Past use of oral contraceptives and cardiovascular disease: a meta-analysis in the context of the Nurses' Health Study

We examined the effects of past use of oral contraceptives on risks of cardiovascular diseases prospectively in the Nurses' Health Study cohort. The 119,061 participants were 30 to 55 years old and free of coronary disease or stroke in 1976. They provided information on biennial questionnaires and were followed for 8 years. There were 380 nonfatal myocardial infarctions and 105 deaths from coronary disease, 282 strokes, and 48 other cardiovascular deaths. We observed virtually no differences in the rates of various cardiovascular diseases between never and past users of oral contraceptives, regardless of duration of use or time since last use. For major coronary disease, the relative risk was 0.8 (95% confidence intervals, 0.6 to 1.0). A quantitative meta-analysis of 13 studies yielded an estimated relative risk of 1.01 (95% confidence intervals, 0.91 to 1.13) for coronary heart disease. Past use of oral contraceptives has little or no impact on risks of subsequent cardiovascular diseases.

Menopause and heart disease. A review

A large number of studies of disparate design are reasonably consistent in demonstrating that women with early bilateral oophorectomy are at increased risk of coronary heart disease. The evidence for an increase in risk among women with a surgical menopause but without bilateral oophorectomy is inconclusive, but such an effect, if any, could plausibly be explained by decreased ovarian function in many of those women as a consequence of the surgery. These findings, taken together with the lack of excess risk in women with bilateral oophorectomy who take replacement estrogen, support the view that the increased risk is due to estrogen deficiency. This view is further supported by the improvement in the lipid profile induced by estrogen replacement therapy in postmenopausal women. Because ovarian function begins to decline well before menopause, and continues to decline after menopause, it is not surprising that the moment of menopause is not associated with an abrupt increase in risk of heart disease. Moreover, some time is required for the adverse changes in coronary risk factors that occur during the climacteric to be reflected in increased rates of coronary disease. Although natural menopause does not cause an immediate increase in risk of heart disease, it does signal a period of increasing risk that is probably related both to age and to estrogen deficiency.

Patterns of weight change and their relation to diet in a cohort of healthy women

Patterns of weight change for 31,940 non-smoking women aged 30-55 y in 1976 were examined for 8 y of follow-up. Each woman reported her weight every 2 y on questionnaires, and diet was assessed in 1980 with a semiquantitative food frequency questionnaire. Self-reported weight was highly correlated over time, decreasing from r = 0.95 over 2 y to r = 0.89 over 8 y. Weight gain was inversely related to age (r = -0.06). Weight change in a given 2-y interval was inversely related to change in weight over the subsequent 2 y (r = -0.30). Age, relative weight, and prior weight change were stronger predictors of recent weight change than were intake patterns of specific nutrients. Recent prior weight change was the strongest predictor of subsequent weight change. In a population of free-living women, prior weight loss and younger age are far stronger predictors of subsequent weight gain than are the qualitative aspects of diet.

Effectiveness of various mailing strategies among nonrespondents in a prospective cohort study

Measures of association in prospective studies can be distorted by incomplete follow-up. Various mailing strategies were used to contact 12,233 cohort members of the Health Professionals Follow-up Study who had not responded to three successive bulk-rate mailings. Response rates were highest, 79.5% overall, from participants who were sent a certified mailing in phase 1 (63.2%), followed by a repeat certified mailing to nonrespondents (44.3%). Although altering the physical appearance of the envelope and using other postal rates were tested, certified mail was the most effective approach for reaching study members who were nonrespondents to a mailed questionnaire.

Food predictors of plasma beta-carotene and alpha-tocopherol: validation of a food frequency questionnaire

Nutrient intakes from a food frequency questionnaire are usually calculated as the product of frequency of intake and nutrient composition of the food, summed over the food items. This involves assumptions about the accuracy of recording, food composition data, stability during storage and preparation, and bioavailability. This usual method of calculation was compared with one using empirical weights derived by multivariate linear regression. Food intakes reported on a food frequency questionnaire by Boston, Massachusetts, area subjects in 1982-1985 were used to predict plasma levels of beta-carotene among 370 male and female nonsmokers and plasma levels of alpha-tocopherol among 339 male and female nonusers of vitamin supplements. Nutrient intake computed using empirical weights yielded a significant correlation with plasma beta-carotene (r = 0.43, p = 0.0001), similar to the correlation using nutrient intake calculated from food composition tables (r = 0.38, p = 0.0001). However, the use of empirical weights significantly improved the correlation of vitamin E intake with plasma alpha-tocopherol levels (r = 0.32, p = 0.0001), compared with the weak correlation obtained using the food composition table method to calculate intake (r = 0.16). The results support the validity of published food composition data used to compute carotenoid intake and illustrate the potential utility of empirically derived weights for foods to predict plasma levels of some nutrients.

Diet, plasma levels of beta-carotene and alpha-tocopherol, and risk of malignant melanoma

Dietary intake and the plasma levels of retinol, alpha-tocopherol, lycopene, alpha-carotene, and beta-carotene for 204 cases with malignant melanoma were compared with those of 248 controls. Cases and controls were patients 18 years of age or older making their first visit to a dermatology subspecialty clinic for pigmented lesions from July 1, 1982 to September 1, 1985. Intakes of nutrients were estimated using a semiquantitative food frequency questionnaire. No significant associations with malignant melanoma were observed for higher plasma levels of lycopene, retinol, or alpha-carotene in logistic regression analyses after controlling for age, sex, plasma lipids, and known constitutional risk factors (hair color and ability to tan). In similar models, the odds ratio comparing the highest with the lowest quintile was 0.9 (95% confidence interval (CI) 0.5-1.5) for plasma beta-carotene, 0.7 (95% CI 0.5-1.3) for plasma alpha-tocopherol, 0.7 (95% CI 0.4-1.2) for carotene intake, and 0.7 (95% CI 0.4-1.3) for total vitamin E intake. A trend toward reduced risk of melanoma was observed for increasing intake of iron (not including supplements); this was related to the more frequent consumption of baked goods, such as cake, among controls. Alcohol consumption was positively associated with risk of melanoma (chi for trend = 2.1, p = 0.03); the odds ratio for consumption of over 10 g/day compared with persons with no alcohol intake was 1.8 (95% CI 1.0-3.3).

