Demographic data and data for potential confounders were collected and defined as follows: race was self-reported, and categorized as white, black/African American, Asian/Pacific Islander, or other. Body mass index (BMI) was estimated from usual adult weight and height [weight (kg)/height (m2)], and was categorized based on World Health Organization criteria: <25.0 (lean to normal), 25.0–29.9 (overweight), and ≥30.0 (obese). Frequency of recreational physical activity for at least 30 min per episode was recorded as never or <1/month, 1–2/month, 3–4/month, 2–3/week, 4–6/week, and ≥1/day. Participants were defined as smokers if they had smoked ≥100 cigarettes, or cigars or pipes at least once a month for ≥6 months in their lifetime. Cigarette smokers were categorized into four groups: never smokers; former smokers (two groups) who quit >15 years ago or 1–15 years prior to diagnosis/interview; and current smokers including those who had quit within 1 year of diagnosis/interview. Total caloric intake (expressed as kilocalories per day), vitamin intake (vitamins A, B1–B12, C, E, D), and calcium intake were estimated based on results of a food-frequency questionnaire and divided into quartiles based on
