Carotene, carrots, and white blood cells.
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Carotenoids↗
Biomedical subjects
M J Stampfer
Publications and source records attributed to M J Stampfer.
Dietary patterns and the risk of coronary heart disease in women.
BACKGROUND: Although substantial information on individual nutrients or foods and risk of coronary heart disease (CHD) is available, little is known about the role of overall eating pattern. METHODS: Using dietary information from a food frequency questionnaire in 1984 from the Nurses' Health Study, we conducted factor analysis and identified 2 major dietary patterns-"prudent" and "Western"-and calculated factor scores of each pattern for individuals in the cohort. We used logistic regression to examine prospectively the associations between dietary patterns and CHD risk among 69 017 women aged 38 to 63 years in 1984 without history of major chronic diseases. RESULTS: The prudent pattern was characterized by higher intakes of fruits, vegetables, legumes, fish, poultry, and whole grains, while the Western pattern was characterized by higher intakes of red and processed meats, sweets and desserts, french fries, and refined grains. Between 1984 and 1996, we documented 821 CHD cases. After adjusting for coronary risk factors, the prudent diet score was associated with a relative risk (RR) of 0.76 (95% confidence interval (CI), 0.60-0.98; P for trend test,.03) comparing the highest with lowest quintile. Extreme quintile comparison yielded an RR of 1.46 (95% CI, 1.07-1.99; P for trend test,.02) for the Western pattern. Those who were jointly in the highest prudent diet quintile and lowest Western diet quintile had an RR of 0.64 (95% CI, 0.44-0.92) compared with those with the opposite pattern profile. CONCLUSION: A diet high in fruits, vegetables, whole grains, legumes, poultry, and fish and low in refined grains, potatoes, and red and processed meats may lower risk of CHD.
Adult↗
Physical activity, obesity, height, and the risk of pancreatic cancer.
CONTEXT: Diabetes mellitus and elevated postload plasma glucose levels have been associated with an increased risk of pancreatic cancer in previous studies. By virtue of their influence on insulin resistance, obesity and physical inactivity may increase risk of pancreatic cancer. OBJECTIVE: To examine obesity, height, and physical activity in relation to pancreatic cancer risk. DESIGN AND SETTING: Two US cohort studies conducted by mailed questionnaire, the Health Professionals Follow-up Study (initiated in 1986) and the Nurses' Health Study (initiated in 1976), with 10 to 20 years of follow-up. PARTICIPANTS: A total of 46 648 men aged 40 to 75 years and 117 041 women aged 30 to 55 years who were free of prior cancer at baseline and had complete data on height and weight. MAIN OUTCOME MEASURES: Relative risk of pancreatic cancer, analyzed by self-reported body mass index (BMI), height, and level of physical activity. RESULTS: During follow-up, we documented 350 incident pancreatic cancer cases. Individuals with a BMI of at least 30 kg/m(2) had an elevated risk of pancreatic cancer compared with those with a BMI of less than 23 kg/m(2) (multivariable relative risk [RR], 1.72; 95% confidence interval [CI], 1.19-2.48). Height was associated with an increased pancreatic cancer risk (multivariable RR, 1.81; 95% CI, 1.31-2.52 for the highest vs lowest categories). An inverse relation was observed for moderate activity (multivariable RR, 0.45; 95% CI, 0.29-0.70 for the highest vs lowest categories; P for trend <.001). Total physical activity was not associated with risk among individuals with a BMI of less than 25 kg/m(2) but was inversely associated with risk among individuals with a BMI of at least 25 kg/m(2) (pooled multivariable RR, 0.59; 95% CI, 0.37-0.94 for the top vs bottom tertiles of total physical activity; P for trend =.04). CONCLUSION: In 2 prospective cohort studies, obesity significantly increased the risk of pancreatic cancer. Physical activity appears to decrease the risk of pancreatic cancer, especially among those who are overweight.
Adult↗
The 2 x 2 factorial design: its application to a randomized trial of aspirin and carotene in U.S. physicians.
The 2 x 2 factorial design calls for randomizing each participant to treatment A or B to address one question and further assignment at random within each group to treatment C or D to examine a second issue, permitting the simultaneous test of two different hypotheses. This design can increase the efficiency of large-scale clinical trials. The Physicians' Health Study, a randomized trial of aspirin and beta-carotene among U.S. physicians, illustrates some features and potential problems in the design and analysis of a factorial trial. The most common concern, interaction between treatments, is generally an advantage rather than a limitation of this design. Although such interactions are relatively uncommon, this design provides a means to measure an effect which otherwise might not be apparent. If the interaction is sufficiently severe, however, then loss of power is possible.
