Search

Background and purpose Elevated plasma uric acid has been inconsistently associated with an increased risk of total stroke; however, data are sparse amongst women. The association between plasma uric acid concentrations and ischaemic stroke amongst women was examined and the effect modification by key cardiovascular risk factors was evaluated. Methods A nested case−control design with matching by age, race/ethnicity, smoking status, menopausal status, postmenopausal hormone therapy use, date of blood draw and fasting status was utilized amongst female participants of the Nurses' Health Study who provided blood samples between 1989 and 1990. Plasma uric acid was measured on stored blood samples. The National Survey of Stroke criteria were utilized to confirm 460 incident cases of ischaemic stroke by medical records from 1990 to 2006. Multivariable conditional logistic regression models were estimated. Results In matched analysis, risk of ischaemic stroke increased by 15% for each 1 mg/dl increase in plasma uric acid [95% confidence interval ( CI) 3%-28%], but was no longer significant after adjustment for cardiovascular risk factors, particularly history of hypertension. The highest quartile of uric acid was significantly associated with greater risk of ischaemic stroke (relative risk 1.56; 95% CI 1.06-2.29, extreme quartiles) in matched analysis, but estimates were no longer significant after adjustment for cardiovascular risk factors (relative risk 1.43; 95% CI 0.93-2.18). Significant effect modification by key cardiovascular risk factors was not observed. Conclusions Plasma uric acid levels were not independently associated with increased risk of ischaemic stroke in this cohort of women. Whilst plasma uric acid was associated with stroke risk factors, it was not independently associated with stroke risk. [ABSTRACT FROM AUTHOR]

Diabetes is known to increase mortality rate, but the degree to which mild hyperglycaemia may be associated with the risk of death is uncertain. We examined the association between HbA1c measured in stored erythrocytes and mortality rate in women with and without diabetes. We conducted a cohort study of 27,210 women ≥ 45 years old with no history of cardiovascular disease or cancer who participated in the Women’s Health Study, a randomised trial of vitamin E and aspirin. Over a median of 10 years of follow-up, 706 women died. Proportional hazards models adjusted for age, smoking, hypertension, blood lipids, exercise, postmenopausal hormone use, multivitamin use and C-reactive protein were used to estimate the relative risk of mortality. Among women without a diagnosis of diabetes and HbA1c <5.60%, those in the top quintile (HbA1c 5.19–5.59%) had a relative risk of mortality of 1.28 (95% CI 0.98–1.69, p value for linear trend = 0.14) compared with those with HbA1c 2.27–4.79%. Women with HbA1c 5.60–5.99% and no diagnosis of diabetes had a 54% increased risk of mortality (95% CI 1–136%) compared with those with HbA1c 2.27–4.79%. HbA1c was significantly associated with mortality across the range 4.50–7.00% ( p value for linear trend = 0.02); a test of deviation from linearity was not statistically significant ( p = 0.67). Diabetic women had more than twice the mortality risk of non-diabetic women. This study provides further evidence that chronic mild hyperglycaemia, even in the absence of diagnosed diabetes, is associated with increased risk of mortality. ClinicalTrials.gov ID no.: NCT00000479 [ABSTRACT FROM AUTHOR]

