School Milk and Risk of Colorectal Cancer: A National Case-Control Study

Abstract

To determine whether school milk consumption in childhood decreased the risk of adult colorectal cancer, the authors conducted a national population-based, case-control study of 562 cases and 571 controls. The authors identified new cases of colorectal cancer in 2007 among people aged 30–69 years from the New Zealand Cancer Registry. Controls were randomly selected from the electoral rolls and frequency matched to cases in 5-year age groups. Participation in school milk programs was associated with a reduced odds ratio for colorectal cancer (odds ratio (OR) = 0.70, 95% confidence interval (CI): 0.51, 0.96). Odds ratios decreased with increasing numbers of bottles of milk drunk compared with no school milk (for 1–799 bottles, OR = 1.04, 95% CI: 0.66, 1.67; for 800–1,199 bottles, OR = 0.81, 95% CI: 0.51, 1.29; for 1,200–1,599 bottles, OR = 0.62, 95% CI: 0.41, 0.93; for 1,600–1,799 bottles, OR = 0.57, 95% CI: 0.37, 0.90; and for 1,800 or more bottles, OR = 0.62, 95% CI: 0.41, 0.96). Participation in school milk programs in New Zealand was associated with a 2.1% reduction (95% CI: 0.7, 3.5) in the odds ratio for colorectal cancer for every 100 half-pint bottles drunk (1 half-pint bottle = 284 mL).

calcium, case-control studies, child, colorectal neoplasms, milk