Folate and cardiovascular disease. Why we need a trial now.
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Cardiovascular Diseases↗
Biomedical subjects
M J Stampfer
Publications and source records attributed to M J Stampfer.
Three-year follow-up of participants in a commercial weight loss program. Can you keep it off?
BACKGROUND: One third of Americans are obese, according to the 1988-1991 National Health and Nutrition Endpoint Survey III survey. Obesity increases the risk of death and a variety of chronic diseases. Numerous commercial weight loss programs demonstrate short-term success. OBJECTIVE: To assess maintenance of weight loss achieved during dieting. METHODS: We surveyed 192 participants in the Sandoz Nutrition (Sandoz Pharmaceuticals, Minneapolis, Minn) diet program approximately 3 years after participation. Initial date were supplied by the diet clinics and follow-up data, including weight at various points after the program, participation in other weight loss programs, and lifestyle variables, such as exercise, smoking, and television watching, were collected by a mailed questionnaire. RESULTS: On average, the group lost 22 kg during the diet program. After the follow-up period, the mean weight (mean, 102.6 kg) was only modestly less than the group's original weight at the start of the diet (mean, 105.9 kg). Twelve percent of the subjects maintained 75% of their weight loss after leaving the diet program, 57% maintained at least 5% of the loss, and 40% gained back more than they had lost during the diet. The frequency of exercise after the diet program was the strongest predictor of weight loss maintenance, while television viewing predicted a gain in weight. CONCLUSION: Given the apparent lack of substantial, long-term success at weight reduction, perhaps greater emphasis should be placed on prevention of obesity.
Commerce↗
Jewish religion and risk of breast cancer.
BACKGROUND: The excess risk of breast cancer among Jewish women has been attributed to the effects of difference in lifestyle and reproductive patterns, but there is now evidence that Jewish women may be more likely than other women to inherit mutations in breast-cancer genes. We investigated whether any excessive risk among Jewish women is confined to those with a family history of breast cancer. METHODS: We assessed the effect of Jewish religion on breast cancer in a large population-based case-control study (6611 women with breast cancer and 9026 controls) in USA. Participants were given telephone interviews and asked about known and suspected risk factors for breast cancer. FINDINGS: Overall, Jewish women had only a slightly raised relative risk of breast cancer (1.10 [95% CI 0.84-1.44]; p=0.49). However, the relative risk was much higher for Jewish women with a first-degree relative who had breast cancer (3.78 [1.74-8.16]; p<0.001). The effect of family history was greater in Jewish women than in women of other religions (p interaction = 0.05). INTERPRETATION: These results are consistent with data suggesting that certain groups of Jewish women have a higher than expected rate of mutation in the breast-cancer gene BRCA1.
Aged↗
Homocysteine metabolism and risk of myocardial infarction: relation with vitamins B6, B12, and folate.
Elevated plasma homocyst(e)ine levels are an independent risk factor for vascular disease. In a case-control study, the authors studied the associations of fasting plasma homocyst(e)ine and vitamins, which are important cofactors in homocysteine metabolism, with the risk of myocardial infarction. The cases were 130 Boston area patients hospitalized with a first myocardial infarction and 118 population controls, less than 76 years of age, enrolled in 1982 and 1983. Dietary intakes of vitamins B6, B12, and folate were estimated from a food frequency questionnaire. After adjusting for sex and age, the authors found that the geometric mean plasma homocyst(e)ine level was 11% higher in cases compared with controls (p = 0.006). There was no clear excess of cases with extremely elevated levels. The age- and sex-adjusted odds ratio for each 3-mumol/liter (approximately 1 standard deviation) increase in plasma homocyst(e)ine was 1.35 (95% confidence interval 1.05-1.75; p trend = 0/007). After further control for several risk factors, the odds ratio was not affected, but the confidence interval was wider and the p value for trend was less significant. Dietary and plasma levels of vitamin B6 and folate were lower in cases than in controls, and these vitamins were inversely associated with the risk of myocardial infarction, independently of other potential risk factors. Vitamin B12 showed no clear association with myocardial infarction, although methylmalonic acid levels were significantly higher in cases. Comparing the mean levels of several homocysteine metabolites among cases and controls, the authors found that impairment of remethylation of homocyst(e)ine (dependent of folate and vitamin B12 rather than on vitamin B6-dependent transsulfuration) was the predominant cause of high homocyst(e)ine levels in cases. Accordingly, plasma folate and, to a lesser extent, plasma vitamin B12, but not vitamin B6, correlated inversely with plasma homocyst(e)ine, even for concentrations at the high end of normal values. These data provide further evidence that plasma homocyst(e)ine is an independent risk factor for myocardial infarction. In this population, folate was the most important determinant of plasma homocyst(e)ine, even in subjects with apparently adequate nutritional status of this vitamin.
