Abstract
The latest report by the World Cancer Research Fund/American Institute of Cancer Research concluded that there is convincing evidence that adult height and obesity are risk factors for colorectal cancer. However, studies relating body fatness during early life to the risk of colorectal cancer or adenoma are scarce. In the Nurses' Health Study II, participants recalled adult attained height and body shape at ages 5, 10, and 20 years (using a 9-level pictogram: 1 = most lean body shape, 9 = most overweight body shape) at baseline. Among 32,707 women who had at least one lower bowel endoscopy between 1991 and 2005, 2,327 colorectal adenomas were documented. Adult height was positively associated with risk of colorectal adenoma (multivariate OR per 2 inch increment 1.05, 95% CI: 1.01-1.09). Comparing women who were overweight (body shape level 6 or higher) to women who were most lean (body shape level 1), ORs (95% CI, P(trend)) of colorectal adenoma for body shapes at ages 5, 10, and 20 years were 1.44 (1.04-1.99, 0.01), 1.21 (0.93-1.56, 0.05), and 1.03 (0.74-1.42, 0.58), respectively. Adjustment for adult body mass index did not change results substantially. The positive associations for body fatness at ages 5 and 10 years as well as adult height were restricted to distal adenoma, while not seen for proximal or rectal adenoma. Higher height and body fatness during childhood was associated with increased risk of distal adenoma later in life, independent of adult body weight.