Childhood Body Mass Index is associated with risk of adult colon cancer in men - an association modulated by pubertal change in Body Mass Index
Menée en Suède auprès de 37 663 hommes, cette étude évalue l'association entre l'indice de masse corporelle à l'âge de 8 ans et de 20 ans et le risque de cancer colorectal à l'âge adulte (257 cas de cancer du côlon, 159 cas de cancer du rectum)
Background : The relative contribution of childhood and pubertal BMI for the risk of adult colorectal cancer is not known. The aim of this study was to evaluate the independent associations for childhood BMI and pubertal BMI change with risk of colorectal cancer in men. Materials and Methods : We included 37 663 men born 1946-1961 who had weight and height measured at age 8 (childhood) and 20 (young adult age) years of age available from the BMI Epidemiology Study (BEST). Information on colorectal cancer was retrieved from the Swedish National Patient Register (257 cases of colon cancer, 159 cases of rectal cancer). Results : Childhood BMI at 8 years of age (Hazard Ratio 1.19 per SD increase [95% Confidence Interval 1.06;1.33]), but not pubertal BMI change (HR 1.02 [0.90;1.15]), was associated with increased risk of colon cancer. Due to a significant interaction between childhood BMI and pubertal BMI change (p<0.001), we stratified the analyses according to the median of pubertal BMI change. Childhood BMI was associated with risk of colon cancer in individuals with a pubertal BMI change above, but not below, the median (above:1.48 [1.26;1.74]; below 0.95 [0.80;1.12]). Neither childhood BMI nor pubertal BMI change was associated with rectal cancer. Conclusions : High childhood BMI was associated with increased risk of colon cancer only if it was followed by a pubertal BMI increase above the median. Impact : Further studies should evaluate pre-pubertal childhood BMI in relation to pubertal BMI change and BMI in middle age for the risk of colon cancer.