Case-Control Studies↗
Calcium, vitamin D, and dairy foods and the occurrence of colon cancer in men.
To examine the associations between intakes of calcium, Vitamin D, and dairy foods and the risk of colon cancer, the authors analyzed data from a prospective study of 47,935 US male professionals, 40-75 years of age and free of cancer in 1986. Within this cohort, 203 new cases of colon cancer were documented between 1986 and 1992. After adjusting for age and total energy intake, the authors found that the intake of calcium from foods and supplements was inversely associated with colon cancer risk (relative risk (RR) = 0.58, 95% confidence interval (CI) 0.39-087 between high and low intakes of calcium). However, after adjusting for confounding variables, they found that the trend was no longer statistically significant (p = 0.22), and the relative risk for the highest quintile group of intake was attenuated: 0.75 (95% CI 0.48-1.15). Similar results were observed for total vitamin D intake; the age- and energy-adjusted relative risk was 0.54% (95% CI 0/34-0/85) for the highest versus lowest quintile group, and this was attenuated in the multivariate model (RR = 0.66, 95% CI 0.42-1.05). The inverse association was weaker for dietary vitamin D (RR highest vs. lowest quintile = 0.88. 95% CI 0.54-1.42) and strongest for vitamin D arising from vitamin supplements (RR = 0.48, 95% CI 0.22-1.02). Thus, it is possible that other components of multivitamin use rather than vitamin D accounted for the reduction in risk. Consumption of milk and fermented dairy products was not significantly associated with the risk of colon cancer; individuals consuming two or more glasses of "whole" or skim milk per day had a relative risk of 1.09 (95% CI 0.69-1.72), compared with those who consumed "whole or skim milk less than once a month. These prospective data do not support the hypothesis that calcium intake is strongly protective against colon cancer risk, although a modest association cannot be excluded.
Adult↗
Review of moderate alcohol consumption and reduced risk of coronary heart disease: is the effect due to beer, wine, or spirits.
OBJECTIVES: To review the effect of specific types of alcoholic drink on coronary risk. DESIGN: Systematic review of ecological, case-control, and cohort studies in which specific associations were available for consumption of beer, wine, and spirits and risk of coronary heart disease. SUBJECTS: 12 ecological, three case-control, and 10 separate prospective cohort studies. MAIN OUTCOME MEASURES: Alcohol consumption and relative risk of morbidity and mortality from coronary heart disease. RESULTS: Most ecological studies suggested that wine was more effective in reducing risk of mortality from heart disease than beer or spirits. Taken together, the three case-control studies did not suggest that one type of drink was more cardioprotective than the others. Of the 10 prospective cohort studies, four found a significant inverse association between risk of heart disease and moderate wine drinking, four found an association for beer, and four for spirits. CONCLUSIONS: Results from observational studies, where alcohol consumption can be linked directly to an individual's risk of coronary heart disease, provide strong evidence that all alcoholic drinks are linked with lower risk. Thus, a substantial portion of the benefit is from alcohol rather than other components of each type of drink.
Adult↗
A prospective study of coffee drinking and suicide in women.
