Vegetarianism, low meat consumption and the risk of lung, postmenopausal breast and prostate cancer in a population-based cohort study

BACKGROUND/OBJECTIVES: The few prospective studies that examined lung, female breast and prostate cancer risk in vegetarians have yielded mixed results, whereas none have studied the effects of low meat diets. Moreover, little is known about the explanatory role of (non-) dietary factors associated with these diets. SUBJECTS/METHODS: The Netherlands Cohort Study-Meat Investigation Cohort (NLCS-MIC)-is an analytical cohort of 11 082 individuals including 1133 self-reported vegetarians (aged 55-69 years at baseline). At baseline (1986), subjects completed a questionnaire on dietary habits and other risk factors for cancer and were classified into vegetarians (n = 691), pescetarians (n = 389), 1 day per week (n = 1388), 2-5 days per week (n = 2965) and 6-7 days per week meat consumers (n = 5649). RESULTS: After 20.3 years of follow-up, 279 lung, 312 postmenopausal breast and 399 prostate cancer cases (including 136 advanced) were available for analyses. After adjustment for confounding variables, we found no statistically significant association between meat consumption groups and the risk of lung cancer. As well, no significant associations were observed for postmenopausal breast and overall prostate cancer. After adjustment for confounders, individuals consuming meat 1 day per week were at a 75% increased risk of advanced prostate cancer compared with 6-7 days per week meat consumers (95% CI 1.03-2.97). CONCLUSIONS: Vegetarians, pescetarians and 1 day per week meat consumers did not have a reduced risk of lung, postmenopausal breast and overall prostate cancer compared with individuals consuming meat on a daily basis after taking confounders into account.