A prospective study of obesity and risk of coronary heart disease in women

We examined the incidence of nonfatal and fatal coronary heart disease in relation to obesity in a prospective cohort study of 115,886 U.S. women who were 30 to 55 years of age in 1976 and free of diagnosed coronary disease, stroke, and cancer. During eight years of follow-up (775,430 person-years), we identified 605 first coronary events, including 306 nonfatal myocardial infarctions, 83 deaths due to coronary heart disease, and 216 cases of confirmed angina pectoris. A higher Quetelet index (weight in kilograms divided by the square of the height in meters) was positively associated with the occurrence of each category of coronary heart disease. For increasing levels of current Quetelet index (less than 21, 21 to less than 23, 23 to less than 25, 25 to less than 29, and greater than or equal to 29), the relative risks of nonfatal myocardial infarction and fatal coronary heart disease combined, as adjusted for age and cigarette smoking, were 1.0, 1.3, 1.3, 1.8, and 3.3 (Mantel-extension chi for trend = 7.29; P less than 0.00001). As expected, control for a history of hypertension, diabetes mellitus, and hypercholesterolemia--conditions known to be biologic effects of obesity--attenuated the strength of the association. The current Quetelet index was a more important determinant of coronary risk than that at the age of 18; an intervening weight gain increased risk substantially. These prospective data emphasize the importance of obesity as a determinant of coronary heart disease in women. After control for cigarette smoking, which is essential to assess the true effects of obesity, even mild-to-moderate overweight increased the risk of coronary disease in middle-aged women.

Relation of moderate alcohol consumption and risk of systemic hypertension in women

The relation between alcohol consumption and the risk of development of hypertension was studied among 58,218 US female registered nurses aged 39 to 59 years who were free of diagnosed systemic hypertension and other major diseases. In 1980, all of these women completed an independently validated dietary questionnaire, which included use of alcoholic beverages. During 4 years of follow-up, 3,275 women reported an initial diagnosis of hypertension; validity of the self-report measure was demonstrated in a subsample. When compared to nondrinkers, women drinking 20 to 34 g of alcohol per day (about 2 or 3 drinks) had a significantly elevated relative risk of 1.4; the 95% confidence interval (CI) was 1.2 to 1.7 after adjustment for age and Quetelet's index. For women consuming greater than 35 g/day, the relative risk was 1.9 (95% CI 1.6 to 2.2). Adjustment for smoking and dietary variables did not alter these results. Independent significant associations were observed for the consumption of beer, wine and liquor. These prospective data suggest that alcohol intake of up to about 20 g/day does not increase the risk of hypertension among women, but beyond this level, the risk increases progressively.

Effect of transport conditions on the stability of biochemical markers in blood

We examined the stability of lipids, carotenoids, alpha-tocopherol, and endogenous hormones in plasma prepared from whole blood that had been mailed to a central location for processing. Initially, to simulate transport conditions, whole-blood samples were stored in the laboratory, either at room temperature or cooled, for up to 72 h before processing. In the latter samples, lipid concentrations changed up to 1.4% per day, carotenoids up to -5.5%, and hormones up to 9.5%. In a second study, analyte concentrations in plasma from cooled whole blood mailed via overnight courier were compared with those from plasma that had been immediately separated, frozen, and mailed via overnight courier. Concentrations of cholesterol, high-density lipoprotein subfraction 3, apolipoprotein B, and retinol were stable. Overall, for each marker except estradiol, the between-person variation was at least twice the within-person variation. In a third study, at least 340 micrograms of DNA was recovered from 30 mL of cool-shipped whole blood. Our results indicate that shipping whole-blood samples by overnight courier is feasible for assay of several biochemical markers of interest in epidemiological research.

Effect of transport conditions on the stability of biochemical markers in blood

We examined the stability of lipids, carotenoids, alpha-tocopherol, and endogenous hormones in plasma prepared from whole blood that had been mailed to a central location for processing. Initially, to simulate transport conditions, whole-blood samples were stored in the laboratory, either at room temperature or cooled, for up to 72 h before processing. In the latter samples, lipid concentrations changed up to 1.4% per day, carotenoids up to -5.5%, and hormones up to 9.5%. In a second study, analyte concentrations in plasma from cooled whole blood mailed via overnight courier were compared with those from plasma that had been immediately separated, frozen, and mailed via overnight courier. Concentrations of cholesterol, high-density lipoprotein subfraction 3, apolipoprotein B, and retinol were stable. Overall, for each marker except estradiol, the between-person variation was at least twice the within-person variation. In a third study, at least 340 micrograms of DNA was recovered from 30 mL of cool-shipped whole blood. Our results indicate that shipping whole-blood samples by overnight courier is feasible for assay of several biochemical markers of interest in epidemiological research.

Food-based validation of a dietary questionnaire: the effects of week-to-week variation in food consumption

The reproducibility and validity of responses for 55 specific foods and beverages on a self-administered food frequency questionnaire were evaluated. One hundred and seventy three women from the Nurses' Health Study completed the questionnaire twice approximately 12 months apart and also recorded their food consumption for seven consecutive days, four times during the one-year interval. For the 55 foods, the mean of correlation coefficients between frequencies of intake for first versus second questionnaire was 0.57 (range = 0.24 for fruit punch to 0.93 for beer). The mean of correlation coefficients between the dietary records and first questionnaire was 0.44 (range = 0.09 for yellow squash to 0.83 for beer and tea) and between the dietary records and the second questionnaire was 0.52 (range = 0.08 for spinach to 0.90 for tea). Ratios of within- to between-person variance for the 55 foods were computed using the mean four one-week dietary records for each person as replicate measurements. For most foods this ratio was greater than 1.0 (geometric mean of ratios = 1.88), ranging from 0.25 (skimmed milk) to 14.76 (spinach). Correlation coefficients comparing questionnaire and dietary record for the 55 foods were corrected for the within-person variation (mean corrected value = 0.55 for dietary record versus first questionnaire and 0.66 versus the second). Mean daily amounts of each food calculated by the questionnaire and by the dietary record were also compared; the observed differences suggested that responses to the questionnaire tended to over-represent socially desirable foods. This analysis documents the validity and reproducibility of the questionnaire for measuring specific foods and beverages, as well as the large within-person variation for food intake measured by dietary records. Differences in the degree of validity for specific foods revealed in this type of analysis can be useful in improving questionnaire design and in interpreting findings from epidemiological studies that use the instrument.