BACKGROUND: Among the many reported central nervous system effects of long-term caffeine use is improvement in mood. OBJECTIVE: To examine prospectively the relationship of coffee and caffeine intake to risk of death from suicide. METHODS: We conducted a 10-year follow-up study (1980 to 1990) in an ongoing cohort of 86 626 US female registered nurses aged 34 to 59 years in 1980, who were free of diagnosed coronary heart disease, stroke, or cancer. Information on coffee and caffeine intake was collected by a semiquantitative food frequency questionnaire in 1980. Deaths from suicide were determined by physician review of death certificates. RESULTS: Fifty-six cases of suicide occurred during 832 704 person-years of observation. Compared with non-drinkers of coffee, the age-adjusted relative risk of suicide in women who consumed two to three cups per day was 0.34 (95% confidence interval [CI, 0.17 to 0.68) and 0.42 (95% CI, 0.21 to 0.86) in women who consumed four or more cups per day (P for linear trend=.002). These findings remained essentially unchanged after adjusting for a broad range of potential confounding factors, including smoking habit, alcohol intake, medication use (diazepam and phenothiazine), history of comorbid disease (hypertension, hypercholesterolemia, or diabetes), marital status, and self-reported stress. A strong inverse relationship was similarly found for caffeine intake from all sources and risk of suicide. CONCLUSIONS: The data suggest a strong inverse association between coffee intake and risk of suicide. Whether regular intake of coffee or caffeine has clinically significant effects on the maintenance of affect or the prevention of depression merits further investigation in clinical trials and population-based prospective studies.
Adult↗
Protein consumption and bone fractures in women.
Dietary protein increases urinary calcium losses and has been associated with higher rates of hip fracture in cross-cultural studies. However, the relation between protein and risk of osteoporotic bone fractures among individuals has not been examined in detail. In this prospective study, usual dietary intake was measured in 1980 in a cohort of 85,900 women, aged 35-59 years, who were participants in the Nurses' Health Study. A mailed food frequency questionnaire was used and incident hip (n = 234) and distal forearm (n = 1,628) fractures were identified by self-report during the following 12 years. Information on other factors related to osteoporosis, including obesity, use of postmenopausal estrogen, smoking, and physical activity, was collected on biennial questionnaires. Dietary measures were updated in 1984 and 1986. Protein was associated with an increased risk of forearm fracture (relative risk (RR) = 1.22, 95% confidence interval (Cl) 1.04-1.43, p for trend = 0.01) for women who consumed more than 95 g per day compared with those who consumed less than 68 g per day. A similar increase in risk was observed for animal protein, but no association was found for consumption of vegetable protein. Women who consumed five or more servings of red meat per week also had a significantly increased risk of forearm fracture (RR = 1.23, 95% Cl 1.01-1.50) compared with women who ate red meat less than once per week. Recall of teenage diet did not reveal any increased risk of forearm fracture for women with higher consumption of animal protein or red meat during this earlier period of life. No association was observed between adult protein intake and the incidence of hip fractures, though power to assess this association was low.
Adult↗
Vegetable, fruit, and cereal fiber intake and risk of coronary heart disease among men.
OBJECTIVE: To examine prospectively the relationship between dietary fiber and risk of coronary heart disease. DESIGN: Cohort study. SETTING: In 1986, a total of 43,757 US male health professionals 40 to 75 years of age and free from diagnosed cardiovascular disease and diabetes completed a detailed 131-item dietary questionnaire used to measure usual intake of total dietary fiber and specific food sources of fiber. MAIN OUTCOME MEASURE: Fatal and nonfatal myocardial infarction (MI). RESULTS: During 6 years of follow-up, we documented 734 cases of MI (229 were fatal coronary heart disease). The age-adjusted relative risk (RR) for total MI was 0.59 (95% confidence interval [CI], 0.46 to 0.76) among men in the highest quintile of total dietary fiber intake (median, 28.9 g/d) compared with men in the lowest quartile (median, 12.4 g/d). The inverse association was strongest for fatal coronary disease (RR, 0.45; 95% CI, 0.28 to 0.72). After controlling for smoking, physical activity and other known nondietary cardiovascular risk factors, dietary saturated fat, vitamin E, total energy intake, and alcohol intake, the RRs were only modestly attenuated. A 10-g increase in total dietary fiber corresponded to an RR for total MI of 0.81 (95% CI, 0.70 to 0.93). Within the three main food contributors to total fiber intake (vegetable, fruit, and cereal), cereal fiber was most strongly associated with a reduced risk of total MI (RR, 0.71; 95% CI, 0.55 to 0.91 for each 10-g increase in cereal fiber per day). CONCLUSIONS: Our results suggest an inverse association between fiber intake and MI. These results support current national dietary guidelines to increase dietary fiber intake and suggest that fiber, independent of fat intake, is an important dietary component for the prevention of coronary disease.
Adult↗
Coffee consumption and coronary heart disease in women. A ten-year follow-up.
