intake) and those with the *1*2 genotype (intermediate alcohol intake) were 2.42 and 1.72 times more likely, respectively, to have hypertension than those with the *2*2 genotype (lowest alcohol intake). There was no association between ALDH2 genotype and hypertension among the women in these studies because they drank very little. Systolic and diastolic blood pressures showed a similar relationship to ALDH2 genotype in a second meta-analysis of relevant studies. Finally, the researchers estimated that for men the lifetime effect of drinking 1 g of alcohol a day (one unit of alcohol contains 8 g of alcohol in the UK and 14 g in the US; recommended daily limits in these countries are 3–4 and 1–2 units, respectively) would be an increase in systolic blood pressure of 0.24 mmHg.
What Do These Findings Mean?
These findings support the suggestion that alcohol has a marked effect on blood pressure and hypertension. Consequently, some cases of hypertension could be prevented by encouraging people to reduce their daily alcohol intake. Although the Mendelian randomization approach avoids most of the confounding intrinsic to observational studies, it is possible that a gene near ALDH2 that has no effect on alcohol intake affects blood pressure, since genes are often inherited in blocks. Alternatively, ALDH2 could affect blood pressure independent of alcohol intake. The possibility that ALDH2 could effect blood pressure independently of alcohol is intake made unlikely by the fact that no effect of genotype on blood pressure is seen among women who drink very little. Additional large-scale studies are needed to address these possibilities, to confirm the current finding in more people, and to improve the estimates of the effect that alcohol intake has on blood pressure.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050052.
The MedlinePlus encyclopedia has a page on hypertension (in English and Spanish)
The American Heart Association provides information for patients and health professionals about hypertension
The UK Blood Pressure Association provides information for patients and health professionals on all aspects of hypertension, including information about alcohol affects blood pressure
The Explore@Bristol science center (a UK charity) provides an alcohol unit calculator and information on the effects of alcohol
The International Center for Alcohol Policies provides drinking guidelines for countries around the world
doi:10.1371/journal.pmed.0050052
PMCID: PMC2265305  PMID: 18318597
24.  Association between Usual Sodium and Potassium Intake and Blood Pressure and Hypertension among U.S. Adults: NHANES 2005–2010 
PLoS ONE  2013;8(10):e75289.
Objectives
Studies indicate high sodium and low potassium intake can increase blood pressure suggesting the ratio of sodium-to-potassium may be informative. Yet, limited studies examine the association of the sodium-to-potassium ratio with blood pressure and hypertension.
Methods
We analyzed data on 10,563 participants aged ≥20 years in the 2005–2010 National Health and Nutrition Examination Survey who were neither taking anti-hypertensive medication nor on a low sodium diet. We used measurement error models to estimate usual intakes, multivariable linear regression to assess their associations with blood pressure, and logistic regression to assess their associations with hypertension.
Results
The average usual intakes of sodium, potassium and sodium-to-potassium ratio were 3,569 mg/d, 2,745 mg/d, and 1.41, respectively. All three measures were significantly associated with systolic blood pressure, with an increase of 1.04 mmHg (95% CI, 0.27–1.82) and a decrease of 1.24 mmHg (95% CI, 0.31–2.70) per 1,000 mg/d increase in sodium or potassium intake, respectively, and an increase of 1.05 mmHg (95% CI, 0.12–1.98) per 0.5 unit increase in sodium-to-potassium ratio. The adjusted odds ratios for hypertension were 1.40 (95% CI, 1.07–1.83), 0.72 (95% CI, 0.53–0.97) and 1.30 (95% CI, 1.05–1.61), respectively, comparing the highest and lowest quartiles of usual intake of sodium, potassium or sodium-to-potassium ratio.
Conclusions
Our results provide population-based evidence that concurrent higher sodium and lower potassium consumption are associated with hypertension.
doi:10.1371/journal.pone.0075289
PMCID: PMC3794974  PMID: 24130700
25.  Association of Uric Acid with Metabolic Syndrome in Men, Premenopausal Women and Postmenopausal Women 
Objective: To explore the relationship between serum uric acid (SUA) and metabolic syndrome (MS) in men, premenopausal women and postmenopausal women. Methods: A cross-sectional study was conducted in 1,834 community-based Southern Chinese participants from June to October 2012. Sex-specific SUA quartiles were used as follows: <345, 345–<400, 400–<468, ≥468 µmol/L in males; and <248, 248–<288, 288–<328, ≥328 µmol/L in females. MS was defined by the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) Criteria. The association between SUA and MS was then analyzed using the STATA software. Results: The odds ratio (OR) for having MS in the highest versus lowest quartiles of SUA levels was 2.46 (95% confidence interval [CI], 1.39 to 4.34, p = 0.002) in men after adjusting for age, sex, history of coronary heart disease, history of stroke, current current smoking, current alcohol use, physical inactivity, education status, and BMI. Further adjusting for above confounders, hypertension and diabetes, the OR for having MS in the highest versus lowest quartiles of SUA was 3.06 (95% CI, 1.64 to 5.70, p < 0.001). The OR for having MS in the highest versus lowest quartiles of SUA was 3.45 (95% CI, 1.38 to 8.64, p = 0.008) and 1.98 (95% CI, 1.16 to 3.37, p = 0.08) in premenopausal women and postmenopausal women after adjusting for age, sex, history of coronary heart disease, history of stroke, current smoking, current alcohol use, physical inactivity, education status, and BMI. Further adjusting for above confounders, hypertension and diabetes, the OR for having MS in the highest versus lowest quartiles of SUA was 3.42 (95% CI, 1.15 to 10.18, p = 0.03) and 1.87 (95% CI, 1.05 to 3.33, p = 0.03) in premenopausal women and postmenopausal women. Conclusions: Higher SUA levels are positively associated with the presence of MS in males and females. Higher SUA levels had a higher risk of having MS in premenopausal women than in postmenopausal women.
doi:10.3390/ijerph110302899
PMCID: PMC3987011  PMID: 24619122
uric acid; metabolic syndrome; premenopausal women and postmenopausal women

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