Genetic variation in the lactase gene, dairy product intake and risk for prostate cancer in the European prospective investigation into cancer and nutrition.

High dairy protein intake has been found to be associated with increased prostate cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC). To further examine this possible relationship, we investigated the hypothesis that a genetic polymorphism in the lactase (LCT) gene might be associated with elevated dairy product intake and increased prostate cancer risk in a case-control study nested in EPIC. The C/T-13910 lactase variant (rs4988235) was genotyped in 630 men with prostate cancer and 873 matched control participants. Dairy product consumption was assessed by diet questionnaire. Odds ratios (ORs) for prostate cancer in relation to lactase genotype were estimated by conditional logistic regression. Lactase genotype frequency varied significantly between countries, with frequencies of the T (lactase persistence) allele ranging from 7% in Greece to 79% in Denmark. Intake of milk and total dairy products varied significantly by lactase genotype after adjustment for recruitment center; adjusted mean intakes of milk were 44.4, 69.8 and 82.3 g/day among men with CC, CT and TT genotypes, respectively. The lactase variant was not significantly associated with prostate cancer risk, both in our data (adjusted OR for TT vs. CC homozygotes: 1.10, 95% CI: 0.76-1.59) and in a meta-analysis of all the published data (combined OR for T allele carriers vs. CC homozygotes: 1.12, 0.96-1.32). These findings show that while variation in the lactase gene is associated with milk intake in men, the lactase polymorphism does not have a large effect on prostate cancer risk.

Lifestyle factors and serum androgens among 636 middle aged men from seven countries in the European Prospective Investigation into Cancer and Nutrition (EPIC).

OBJECTIVE: To evaluate the association between lifestyle and dietary factors and serum concentrations of androgens in middle-aged healthy men. METHODS: We conducted a cross-sectional analysis of the association of lifestyle factors with circulating concentrations of androstenedione (A-dione), 3-alpha-androstanediol glucuronide (A-diol-g), testosterone (T), SHBG (sex hormone-binding globulin), and free testosterone (FT) among 636 men in the European Prospective Investigation into Cancer and Nutrition. RESULTS: Compared with the youngest age group (40-49 years), the oldest (70-79 years) had a higher mean concentration of SHBG (by 44%) and lower mean concentrations of A-diol-g (by 29%) FT (19%). Men in the highest BMI group (> or =29.83 kg/m(2)) had a higher mean A-diol-g concentration (by 38%) and lower mean concentration of T (by 20%) SHBG (29%) compared with the lowest (<24.16 kg/m(2)). Current smokers had higher mean concentrations of T (by 13%), SHBG (14%), and A-dione (15%) compared with never smokers. Physical activity and dietary factors were not associated with androgen concentrations, although men in the highest fifth of alcohol intake had higher mean concentrations of A-dione (by 9%), FT (11%) compared with the lowest. CONCLUSION: Our results suggest that age, body weight, smoking, and alcohol intake are associated with circulating androgen concentrations in men.

Nitrosamines and heme iron and risk of prostate cancer in the European prospective investigation into cancer and nutrition.

BACKGROUND: The evidence about nitrosamines and heme iron intake and cancer risk is limited, despite the biologic plausibility of the hypothesis that these factors might increase cancer risk. We investigated the association between dietary nitrosamines and heme iron and the risk of prostate cancer among participants of European Prospective Investigation into Cancer and Nutrition (EPIC). METHODS: Data on food consumption and complete follow-up for cancer occurrence was available for 139,005 men, recruited in 8 European countries. Estimates of HRs were obtained by proportional hazard models, stratified by age at recruitment, and study center, and adjusted for total energy intake, smoking status, marital status, dairy products, educational level, and body mass index. RESULTS: After a mean follow-up of 10 years, 4,606 participants were diagnosed with first incident prostate cancer. There was no overall association between prostate cancer risk and nitrosamines exposure (preformed and endogenous) or heme iron intake (HR for a doubling of intake: 1.00; 95% CI: 0.98-1.03 for N-Nitrosodimethlyamine, 0.95; 95% CI: 0.88-1.03 for endogenous Nitrosocompounds, and 1.00; 95 CI: 0.97-1.03 for heme iron). CONCLUSIONS AND IMPACT: Our findings do not support an effect of nitrosamines (endogenous and exogenous) and heme iron intake on prostate cancer risk.