OBJECTIVE--To assess the relationship between coffee consumption and risk of coronary heart disease (CHD) among women. DESIGN--Prospective cohort study with coffee consumption measured in 1980, 1984, and 1986, and follow-up through 1990. SETTING--Female registered nurses in the United States. PARTICIPANTS--A total of 85,747 US women 34 to 59 years of age in 1980 and without history of CHD, stroke, or cancer. MAIN OUTCOME MEASURE--Ten-year incidence of CHD (defined as nonfatal myocardial infarction or fatal CHD). RESULTS--During 10 years of follow-up we documented 712 cases of CHD. After adjustment for age, smoking, and other CHD risk factors, we found no evidence for any positive association between coffee consumption and risk of subsequent CHD. For women drinking six or more cups of caffeine-containing coffee per day in 1980, the relative risk was 0.95 (95% confidence interval, 0.73 to 1.26) compared with women who did not consume this beverage. Similarly, there was no association when the first 4 years of follow-up were excluded, when nonfatal and fatal CHD end points were examined separately, or when we updated coffee consumption in 1984 or 1986 and examined only CHD during the next 2-year interval. Further, there was no association with caffeine intake from all sources combined or with decaffeinated coffee consumption. CONCLUSIONS--These data indicate that coffee as consumed by US women is not an important cause of CHD.
Adult↗
Prospective study of beverage use and the risk of kidney stones.
Patients with kidney stones are routinely advised to increase their fluid intake to decrease the risk of stone recurrence. However, there has been no detailed examination to determine whether the effect on recurrence varies by the type of beverage consumed. The authors conducted a prospective study of the relation between the intake of 21 different beverages and the risk of symptomatic kidney stones in a cohort of 45,289 men, 40-75 years of age, who had no history of kidney stones. Beverage use and other dietary information was measured by means of a semiquantitative food frequency questionnaire in 1986. During 6 years of follow-up (242,100 person-years), 753 incident cases of kidney stones were documented. After adjusting simultaneously for age, dietary intake of calcium, animal protein and potassium, thiazide use, geographic region, profession, and total fluid intake, consumption of specific beverages significantly added to the prediction of kidney stone risk (p < 0.001). After mutually adjusting for the intake of other beverages, the risk of stone formation decreased by the following amount for each 240-ml (8-oz) serving consumed daily: caffeinated coffee, 10% (95% confidence interval 4-15%); decaffeinated coffee, 10% (3-16%); tea, 14% (5-22%); beer, 21% (12-30%); and wine, 39% (10-58%). For each 240-ml serving consumed daily, the risk of stone formation increased by 35% (4-75%) for apple juice and 37% (1-85%) for grapefruit juice. The authors conclude that beverage type may have an effect on stone formation that involves more than additional fluid intake alone.
Adult↗
Physical activity, obesity, and risk of colorectal adenoma in women (United States).
The relationship between physical inactivity, body mass index (BMI) (wt[kg]/ht[m]2), and pattern of adipose distribution with risk of colorectal adenomas (precursors of cancer) was examined in 13,057 female nurses in the United States, 40 to 65 years of age in 1986, who had an endoscopy between 1986 and 1992. From 1986 to 1992, 439 participants were newly diagnosed with adenomas of the distal colorectum. After controlling for age, prior endoscopy, parental history of colorectal cancer, smoking, aspirin, and intakes of animal fat, dietary fiber, folate, methionine, and alcohol, physical activity was associated inversely with risk of large (> or = 1 cm) adenomas in the distal colon (relative risk [RR] = 0.57, 95 percent confidence interval [CI] = 0.30-1.08, comparing high and low quintiles of average weekly energy expenditure from leisure-time activities; P trend = 0.05). Much of the benefit came from activities of moderate intensity such as brisk walking. In addition, BMI was associated directly with risk of large adenomas in the distal colon (multivariate RR = 2.21 [CI = 1.18-4.16], P trend = 0.0001, for BMI > or = 29 cf < 21 kg/m2). Waist circumference and the waist-to-hip ratio (WHR) were not related significantly to adenoma independently of BMI, but women with both a high BMI and high WHR were at greater risk of large colon adenoma (multivariate RR = 1.99, CI = 0.98-4.05) than women with high BMI but relatively low WHR (multivariate RR = 1.35, CI = 0.61-2.97). BMI was not related to small (< 1 cm) adenoma risk but physical activity had an inverse association with small adenomas in the distal colon (multivariate RR = 0.68, CI = 0.40-1.15, P trend = 0.03). The relationships between BMI or physical activity were considerably weaker and inconsistent for rectal adenomas. These results, in women, support an inverse association between physical activity and occurrence or progression of adenomas in the distal colon; obesity is associated with an elevated risk of large adenomas.
