Cumulative risk of colon cancer up to age 70 years by risk factor status using data from the Nurses' Health Study

Abstract

The authors developed a comprehensive model of colon cancer incidence that allows for nonproportional hazards and accounts for the temporal nature of risk factors. They estimated relative risk based on cumulative incidence of colon cancer by age 70 years. Using multivariate, nonlinear Poisson regression, they determined colon cancer risk among 83,767 participants in the Nurses' Health Study. The authors observed 701 cases of colon cancer between 1980 and June 1, 2004. There was increased risk for a positive family history of colon or rectal cancer (55%), 10 or more pack-years of cigarette smoking before age 30 years (16%), and tallness (67 inches (170 cm) vs. 61 inches (155 cm): 19%). Reduced risk was observed for current postmenopausal hormone use (-23%), being physically active (21 metabolic equivalent (MET)-hours/week vs. 2 MET-hours/week: -49%), taking aspirin (7 tablets/week vs. none: -29%), and being screened (-24%). Women who smoked, had a consistently high relative weight, had a low physical activity level, consumed red or processed meat daily, were never screened, and consumed low daily amounts of folate had almost a 4-fold higher cumulative risk of colon cancer by age 70 years. For women with a high risk factor profile, adopting a healthier lifestyle could dramatically reduce colon cancer risk.

Figure 1.

Age-specific incidence of colon cancer per 100,000 person-years for A) a woman with 2 metabolic equivalent (MET)-hours/week of physical activity and a woman who reported 21 MET-hours/week of physical activity from age 30 years to age 70 years; B) a woman who consumed 1 serving of red or processed meat per day from age 30 years to age 70 years and a woman who consumed no red or processed meat at the same ages; C) a nonsmoking woman and a woman with 10 pack-years of smoking before the age of 30 years; and D) a woman with no aspirin use and a woman who used 7 tablets of aspirin per week from age 30 years to age 70 years, Nurses’ Health Study, 1980–2004. Unless otherwise specified, all women were assumed to have no postmenopausal hormone use, no family history of colon or rectal cancer, average height, no pack-years of smoking before age 30 years, no aspirin use, no red meat or processed meat intake, folate intake of 300 μg/day, and physical activity of 13.5 MET-hours/week, and to have never been screened for colon cancer.

Figure 2.

Age-specific incidence of colon cancer per 100,000 person-years from age 30 years to age 70 years 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, and had a folate intake of 150 μg/day); 2) 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, and had a folate intake of 300 μg/day); and 3) 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, 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, and to have never been screened for colon cancer.

Figure 3.

Age-specific incidence of colon cancer per 100,000 person-years from age 30 years to age 70 years, according to aspirin use, 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, and had a folate intake of 150 μg/day) and 2) 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, 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, and to have never been screened for colon cancer.

Figure 4.

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.