Prospective study of relative weight, height, and risk of breast cancer

We examined relative weight and height in relation to subsequent breast cancer risk among 115,534 women 30 to 55 years of age and free from cancer in 1976. By 1984, six hundred fifty-eight premenopausal and 420 postmenopausal breast cancers were documented during 734,716 person-years. Among premenopausal women, risk of breast cancer decreased significantly with increasing relative weight (relative risk for the highest category was 0.6). A similar inverse association was seen for recalled relative weight at 18 years of age. Postmenopausal breast cancer was not associated with relative weight, either recent or at age 18. Height was not associated with breast cancer risk among premenopausal women and only weakly related among postmenopausal women. These data suggest that obesity among premenopausal and early postmenopausal women does not increase breast cancer risk substantially.

A prospective study of nutritional factors and hypertension among US women

The relation of various nutritional factors with hypertension was examined prospectively among 58,218 predominantly white US female registered nurses, aged 34-59 years. In 1980, all women completed an independently validated dietary questionnaire. During 4 years of follow-up, 3,275 women reported a diagnosis of hypertension; the validity of the self-report was shown in a subsample. Age, relative weight, and alcohol consumption were the strongest predictors for the development of hypertension. Dietary calcium and magnesium had independent and significant inverse associations with hypertension. For women with a calcium intake of at least 800 mg/day, the relative risk of hypertension was 0.78 (95% confidence interval, 0.69-0.88) when compared with an intake of less than 400 mg/day. The relative risk for magnesium intake of 300 mg/day or more compared with an intake of less than 200 mg/day was 0.77 (95% confidence interval, 0.67-0.88). For women with high intakes of both calcium and magnesium compared with those having low intakes of both, the relative risk of hypertension was 0.65 (95% confidence interval, 0.53-0.80). No independent associations with hypertension were observed for intakes of potassium, fiber, and saturated and polyunsaturated fatty acids. These prospective findings add to the growing evidence to support the need for randomized trials to determine whether there is a protective role of dietary calcium and magnesium in the regulation of blood pressure.

Prospective study of smoking and the risk of breast cancer

In 1976, 117,557 women in the United States aged 30-55 years and without a history of cancer provided detailed information on current smoking habits. By 1986, 1,788 cases of breast cancer had been documented during 1,133,682 person-years. There was no association between current smoking and risk of breast cancer (multivariate-adjusted relative risk for smokers of greater than or equal to 25 cigarettes/day compared to nonsmokers: 1.02, 95% confidence interval, 0.96-1.22). Past smoking also was unrelated to breast cancer risk (relative risk, 1.08; 95% confidence interval, 0.96-1.20). The results did not differ by menopausal status. Tumor size and the presence of nodal metastases were unrelated to smoking. Smoking was weakly associated with estrogen receptor-positive tumors (relative risk for smokers of greater than or equal to 25 cigarettes/day compared with never smokers, 1.38; 95% confidence interval, 1.04-1.84), but there was no dose-response relationship across categories of current smoking. These results suggest that smoking and breast cancer are not materially related.

A prospective study of high blood pressure and cardiovascular disease in women

The relation of self-reported high blood pressure to the subsequent development of coronary heart disease and stroke was examined in a cohort of 119,963 women, aged 30-55 years, who were initially free from cardiovascular disease. Participants in the Nurses' Health Study reported high blood pressure and other cardiovascular risk factors on baseline questionnaires mailed in 1976. During six years of follow-up, there were 308 incident cases of coronary heart disease (66 fatal and 242 nonfatal myocardial infarctions) and 175 strokes (50 fatal and 125 nonfatal). Fatal as well as nonfatal coronary heart disease and stroke were all significantly more frequent among the women who had reported high blood pressure. After adjusting simultaneously for age and other risk factors, the relative risks were 3.5 (95% confidence interval (Cl) 2.8-4.5) for total coronary heart disease and 2.6 (95% Cl 1.8-3.5) for total stroke. This association was evident at all levels of relative weight. The results emphasize the importance of high blood pressure as an independent predictor of coronary heart disease and stroke in middle-aged women and suggest that the increased risk occurs in both lean and obese women.

Prospective study of oral contraceptive use and risk of breast cancer in women

In 1976, 118,273 female nurses 30-55 years of age with no history of cancer completed a questionnaire regarding possible risk factors. By 1986, after 1,137,415 person-years of follow-up, we had documented 1,799 newly diagnosed cases of breast cancer. Compared with the risk of breast cancer for nonusers of oral contraceptives, the multivariate relative risks were 1.07 (95% confidence interval, 0.97-1.19) for all users, 1.06 (95% confidence interval, 0.96-1.18) for past users, and 1.53 (95% confidence interval, 1.06-2.19) for current users--women who used oral contraceptives up to 2 years before diagnosis of breast cancer. We conclude that overall past use of oral contraceptives is not associated with a substantial increase in the risk of breast cancer. Although we did not find women who used oral contraceptives before the first pregnancy to have an increased risk of breast cancer, the number of women who used oral contraceptives for a long duration in early reproductive life was too small to permit firm conclusions regarding the risk in this subgroup.

Weight, diet, and the risk of symptomatic gallstones in middle-aged women

To assess the risk factors for symptomatic gallstones, 88,837 women in the Nurses' Health Study cohort (age range, 34 to 59 years) were followed for four years after completing a detailed questionnaire about food and alcohol intake in 1980. A total of 433 cholecystectomies and 179 cases of newly symptomatic, unremoved gallstones, diagnosed by ultrasonographic examination or x-ray films, were reported during the four-year follow-up. The age-adjusted relative risk for very obese women, who had a Quetelet index of relative weight (weight in kilograms divided by the square of the height in meters) of more than 32 kg per square meter, was 6.0 (95 percent confidence interval, 4.0 to 9.0), as compared with women whose relative weight was less than 20 kg per square meter. For slightly overweight women (relative weight, 24 to 24.9 kg per square meter), the relative risk was 1.7 (95 percent confidence interval, 1.1 to 2.7). Overall, we observed a roughly linear relation between relative weight and the risk of gallstones. Among the 59,306 women whose relative weight was less than 25 kg per square meter, a high energy intake (greater than 8200 J per day), as compared with a low energy intake (less than 4730 J per day), was associated with an increased incidence of symptomatic gallstones (relative risk, 2.1; 95 percent confidence interval, 1.4 to 3.3), and an alcohol intake of at least 5 g per day was associated with a decreased incidence as compared with abstention (relative risk, 0.6; 95 percent confidence interval, 0.4 to 0.8). Parity did not appear to be an important risk factor after an adjustment was made for relative weight. These data support a strong association between obesity and symptomatic gallstones and suggest that even moderate overweight may increase the risk.

