a b s t r a c t
Purpose: Epidemiologic and experimental studies suggest that dietary fat intake may affect risk of pancreatic cancer, but published results are inconsistent.
Methods: We examined risk associations for specific types of dietary fat intakes and related food sources among 111,416 participants in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. We used Cox proportional hazards regression to examine associations between fat intake and pancreatic cancer risk.
Results: Over a mean 8.4 years of follow-up, 411 pancreatic cancer cases were identified. We observed an inverse association between saturated fat intake and pancreatic cancer risk (hazard ratio [HR], 0.64 comparing extreme quintiles; 95% confidence interval [CI], 0.46e0.88), but the association became weaker and nonsignificant when individuals with fewer than 4 years of follow-up were excluded to avoid possible reverse causation (HR, 0.88; 95% CI, 0.58e1.33). Total fat intake showed a similar pattern of association, whereas intakes of monounsaturated and polyunsaturated fats and fats from animal or plant sources showed no associations with risk.
Conclusions: These results do not support the hypothesis of increased pancreatic cancer risk with higher fat consumption overall or by specific fat type or source. Dietary changes owing to undetected disease may explain the observed inverse association with saturated fat.
In conclusion, our findings do not support a positive association between dietary fat intake and risk of pancreatic cancer. Instead we observed an inverse association that was attenuated with exclusion of cases with shorter term follow-up. Our results highlight the need to carefully examine possible reverse causation in studies of diet and pancreatic malignancy and the importance of basing conclusions on a body of evidence from studies with longer term follow-up.