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Biomedical subjects

J E Manson

Publications and source records attributed to J E Manson.

At least 217 records · Page 12Linked to original sources
PubMed1995

Reproducibility of plasma hormone levels in postmenopausal women over a 2-3-year period.

We evaluated the reproducibility of plasma hormone levels over time in 79 healthy postmenopausal women, ages 51-69 years at baseline, who were not using postmenopausal hormones. Three blood samples were collected between 1989 and 1992 from each of these women. We assessed plasma levels of estradiol, free estradiol, percentage of free estradiol, bioavailable estradiol, percentage of bioavailable estradiol, estrone, estrone sulfate, sex hormone-binding globulin (SHBG), androstenedione, testosterone, dehydroepiandrosterone, dehydroepiandrosterone sulfate, and prolactin at each of three sample collections. The means and SD for each of the plasma estrogens, SHBG, and prolactin were similar at each collection. For the androgens, plasma levels tended to decrease over time consistent with an aging effect; decreases with increasing age were statistically significant for androstenedione, dehydroepiandrosterone, and dehydroepiandrosterone sulfate. Intraclass correlation coefficients (ICCs) ranged from 0.92 (95% confidence interval = 0.89-0.95) for SHBG to 0.53 (95% confidence interval = 0.43-0.69) for prolactin. Most correlations were at least 0.70. The ICCs did not vary by age or time since menopause. Women who changed weight over the course of the study tended to have lower ICCs for a number of the hormones, although these differences were not statistically significant. These data indicate that, for most of these plasma hormones, a single measurement can reliably categorize average levels over at least a 3-year period in postmenopausal women.

Age Distribution↗
PubMed1995

Physical activity in the treatment and prevention of diabetes.

The current available epidemiologic evidence supports a substantial benefit from maintaining a physically active, as compared to a sedentary life-style. Clinician counseling and prescription of regular physical activity should represent a major goal in the treatment and primary prevention of diabetes. This responsibility is of paramount importance, particularly in light of the high prevalence of physical inactivity (based on national survey data, 56% of men and 61% of women in the United States either never or irregularly engage in physical activity), and the high incidence of diabetes and its complications, including severe atherosclerotic disease, in the United States and throughout the world.

Adult↗
PubMed1994

Dehydroepiandrosterone sulfate and the risk of myocardial infarction in US male physicians: a prospective study.

High levels of dehydroepiandrosterone sulfate (DHEAS) have been associated with decreased risks of cardiovascular disease. The authors analyzed DHEAS in plasma collected at baseline among 169 participants in the Physicians' Health Study who subsequently had a myocardial infarction and 169 matched controls. The mean prediagnostic plasma DHEAS levels between cases (p = 0.33) (mean, 3.54 mumol/liter; standard deviation, 2.30) and controls (mean, 3.61 mumol/liter; standard deviation, 2.16) did not differ significantly. The relative risk was 1.04 (95 percent confidence interval 0.42-2.60) comparing extreme quintiles after adjustment for several coronary risk factors. In conclusion, these findings do not support the hypothesis that elevated plasma DHEAS is associated with a decreased risk of coronary disease in men, but a small to moderate association cannot be excluded.

Adult↗
PubMed1994

Prospective study of endogenous tissue plasminogen activator and risk of stroke.

Few haematological or lipid risk factors have been identified for stroke, by contrast with coronary heart disease. To find out whether a marker of endogenous fibrinolytic function might be associated with stroke risk, we measured tissue plasminogen activator (tPA) antigen concentrations in baseline plasma samples from 88 healthy participants in the Physicians' Health Study who subsequently had first-ever strokes (71 thromboembolic, 12 haemorrhagic, 5 indeterminate) and from 471 participants who remained free of cardiovascular disease during 5 years of follow-up (controls). Mean baseline tPA concentrations were significantly higher among men who later had strokes than in the controls (11.14 [SE 0.80] vs 9.59 [0.27] ng/mL, p = 0.03). The difference was largely due to an excess of abnormally high values among stroke cases. The age-adjusted relative risk for stroke among men with baseline tPA concentrations above the 95th percentile of the control distribution was 3.51 (95% CI 1.72-7.17, p = 0.0006) for total stroke and 3.89 (1.83-8.26, p = 0.0004) for thromboembolic stroke. These findings did not change substantially in analyses that also controlled for stroke risk factors (high blood pressure, body-mass index, smoking, presence of diabetes, and parental history of myocardial infarction) or the plasma lipid profile. This prospective study shows that high concentrations of tPA antigen among apparently healthy men are independently associated with high risks of future stroke, especially thromboembolic stroke. This finding is consistent with the hypothesis that activation of the endogenous fibrinolytic system occurs years in advance of arterial vascular occlusion.

