Folate supplementation and cardiovascular disease.
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Antioxidants↗
Biomedical subjects
Walter Willett
Publications and source records attributed to Walter Willett.
Comparison of bioelectrical impedance and BMI in predicting obesity-related medical conditions.
OBJECTIVE: To determine the relative validity of specific bioelectrical impedance analysis (BIA) prediction equations and BMI as predictors of physiologically relevant general adiposity. RESEARCH METHODS AND PROCEDURES: Subjects were >12,000 men and women from the Third National Health and Nutrition Examination Survey population. We examined the correlations between BMI and percentage body fat based on 51 different predictive equations, blood pressure, and blood levels of glucose, high-density lipoprotein cholesterol, and triglycerides, which are known to reflect adiposity, while controlling for other determinants of these physiological measures. RESULTS: BMI consistently had one of the highest correlations across biological markers, and no BIA-based measure was superior. Percent body fat estimated from BIA was minimally predictive of the physiological markers independent of BMI. DISCUSSION: These results suggest that BIA is not superior to BMI as a predictor of overall adiposity in a general population.
Adult↗
Folate, vitamin B(6), and vitamin B(12) intake and the risk of breast cancer among Mexican women.
BACKGROUND: High intake of folate, vitamin B(6), and vitamin B(12) have been hypothesized to lower the risk for breast cancer. We conducted a population-based case-control study to evaluate the risk for breast cancer among Mexican women with relatively low vitamin intakes. METHODS: We included 475 women (median age, 53 years; range, 23-87 years) diagnosed with incident breast cancer through six hospitals in Mexico City and interviewed them to obtain data on breast cancer risk factors and their usual diet using a food frequency questionnaire. We selected 1,391 (median age, 49 years; range, 18-82 years) controls from the Mexico City population using a national sampling frame. RESULTS: Compared with women in the lowest quartile, the odds ratio for breast cancer for women in the highest quartile of folate intake was 0.64 [95% confidence intervals (CI), 0.45-0.90; P, test for trend = 0.009] and 0.32 (95% CI, 0.22-0.49; P, test for trend < 0.0001) for vitamin B(12) intake. Among postmenopausal women, intakes of folate and vitamin B(12) were associated with a lower risk of breast cancer and those associations were stronger than among premenopausal women. The inverse association of folate and breast cancer was stronger among women who consumed a high level of vitamin B(12) as compared with women consuming diets low in vitamin B(12). No association was observed for vitamin B(6) intake. CONCLUSIONS: In this population, high intakes of folate and vitamin B(12) were independently associated with decreased breast cancer risk, particularly among postmenopausal women.
Adult↗
Changes in dietary fat and declining coronary heart disease in Poland: population based study.
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Adult↗
Glycemic load, glycemic index, and the risk of breast cancer among Mexican women.
OBJECTIVE: The amount and composition of dietary carbohydrates is a major determinant of postprandial blood glucose and insulin, and risk of breast cancer has been positively associated with plasma levels of insulin and insulin-like growth factor 1. We sought to evaluate dietary glycemic load (GL) and overall glycemic index (GI) in relation to breast cancer risk in Mexican women. METHODS: We examined dietary GL and overall GI and breast cancer risk among 475 women with histologically-confirmed breast cancer and a random sample of 1391 women from Mexico City households. Diet was assessed using a food frequency questionnaire adapted to the Mexican population. RESULTS: The multivariate adjusted or for all women comparing the highest quartile of dietary GL with the lowest quartile was 1.62 (95% CI 1.13-2.32; p-test for trend = 0.02) with a significant trend. In postmenopausal women, the multivariate adjusted or comparing the extreme quartiles was 2.18 (95% CI 1.34-3.55; p-test for trend=0.005). Overall GI was not significantly associated with risk of breast cancer. CONCLUSION: High intake of rapidly absorbed carbohydrate appears to play an important role in the risk of breast cancer in Mexican women.
Adult↗
Toward optimal health: Walter Willett, M.D., DR.P.H. discusses dietary guidelines.
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Diet↗
Alcohol intake and risk of incident gout in men: a prospective study.