Nonfamilial cutaneous melanoma incidence in women associated with sun exposure before 20 years of age

Despite strong evidence that sun exposure causes malignant melanoma, the details of this relation remain unclear. A nested case-control analysis was conducted within the Nurses' Health Study cohort to examine the relation between timing of severe sun exposure and incidence of melanoma. The subjects were 130 white women aged 38 to 65 years with confirmed cutaneous melanoma (other than acral lentigenous) who reported no history of melanoma in first-degree relatives. The control subjects were 300 women matched by race, date of birth, and cycle of questionnaire who also reported no history of melanoma in first-degree relatives. We used conditional logistic regression to evaluate the relation of sun damage after 30 years of age and sun damage from 15 to 20 years of age to the incidence of melanoma. Blistering sunburns between 15 to 20 years of age were associated with risk of melanoma (relative risk = 2.2 for five or more burns vs none, 95% confidence interval 1.2 to 3.8). This association persisted when a history of burns after 30 years of age was controlled in the analysis. No material association was found between blistering sunburns after 30 years of age and melanoma. Similarly, a more equatorial latitude of residence between 15 and 20 years of age was positively associated with melanoma; latitude after 30 years of age was less strongly and not significantly related to melanoma risk. Sun exposure prior to 20 years of age is more closely associated with melanoma risk than sun exposure after 30 years of age.

Moles and site-specific risk of nonfamilial cutaneous malignant melanoma in women

We examined the relationship between self-reported mole counts and cutaneous melanoma with respect to anatomic site in 110 case and 231 control female nurses. Counts of moles on the lower leg were better predictors of melanoma risk than were counts of moles on the arm. The relative risk for the highest quintile of lower leg mole counts versus no lower leg moles was 4.2. Mole counts at each site (arm, thigh, and lower leg) were associated with risk of melanoma of the trunk and lower leg, but none were associated with the risk of melanoma of the upper extremity. The absence of direct site-specificity suggests that mole counts primarily indicate systemic melanoma risk, rather than direct risk from the moles themselves.

Fractures and lifestyle: effect of cigarette smoking, alcohol intake, and relative weight on the risk of hip and forearm fractures in middle-aged women

Cigarette smoking, alcohol consumption and low relative weight are often cited as risk factors for osteoporosis. In a prospective cohort study of 96,508 middle-aged nurses 35 to 59 years of age we found that smoking was not a risk factor for hip and forearm fracture. Women who drank more than 15 grams of alcohol per day and whose relative weight was less than 21 kg/m2 were at increased risk of fractures, but these risk factors were not independent. Only the combination of alcohol intake and thinness substantially increased the likelihood of fracture. The low weight women consuming more than one drink per day comprised but 4 per cent of our population of middle-class women and sustained 6 per cent of the fractures.

A prospective study of past use of oral contraceptive agents and risk of cardiovascular diseases

We evaluated the effects of past use of oral contraceptive agents on the risk of various cardiovascular diseases among women in the Nurses' Health Study cohort. We studied 119,061 women who were 30 to 55 years of age in 1976, who provided information on their use of oral contraceptives, and who at entry had had no previous coronary disease or stroke. End points were documented by medical records. During eight years of follow-up (484,096 person-years among those who had never used oral contraceptives, 415,488 among past users, and 22,376 among current users), there were 485 new cases of major coronary disease (380 nonfatal myocardial infarctions and 105 deaths from coronary disease), 282 strokes (205 nonfatal and 77 fatal), and 48 other deaths from cardiovascular causes. We found no evidence to suggest an increase in the risk of cardiovascular diseases among past users of oral contraceptives, even with prolonged previous use. After adjustment for a variety of risk factors, the relative risk of major coronary disease for women who had used oral contraceptives in the past, as compared with those who had never used such agents, was 0.8 (95 percent confidence interval, 0.6 to 1.0); of stroke, 1.0 (95 percent confidence interval, 0.7 to 1.3); and of death from all cardiovascular causes, 0.9 (95 percent confidence interval, 0.7 to 1.2). We found neither evidence of increased risk with longer use nor any trend with the amount of time since the last use. According to these prospective data, the use of oral contraceptive agents in the past does not materially raise a woman's risk of subsequent cardiovascular disease.

A prospective study of moderate alcohol drinking and risk of diabetes in women

Several investigators have observed an association between alcohol consumption and elevated glucose levels, raising the possibility that alcohol may increase the risk of diabetes. This hypothesis was evaluated prospectively among 85,051 women participating in the Nurses' Health Study who were 34 to 59 years of age in 1980 and had no history of cancer, coronary heart disease, or diabetes. At baseline, participants completed an independently validated dietary questionnaire which included information on the consumption of beer, wine, and liquor. Incident cases of non-insulin-dependent diabetes were reported on follow-up questionnaires sent in 1982 and 1984 (98% response to at least one follow-up); 526 cases were confirmed by a supplementary questionnaire regarding symptoms, laboratory values, and treatment. The risk of diabetes decreased monotonically with increasing alcohol consumption (chi trend = -9.4, p less than 0.0001). Compared with nondrinkers, women consuming 5-14.9 g of alcohol per day (about 4-10 drinks per week) had an age-adjusted relative risk of diabetes of 0.4 (95% confidence interval (CI) 0.3-0.6); for 15 g or more per day, the relative risk was 0.3 (95% CI 0.2-0.4). However, a strong inverse association between alcohol drinking and body weight explained much of the apparent protective effect of alcohol. After simultaneous adjustment for Quetelet index (weight (kg)/height (m)2), family history of diabetes, total caloric intake, and age, the relative risk of diabetes for consumers of 5-14.9 g per day was 0.8 (95% CI 0.6-1.2), and for women who drank 15+ g per day, the relative risk was 0.6 (95% CI 0.3-0.9). These data provide no support for the hypothesis that moderate alcohol intake increases the risk of non-insulin-dependent diabetes.