Adult↗
PubMed1994

Cigarette smoking and stroke in a cohort of U.S. male physicians.

OBJECTIVE: To examine the association between cigarette smoking and the risk for stroke in men. DESIGN: Prospective cohort study. SETTING: Participants in the Physicians' Health Study, a randomized trial of aspirin and beta-carotene among U.S. male physicians. PATIENTS: 22,071 men, 40 to 84 years of age at entry, free from self-reported myocardial infarction, stroke, and transient ischemic attack; followed for an average of 9.7 years; and classified as never-smokers, current smokers, and former smokers based on self-report. MEASUREMENTS: Incidence rates of total, ischemic, and hemorrhagic stroke. RESULTS: With never-smokers as the reference group (relative risk, 1.00), relative risks (adjusted for age and treatment assignment) for total nonfatal stroke (n = 312) were as follows: former smoking, 1.20 (95% CI, 0.94 to 1.53); currently smoking fewer than 20 cigarettes daily, 2.02 (CI, 1.23 to 3.31); and currently smoking 20 or more cigarettes daily, 2.52 (CI, 1.75 to 3.61) (P for trend, < 0.0001). For participants who had total fatal stroke (n = 28), the risk for stroke was not increased with smoking (P > 0.2). In proportional-hazards models that controlled simultaneously for other risk factors, these associations were not materially altered. CONCLUSIONS: Current but not former cigarette smoking was significantly associated with an increased risk for stroke in men. Smoking may account for a substantial amount of stroke-associated morbidity and mortality.

Adult↗
PubMed1994

Smoking cessation and time course of decreased risks of coronary heart disease in middle-aged women.

BACKGROUND: We examined prospectively the relation of time since stopping smoking with risk of coronary heart disease in middle-aged women. METHODS: The study was based on 12 years' follow-up data (1976 through 1988) from the Nurses' Health Study, an ongoing prospective cohort study, in which information on smoking habits was updated every 2 years by a mailed questionnaire. The study population consisted of 117,006 female registered nurses aged 30 to 55 years in 1976 who were free of coronary heart disease, stroke, and cancer at baseline. The outcome measure used was incident coronary heart disease, defined as nonfatal myocardial infarction plus fatal coronary heart disease. RESULTS: A total of 970 incident cases of coronary heart disease (215 among participants who never smoked, 214 among former smokers, and 541 among current smokers) occurred during 1.37 million person-years of follow-up. The multivariate relative risk of total coronary heart disease among current smokers compared with participants who never smoked was 4.23 (95% confidence interval, 3.60 to 4.96). Risk of coronary heart disease was highest among smokers who started smoking before the age of 15 years (relative risk, 9.25; 95% confidence interval, 5.27 to 16.23). The relative risk among former smokers was 1.48 (95% confidence interval, 1.22 to 1.79). On stopping smoking, one third of the excess risk of coronary heart disease was eliminated within 2 years of cessation. Thereafter, the excess risk returned to the level of those who never smoked during the interval 10 to 14 years following cessation. CONCLUSION: Women who stop smoking will experience an immediate benefit as well as a further longer-term decline in excess risk of coronary heart disease to the level of those who never smoked.

Adult↗
PubMed1994

Postmenopausal hormone therapy and atherosclerotic disease.

Several lines of evidence suggest that estrogen is an important determinant of cardiovascular risk in women. Epidemiologic data document low rates of coronary heart disease (CHD) in premenopausal women, a narrowing of the gender gap in CHD mortality after menopause, and elevated risk of CHD among young women with bilateral oophorectomy not treated with estrogen. Nearly all of the more than 30 observational studies of exogenous estrogen replacement therapy have indicated a reduced risk of CHD among women receiving estrogen therapy. In a meta-analysis comparing estrogen users and nonusers, the estimated reduction of CHD among users was 44%. In angiographic studies, women taking estrogen were less likely to have coronary artery stenosis. Estrogen is known to affect a wide range of physiologic processes that may have an impact on CHD risk. Use of oral estrogen has favorable effects on serum lipid profiles; it increases high-density lipoprotein cholesterol levels by 10% to 15% and decreases low-density lipoprotein cholesterol levels by a similar magnitude. Other proposed mechanisms include inhibition of endothelial hyperplasia, reduced arterial impedance, enhanced production of prostacyclin, increased insulin sensitivity, and inhibition of oxidation of low-density lipoprotein. Nevertheless, the role of hormone replacement therapy in preventing clinical atherosclerotic events in women remains inconclusive because of the absence of randomized trial data. The benefit-to-risk ratio must be reliably assessed, because estrogen has complex actions, including postulated benefits (CHD, osteoporosis, and menopausal symptoms) and postulated risks (endometrial cancer, breast cancer, and gallstones.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Adolescent body mass index and infertility caused by ovulatory disorder.

