Milk and other dairy foods in relation to prostate cancer progression: Data from the Cancer of the Prostate Strategic Urologic Research Endeavor (CAPSURE).

Abstract

168 Background: Recent research suggests a positive relationship between intake of high-fat dairy, particularly whole milk, and prostate cancer (PC) mortality. However, data are limited in men after PC diagnosis. Methods: We conducted a prospective cohort study among 1336 men with non-metastatic PC in CaPSURE. The men answered a food frequency questionnaire (FFQ) in 2004-2005 (median time from diagnosis to the FFQ: 2 y) and were followed for PC progression until April 2016. PC progression was defined as: prostate cancer death, bone metastasis from PC, biochemical recurrence, or secondary treatment. Multivariate Cox Proportional Hazards regression was used to calculate hazards ratios (HR) and 95% confidence intervals (CI) for associations between total, whole fat, and low-fat milk; total, high-fat, and low-fat dairy; and specific dairy items and PC progression. We adjusted for time from diagnosis to FFQ, calories, age at diagnosis, CAPRA score, smoking, BMI, walking pace, and primary PC treatment. Results: 314 events were observed (mean follow-up: 7.2 y). Whole milk was associated with an increased risk of PC progression when adjusting for age, calories, and time since diagnosis (HR ≥1 vs. <1 serving/wk: 1.37; 95% CI: 1.03, 1.84; p-value: 0.03). This association was slightly attenuated, and not statistically significant, when adjusting for clinical and other lifestyle factors (HR: 1.27; 95% CI: 0.91, 1.77; p-value: 0.15). High-fat dairy intake also appeared associated with an increased risk of PC progression, but the association was not statistically significant (adjusted HR ≥4 vs. <1 servings/day: 1.40; 95% CI: 0.92, 2.13; p-trend: 0.18). Post-diagnostic intakes of low-fat milk and other dairy foods were not associated with PC progression. Conclusions: Post-diagnostic intake of milk and other dairy foods was not associated with PC progression. Research in populations with greater intake of whole milk is warranted to further investigate whether post-diagnostic whole milk intake increases risk of PC progression. Funding: This work was funded by the DOD Prostate Cancer Research Program (W81XWH-13-2-0074) and the NIH (K07CA197077).