A prospective study of moderate alcohol consumption and the risk of coronary disease and stroke in women

In 1980, 87,526 female nurses 34 to 59 years of age completed a dietary questionnaire that assessed their consumption of beer, wine, and liquor. By 1984, during 334,382 person-years of follow-up, we had documented 200 incident cases of severe coronary heart disease (164 nonfatal myocardial infarctions and 36 deaths due to coronary disease), 66 ischemic strokes, and 28 subarachnoid hemorrhages. Follow-up was 98 percent complete. As compared with nondrinkers, women who consumed 5 to 14 g of alcohol per day (three to nine drinks per week) had a relative risk of coronary disease of 0.6 (95 percent confidence interval, 0.4 to 0.9); for 15 to 24 g per day the relative risk was 0.6 (0.3 to 1.1), and for 25 g or more per day it was 0.4 (0.2 to 0.8), after adjustment for risk factors for coronary disease. Alcohol intake was also associated with a decreased risk of ischemic stroke. For 5 to 14 g of alcohol per day the relative risk was 0.3 (0.1 to 0.7), and for 15 g per day or more it was 0.5 (0.2 to 1.1). In contrast, although the number of cases of subarachnoid hemorrhage was small, alcohol intake tended to be associated with an increased risk of this disorder; for 5 to 14 g per day the relative risk was 3.7 (1.0 to 13.8). These prospective data suggest that among middle-aged women, moderate alcohol consumption decreases the risks of coronary heart disease and ischemic stroke but may increase the risk of subarachnoid hemorrhage.

Variability in portion sizes of commonly consumed foods among a population of women in the United States

The use of food frequency questionnaires for measuring dietary intake has become widespread in epidemiologic studies. It has been suggested that inquiring about a person's usual serving size of each food, in addition to the frequency of consumption, will improve the accuracy of this method. This approach implies that individuals characteristically eat a specific amount of any particular food, and that this amount can be reported with reasonable accuracy. To investigate the variability of portion sizes, the authors analyzed data for 68 commonly consumed foods, based on four one-week weighed diet histories recorded by 194 Boston-area women aged 34-59 years during 1980 and 1981. For each food, total population variance in portion size was partitioned into within-person (intraindividual) and between-person (interindividual) components. For all but seven food items (yogurt, liver, mixed vegetables, watermelon, pancakes/waffles, cold cereal, and cooked cereal) the within-person variance in portion size exceeded the between-person variance. The mean of the within-person to between-person variance ratios, after exclusion of two outlying foods, was 3.4 for untransformed portion sizes, and 3.2 after portion sizes were loge-transformed. Foods with a high within-person variance also tended to have a high between-person variance. The dominance of within-person variance in portion sizes suggests that the concept of usual portion size is complex, and that subjects may experience substantial difficulty in specifying their "usual" portion size. The smaller contribution of between-person variance to the total variance in portion size suggests that specification of a standard portion size by the investigator may not introduce a large error in the estimation of food and nutrient intake.

Cigarette smoking and risk of stroke in middle-aged women

It is known that cigarette smoking is associated with increased risk of both thrombotic and hemorrhagic stroke among men. To test for such an association among women, we examined the incidence of stroke in relation to cigarette smoking in a prospective cohort study of 118,539 women 30 to 55 years of age and free from coronary heart disease, stroke, and cancer in 1976. During eight years of follow-up (908,447 person-years), we identified 274 strokes, comprising 71 subarachnoid hemorrhages, 26 intracerebral hemorrhages, 122 thromboembolic strokes, and 55 strokes about which information was insufficient to permit classification. The number of cigarettes smoked per day was associated positively with the risk of stroke. Compared with the women who had never smoked, those who smoked 1 to 14 cigarettes per day had an age-adjusted relative risk of 2.2 (95 percent confidence interval, 1.5 to 3.3), whereas those who smoked 25 or more cigarettes per day had a relative risk of 3.7 (95 percent confidence interval, 2.7 to 5.1). For women in this latter group, the relative risk of subarachnoid hemorrhage was 9.8 (95 percent confidence interval, 5.3 to 17.9), as compared with those who had never smoked. Adjustment for the effects of relative weight, hypertension, diabetes, history of high cholesterol, previous use of oral contraceptives, postmenopausal estrogen therapy, and alcohol intake did not appreciably alter the association between cigarette use and incidence of stroke. These prospective data support a strong causal relation between cigarette smoking and stroke among young and middle-aged women.

Self-reports of mole counts and cutaneous malignant melanoma in women: methodological issues and risk of disease

The relation of the presence of moles (nevi) on all four limbs to risk of cutaneous malignant melanoma was explored among 98 incident cases aged 32-59 years at diagnosis and 190 age-matched controls drawn from the Nurses' Health Study, a prospective cohort of female nurses in the United States. Cases diagnosed during follow-up from 1976 to 1982 were included in this study. Participants reported counts of all moles and raised moles alone on postal questionnaires. Distributions of moles were similar for right and left sides on upper and lower limbs for cases and controls. Counts declined with increasing age for all women, from a median of 15 for the youngest tertile of controls (aged 36-46 years) to three for the oldest (aged 54-62 years). Cases had more moles than did controls (medians of 23 and 9, respectively, for total moles on all four limbs): The presence of any mole on a limb gave relative risks for melanoma ranging from 2.2 (95% confidence interval (CI) = 1.2-4.0) for one or more moles on an arm to 2.9 (95% CI = 1.6-5.3) for one or more moles on the lower limb. For raised moles, relative risks were 1.7 (95% CI = 1.0-2.7) for arm, 2.1 (95% CI = 1.3-3.5) for lower limb, and 3.5 (95% CI = 2.0-6.3) for leg (below knee). The highest site-specific risk (i.e., for any moles on the same limb as the melanoma vs. no moles on that limb) was for moles on the lower limb (relative risk = 5.0 (95% CI = 1.8-13.5)). There were positive and significant trends in overall and site-specific risk with increasing numbers of moles on all limbs when absolute mole counts were considered, e.g., for total moles on all four limbs combined, chi for trend = 4.0, one-sided p less than 0.001, with relative risk for more than 100 moles versus none of 6.0. Inclusion of sun exposure and other constitutional factors in logistic regression analyses did not alter these observed relations between the presence of moles and risk of melanoma.

