BMI at younger vs older age strongly predicts pancreatic cancer

A higher body mass index (BMI) appears to translate to an increased risk of developing pancreatic cancer in men and women aged <50 years but not in those who are older, a study has found.

The study used data from the Cancer Prevention Study-II in 1982 and included 963,317 adults (55.94 percent female) aged 30–89 years at baseline. The average age at BMI assessment was 56 years.

During follow-up through 2014, 8,354 participants died of pancreatic cancer. Proportional hazards regression showed that the risk of pancreatic cancer declined steadily with age at BMI assessment. Hazard ratios (HRs) per 5 BMI-units ranged from 1.25 (95 percent confidence interval [CI], 1.18–1.33) in those aged 30–49 years to 1.13 (95 percent CI, 1.02–1.26) in those aged 70–89 years (p-trend=0.005).

Researchers noted that based on an HR estimate of 1.25 per 5 BMI-units at age 45 years, 28 percent of pancreatic cancer deaths in the US among individuals born from 1970–1974 will be attributable to BMI >25 kg/m². This number is nearly twice the estimated 15 percent pancreatic cancer deaths among men and women born in the 1930s, a birth cohort with much lower BMI in middle age.

The present data suggest that BMI measured only at older ages is unlikely to fully capture the impact of high BMI earlier in life on the risk of pancreatic cancer, the researchers said. They emphasized the importance of preventing weight gain before middle age, at both individual and community-level, for reducing rates of this highly fatal cancer in the 2030s and beyond.