At baseline, participants completed a questionnaire to ascertain age, race or ethnicity, education, smoking habits (current, former, or never), alcohol consumption (drinks per week), and exercise or walking activity. Physical examination variables measured at baseline were body weight, height, waist and hip circumference, and systolic and diastolic blood pressure. At baseline, at year 1, and at the end-of-trial visit, participants had fasting blood tests for levels of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, and lipoprotein(a) measured by the Lipoprotein Analytical Laboratory at Johns Hopkins Hospital, Baltimore, Maryland. Fasting serum glucose level was measured at baseline, at year 1, and at the end-of-trial visit. Venous blood was obtained in the morning after a 12-hour fast, and SmithKline Beecham Clinical Laboratory, Van Nuys, California, analyzed the samples using the hexokinase enzymatic method. We determined coefficients of variation by using ChemTrac (Medical Analysis Systems, Inc., Camarillo, California) control. The coefficient of variation for serum glucose level was 1.6% at a mean value (±SD) of 4.2 ± 0.05 mmol/L (77 ± 1.0 mg/dL) and 1.1% at a mean value (±SD) of 14.6 ± 0.16 mmol/L (266 ± 3.0 mg/dL). Adherence to study medication was reassessed every 4 months, at each visit.