The Association of Body Mass Index with Pancreatic Cancer: Variation by Age at Body Mass Index Assessment
Menée aux Etats-Unis auprès de 424 391 hommes et de 538 926 femmes âgés de 30 à 89 ans (durée médiane de suivi : 24,4 ans), cette étude analyse, en fonction de l'âge à l'évaluation, l'association entre l'indice de masse corporelle et la mortalité par cancer du pancréas (8 354 cas)
Higher body mass index (BMI) is associated with increased risk of pancreatic cancer in epidemiologic studies but BMI has usually been assessed at older ages, potentially underestimating the full impact of excess weight. We examined the association between BMI and pancreatic cancer mortality among 963,317 adults aged 30-89 years at enrollment into Cancer Prevention Study-II in 1982. During follow-up through 2014, 8,354 participants died of pancreatic cancer. Hazard ratios (HRs) per 5 BMI-units, calculated using proportional hazards regression, declined steadily with age at BMI assessment, from 1.25 (95% confidence interval (CI) 1.18, 1.33) in those aged 30-49 at enrollment to 1.13 (95% CI 1.02, 1.26) in those aged 70-89 (p-trend=0.005). Based on a HR of 1.25 per 5 BMI-units at age 45, we estimate 28% of US pancreatic cancer deaths in those born from 1970-74 will be attributable to BMI≥25, nearly twice the equivalent proportion in those born in the 1930s, a birth cohort with much lower BMI in middle age. These results suggest BMI before age 50 is more strongly associated with pancreatic cancer risk than BMI at older ages and underscore the importance of avoiding excess weight gain before middle age for preventing this highly fatal cancer.