Introduction: Literature is limited regarding post-diagnostic dairy intake and prostate cancer survival. We evaluated dietary intake of total, high-fat, and low-fat dairy in relation to disease-specific and total mortality after prostate cancer diagnosis.
Methods: We included 926 men from the Physicians' Health Study diagnosed with non-metastatic prostate cancer from 1982 to 2012, who completed a food frequency questionnaire a median of 5.1 years after diagnosis and were followed thereafter to assess mortality for a median of 9.9 years. Cox proportional hazards regression estimated the association between frequency categories of dairy intake and prostate cancer-specific and all-cause mortality. Person-years of follow-up were counted from the date of FFQ completion until death or end of follow-up, whichever came first. Models were adjusted for age at diagnosis, total energy intake, vigorous exercise, body mass index, smoking status, clinical stage, Gleason score, prostate specific antigen levels at diagnosis, indicators for prudent dietary pattern and western dietary pattern, and time interval between diagnosis and FFQ completion.
Results: A total of 333 men died during follow-up, including 56 due to prostate cancer. Post-diagnosed dairy consumption was relatively limited, with medians of 1.7 servings/day for total dairy intake, 0.64 servings/day for high-fat dairy intake, and 1 serving/day for low-fat dairy intake. Men consuming dairy foods more than 3 times per day had a 76% higher risk of total mortality and a 144% increased risk of prostate cancer specific mortality than those consuming less than one dairy product per day (relative risk (RR)=1.76, 95% confidence interval (CI): 1.21, 2.55, Plinear-trend=0.001 for total mortality; RR=2.44, 95%CI: 0.99, 6.03, Plinear-trend=0.03 for disease-specific mortality). For total mortality, high-fat dairy intake (RR≥2 times/day vs <3 times/week=1.69, 95%CI: 1.11, 2.57) appeared to be more deleterious than low-fat dairy intake (RR≥2 times/day vs <3 times/week=1.25, 95%CI: 0.88, 1.77). The elevated risks of prostate cancer- specific mortality were comparable for high-fat dairy (RR≥2 times/day vs <3 times/week=1.81, 95% CI=0.71, 4.59) and low fat-dairy (RR≥2 times/day vs <3 times/week=1.83, 95%CI=0.75, 4.47).
Conclusions: Among men diagnosed with non-metastatic prostate cancer, post-diagnostic dairy food intake was associated with greater prostate cancer-specific and all-cause mortality. The associations of low-fat and high-fat dairy were comparable for prostate cancer-specific mortality, while intake of high-fat dairy products may be particularly detrimental for total mortality.
Citation Format: Meng Yang, Stacey A. Kenfield, Erin L. Van Blarigan, Kathryn M. Wilson, Julie L. Batista, Howard D. Sesso, Jing Ma, Meir J. Stampfer, Jorge E. Chavarro. Dairy intake in relation to disease-specific and total mortality after prostate cancer diagnosis. [abstract]. In: Proceedings of the Thirteenth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2014 Sep 27-Oct 1; New Orleans, LA. Philadelphia (PA): AACR; Can Prev Res 2015;8(10 Suppl): Abstract nr A32.