BACKGROUND: The association between alcohol consumption and risk of gout has been suspected since ancient times, but has not been prospectively confirmed. Additionally, potential differences in risk of gout posed by different alcoholic beverages have not been assessed. METHODS: Over 12 years (1986-98) we used biennial questionnaires to investigate the relation between alcohol consumption and risk of incident gout in 47?150 male participants with no history of gout at baseline. We used a supplementary questionnaire to ascertain whether reported cases of gout met the American College of Rheumatology survey gout criteria. FINDINGS: We documented 730 confirmed incident cases of gout. Compared with men who did not drink alcohol, the multivariate relative risk (RR) of gout was 1.32 (95% CI 0.99-1.75) for alcohol consumption 10.0-14.9 g/day, 1.49 (1.14-1.94) for 15.0-29.9 g/day, 1.96 (1.48-2.60) for 30.0-49.9 g/day, and 2.53 (1.73-3.70) for > or =50 g/day (p for trend <0.0001). Beer consumption showed the strongest independent association with the risk of gout (multivariate RR per 12-oz serving per day 1.49; 95% CI 1.32-1.70). Consumption of spirits was also significantly associated with gout (multivariate RR per drink or shot per day 1.15; 95% CI 1.04-1.28); however, wine consumption was not (multivariate RR per 4-oz serving per day 1.04; 95% CI 0.88-1.22). INTERPRETATION: Alcohol intake is strongly associated with an increased risk of gout. This risk varies substantially according to type of alcoholic beverage: beer confers a larger risk than spirits, whereas moderate wine drinking does not increase the risk.
Adult↗
Purine-rich foods, dairy and protein intake, and the risk of gout in men.
BACKGROUND: Various purine-rich foods and high protein intake have long been thought to be risk factors for gout. Similarly, the possibility that the consumption of dairy products has a role in protecting against gout has been raised by metabolic studies. We prospectively investigated the association of these dietary factors with new cases of gout. METHODS: Over a 12-year period, we prospectively examined the relationship between purported dietary risk factors and new cases of gout among 47,150 men who had no history of gout at base line. We used a supplementary questionnaire to ascertain whether participants met the American College of Rheumatology survey criteria for gout. Diet was assessed every four years by means of a food-frequency questionnaire. RESULTS: During the 12 years of the study, we documented 730 confirmed new cases of gout. The multivariate relative risk of gout among men in the highest quintile of meat intake, as compared with those in the lowest quintile, was 1.41 (95 percent confidence interval, 1.07 to 1.86; P for trend = 0.02), and the corresponding relative risk associated with seafood intake was 1.51 (95 percent confidence interval, 1.17 to 1.95; P for trend = 0.02). In contrast, the incidence of gout decreased with increasing intake of dairy products; the multivariate relative risk among men in the highest quintile, as compared with those in the lowest quintile, was 0.56 (95 percent confidence interval, 0.42 to 0.74; P for trend <0.001). The level of consumption of purine-rich vegetables and the total protein intake were not associated with an increased risk of gout. CONCLUSIONS: Higher levels of meat and seafood consumption are associated with an increased risk of gout, whereas a higher level of consumption of dairy products is associated with a decreased risk. Moderate intake of purine-rich vegetables or protein is not associated with an increased risk of gout.
Adult↗
Changes in whole-grain, bran, and cereal fiber consumption in relation to 8-y weight gain among men.
BACKGROUND: Epidemiologic studies that directly examine changes in whole-grain consumption in relation to weight gain are sparse, and characterization of this association has been obscured by methodologic inconsistencies in the assessment of whole grains. OBJECTIVE: We aimed to ascertain the associations between changes in new quantitative estimates of whole-grain intake and 8-y weight gain among US men. DESIGN: The study was conducted in a prospective cohort of 27 082 men aged 40-75 y at baseline in 1986. Data on lifestyle factors were obtained periodically by using self-reported questionnaires, and participants measured and reported their body weight in 1986 and 1994. RESULTS: In multivariate analyses, an increase in whole-grain intake was inversely associated with long-term weight gain (P for trend < 0.0001). A dose-response relation was observed, and for every 40-g/d increment in whole-grain intake from all foods, weight gain was reduced by 0.49 kg. Bran that was added to the diet or obtained from fortified-grain foods further reduced the risk of weight gain (P for trend = 0.01), and, for every 20 g/d increase in intake, weight gain was reduced by 0.36 kg. Changes in cereal and fruit fiber were inversely related to weight gain. No associations were observed between changes in refined-grain or added germ consumption and body weight. CONCLUSIONS: The increased consumption of whole grains was inversely related to weight gain, and the associations persisted after changes in added bran or fiber intakes were accounted for. This suggests that additional components in whole grains may contribute to favorable metabolic alterations that may reduce long-term weight gain.
Adult↗
Future directions in clinical vitamin E research: panel discussion B.