Vitamin E supplementation effect on human platelet function, arachidonic acid metabolism, and plasma prostacyclin levels

A randomized, placebo-controlled double-blind trial was conducted on 20 adults to assess the effect of vitamin E (800 IU/d 727 mg/d for 5 wk) on platelet function, arachidonic acid metabolism, and prostacyclin generation. Platelet aggregation was measured in response to collagen, arachidonic acid, and adenosine diphosphate. Thromboxane B2 was assayed in serum and in the supernatant plasma after platelet aggregation. Platelets were labeled with [3H]arachidonic acid to assess production and release of cyclooxygenase products (MDA, TXB2, and HHT), a lipoxygenase product (12-HETE), and arachidonic acid in response to stimulation by thrombin or collagen. Prostacyclin was measured in plasma and in blood collected from bleeding-time incisions by a sensitive HPLC-RIA procedure. Despite marked increases in plasma and erythrocyte vitamin E levels in the vitamin E group, there were no significant differences between the vitamin E and placebo groups in any of the variables measured.

Energy intake and other determinants of relative weight

The relationships of relative weight to energy intake and to physical activity were studied among 141 females aged 34-59 y. As observed in previous studies Quetelet index (wt/ht2) was inversely related to energy intake (r = -0.11). However, obese women tended to be older (r = 0.16), exercise less (r = -0.30), and drink less alcohol (r = -0.16) than nonobese women. Older women had lower energy intake (r = -0.23) and exercised less (r = -0.12) than younger women. Energy intake and physical activity were positively related (r = 0.23). After adjustment for age, physical activity, alcohol, and smoking, the inverse correlation between relative weight and energy intake was significantly reduced (p = 0.04) from r = -0.11 to r = -0.02. Obese women reported higher intakes of total fat, and relative weight was significantly correlated with intakes of total fat (r = 0.20) and saturated fatty acids (r = 0.16). These data highlight the importance of considering factors that may confound the relationship between energy intake and obesity, and they suggest that fat intake may play a role in obesity that is independent of total energy intake.

The relation of diet, cigarette smoking, and alcohol consumption to plasma beta-carotene and alpha-tocopherol levels

The relation of diet and nutritional supplements, cigarette use, alcohol consumption, and blood lipids to plasma levels of beta-carotene and alpha-tocopherol was studied among 330 men and women aged 18-79 years. Dietary carotene, preformed vitamin A, and vitamin E intake were estimated by a self-administered semiquantitative food frequency questionnaire. The correlation of dietary carotene with plasma beta-carotene was reduced in smokers compared with nonsmokers (r = 0.02 vs. 0.44 among men; r = 0.19 vs. 0.45 among women). Smokers had much lower plasma levels of beta-carotene than did nonsmokers (geometric mean 8.5 vs. 15.3 micrograms/dl for men; 17.3 vs. 26.3 micrograms/dl for women) despite only slightly lower intakes of carotenoids. In multiple regression analyses, men who smoked one pack per day had 72% (95% confidence interval (CI) 58-89) of the plasma beta-carotene levels of nonsmokers after accounting for dietary carotene and other variables; for women, the corresponding percentage was 79% (CI 64-99). In similar models, men drinking 20 g of alcohol per day had 76% (CI 65-88) of the beta-carotene levels of nondrinkers; women had 89% (CI 73-108) of the levels of nondrinkers. An interaction term for carotene intake and smoking was statistically significant in a model combining both sexes. These results suggest that plasma levels of beta-carotene among smokers and, perhaps, heavy consumers of alcohol may be reduced substantially below levels due to differences in diet. The correlation of calorie-adjusted intake of vitamin E with lipid-adjusted plasma levels of vitamin alpha-tocopherol was 0.53 for men (n = 137) and 0.51 for women (n = 193) and did not differ by alcohol consumption and cigarette use; these correlations were largely accounted for by use of vitamin supplements. In linear regression models, vitamin E intake and plasma lipids were significant predictors of plasma alpha-tocopherol levels.

The use of a self-administered questionnaire to assess diet four years in the past

The use of a mailed, self-administered, semiquantitative food frequency questionnaire to describe past dietary intake was evaluated in 1984 among a group of 150 Boston-area women who had completed four one-week diet records three to four years previously. Correlation coefficients comparing calorie-adjusted nutrient intakes computed from the questionnaire with those obtained from a compressed version of the questionnaire completed during diet record keeping ranged from 0.44 for total carbohydrate to 0.62 for vitamin C including supplements. Coefficients comparing calorie-adjusted nutrient intakes measured by questionnaire with those assessed by the diet records completed three to four years previously ranged from 0.28 for iron without supplements to 0.61 for total carbohydrate. An evaluation of the incremental contribution provided by several open-ended sections of the questionnaire to the estimation of nutrient intake suggested that in this population most of these items might be eliminated without material loss of information. These findings demonstrate that useful estimates of nutrient intake several years previously can be obtained by a relatively inexpensive, mailed, self-administered questionnaire.

Relative and absolute excess risks of coronary heart disease among women who smoke cigarettes

We prospectively examined the incidence of coronary heart disease in relation to cigarette smoking in a cohort of 119,404 female nurses who were 30 to 55 years of age in 1976 and were free of diagnosed coronary disease. During six years of follow-up, 65 of the women died of fatal coronary heart disease and 242 had a nonfatal myocardial infarction. The number of cigarettes smoked per day was positively associated with the risk of fatal coronary heart disease (relative risk = 5.5 for greater than or equal to 25 cigarettes per day), nonfatal myocardial infarction (relative risk = 5.8), and angina pectoris (relative risk = 2.6). Even smoking 1 to 4 or 5 to 14 cigarettes per day was associated with a twofold to three-fold increase in the risk of fatal coronary heart disease or nonfatal infarction. Overall, cigarette smoking accounted for approximately half these events. The attributable (absolute excess) risk of coronary heart disease due to current smoking was highest among women who were already at increased risk because of older age, a parental history of myocardial infarction, a higher relative weight, hypertension, hypercholesterolemia, or diabetes. In contrast, former smokers had little, if any, increase in risk. These prospective data emphasize the importance of cigarette smoking as a determinant of coronary heart disease in women, as well as the markedly increased hazards associated with this habit in combination with other risk factors for this disease.