Adenoma↗
A prospective study of folate and vitamin B6 and risk of myocardial infarction in US physicians.
OBJECTIVE: To assess prospectively the risk of myocardial infarction (MI) associated with decreased plasma levels of folate and pyridoxal phosphate (PLP, a form of vitamin B6) in relation to elevated levels of total homocysteine (tHcy). DESIGN: Nested case-control study using prospectively collected blood samples. SETTING: Participants in the Physicians' Health Study. SUBJECTS: 14,916 male physicians, aged 40-84 years, with no prior MI or stroke provided plasma samples at baseline and were followed for 7.5 years. Samples from 333 men who subsequently developed MI, and their paired controls matched by age and smoking, were analyzed for folate and PLP levels. MEASURES OF OUTCOME: Acute MI or death due to coronary disease. RESULTS: In a model controlling for diabetes, angina, hypertension, Quetelet's index, and total/high-density lipoprotein cholesterol, men with the lowest 20% of folate levels (< 2.0 ng/mL) had a relative risk of 1.4 (95% confidence interval 0.9-2.3) compared with those in the top 80%. For the lowest 20% of vitamin B6 values, the relative risk was 1.5 (95% CI: 1.0-2.2). When we included both folate and B6 in a model with cardiovascular risk factors, the relative risk of MI for low as compared to high levels of folate was 1.3 (95% CI: 0.8-2.1) and for PLP, 1.3 (95% CI: 0.9-2.1). Adding tHcy to this model did not add significant predictive value (chi sq = 2.0, p > 0.05), except in the first half of the follow-up interval when men with the top 5% of tHcy values had an almost three-fold increase in risk of MI. CONCLUSIONS: Although not statistically significant, these prospective data are compatible with the hypothesis that low dietary intake of folate and/or vitamin B6 contribute to risk of MI.
Adult↗
Self-reported birthweight and history of having been breastfed among younger women: an assessment of validity.
BACKGROUND: Recent evidence suggests potential associations between birthweight and infant feeding history and risk of a variety of health outcomes during adulthood. Because studies may rely on self-reported birthweight and infant feeding history, it is important to assess the validity of this information. METHODS: The authors compared birthweights reported by a sample of 538 women, 27-44 years of age, participating in the Nurses' Healthy Study II (NHSII) cohort, with birthweights recalled by their mothers and with those from state birth records. In addition, we compared participants' self-reported history of having breastfed with their breastfeeding history reported by their mothers. RESULTS: For birthweight, the correlation between reports by the cohort participants and by their mothers was high (Spearman r = 0.75). Compared with weights recorded on state birth records, correlations were 0.74 for reports by cohort participants and 0.85 for reports by their mothers. When comparing NHSII participants' self-report of ever having been breastfed with their mothers' report, sensitivity was 82% and specificity was 86%. For duration of breastfeeding, the Spearman correlation between mother and daughter reports was 0.74. In analyses stratified by four ethnic groups (African-American, Asian, Caucasian, and Hispanic) we observed substantial differences in distribution of birthweight and breastfeeding patterns; however, the degree of validity in reporting them was similar. CONCLUSION: The validity of self-reported birthweight and breastfeeding history by these middle-aged women appears to be high.
Adult↗
Reproducibility and validity of a self-administered physical activity questionnaire for male health professionals.
We assessed the reproducibility and validity of a self-administered physical activity questionnaire used in a prospective study of 51,529 men. The questionnaire was administered by mail twice to 238 participants 2 years apart. During this interval, the participants completed a past-week recall and a 1-week activity diary at four times corresponding to different seasons throughout a year. Also, a step test was taken by a subset of the study participants. The intraclass correlation coefficients used to measure reproducibility were 0.39 for inactivity, 0.42 for nonvigorous activity, and 0.52 for vigorous activity. The correlations between diary-based and questionnaire-based activity scores, adjusted for variation in the diary measurements, were 0.41 for inactivity, 0.28 for nonvigorous activity, and 0.58 for vigorous activity. The distribution of activity scores was similar between the questionnaires and the average of past-week recalls, indicating the participants' ability to incorporate seasonal variation into their recall on a questionnaire. The correlation between vigorous activity and resting pulse was -0.45, whereas, for the pulse rate after stepping, the correlation was -0.41. These data indicate that this physical activity questionnaire is reproducible and provides a useful measure of average weekly activity, particularly vigorous activity, over a 1-year period.