OBJECTIVE: Our aim was to examine the association between body mass index at age 18 and subsequent primary ovulatory infertility. STUDY DESIGN: A nested case-control study was conducted within a cohort of 116,678 female registered nurses residing in 14 U.S. states. Cases comprised 2527 married nulliparous nurses unable to become pregnant for at least 1 year because of ovulatory disorder; controls comprised 46,718 married parous nurses with no history of infertility. The risk of ovulatory infertility for women at different levels of body mass index at age 18 was compared with that for women whose body mass index at age 18 was 20 to 21.9 (median for the cohort). Logistic regression was used to adjust for age at infertility or first birth, year of birth, age at menarche, physical activity during ages 18 to 22, smoking at ages 15 to 19, ethnicity, alcohol use at ages 18 to 22, use of oral contraceptives before age 22, and diagnosis of diabetes mellitus. RESULTS: Multivariate relative risks for infertility were: 1.2 (body mass index < 16), 1.1 (body mass index 16 to 17.9), 1.0 (body mass index 18 to 19.9), 1.0 (referent body mass index 20 to 21.9), 1.1 (body mass index 22 to 23.9), 1.3 (body mass index 24 to 25.9), 1.7 (body mass index 26 to 27.9), 2.4 (body mass index 28 to 29.9), 2.7 (body mass index 30 to 31.9), and 2.7 (body mass index > or = 32). The relative risks for all categories of body mass index above 23.9 were statistically significantly elevated. Greater body mass index at age 18 was a predictor of ovulatory infertility in women with and without a diagnosis of polycystic ovary syndrome. CONCLUSION: These findings suggest that elevated body mass index at age 18, even at levels lower than those considered to be obese, is a risk factor for subsequent ovulatory infertility.

Adolescent↗
PubMed1994

Reproducibility and validity of a self-administered physical activity questionnaire.

BACKGROUND: The reproducibility and validity of self-administered questionnaires on physical activity and inactivity were examined in a random (representative) sample of the Nurses' Health Study II cohort and a random sample of African-American women in that cohort. METHODS: Repeat questionnaires were administered 2 years apart. Past-week activity recalls and 7-day activity diaries were the referent methods; these instruments were sent to participants four times over a 1-year period. RESULTS: The 2-year test-retest correlation for activity was 0.59 for the representative sample (n = 147) and 0.39 for the African-American sample (n = 84). Correlations between activity reported on recalls and that reported on questionnaire were 0.79 and 0.83 for the representative and African-American samples, respectively. Correlations between activity reported in diaries and that reported on questionnaire were 0.62 and 0.59, respectively. Test-retest coefficients for inactivity were 0.52 and 0.55, respectively. Correlations between inactivity reported in diaries and that reported on questionnaire were 0.41 and 0.44, respectively. CONCLUSION: The simple, short questionnaires on activity and inactivity used in the Nurses' Health Study II are reasonably valid measures for epidemiological research.

Adult↗
PubMed1994

Risk factors for non-insulin-dependent diabetes mellitus requiring treatment in the elderly.