A prospective study of age at menarche, parity, age at first birth, and coronary heart disease in women

Reproductive events in women are associated with alterations in blood lipids and blood pressure and may therefore influence determinants of coronary heart disease. To investigate the risk of coronary heart disease in relation to age at menarche, parity, and age at first birth, the authors evaluated prospectively the experience of 119,963 US women aged 30-55 years who were free from coronary heart disease in 1976 and were followed through 1982. During 700,809 person-years of observation, 308 incident cases of nonfatal myocardial infarction or fatal coronary heart disease occurred. Younger age at menarche was weakly associated with coronary heart disease (age-adjusted rate ratio of 1.3 for menarche before age 11 years compared with menarche at age 13 years; chi, Mantel extension test for trend = -1.1, p = 0.2). Nulliparous women experienced only a slightly higher rate of coronary heart disease than parous women (rate ratio = 1.2, 95 per cent confidence interval 0.8-1.8). Among parous women, there was no alteration in risk with increasing number of births. Likewise, there was no significant association between age at first birth and coronary heart disease (chi, Mantel extension test for trend = -0.4, p = 0.4). Established risk factors for coronary heart disease nevertheless showed expected relations. These findings show no important association between reproductive experiences and risk of coronary heart disease.

Effect of dietary fats and carbohydrate on blood pressure of mildly hypertensive patients

The effect on blood pressure (BP) of replacing dietary saturated fat with either polyunsaturated fat (linoleic acid) or carbohydrate was studied in 21 untreated mildly hypertensive patients. In a randomized, double-blind, crossover protocol, all subjects received dietary supplements of cream, safflower oil, and carbohydrate in random sequence, each prepared in flavored yogurt or milk. Each supplement was administered for 6 weeks and followed by a 4-week washout period of no supplementation. Dietary linoleic acid increased from 4.6 to 13% of energy intake when the safflower oil replaced cream, while saturated fat decreased from 16 to 10%. Total fat intake was 37 to 38% during the cream and safflower oil periods but was 28% during the carbohydrate period. Compliance with the diets was demonstrated by significant changes in fasting plasma fatty acid measurements. Mean clinic BP was 135 +/- 9/93 +/- 6 mm Hg at baseline. There were no significant differences in BP measured in the clinic or at home among the three dietary periods. The protocol had more than 80% power to detect a mean effect of diet of 3 mm Hg systolic or 2 mm Hg diastolic BP. Therefore, replacing dietary saturated fat with carbohydrate or with linoleic acid does not affect BP in subjects with mild hypertension.

The influence of age, relative weight, smoking, and alcohol intake on the reproducibility of a dietary questionnaire

To evaluate factors that affect the reproducibility of a semi-quantitative food frequency questionnaire used in a large prospective study we compared an extended 99-item questionnaire with a shorter, 61-item form completed by 1497 women with an interval of nine months between. Correlation coefficients for individual items assessed by the two questionnaires were highest for beverages (Spearman r = 0.70). For other foods, coefficients ranged from 0.60 to 0.70 for items eaten frequently (or habitually), to values between 0.34 and 0.45 for foods, such as sweet potatoes and ready made pie, that were eaten less frequently. For food items, the correlation between mean frequency of consumption and the reproducibility coefficient (Spearman r) was 0.51 (p less than 0.01), formally confirming that the reproducibility of measurements was positively associated with frequency of use. Pearson correlation coefficients for calorie-adjusted intakes of nutrients between the two questionnaires ranged from 0.40 for trans-fatty acids to 0.71 for vitamin E (including supplements). These correlation coefficients did not vary materially between subjects in different categories of smoking status or tertiles of age or relative weight. Moderate alcohol use had minimal effect on correlation coefficients, but reproducibility was slightly reduced among heavier drinkers. These data indicate that this self-administered dietary questionnaire can provide reproducible information about individual food and nutrient intakes which is not altered materially by age and a number of important health habits.

Use of permanent hair dyes and risk of breast cancer

Aromatic amines contained in permanent hair dyes can be absorbed percutaneously and are mutagenic and carcinogenic in some laboratory studies. Concern has been raised that use of these dyes may increase the risk of human cancers. Therefore, the present study examined the relationship between permanent hair dye use and incidence of breast cancer among 118,404 U.S. women aged 30-55 years who were followed prospectively for 6 years. Among women who had ever used permanent hair dyes, 353 developed breast cancer during 246,848 person-years of follow-up, while 505 cases occurred during 397,460 person-years among never users (age-adjusted rate ratio = 1.1; 95% confidence interval = 0.9-1.2). Identical rate ratios were observed when women who had ever used hair dyes were subdivided into current and past users. Adjustment for known determinants of breast cancer in multivariate models did not alter these relationships. The risk of breast cancer did not increase with more frequent use, longer duration of use, or interval since first use. On the basis of these data and previous findings, it appears unlikely that the use of permanent hair dyes causes any important increase in risk of breast cancer.

Reproducibility and validity of self-reported menopausal status in a prospective cohort study

The reproducibility and validity of self-reported menopausal status were evaluated among the 121,700 female US registered nurses aged 30-55 years in 1976 who are participants in the Nurses' Health Study, a prospective cohort study of diseases in women. When questioned in 1978, 6,591 of the women who were premenopausal in 1976 reported that their menses had ceased and provided their age at menopause. Two years later, in 1980, 98.8 per cent of the 6,591 women again reported that they were postmenopausal and again gave the reasons for menopause (natural or surgical). Among those women who reported surgical menopause during the 1976-1978 follow-up interval, age at menopause was reported to within one year on both the 1978 and 1980 questionnaires by 95 per cent of women. Among those reporting natural menopause during the 1976-1978 period, 82 per cent of women reported their age at menopause to within one year on the two follow-up questionnaires. A random sample of 255 women reporting surgical menopause between 1982 and 1984 was identified and medical records were obtained for 200. For all but two women, there was complete agreement between self-report and medical record for details of hysterectomy and extent of ovarian surgery. The reproducibility of self-reported age at menopause was assessed among 31,405 women who were menopausal in 1976. Reported age at menopause on consecutive questionnaires showed increasing within-person variance with increasing duration since menopause.(ABSTRACT TRUNCATED AT 250 WORDS)

A prospective cohort study of postmenopausal hormone use and risk of breast cancer in US women

The association between history of postmenopausal hormone use as of 1976 and breast cancer incidence during 1976-1980 was examined prospectively among 33,335 married, postmenopausal registered nurses aged 30-55 years at entry. Half the women reported postmenopausal hormone use, and one fourth had taken these drugs for over five years. During 1976-1980, 221 new cases of breast cancer were identified. The relative risk (RR) for those who had used postmenopausal hormones when compared with women who had never used them was 1.1 (95% confidence limits (CL) 0.8, 1.4); for current and past users, the relative risks were 1.0 (95% CL 0.7, 1.4) and 1.3 (95% CL 0.9, 1.8), respectively. These ratios were not substantially modified by whether or not a woman's ovaries had been removed or by other known breast cancer risk factors. No increase in breast cancer risk was apparent among women who had used postmenopausal hormones for less than five years (RR = 1.0, 95% CL 0.5, 1.6). An apparent effect among the subgroup of women who had used them for five to nine years (RR = 1.5, 95% CL 1.0, 2.2) was not present among the few women with longer-term use (RR = 0.9, 95% CL 0.4, 1.6). These findings are moderately reassuring, but since there are as yet few women in this cohort with long-term durations of use and, particularly, with long intervals since first use, continued follow-up of this and other cohorts will be required before firm conclusions can be drawn, especially among specific subgroups.

