APooled analysis of body mass index and pancreatic cancer mortality in African Americans

Background: Pancreatic cancer is a leading cause of cancer-related mortality in the United States and both incidence and mortality are highest in African Americans. Obesity is also disproportionately high in African Americans, but limited data are available on the relation of obesity to pancreatic cancer in this population. Methods: Seven large prospective cohort studies pooled data from African American participants. Body mass index (BMI) was calculated from self-reported height and weight at baseline. Cox regression was used to calculate HRs and 95% confidence intervals (CI) for levels of BMI relative to BMI 18.5-24.9, with adjustment for covariates. Primary analyses were restricted to participants with ≥5 years of follow-up because weight loss before diagnosis may have influenced baseline BMI in cases who died during early follow-up. Results: In follow-up of 239,597 participants, 897 pancreatic cancer deaths occurred. HRs were 1.08 (95% CI, 0.90-1.31) for BMI 25.0 to 29.9, 1.25 (95% CI, 0.99-1.57) for BMI 30.0 to 34.9, and 1.31 (95% CI, 0.97-1.77) for BMI ≥35.0 among those with ≥5 years of follow-up (P_trend = 0.03). The association was evident among both sexes and was independent of a history of diabetes.Astronger association was observed among never-smokers (BMI ≥30 vs. referent: HR = 1.44; 95% CI, 1.02-2.03) than among smokers (HR = 1.16; 95% CI, 0.87-1.54; P_interaction = 0.02). Conclusion: The findings suggest that obesity is independently associated with increased pancreatic cancer mortality in African Americans. Impact: Interventions to reduce obesity may also reduce risk of pancreatic cancer mortality, particularly among never-smokers.