OBJECTIVE: To examine the relationship of possible modifiable risk factors, including obesity, physical activity level, alcohol consumption, blood pressure, and thiazide diuretic use with the development of non-insulin-dependent diabetes mellitus (NIDDM) requiring treatment among a large cohort of community-dwelling elderly. SETTING: The East Boston Senior Health Project, one of four components of the National Institute on Aging-sponsored Established Populations for the Epidemiologic Study of the Elderly (EPESE). PARTICIPANTS: Residents of East Boston who were 65 years of age or older. MEASUREMENTS: We performed a prospective cohort study with follow-up over two consecutive 3-year time periods beginning in 1982-1983. The main outcome measure was the occurrence of NIDDM, defined as new treatment with a hypoglycemic agent. A total of 2737 study participants contributed 4682 3-year intervals for analysis. MAIN RESULTS: NIDDM requiring hypoglycemic therapy occurred in 185 participants over the duration of the study. High body mass index (> 26 kg/m2) (adjusted odds ratio 2.4, 95% confidence interval 1.3-4.4) and low physical activity level (adjusted odds ratio 1.5, 95% confidence interval 1.0-2.1) were significant predictors of NIDDM in a multiple logistic regression model adjusting for age, sex, blood pressure, and self-report of "high blood sugar" moderate alcohol consumption (0.5-<1 ounce per day) had an inverse relation to NIDDM of borderline significance (adjusted odds ratio 0.4, 95% confidence interval 0.2-1.0). Those receiving one or more non-thiazide antihypertensive agents had a higher risk of developing NIDDM in a model including age, sex, body mass index, various antihypertensive regimens, physical activity level, alcohol consumption, blood pressure, and self-report of "high blood sugar." Thiazide diuretic therapy alone or in combination with another antihypertensive was not associated with NIDDM. CONCLUSIONS: Our findings suggest a positive relationship of obesity and low physical activity level with the development of NIDDM requiring treatment in elderly persons. The inverse association of borderline significance between moderate alcohol use and NIDDM deserves further study. Thiazide diuretic therapy conferred no excess risk for developing NIDDM in this older population although selection factors in the choice of antihypertensive therapy may partially explain the absence of a thiazide effect.

Age Factors↗
PubMed1994

The use of vitamin supplements and the risk of cataract among US male physicians.

OBJECTIVES: The purpose of this study was to examine prospectively the association between reported use of vitamin supplements and risk of cataract and cataract extraction. METHODS: The study population consisted of 17,744 participants in the Physicians' Health Study, a randomized trial of aspirin therapy and beta-carotene among US male physicians 40 to 84 years of age in 1982 who did not report cataract at baseline and provided complete information about vitamin supplementation and other risk factors for cataract. Self-reports of cataract and cataract extraction were confirmed by medical record review. RESULTS: During 60 months of follow-up, there were 370 incident cataracts and 109 cataract extractions. In comparison with physicians who did not use any supplements, those who took only multivitamins had a relative risk of cataract of 0.73 after adjustment for other risk factors. For cataract extraction, the corresponding relative risk was 0.79. Use of vitamin C and/or E supplements alone was not associated with a reduced risk of cataract, but the size of this subgroup was small. CONCLUSIONS: These data suggest that men who took multivitamin supplements tended to experience a decreased risk of cataract and support the need for rigorous testing of this hypothesis in large-scale randomized trials in men and women.

Adult↗
PubMed1994

Confirmation of self-reported cataract in the Physicians' Health Study.

Large-scale prospective studies of disease development often rely on self-reported data. To assess the accuracy of self-reports of cataract, we compared the self-reports with medical record data obtained from diagnosing ophthalmologists and optometrists for participants in the Physicians' Health Study, a randomized trial of aspirin and beta-carotene among 22,071 male U.S. physicians aged 40-84 years. A report of cataract, defined as a positive response to a question about whether cataract had ever been diagnosed in either eye and the date of diagnosis, was found to be a very good indicator of lens opacification but was not a good indicator of an incident, age-related opacity that reduced visual acuity. These results indicate that in large prospective studies of clinically significant cataract, where examination of all study participants is not feasible and self-reported data are used, additional documentation to supplement the self-reports should be obtained and strict diagnostic criteria applied to minimize the likely effects of misclassification.

Adult↗
PubMed1994

A prospective study of symptomatic gallstones in women: relation with oral contraceptives and other risk factors.

OBJECTIVE: To examine the relation between oral contraceptives (OCs), body mass index (BMI), weight change, alcohol use, parity, smoking, and symptomatic gallstones in women less than 45 years of age. METHODS: In this prospective study, associations between the various self-reported exposures and symptomatic gallstones were assessed in 96,211 female United States nurses with 425 cases of gallstones, using multiple logistic regression. RESULTS: We found little relation between ever-use of OCs and symptomatic gallstones (relative risk [RR] 1.2, 95% confidence interval [CI] 0.9-1.6), although there was a modest elevation in risk for long-term use (RR 1.5, 95% CI 1.0-2.2 for 10-14 years; RR 1.6, 95% CI 1.0-2.4 for 15 or more years). There was also an increased risk in current users of OCs (RR 1.6, 95% CI 1.1-2.4). The risk of symptomatic gallstones increased with increasing BMI and weight gain since age 18. Women with four or more births had an elevated risk of symptomatic gallstones (RR 2.0, 95% CI 1.3-3.2), and current cigarette smokers had a slightly higher risk than never-smokers (RR 1.3, 95% CI 1.0-1.7). The risk decreased with increasing alcohol intake. CONCLUSION: We found no substantial increase in the risk of symptomatic gallstones among ever-OC users, although current and long-term users had somewhat elevated risks. Body mass index remains the strongest predictor of symptomatic gallstones among young women.