Aspirin↗
The impact of different therapies on symptoms of benign prostatic hyperplasia: a prospective study.
We conducted an observational study to evaluate prospectively the effectiveness of four modes of treatment for benign prostatic hyperplasia (BPH)-watchful waiting, alpha-blocker therapy, finasteride therapy, and surgery (transurethral prostatectomy). A total of 1459 men aged 48 to 84 years, who were diagnosed for the first time by physicians as having BPH in 1994 and who had not received treatment, participated in the study. During 1 year of follow-up, 1064 (72.9%) men remained on no treatment (watchful waiting), 156 (10.7%) were treated with finasteride, 198 (13.6%) were treated with an alpha-blocker, and 41 (2.8%) underwent prostatectomy. The American Urological Association (AUA) Symptom Index was administered to the cohort before the initiation of treatment in 1994, as well as 1 year later. Improvements in lower urinary tract symptoms, as measured by the AUA Symptom Index, were assessed using linear and logistic regression, adjusting for age and baseline. Men who underwent prostatectomy reported the biggest improvements in lower urinary tract symptoms, whether assessed by mean changes in symptom scores relative to no treatment (-5.44; 95% confidence interval [CI]-6.91 to -3.97) or by the odds of improving by 5 or more points on the AUA Symptom Index (odds ratio, 12.66; 95% CI, 5.93 to 27.0). Irrespective of the initial degree of symptom severity, prostate surgery resulted in larger improvements than those reported for either finasteride or alpha-blocker therapy. In this prospective, observational study, prostatic surgery was associated with statistically and clinically significant improvements in BPH symptoms.
Adrenergic alpha-Antagonists↗
Prospective study of herpes simplex virus, cytomegalovirus, and the risk of future myocardial infarction and stroke.
BACKGROUND: It has been hypothesized that infection with either herpes simplex virus (HSV) or cytomegalovirus (CMV) is associated with atherogenesis. However, prospective data relating evidence of prior exposure to these agents with risks of future myocardial infarction (MI) and stroke are sparse. METHODS AND RESULTS: In a prospective, nested case-control study of apparently healthy men, the baseline prevalence of antibodies directed against HSV or CMV was similar among 643 men who subsequently developed a first MI or thromboembolic stroke and among 643 age- and smoking-matched men who remained free of reported vascular disease over a 12-year follow-up period. Specifically, the relative risks for future MI and stroke were 0.94 (95% CI, 0.7 to 1.2) for HSV seropositivity and 0.72 (95% CI, 0.6 to 0.9) for CMV seropositivity, after adjustment for other cardiovascular risk factors. These findings were not materially altered in comparisons of early versus late events or in analyses stratified by smoking status. There was no evidence of association between HSV or CMV antibodies and plasma concentration of C-reactive protein, a marker of inflammation that predicts vascular risk in this cohort. CONCLUSIONS: Among apparently healthy middle-aged men, IgG antibodies directed against HSV or CMV do not appear to be a marker for increased atherothrombotic risk. The observed possible inverse relationship of CMV with MI and stroke was unexpected and may well be due to chance, because the direction of association is not compatible with the a priori hypothesis based on proposed biological mechanisms or previous cross-sectional and retrospective data.
Antibodies, Viral↗
Estrogens and breast cancer.
In this review, we summarize the epidemiologic evidence for the associations of oral contraceptives and postmenopausal hormones with risk of breast cancer. We also describe the biologic plausibility of these relationships. Overall, there appears to be little, if any, increase in risk with oral contraceptive use in general, even among users for 10 or more years. However, compared to never users, current oral contraceptive users appear to have a modest elevation in risk that subsides within about 10 years after cessation of use. For postmenopausal hormones, the weight of the evidence suggests little or no increase in risk among users of short duration, or for use in the past. However, current longer term use is associated with an increased risk of breast cancer that increases with duration. This increase in risk is large enough, and well enough supported, to be considered along with the other risks and benefits of postmenopausal hormone therapy.
Adult↗
A prospective study of aspirin use and primary prevention of cardiovascular disease in women.
