Age-specific incidence of colon cancer per 100,000 person-years from age 30 years to age 70 years, according to screening behavior, for 1) a high-risk” participant (one who accrued 10 pack-years of smoking before age 30 years, had a consistently high relative body weight, had physical activity of 2 metabolic equivalent (MET)-hours/week, consumed 1 serving of red or processed meat per day, was never screened for colon cancer, and had a folate intake of 150 μg/day); 2) a high-risk participant who was screened from age 50 years to age 70 years; 3) a “moderate-risk” participant (one who was a nonsmoker, had an average body mass index, had physical activity of 13.5 MET-hours/week, did not consume red or processed meat, was never screened, and had a folate intake of 300 μg/day); and 4) a “low-risk” participant (one who was a nonsmoker, had a consistently low relative body weight, had physical activity of 21 MET-hours/week, did not consume red or processed meat, was never screened, and had a folate intake of 400 μg/day), Nurses’ Health Study, 1980–2004. All women were assumed to have no postmenopausal hormone use, no family history of colon or rectal cancer, average height, and no aspirin use.