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Animals↗
Carbohydrates and the risk of breast cancer among Mexican women.
OBJECTIVE: High carbohydrate intake has been hypothesized to be a risk factor for breast cancer, possibly mediated by elevated levels of free insulin, estrogens, and insulin-like growth factor-1. Therefore, we conducted a population-based case-control study among a Mexican population characterized by relatively low fat and high carbohydrate intakes. METHODS: Women ages 20 to 75 years, identified through six hospitals in Mexico City (n = 475), were interviewed to obtain data relating to diet (using a food frequency questionnaire) and breast cancer risk factors. Controls (n = 1,391) were selected from the Mexico City population using a national sampling frame. RESULTS: Carbohydrate intake was positively associated with breast cancer risk. Compared with women in the lowest quartile of total carbohydrate intake, the relative risk of breast cancer for women in the highest quartile was 2.22 [95% confidence interval (95% CI) 1.63-3.04], adjusting for total energy and potential confounding variables (P for trend < 0.0001). This association was present in premenopausal and postmenopausal women (for highest versus lowest quartile, odds ratio 2.31, 95% CI 1.36-3.91 in premenopausal women and odds ratio 2.22, 95% CI 1.49-3.30 in postmenopausal women). Among carbohydrate components, the strongest associations were observed for sucrose and fructose. No association was observed with total fat intake. DISCUSSION: In this population, a high percentage of calories from carbohydrate, but not from fat, was associated with increased breast cancer risk. This relation deserves to be investigated further, particularly in populations highly susceptible to insulin resistance.
Adult↗
Risk factors for advanced colonic neoplasia and hyperplastic polyps in asymptomatic individuals.
CONTEXT: Knowledge of risk factors for colorectal neoplasia could inform risk reduction strategies for asymptomatic individuals. Few studies have evaluated risk factors for advanced colorectal neoplasia in asymptomatic individuals, compared risk factors between persons with and without polyps, or included most purported risk factors in a multivariate analysis. OBJECTIVE: To determine risk factors associated with advanced colorectal neoplasia in a cohort of asymptomatic persons with complete colonoscopy. DESIGN, SETTING, AND PARTICIPANTS: Prospective, cross-sectional study of 3121 asymptomatic patients aged 50 to 75 years from 13 Veterans Affairs medical centers conducted between February 1994 and January 1997. All participants had complete colonoscopy to determine the prevalence of advanced neoplasia, defined as an adenoma that was 10 mm or more in diameter, a villous adenoma, an adenoma with high-grade dysplasia, or invasive cancer. Variables examined included history of first-degree relative with colorectal cancer, prior cholecystectomy, serum cholesterol level, physical activity, smoking, alcohol use, and dietary factors. MAIN OUTCOME MEASURES: An age-adjusted analysis was performed for each variable to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) associated with having advanced neoplasia compared with having no polyps. We developed a multivariate logistic regression model to identify the most informative risk factors. A secondary analysis examined risk factors for having hyperplastic polyps compared with having no polyps and compared with having advanced neoplasia. RESULTS: Three hundred twenty-nine participants had advanced neoplasia and 1441 had no polyps. In multivariate analyses, we found positive associations for history of a first-degree relative with colorectal cancer (OR, 1.66; 95% CI, 1.16-2.35), current smoking (OR, 1.85; 95% CI, 1.33-2.58), and current moderate to heavy alcohol use (OR, 1.02; 95% CI, 1.01-1.03). Inverse associations were found for cereal fiber intake (OR, 0.95; 95% CI, 0.91-0.99), vitamin D intake (OR, 0.94; 95% CI, 0.90-0.99), and use of nonsteroidal anti-inflammatory drugs (NSAIDs) (OR, 0.66; 95% CI, 0.48-0.91). In the univariate analysis, the inverse association was found with cereal fiber intake greater than 4.2 g/d, vitamin D intake greater than 645 IU/d, and daily use of NSAIDs. Marginal factors included physical activity, daily multivitamin use, and intake of calcium and fat derived from red meat. No association was found for body mass index, prior cholecystectomy, or serum cholesterol level. Three hundred ninety-one patients had hyperplastic polyps as the worst lesion found at colonoscopy. Risk variables were similar to those for patients with no polyps, except that past and current smoking were associated with an increased risk of hyperplastic polyps. CONCLUSIONS: Our data endorse several important risk factors for advanced colonic neoplasia and provide a rationale for prudent risk reduction strategies. Further study is needed to determine if lifestyle changes can moderate the risk of colorectal cancer.