OBJECTIVE: The aim of the study was to examine prospectively the association between regular aspirin use and the risk of a first myocardial infarction and other cardiovascular events in women. DESIGN: Prospective cohort study including 6 years of follow-up. SETTING: Registered nurses residing in 11 US states. PARTICIPANTS: US registered nurses (n = 87,678) aged 34 to 65 years and free of diagnosed coronary heart disease, stroke, and cancer at baseline. Followup was 96.7% of total potential person-years of follow-up. MAIN OUTCOME MEASURES: Incidence of myocardial infarction, stroke, cardiovascular death, and all important vascular events. RESULTS: During 475,265 person-years of follow-up, we documented 240 nonfatal myocardial infarctions, 146 nonfatal strokes, and 130 deaths due to cardiovascular disease (total, 516 important vascular events). Among women who reported taking one through six aspirin per week, the age-adjusted relative risk (RR) of a first myocardial infarction was 0.68 (95% confidence interval [CI], 0.52 to 0.89; P = .005), as compared with those women who took no aspirin. After simultaneous adjustment for risk factors for coronary disease, the RR was 0.75 (95% CI, 0.58 to 0.99; P = .04). For women aged 50 years and older, the age-adjusted RR was 0.61 (95% CI, 0.45 to 0.84; P = .002) and the multivariate RR was 0.68 (95% CI, 0.50 to 0.93; P = .02). We observed no alteration in the risk of stroke (multivariate RR = 0.99; P = .94). The multivariate RR of cardiovascular death was 0.89 (P = .56) and of important vascular events was 0.85 (P = .12). When examined separately, the results were nearly identical for the subgroups who took one through three and four through six aspirin per week. Among women who took seven or more aspirin per week, there were no apparent reductions in risk. CONCLUSIONS: The use of one through six aspirin per week appears to be associated with a reduced risk of a first myocardial infarction among women. A randomized trial in women is necessary, however, to provide conclusive data on the role of aspirin in the primary prevention of cardiovascular disease in women.
Adult↗
Biochemical markers of compliance in the Physicians' Health Study.
The Physicians' Health Study is a randomized, double-blind, placebo-controlled trial using a 2 x 2 factorial design to test the effects of low-dose aspirin on risk of cardiovascular disease and beta-carotene supplementation on the incidence of cancer. To evaluate self-reported compliance with assigned treatment, we measured serum thromboxane B2, which is decreased after aspirin use, and plasma beta-carotene in samples of study participants drawn from three geographic locations in three different time periods. Thromboxane B2 levels were markedly lower in those assigned to aspirin (median = 63.5 pg/mL) than in those given aspirin placebo (median = 3,600 pg/mL, P less than .0001). Similarly, those assigned to beta-carotene had significantly higher levels (median = 1,176 ng/mL) than those given placebo (median = 306 ng/mL, P less than .0001). In addition, there was a highly significant positive correlation between levels of these biochemical markers and the self-reports of compliance (r = 0.65 for thromboxane B2 and r = 0.69 for beta-carotene, P less than .0001). These findings support the validity of the self-reported compliance in the Physicians' Health Study.
Adult↗
Toenail trace element levels as biomarkers: reproducibility over a 6-year period.
We assessed the reproducibility over a 6-year period of 16 trace elements measured in toenails by comparing levels in paired specimens collected in 1982-1983 and 1988 from 127 women in the United States. The Spearman correlation coefficients for the reproducibility of toenail levels of selenium and arsenic (both known to reflect intake of these elements) were 0.48 and 0.54. Correlations for other elements ranged from 0.26 (copper) to 0.58 (zinc). In utilizing biomarkers to assess exposure in epidemiological studies of cancer and other chronic disease, random within-person variability in exposure leads to attenuation of measures of association between exposure and disease. We demonstrate the effect of such variability on odds ratios from a hypothetical case-control study. For a true odds ratio of 3.0 (for a comparison of the highest quintile versus the remaining 4 quintiles of exposure) the odds ratios which would be observed in the presence of the degree of within-person variability demonstrated in this study were 2.15 for toenail arsenic and 1.67 for toenail copper levels. Toenail concentrations of certain trace elements are useful biomarkers of exposure in which a single sample is assumed to represent long-term exposure. However, substantial attenuation in measures of association may occur.
Adult↗