BACKGROUND: Waist circumference is a simpler measure of abdominal adiposity than waist/hip ratio (WHR), but few studies have directly compared the two measures as predictors of coronary heart disease (CHD) in men. In addition, whether the association of abdominal adiposity is independent of total adiposity as measured by body mass index (BMI) in men remains uncertain. OBJECTIVE: To compare waist circumference and WHR as predictors of CHD in men, and to determine whether the association is independent of BMI. DESIGN: Prospective cohort study. METHODS: We compared WHR, waist circumference and BMI with risk of CHD (myocardial infarction or coronary revascularization) among men in the Physicians' Health Study, a randomized trial of aspirin and beta-carotene among 22 071 apparently healthy US male physicians, aged 40-84 y at baseline in 1982. Men reported height at baseline, and weight, waist and hip measurements on the 9 y follow-up questionnaire. RESULTS: Among the 16 164 men who reported anthropometric measurements and were free from prior CHD, stroke or cancer, a total of 552 subsequent CHD events occurred during an average follow-up of 3.9 y. After adjusting for age, randomized study agent, smoking, physical activity, parental history of myocardial infarction, alcohol intake, multivitamin and aspirin use, men in the highest WHR quintile (≥0.99) had a relative risk (RR) for CHD of 1.50 (95% CI 1.14-1.98) compared with those in the lowest quintile (< 0.90). Men in the highest waist circumference quintile (≥103.6 cm) had a RR of 1.60 (CI, 1.21-2.11 ) for CHD compared with men in the lowest quintile (<88.4 cm). Further adjustment for BMI substantially attenuated these associations: men in the highest WHR and waist circumference quintiles had relative risks for CHD of 1.23 (CI, 0.92-1.66) and 1.06 (CI, 0.741.53), respectively. Men in the highest BMI quintile (≥27.6 kg/m²) had a multivariate RR of CHD of 1.73 (CI, 1.29-2.32), after adjustment for WHR.... [ABSTRACT FROM AUTHOR]

Context: Physically active women have lower coronary heart disease (CHD) rates than inactive women. However, whether the association differs by intensity of activity or in women at high risk for CHD is unclear.Objective: To examine the relation between physical activity, specifically investigating walking (a light-to-moderate activity depending on pace), and CHD among women, including those at high risk for CHD.Design, Setting, and Participants: Cohort study of 39 372 healthy female health professionals aged 45 years or older, enrolled throughout the United States between September 1992 and May 1995, with follow-up to March 1999. Recreational activities, including walking and stair climbing, were reported at study entry.Main Outcome Measure: Correlation of CHD with energy expended on all activities, vigorous activities, and walking.Results: A total of 244 cases of CHD occurred. Adjusting for potential confounders, the relative risks (RRs) of CHD for less than 200, 200-599, 600-1499, and 1500 or more kcal/wk expended on all activities were 1.00 (referent), 0.79 (95% confidence interval [CI], 0.56-1.12), 0.55 (95% CI, 0.37-0.82), and 0.75 (95% CI, 0.50-1.12), respectively (P for linear trend =.03). Vigorous activities were associated with lower risk (RR, 0.63; 95% CI, 0.38-1.04 comparing highest and lowest categories). Walking also predicted lower risk among women without vigorous activities. Among these women, the multivariate RRs for walking 1 to 59 min/wk, 1.0 to 1.5 h/wk, and 2 or more h/wk, compared with no regular walking, were 0.86 (95% CI, 0.57-1.29), 0.49 (95% CI, 0.28-0.86), and 0.48 (95% CI, 0.29-0.78), respectively. For walking paces of less than 3.2 km/h (2.0 mph), 3.2 to 4.7 km/h (2.0-2.9 mph), and 4.8 km/h (3.0 mph) or more, compared with no regular walking, RRs were 0.56 (95% CI, 0.32-0.97), 0.71 (95% CI, 0.47-1.05), and 0.52 (95% CI, 0.30-0.90), respectively. When analyzed simultaneously, time spent walking (P for linear trend =.01) but not walking pace (P for linear trend =.55) predicted lower risk. The inverse association between physical activity and CHD risk did not differ by weight or cholesterol levels (P for interaction =.95 and.71, respectively), but there were significant interactions by smoking and hypertension status. Physical activity was inversely related to risk in current smokers but not hypertensive women (P for interaction =.01 and.001, respectively).Conclusions: These data indicate that even light-to-moderate activity is associated with lower CHD rates in women. At least 1 hour of walking per week predicted lower risk. The inverse association with physical activity was also present in women at high risk for CHD, including those who were overweight, had increased cholesterol levels, or were smokers. [ABSTRACT FROM AUTHOR]

