Epidemiology in Medicine, Volume 515

analysis aspirin assess attributable risk bacteriuria beta-carotene blood pressure breast cancer calculated case-control study cholesterol cholesterol levels cigarette smoking compared comparison group confidence interval confounding factor considered consumption coronary heart disease death rates detect diagnosis disease status distribution endometrial cancer Engl Epidemiol epidemiologic epidemiologic studies estrogens evaluation example exposed and nonexposed exposure and disease exposure status follow-up Health Study Hennekens hospital hypertension hypothesis incidence rate increased risk intervention study investigation lung cancer magnitude matching measure mg/dl misclassification myocardial infarction null oral contraceptive outcome of interest participants particular patients percent period physical activity placebo possible potential confounding prevalence proportion public health ratio relationship relative risk reported risk factors sample screening program screening test selection bias specific standard statistically significant study design study groups study population subjects Table tion total number treatment valid valid statistical variables women