Vegetarianism as a Protective Factor for Colorectal Adenoma and Advanced Adenoma in Asians

Abstract

Although epidemiologic and animal studies suggest a vegetarian diet protects against the development of colorectal cancer, the relationship between vegetarian diet and incidence of colorectal adenoma is not yet conclusive, especially for Asians. The purpose of this study was to examine the protective effect of a vegetarian diet against colorectal adenoma and advanced adenoma. This cross-sectional study compared the prevalence of colorectal adenoma among Buddhist priests, who are obligatory vegetarians, with that among age and sex-matched controls. All the subjects underwent health checkups in a health-promotion center in Korea. Colorectal adenoma and advanced adenoma were both more prevalent in the general population group than in the Buddhist priest group (25.2 vs. 17.9 %, 6.7 vs. 2.0 %). However, the prevalence of metabolic syndrome, high body mass index, and waist circumference were higher in the Buddhist priest group. According to univariate analysis, non-vegetarian diet (general population) significantly increased the prevalence of colorectal adenoma and advanced adenoma compared with a vegetarian diet (Buddhist priests) (OR 1.54, 95 % CI 1.08-2.21, P = 0.018; OR 3.60, 95 % CI 1.53-8.48, P = 0.003). In a conditional regression analysis model, non-vegetarian diet was also a significant risk factor for colorectal adenoma and advanced adenoma (OR 1.52, 95 % CI 0.75-2.07, P = 0.043; OR 2.94, CI 0.97-7.18, P = 0.036). Vegetarianism may be effective in preventing both colorectal adenoma and advanced adenoma in Asians.