Objectives: To study the association between waist circumference and colorectal cancer, and whether it is independent of body mass index (BMI).
Methods: Between 1997 and 2005, 953 incident colorectal cancer cases (546 men and 407 women) were identified among 95,151 participants (44,068 men and 51,083 women) from the Cancer Prevention Study-II Nutrition Cohort.
Results: Waist circumference was associated with increased colorectal cancer incidence in both men (multivariable adjusted rate ratio (RR) 1.68, 95% confidence interval (CI) 1.12-2.53 for waist circumference > or =120 cm compared to <95 cm, p trend = 0.006) and women (RR 1.75, 95% CI 1.20-2.54 for > or =110 compared to <85 cm, p trend = 0.003). High levels of BMI were also associated with increased risk. After adjustment for BMI, waist circumference remained associated with a nonstatistically significant increase in colorectal cancer incidence in both men (RR 1.41, 95% CI 0.81-2.45 for > or =120 compared to <95 cm, p trend = 0.10) and women (RR 1.48, 95% CI 0.89-2.48 for > or =110 compared to <85 cm, p trend = 0.13).
Conclusions: Our results confirm that waist circumference is associated with increased colorectal cancer incidence, possibly partially independent of BMI.