Objective: It is biologically plausible for physical activity to decrease breast cancer risk; however, epidemiologic studies have yielded inconsistent findings. We therefore examined physical activity and breast cancer risk in the Women's Health Study.Methods: We assessed physical activity among 39,322 apparently healthy women, aged > or = 45 years, and prospectively followed them for an average of 48 months. Four hundred eleven women developed breast cancer, with 222 positive for both estrogen and progesterone receptors.Results: Among all women the multivariate relative risks of all breast cancer associated with < 840, 840-2519, 2520-6299, and > or = 6300 kJ/week expended on recreational activities and stair climbing were 1.00 (referent), 1.04 (95% confidence interval, 0.77-1.40), 0.86 (0.64-1.17), and 0.80 (0.58-1.12), respectively; p-trend = 0.11. However, among postmenopausal women there was a significant inverse trend for all breast cancer; the corresponding relative risks were 1.0 (referent), 0.97 (0.68-1.4), 0.78 (0.54-1.1), and 0.67 (0.44-1.0), respectively; p-trend = 0.03. Physical activity was unrelated to breast cancers positive for both estrogen and progesterone receptors either among all or postmenopausal women (p-trend = 0.50 and 0.26, respectively). When we assessed only vigorous recreational activity, requiring > or = 6 METs or multiples of resting metabolic rate, we observed no significant associations with all or steroid hormone receptor positive breast cancer, either among all or postmenospausal women.Conclusions: These data suggest that physical activity during middle age and older is not uniformly associated with decreased breast cancer risk. Among postmenopausal women only, higher levels of physical activity may decrease the risk of breast cancer. This study, however, had limited statistical power to detect small effects. [ABSTRACT FROM AUTHOR]

Context: Although increased intake of grain products has been recommended to prevent cardiovascular disease (CVD), prospective data examining the relation of whole grain intake to risk of ischemic stroke are sparse, especially among women.Objective: To examine the hypothesis that higher whole grain intake reduces the risk of ischemic stroke in women.Design, Setting, and Participants: A prospective cohort of 75,521 US women aged 38 to 63 years without previous diagnosis of diabetes mellitus, coronary heart disease, stroke, or other CVDs in 1984, who completed detailed food frequency questionnaires (FFQs) in 1984, 1986, 1990, and 1994, and were followed up for 12 years as part of the Nurses' Health Study.Main Outcome Measure: Incidence of ischemic stroke, confirmed by medical records, by quintile of whole grain intake according to FFQ responses.Results: During 861,900 person-years of follow-up, 352 confirmed incident cases of ischemic stroke occurred. We observed an inverse association between whole grain intake and ischemic stroke risk. The age-adjusted relative risks (RRs) from the lowest to highest quintiles of whole grain intake were 1.00 (referent), 0.68 (95% confidence interval [CI], 0.49-0.94), 0.69 (95% CI, 0.51-0.95), 0.49 (95% CI, 0.35-0.69), and 0.57 (95% CI, 0.42-0.78; P =.003 for trend). Adjustment for smoking modestly attenuated this association (RR comparing extreme quintiles, 0.64; 95% CI, 0.47-0.89). This inverse association remained essentially unchanged with further adjustment for known CVD risk factors, including saturated fat and transfatty acid intake (multivariate-adjusted RR comparing extreme quintiles, 0.69; 95% CI, 0.50-0.98). The inverse relation between whole grain intake and risk of ischemic stroke was also consistently observed among subgroups of women who never smoked, did not drink alcohol, did not exercise regularly, or who did not use postmenopausal hormones. No significant association was observed between total grain intake and risk of ischemic stroke.Conclusions: In this cohort, higher intake of whole grain foods was associated with a lower risk of ischemic stroke among women, independent of known CVD risk factors. These prospective data support the notion that higher intake of whole grains may reduce the risk of ischemic stroke. [ABSTRACT FROM AUTHOR]