Aged↗
Antioxidant intake and primary open-angle glaucoma: a prospective study.
The relation between dietary antioxidant intake and primary open-angle glaucoma risk was examined in participants aged over 40 years in the Nurses' Health Study (n = 76,200) and the Health Professionals Follow-up Study (n = 40,284). They were followed biennially from 1980 and 1986, respectively, to 1996, during periods when they received an eye examination. Dietary intakes were measured repeatedly from 1980 in the Nurses' Health Study and from 1986 in the Health Professionals Follow-up Study using validated food frequency questionnaires. The authors analyzed 474 self-reported glaucoma cases confirmed by medical chart review to have primary open-angle glaucoma with visual field loss. The authors used Cox proportional hazards models for cohort-specific multivariate analyses, and results were pooled using random effects models. The pooled multivariate rate ratios for primary open-angle glaucoma comparing the highest versus lowest quintile of cumulative updated intake were 1.17 (95% confidence interval (CI): 0.87, 1.58) for alpha-carotene, 1.10 (95% CI: 0.82, 1.48) for beta-carotene, 0.95 (95% CI: 0.70, 1.29) for beta-cryptoxanthin, 0.82 (95% CI: 0.60, 1.12) for lycopene, 0.92 (95% CI: 0.69, 1.24) for lutein/zeaxanthin, 1.05 (95% CI: 0.59, 1.89) for vitamin C, 0.97 (95% CI: 0.62, 1.52) for vitamin E, and 1.11 (95% CI: 0.82, 1.51) for vitamin A. In conclusion, the authors did not observe any strong associations between antioxidant consumption and the risk of primary open-angle glaucoma.
Adult↗
Plasma carotenoids and tocopherols and risk of myocardial infarction in a low-risk population of US male physicians.
BACKGROUND: Increased intake of carotenoids and vitamin E may protect against myocardial infarction (MI). However, prospective data on blood levels of carotenoids other than beta-carotene and vitamin E (tocopherol) and risk of MI are sparse. METHODS AND RESULTS: We conducted a prospective, nested case-control analysis among male physicians without prior history of cardiovascular disease who were followed for up to 13 years in the Physicians' Health Study. Samples from 531 physicians diagnosed with MI were analyzed together with samples from paired control subjects, matched for age and smoking, for 5 major carotenoids (alpha- and beta-carotene, beta-cryptoxanthin, lutein, and lycopene), retinol, and alpha- and gamma-tocopherol. Overall, we found no evidence for a protective effect against MI for higher baseline plasma levels of retinol or any of the carotenoids measured. Among current and former smokers but not among never-smokers, higher baseline plasma levels of beta-carotene tended to be associated with lower risk (P for interaction=0.02). Men with higher plasma levels of gamma-tocopherol tended to have an increased risk of MI (P for trend=0.01). CONCLUSIONS: These prospective data do not support an overall protective relation between plasma carotenoids or tocopherols and future MI risk among men without a history of prior cardiovascular disease.
Adult↗
Oral health and peripheral arterial disease.
BACKGROUND: Many studies have reported the association between poor oral health and coronary heart disease or stroke, but few of them evaluated peripheral arterial disease (PAD). Hence, in this study we examined the associations between oral health and PAD. METHODS AND RESULTS: In the prospective study of 45,136 eligible male health professionals free of cardiovascular diseases at baseline, we identified 342 cases of PAD during a 12-year follow-up period. We evaluated the association between different measures of oral diseases and the occurrence of PAD. Baseline number of teeth was not related to the risk of PAD, but cumulative incident tooth loss was significantly associated with elevated risk of subsequent occurrence of PAD. The relative risk for history of periodontal disease was 1.41 (95% CI, 1.12 to 1.77) and for any tooth loss during the follow-up period was 1.39 (95% CI, 1.07 to 1.82), controlling for traditional risk factors of cardiovascular disease. Among men with a history of periodontal diseases, the relative risk of tooth loss increased to 1.88 (95% CI, 1.27 to 2.77), whereas no association was found between tooth loss and PAD among those without periodontal diseases (RR, 0.92; 95% CI, 0.61 to 1.38). We further explored the potential induction period of tooth loss and found that tooth loss in the previous 2 to 6 years was most strongly associated with PAD. CONCLUSIONS: We found that incident tooth loss was significantly associated with PAD, especially among men with periodontal diseases. The results support a potential oral infection-inflammation pathway.
Adult↗
Lessons from dietary studies in Adventists and questions for the future.
