Age at index date was based on self-report and confirmed in health plan databases. Subjects also provided self-reported information on gender, racial and ethnic group, marital status, employment status, annual household income, parental and sibling history of CHD, personal medical history of stroke, prior peripheral artery disease, diabetes mellitus, and hypertension. Self-reported information on smoking status at index date (current, former, or never) as well as alcohol drinking pattern and intensity of leisure-time activity during the 12 months before the study visit date were obtained. The most recent outpatient systolic and diastolic blood pressure values before index date were obtained from ambulatory visit databases, which have been shown to reliably reflect chronic blood pressure levels in our database (15). Body mass index (kilograms per square meter) was measured at the study visit using standard procedures. We used automated health plan pharmacy databases to identify receipt of selected cardiac medications during the 160 days before index date. This time period was chosen to identify medications prescribed for chronic conditions, which are generally given as a 90- to 100-day supply. We identified recent use of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins), niacin or nicotinic acid derivatives, fibrates, bile acid–binding resins, beta-adrenergic antagonists, calcium-channel antagonists, alpha-adrenergic antagonists, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, diuretic agents, and, among women, hormone replacement therapy (estrogen with or without progestins). We searched health plan laboratory databases for evidence of testing for total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglyceride levels before index date. LDL cholesterol values were routinely calculated using the Friedewald equation (16). Among tested patients, we examined the most recent value for each lipoprotein component before index date.