Moderate alcohol consumption and the risk of breast cancer

In 1980, 89,538 U.S. women 34 to 59 years of age, with no history of cancer, completed an independently validated dietary questionnaire that included the use of beer, wine, and liquor. During the ensuring four years, 601 cases of breast cancer were diagnosed among cohort members. Among the women consuming 5 to 14 g of alcohol daily (about three to nine drinks per week), the age-adjusted relative risk of breast cancer was 1.3 (95 percent confidence limits, 1.1 and 1.7). Consumption of 15 g of alcohol or more per day was associated with a relative risk of 1.6 (95 percent confidence limits, 1.3 and 2.0; Mantel extension chi for linear trend = +4.2; P less than 0.0001). Adjustment for known breast cancer risk factors and a variety of nutritional variables did not materially alter this relation. Significant associations were observed for beer and liquor when considered separately. Among women without risk factors for breast cancer who were under 55 years of age, the relative risk associated with consumption of 15 g of alcohol or more per day was 2.5 (95 percent confidence limits, 1.5 and 4.2). These prospective data derived from measurements of alcohol intake recorded before the diagnosis of breast cancer confirm the findings of several previous case-control studies. Viewed collectively, they suggest that alcohol intake may contribute to the risk of breast cancer.

Smoking behavior among participants in the nurses' health study

We analyzed smoking behavior of 91,651 married female nurses, aged 30-55 years in 1976. The prevalence of smoking was similar among all birth cohorts. The largest percentage increase in starting to smoke occurred between ages 15 and 25 years; by age 25, 50 per cent had started smoking. The cessation rate was lowest in earlier birth cohorts and among nurses starting to smoke at earlier ages. The cessation rate increased substantially between 1963-73 compared with the period 1948-58.

Menopause and the risk of coronary heart disease in women

To determine the relation of menopause to the risk of coronary heart disease, we analyzed data on a prospective cohort of 121,700 U.S. women 30 to 55 years old who were followed from 1976 to 1982. Information on menopausal status, the type of menopause, and other risk factors was obtained in 1976 and updated every two years by mailing questionnaires. Through 1982, the follow-up rate was 98.3 percent for mortality and 95.4 percent for nonfatal events. After we controlled for age and cigarette smoking, women who had had a natural menopause and who had never taken replacement estrogen had no appreciable increase in the risk of coronary heart disease, as compared with premenopausal women (adjusted rate ratio, 1.2; 95 percent confidence limits, 0.8 and 1.8). Again compared with premenopausal women, the occurrence of a natural menopause together with the use of estrogens did not affect the risk (rate ratio, 0.8, 95 percent confidence limits, 0.4 and 1.3). Women who had undergone bilateral oophorectomy and who had never taken estrogens after menopause had an increased risk (rate ratio, 2.2; 95 percent confidence limits, 1.2 and 4.2). However, the use of estrogens in the postmenopausal period appeared to eliminate this increased risk among these women as compared with premenopausal women (rate ratio, 0.9; 95 percent confidence limits, 0.6 and 1.6). These data suggest that, in contrast to a natural menopause, bilateral oophorectomy increases the risk of coronary heart disease. This increase appears to be prevented by estrogen-replacement therapy.

Effect of linoleic and oleic acids on blood pressure, blood viscosity, and erythrocyte cation transport

It has been proposed that dietary linoleic acid lowers blood pressure (BP) by being converted to arachidonic acid and prostanoids of the two-ene series. We tested the effects of linoleic acid on plasma arachidonic acid, blood pressure, blood viscosity, and RBC cation transport. Oleic acid, the major dietary monounsaturated fat and which is not a prostanoid precursor, was used as a control. Seventeen adults consumed 23 g/d of linoleic acid or oleic acid provided by genetic variants of safflower seed, each for 4 weeks in a double-blind crossover design. Linoleic and oleic acids were enriched significantly in the plasma cholesteryl esters, phospholipids and triglycerides during the respective periods of supplementation but there was no increase in arachidonate. Mean BP was 116.1/76.8 during ingestion of oleic and 113.6/74.6 during ingestion of linoleic acid (p = 0.09 systolic, p = 0.12 diastolic). The power of the study was over 75% for detecting a significant (p less than 0.05) effect of 4 mm Hg in systolic BP or diastolic BP. Whole blood and plasma viscosity, and RBC Li/Na countertransport, Na/K cotransport, and Na pump systems (Vmax) were unchanged during the protocol. Therefore, variations in dietary linoleic or oleic acids are unlikely to have major effects on BP or on several membrane-dependent erythrocyte functions related to hypertension.

Nonspecific electrocardiographic abnormality as a predictor of coronary heart disease: the Framingham Study

The risk of developing overt coronary heart disease is examined in relation to occurrence of non-specific electrocardiographic S-T and T-wave abnormalities (NSA-ECG) in the Framingham Study. In the course of follow-up, 14% of the 5127 men and women had or developed NSA-ECG without clinically apparent intervening coronary heart disease. During 30 years of surveillance, 760 men and 578 women developed a first overt clinical manifestation of coronary heart disease. NSA-ECG appears to be a hallmark of a compromised coronary circulation which predicted the occurrence of every clinical manifestation of coronary heart disease independently of known risk factors including hypertension, its chief determinant. Coronary morbidity and mortality was increased twofold in each sex. The more common T-wave abnormality alone carried a significant increased risk, although the combination of S-T and T-wave seemed most hazardous. Persons who develop NSA-ECG without other explanation warrant vigorous preventive management against coronary heart disease.