Red meat consumption, cooking mutagens, NAT1/2 genotypes and pancreatic cancer risk in two ethnically diverse prospective cohorts

There is limited evidence on the association between red meat consumption and pancreatic cancer among ethnic minorities. We assessed this relationship in two large prospective cohorts: the Multiethnic Cohort Study (MEC) and the Southern Community Cohort Study (SCCS). Demographic, dietary, and other risk factor data were collected at cohort entry. Red meat intake was assessed using cohort-specific validated food frequency questionnaires. Incident pancreatic cancer cases were identified via linkages to state cancer registries. Cox regression was used to calculate relative risks (RRs) and 95% confidence intervals (CIs) for the association of red meat intake with pancreatic cancer risk in each cohort. We performed additional analyses to evaluate cooking methods, mutagens and effect modification by NAT1/2 genotypes. From a total of 184,542 (MEC) and 66,793 (SCCS) at-risk participants, we identified 1,618 (MEC) and 266 (SCCS) incident pancreatic cancer cases. Red meat consumption was associated with pancreatic cancer risk in the MEC (RR(Q4vsQ1) 1.18, 95% CI 1.02–1.37) and with borderline statistical significance in the SCCS (RR(Q4vsQ1) 1.31, 95% CI 0.93–1.86). This association was significant in African Americans (RR(Q4vsQ1) 1.49, 95% CI 1.06–2.11) and Latinos (RR(Q4vsQ1) 1.44, 95% CI 1.02–2.04) in the MEC, and among African Americans (RR(Q4vsQ1) 1.55, 95% CI 1.03–2.33) in the SCCS. NAT2 genotypes appeared to modify the relationship between red meat and pancreatic cancer in the MEC (p(interaction)=0.03). Our findings suggest that the associations for red meat may be strongest in African Americans and Latinos. The mechanisms underlying the increased risk for these populations should be further investigated.