Adult↗
PubMed1993

Body weight and mortality. A 27-year follow-up of middle-aged men.

OBJECTIVE: To investigate the nature of the relation between body weight and all-cause mortality. DESIGN: Prospective cohort study, following up men from 1962 or 1966 (1962/1966) through 1988. SETTING/PARTICIPANTS: Harvard University alumni with a mean age of 46.6 years in 1962/1966 and without self-reported, physician-diagnosed coronary heart disease, stroke, or cancer, who completed questionnaires on weight, height, cigarette smoking habit, and physical activity (n = 19,297). We calculated body mass index (weight in kilograms divided by the square of height in meters) using self-reported measures. MAIN OUTCOME MEASURE: All-cause mortality (4370 deaths). RESULTS: In multivariate analysis adjusting for age, cigarette smoking habit, and physical activity, we found a J-shaped relation between body mass index and mortality. Relative risks of dying for men with a body mass index of less than 22.5, 22.5 to less than 23.5, 23.5 to less than 24.5, 24.5 to less than 26.0, and 26.0 or greater were 1.00 (referent), 0.99 (95% confidence interval, 0.89 to 1.20), 0.95 (0.87 to 1.05), 1.01 (0.91 to 1.10), and 1.18 (1.08 to 1.28), respectively (P for linear trend = .0008). Among current smokers, the relation between body mass index and mortality was U-shaped, with lowest risk of death at a body mass index of 23.5 to less than 24.5. During early follow-up (1962/1966 through 1974), we also observed a U-shaped curve, this time with lowest mortality risk at a body mass index of 24.5 to less than 26.0. To minimize confounding by cigarette smoking and bias from antecedent disease and early mortality, we conducted analysis only among never smokers and omitted the first 5 years of follow-up (510 deaths). The corresponding relative risks from this analysis, adjusted for age and physical activity, were 1.00, 1.23 (95% confidence interval, 0.90 to 1.67), 1.06 (0.80 to 1.42), 1.27 (0.96 to 1.68), and 1.67 (1.29 to 2.17), respectively (P for linear trend = .0001). CONCLUSIONS: In these prospective data, body weight and mortality were directly related. After accounting for confounding by cigarette smoking and bias resulting from illness-related weight loss or inappropriate control for the biologic effects of obesity, we found no evidence of excess mortality among lean men. Indeed, lowest mortality was observed among men weighing, on average, 20% below the US average for men of comparable age and height.

Body Mass Index↗
PubMed1993

Smoking cessation in relation to total mortality rates in women. A prospective cohort study.

OBJECTIVE: To examine the temporal relationship between stopping smoking and total mortality rates among middle-aged women. DESIGN: Prospective cohort study with 12 years of follow-up. SETTING: Registered nurses residing in the United States. PARTICIPANTS: 117,001 female registered nurses, ages 30 to 55 years, who were free of manifest coronary heart disease, stroke, and cancer (except nonmelanoma skin cancer) in 1976. MAIN OUTCOME MEASURES: Total mortality, further categorized into deaths from cardiovascular diseases, cancers, and violent deaths. RESULTS: A total of 2847 deaths (933 among "never smokers," 799 among former smokers, and 1115 among current smokers) occurred during 1.37 million person-years of follow-up. The multivariate relative risks for total mortality compared with never smokers were 1.87 (95% CI, 1.65 to 2.13) for current smokers and 1.29 (CI, 1.14 to 1.46) for former smokers. Participants who started smoking before the age of 15 years had the highest risks for total mortality (multivariate relative risk, 3.15; CI, 2.16 to 4.59), cardiovascular disease mortality (relative risk, 9.94; CI, 5.15 to 19.19), and deaths from external causes of injury (relative risk, 5.39; CI, 1.84 to 15.78). Compared with continuing smokers, former smokers had a 24% reduction in risk for cardiovascular disease mortality within 2 years of quitting. The excess risks for total mortality and both cardiovascular disease and total cancer mortality among former smokers approached the level of that for never smokers after 10 to 14 years of abstinence. The health benefits of cessation were clearly present regardless of the age at starting and daily number of cigarettes smoked. CONCLUSIONS: The risk of cigarette smoking on total mortality among former smokers decreases nearly to that of never smokers 10 to 14 years after cessation.

