Measured body mass index in adolescence and the incidence of colo-rectal cancer in a cohort of 1.1 million males
Cette étude de cohorte israélienne incluant plus d'un million de participants masculins évalue l'association entre l'indice de masse corporelle à l'adolescence (de 16 à 19 ans) et le risque de cancer colorectal
Background & Aims: The increasing prevalence of adolescent obesity affects adult health. We investigated the association of adolescent overweight with colorectal cancer incidence in a large cohort of males. Methods: Body mass index (BMI) was measured in 1.1 million Jewish Israeli males who underwent a general health examination at ages 16-19 between the years 1967-2005. Overweight was defined as BMI ≥85th percentile of the standard United States distribution in adolescence. Colorectal cancer was identified by linkage with the Israel National Cancer Registry up to 2006. The mean follow-up period was 17.6±10.9 years, reflecting 19.5 million person years. Cox proportional hazards modeling was used. Results: The prevalence of adolescent overweight increased from 9.9% to 16.8% in the first 10 and last 10 annual examination cohorts. 445 colon and 193 rectal cancer cases were detected. Overweight predicted an increased risk of colon cancer [hazard ratio (HR) =1.53; 95% confidence interval (CI), 1.17-2.02, P=0.002], but not of rectal cancer (HR=1.09; 95% CI, 0.38-1.73, P=0.72). The risk was greatest for non-mucinous adenocarcinoma of the colon (HR=1.68, 95% CI 1.26-2.23, P=0.001). The association of BMI ≥ 85th with colon cancer was even more pronounced in analyses that were restricted to men followed until at least 40 years of age [N= 367,478; HR=1.75 (95% CI: 1.33-2.3, P<0.001)]. Conclusions: Adolescent overweight is substantially associated with colon cancer incidence in young to middle-aged adults. Impact: These long-term sequelae add to the urgency to seriously address increasing childhood and adolescent obesity with its attendant increasing population impact.