Adult↗
A prospective study of social networks in relation to total mortality and cardiovascular disease in men in the USA.
STUDY OBJECTIVE: Previous studies have established a relationship between low levels of social networks and total mortality, but few have examined cause specific mortality or disease incidence. This study aimed to examine prospectively the relationships between social networks and total and cause specific mortality, as well as cardiovascular disease incidence. DESIGN: This was a four year follow up study in an ongoing cohort of men, for whom information on social networks was collected at baseline. The main outcome measures were total mortality, further categorised into deaths from cardiovascular disease (stroke and coronary heart disease), total cancer, accidents/suicides, and all other causes; as well as stroke and coronary heart disease incidence. PARTICIPANTS: Altogether 32,624 US male health professionals aged 42 to 77 years in 1988, who were free of coronary heart disease, stroke, and cancer at baseline. RESULTS: A total of 511 deaths occurred during 122,911 person years of follow up. Compared with men with the highest level of social networks, socially isolated men (not married, fewer than six friends or relatives, no membership in church or community groups) were at increased risk for cardiovascular disease mortality (age adjusted relative risk, 1.90; 95% CI 1.07, 3.37) and deaths from accidents and suicides (age adjusted relative risk 2.22; 95% CI 0.76, 6.47). No excess risks were found for other causes of death. Socially isolated men were also at increased risk of stroke incidence (relative risk, 2.21; 95% CI, 1.12, 4.35), but not incidence of non-fatal myocardial infarction. CONCLUSIONS: Social networks were associated with lower total mortality by reducing deaths from cardiovascular disease and accidents/suicides. Strong social networks were associated with reduced incidence of stroke, though not of coronary heart disease. However, social networks may assist in prolonging the survival of men with established coronary heart disease.
Accidents↗
Prospective study of nutritional factors, blood pressure, and hypertension among US women.
We examined prospectively the relation of nutritional factors with hypertension and blood pressure levels among 41,541 predominantly white US female nurses, aged 38 to 63 years, who completed a detailed semiquantitative food frequency questionnaire in 1984 and were without diagnosed hypertension, cancer, or cardiovascular disease. During 4 years of follow-up, from 1984 to 1988, 2,526 women reported a diagnosis of hypertension. Age, relative weight, and alcohol consumption were the strongest predictors for the development of hypertension. Dietary calcium, magnesium, potassium, and fiber were not significantly associated with risk of hypertension, after adjusting for age, body mass index, alcohol, and energy intake. Among women who did not report hypertension during the follow-up period, calcium, magnesium, potassium, and fiber were each significantly inversely associated with self-reported systolic and diastolic pressures, after adjusting for age, body mass index, alcohol consumption, and energy intake. When the four nutrients were added simultaneously to the regression model, only fiber and magnesium intakes retained significant inverse associations with systolic and diastolic pressures. In analyses of food groups, intakes of fruit and vegetables were inversely associated with systolic and diastolic pressures, and intakes of cereals and meat were directly associated with systolic pressure. These results support hypotheses that age, body weight, and alcohol consumption are strong determinants of risk of hypertension in middle-aged women. They are compatible with the possibilities that magnesium and fiber as well as a diet richer in fruits and vegetables may reduce blood pressure levels.
Adult↗
Post-menopausal hormone use and tooth loss: a prospective study.
Nearly 32 percent of U.S. women aged 65 to 69 years have no teeth. Because some tooth loss may reflect systemic osteoporosis, and because estrogen therapy seems to protect against osteoporosis, the authors examined the risk of tooth loss in relation to hormone use in a prospective study of 42,171 post-menopausal women. The risk of tooth loss was lower in women who currently used hormones. Although few studies have examined this issue, this research suggests that estrogen may reduce tooth loss.
Adult↗