Adult↗
PubMed1993

Low-dose aspirin and incidence of colorectal tumors in a randomized trial.

BACKGROUND: Laboratory, clinical, and epidemiologic studies have recently suggested that regular use of aspirin can reduce colorectal cancer incidence or mortality. However, observational epidemiologic analyses have had limited opportunity to control for confounding bias or to specify aspirin doses used. PURPOSE: Our purpose was to examine the relationship between regular use of low-dose aspirin and incidence of invasive and noninvasive colorectal tumors by utilizing data from the Physicians' Health Study, a randomized, double-blinded, placebo-controlled trial of aspirin and beta carotene. We also attempted to determine whether invasive cancers among aspirin users were associated with rectal bleeding and early stage at diagnosis. METHODS: The Physicians' Health Study includes 22071 U.S. male physicians. The aspirin arm was terminated in 1988 after a mean follow-up of 5 years. Stage at diagnosis and signs and/or symptoms during presentation were abstracted from medical records. Cox proportional hazards models were used to estimate relative risk (RR), 95% confidence intervals (CIs), and the association between aspirin and bleeding. Differences between aspirin and placebo groups in tumor risk over time were visualized with Kaplan-Meier curves. We assessed the association between aspirin and stage at diagnosis with a Mann-Whitney rank sum statistic for non-parametric comparison of two ordinal distributions. RESULTS: The RR of developing colorectal cancer for aspirin compared with placebo was 1.15 (95% CI = 0.80-1.65). For in situ cancers and polyps, the RR was 0.86 (95% CI = 0.68-1.10). There was no significant trend for decreasing RR by year of follow-up for invasive cancers (P = .09) or noninvasive tumors (P = .96). Aspirin and placebo groups did not differ in stage or prevalence of rectal bleeding at diagnosis. CONCLUSIONS: Regular aspirin use, at a dose adequate for preventing myocardial infarction, was not associated with a substantial reduction in the incidence of colorectal cancer during 5 years of randomized treatment and follow-up. A small decrease in polyps in the aspirin group could not be reliably distinguished from a chance association. Our results suggest that among low-dose aspirin users, (a) colorectal cancer mortality is not likely to be reduced by earlier detection and (b) incidence is not likely to be increased due to aspirin-induced gastrointestinal bleeding. IMPLICATIONS: The potential for a benefit from higher doses of aspirin or longer duration of use should be addressed by more detailed observational epidemiologic studies and prevention trials with longer follow-up of randomized participants.

Adult↗
PubMed1993

A prospective study of the intake of vitamins C, E, and A and the risk of breast cancer.

BACKGROUND: Although it has been hypothesized that large intakes of the antioxidant vitamins C, E, and A reduce the risk of breast cancer, few prospective data are available. METHODS: We prospectively studied 89,494 women who were 34 to 59 years old in 1980 and who did not have cancer. Their intakes of vitamins C, E, and A from foods and supplements were assessed at base line and in 1984 with the use of a validated semiquantitative food-frequency questionnaire. RESULTS: Breast cancer was diagnosed in 1439 women during eight years of follow-up. After multivariate adjustment for known risk factors, the relative risk among women in the highest quintile group for intake of vitamin C as compared with the risk among those in the lowest quintile group was 1.03 (95 percent confidence interval, 0.87 to 1.21); for vitamin E, after vitamin A intake had been controlled for, the relative risk was 0.99 (95 percent confidence interval, 0.83 to 1.19). In contrast, among women in the highest quintile group for intake of total vitamin A the relative risk was 0.84 (95 percent confidence interval, 0.71 to 0.98; P for trend = 0.001). Among women in the lowest quintile group for intake of vitamin A from food, consumption of vitamin A from supplements was associated with a reduced risk (P = 0.03). The significant inverse association of vitamin A intake with the risk of breast cancer was also found on study of data based on the 1984 questionnaire and four years of follow-up. CONCLUSIONS: Large intakes of vitamin C or E did not protect women in our study from breast cancer. A low intake of vitamin A may increase the risk of this disease; any benefit of vitamin A supplements may be limited to women with diets low in vitamin A.

Adult↗