Iron is a risk factor for both diabetes and pancreatic cancer, but whether iron works synergistically with diabetes to increase pancreatic cancer is unknown. Furthermore, risks of both diabetes and pancreatic cancer are increased among African Americans (AA), without clear differences in either iron stores or dietary iron consumption. We therefore tested whether dietary iron consumption increased risk of subsequent pancreatic cancer in a population of AA and Whites with and without diabetes. We conducted a follow up study of pancreatic cancer incidence (2002-2015), using the Southern Community Cohort, a population of mostly low income AA and White participants aged 40-79, with (n=23,489, 40%) and without (n=35,105, 60%) diabetes, recruited from federally qualified health centers. Logistic regression was used to compute ORs (95% CIs) for the risk of incident pancreatic cancer. All models accounted for age, sex, race, BMI, alcohol consumption, and dietary iron consumption. Alcohol and iron consumption were natural log transformed before analyses. There were 262 incident pancreatic cancer cases. Risk of pancreatic cancer and dietary iron consumption were not associated in subjects without diabetes (OR=1.08, 95% CI=0.81-1.45), but trended toward an association in those with diabetes (OR=1.26, 95% CI=0.84-1.90). However, there was a significant three-way interaction among diabetes, race, and total dietary iron consumption (p-interaction=0.04). When stratified by diabetes and race, total dietary iron consumption increased pancreatic cancer risk by over two-fold among Whites with diabetes (OR=2.47, 95% CI=1.14-5.37), but showed no association in any of the other three groups, namely AA with (1.00, 0.97-1.03) and w/o (1.09, 0.78-1.53) diabetes and Whites w/o diabetes (1.03, 0.56-1.89). Our data suggests that increased dietary iron consumption increases risk of pancreatic cancer among Whites with diabetes.
B. Conway: None. A.G. Hudson: None. D.A. McClain: None. W.J. Blot: None.