Comparisons of diets and disease rates between Adventists and non-Adventists, and prospective cohort studies among Adventists, have contributed greatly to our general understanding of nutrition and health. The most fundamental conclusion drawn from the Adventist Health Studies has been that maintaining a lean body weight throughout life is central for optimal health. Other contributions have included the value of nut consumption for prevention of coronary artery disease, and the roles of red meat and dairy products in the etiologies of cardiovascular disease and cancer. Although much progress has been made, many issues remain unresolved. In particular, rates of breast and prostate cancers remain high among Adventist populations despite an overall healthy lifestyle and long life expectancy. There is even some suggestion that risk of breast cancer may increase with duration of being a vegetarian. One topic that may be uniquely studied among an Adventist population is the effect of soy phytoestrogens in disease prevention. Although soy consumption has been hypothesized to contribute to the low rates of breast cancer in Asian populations, several intervention studies using high doses of soy estrogens have shown changes in breast nipple fluid that would predict higher rates of breast cancer. Also, high dairy product consumption has been associated with risk of prostate and ovarian cancers in some but not all studies. The unusually wide range of milk consumption in Adventists will be particularly informative with regard to these relations. Resolution of these issues is needed to provide optimal guidance regarding healthy diets, and the newly funded Adventist Health Study will contribute importantly in this effort.
Diet↗
Prospective study of the association of changes in dietary intake, physical activity, alcohol consumption, and smoking with 9-y gain in waist circumference among 16 587 US men.
BACKGROUND: Although it is known that abdominal obesity increases the risk of chronic diseases, prospective data examining the relation between lifestyle factors and the accumulation of abdominal adipose tissue are sparse. OBJECTIVE: The objective of the study was to determine the associations of changes in diet, physical activity, alcohol consumption, and smoking with 9-y waist gain among US men. DESIGN: A prospective cohort comprised 16 587 US men aged 40-75 y at baseline in 1986. Data on lifestyle factors were provided periodically with the use of self-reported questionnaires, and participants measured and reported their waist circumference in 1987 and 1996. RESULTS: In multivariate analyses, a 2% increment in energy intake from trans fats that were isocalorically substituted for either polyunsaturated fats or carbohydrates was significantly associated with a 0.77-cm waist gain over 9 y (P < 0.001 for each comparison). An increase of 12 g total fiber/d was associated with a 0.63-cm decrease in waist circumference (P < 0.001), whereas smoking cessation and a 20-h/wk increase in television watching were associated with a 1.98-cm and 0.59-cm waist gain, respectively (P < 0.001). Increases of 25 metabolic equivalent tasks (METs) * h/wk in vigorous physical activity and of >/= 0.5 h/wk in weight training were associated with 0.38-cm and 0.91-cm decreases in waist circumference, respectively (P < 0.001 for each comparison). These associations remained significant after further adjustment for concurrent change in body mass index. Changes in total fat and alcohol consumption and in walking volume were not significantly related to waist gain. CONCLUSIONS: Waist gain may be modulated by changes in trans fat and fiber consumption, smoking cessation, and physical activity.
Abdomen↗
The association between fruit and vegetable consumption and peripheral arterial disease.
BACKGROUND: High fruit and vegetable consumption has been associated with a lower risk of cardiovascular diseases, but few studies have focused on peripheral arterial disease. In this study, we evaluated the association of consumption of fruits and vegetables with peripheral arterial disease. METHODS: In a cohort of 44,059 men initially free of cardiovascular disease and diabetes, we documented 295 cases of peripheral arterial disease during a 12-year follow-up. Fruit and vegetable consumption was assessed by food frequency questionnaire. RESULTS: In the age-adjusted model, men in the highest quintile had a relative risk of 0.55 (95% confidence interval = 0.38-0.80) for overall fruit and vegetable intake, 0.52 (0.36-0.77) for fruit intake, and 0.54 (0.36-0.81) for vegetable intake, compared with those in the lowest quintile of intake. However, the associations were greatly weakened after adjustment for smoking and other traditional cardiovascular disease risk factors. Comparing men in the highest quintile versus the lowest quintile, relative risks and 95% confidence intervals were 0.95 (0.62-1.44) for overall fruit and vegetable intake, 0.97 (0.64-1.48) for fruit intake, and 0.76 (0.50-1.17) for vegetable intake. CONCLUSIONS: We did not find evidence that fruit and vegetable consumption protects against peripheral arterial disease, although a modest benefit cannot be excluded.
Arteriosclerosis↗