Meat and dairy consumption and subsequent risk of prostate cancer in a US cohort study

Objective: To evaluate the association of meat and dairy food consumption with subsequent risk of prostate cancer. Methods: In 1989, 3,892 men 35+ years old, who participated in the CLUE II study of Washington County, MD, completed an abbreviated Block food frequency questionnaire. Intake of meat and dairy foods was calculated using consumption frequency and portion size. Incident prostate cancer cases (n = 199) were ascertained through October 2004. Cox proportional hazards regression was used to calculate hazard ratios (HR) of total and advanced (SEER stages three and four; n = 54) prostate cancer and 95% confidence intervals (CI) adjusted for age, BMI at age 21, and intake of energy, saturated fat, and tomato products. Results: Intakes of total meat (HR = 0.90, 95% CI 0.60-1.33, comparing highest to lowest tertile) and red meat (HR = 0.87, 95% CI 0.59-1.32) were not statistically significantly associated with prostate cancer. However, processed meat consumption was associated with a non-statistically significant higher risk of total (5+ vs. ≤1 servings/week: HR = 1.53, 95% CI 0.98-2.39) and advanced (HR = 2.24; 95% CI 0.90-5.59) prostate cancer. There was no association across tertiles of dairy or calcium with total prostate cancer, although compared to ≤1 serving/week consumption of 5+ servings/week of dairy foods was associated with an increased risk of prostate cancer (HR = 1.65, 95% CI 1.02-2.66). Conclusion: Overall, consumption of processed meat, but not total meat or red meat, was associated with a possible increased risk of total prostate cancer in this prospective study. Higher intake of dairy foods but not calcium was positively associated with prostate cancer. Further investigation into the mechanisms by which processed meat and dairy consumption might increase the risk of prostate cancer is suggested.