Context: Persuasive evidence has demonstrated that increased physical activity is associated with substantial reduction in risk of coronary heart disease. However, the role of physical activity in the prevention of stroke is less well established.Objective: To examine the association between physical activity and risk of total stroke and stroke subtypes in women.Design and Setting: The Nurses' Health Study, a prospective cohort study of subjects residing in 11 US states.Subjects: A total of 72,488 female nurses aged 40 to 65 years who did not have diagnosed cardiovascular disease or cancer at baseline in 1986 and who completed detailed physical activity questionnaires in 1986, 1988, and 1992.Main Outcome Measure: Incident stroke occurring between baseline and June 1, 1994, compared among quintiles of physical activity level as measured by metabolic equivalent tasks (METs) in hours per week.Results: During 8 years (560,087 person-years) of follow-up, we documented 407 incident cases of stroke (258 ischemic strokes, 67 subarachnoid hemorrhages, 42 intracerebral hemorrhages, and 40 strokes of unknown type). In multivariate analyses controlling for age, body mass index, history of hypertension, and other covariates, increasing physical activity was strongly inversely associated with risk of total stroke. Relative risks (RRs) in the lowest to highest MET quintiles were 1. 00, 0.98, 0.82, 0.74, and 0.66 (P for trend=.005). The inverse gradient was seen primarily for ischemic stroke (RRs across increasing MET quintiles, 1.00, 0.87, 0.83, 0.76, and 0.52; P for trend=.003). Physical activity was not significantly associated with subarachnoid hemorrhage or intracerebral hemorrhage. After multivariate adjustment, walking was associated with reduced risk of total stroke (RRs across increasing walking MET quintiles, 1.00, 0. 76, 0.78, 0.70, and 0.66; P for trend=.01) and ischemic stroke (RRs across increasing walking MET quintiles, 1.00, 0.77, 0.75, 0.69, and 0.60; P for trend=.02). Brisk or striding walking pace was associated with lower risk of total and ischemic stroke compared with average or casual pace.Conclusion: These data indicate that physical activity, including moderate-intensity exercise such as walking, is associated with substantial reduction in risk of total and ischemic stroke in a dose-response manner. JAMA. 2000. [ABSTRACT FROM AUTHOR]

Background: Low-carbohydrate diets have been advocated for weight loss and to prevent obesity, but the long-term safety of these diets has not been determined.Methods: We evaluated data on 82,802 women in the Nurses' Health Study who had completed a validated food-frequency questionnaire. Data from the questionnaire were used to calculate a low-carbohydrate-diet score, which was based on the percentage of energy as carbohydrate, fat, and protein (a higher score reflects a higher intake of fat and protein and a lower intake of carbohydrate). The association between the low-carbohydrate-diet score and the risk of coronary heart disease was examined.Results: During 20 years of follow-up, we documented 1994 new cases of coronary heart disease. After multivariate adjustment, the relative risk of coronary heart disease comparing highest and lowest deciles of the low-carbohydrate-diet score was 0.94 (95% confidence interval [CI], 0.76 to 1.18; P for trend=0.19). The relative risk comparing highest and lowest deciles of a low-carbohydrate-diet score on the basis of the percentage of energy from carbohydrate, animal protein, and animal fat was 0.94 (95% CI, 0.74 to 1.19; P for trend=0.52), whereas the relative risk on the basis of the percentage of energy from intake of carbohydrates, vegetable protein, and vegetable fat was 0.70 (95% CI, 0.56 to 0.88; P for trend=0.002). A higher glycemic load was strongly associated with an increased risk of coronary heart disease (relative risk comparing highest and lowest deciles, 1.90; 95% CI, 1.15 to 3.15; P for trend=0.003).Conclusions: Our findings suggest that diets lower in carbohydrate and higher in protein and fat are not associated with increased risk of coronary heart disease in women. When vegetable sources of fat and protein are chosen, these diets may moderately reduce the risk of coronary heart disease. [ABSTRACT FROM AUTHOR]