Measured body mass index in adolescence and the incidence of pancreatic cancer in a cohort of 720,000 Jewish men

Purpose: The increasing prevalence of adolescent obesity affects adult health. We investigated the association of adolescent overweight with pancreatic cancer incidence in a cohort of 720,927 Jewish Israeli men. Methods: Body mass index (BMI) was measured during a general health examination at ages 16-19 between the years 1967 and 1995. Overweight was defined as BMI ≥ 85th percentile of the reference US-CDC distribution in adolescence. Pancreatic cancer was identified by linkage with the Israel National Cancer Registry up to 2006. Results: The mean follow-up period was 23.3 ± 8.0 years. During 16.8 million person-years, 98 cases of pancreatic cancer were detected. Using Cox proportional hazards modeling, overweight in adolescence predicted an increased risk of pancreatic cancer [hazard ratio (HR) = 2.09; 95% confidence interval (CI): 1.26-3.50, p = 0.005]. Compared with adolescents with 'normal' range BMI Z-scores (-1 to +1), adolescents with Z-scores > 1 showed significantly increased risk [HR, 2.28 (95% CI: 1.43-3.64), p = 0.001]. Lower education level (10 or less years of schooling vs. 11-12 years) was also associated with increased risk of pancreatic cancer [HR 1.90 (95% CI: 1.27-2.86, p = 0.002)], whereas height, country of origin and immigration status were not. Conclusions: Adolescent overweight is substantially associated with pancreatic cancer incidence in young to middle-aged adults. Applying our point estimates to the 16.8% prevalence of excess weight in Israeli adolescents in the past decade suggests a population fraction of 15.5% (95% CI: 4.2-29.6%) for pancreatic cancer attributable to adolescent overweight in Israel.