Background: Dietary pattern analyses characterizing combinations of food intakes offer conceptual and statistical advantages over food- and nutrient-based analyses of disease risk. However, few studies have examined dietary patterns and pancreatic cancer risk and none focused on the 2005 Dietary Guidelines for Americans. We used the Healthy Eating Index 2005 (HEI-2005) to estimate the association between meeting those dietary guidelines and pancreatic cancer risk.
Methods: We calculated the HEI-2005 score for 537 218 men and women in the National Institutes of Health-American Association of Retired Persons Diet and Health Study using responses to food frequency questionnaires returned in 1995 and 1996. We used Cox proportional hazards regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for risk of pancreatic cancer according to HEI-2005 quintiles and explored effect modification by known risk factors. P interaction values were calculated using the Wald test. All statistical tests were two-sided.
Results: We identified 2383 incident, exocrine pancreatic cancer cases (median = 10.5 years follow-up). Comparing participants who met the most dietary guidelines (Q5) with those who met the fewest guidelines (Q1), we observed a reduced risk of pancreatic cancer (HR = 0.85, 95% CI = 0.74 to 0.97). Among men there was an interaction by body mass index (P interaction = .03), with a hazard ratio of 0.72 (95% CI = 0.59 to 0.88) comparing Q5 vs Q1 in overweight/obese men (body mass index ≥ 25 kg/m(2)) but no association among normal weight men.
Conclusions: Our findings support the hypothesis that consuming a high-quality diet, as scored by the HEI-2005, may reduce the risk of pancreatic cancer.