Meat-based dietary pattern is associated with an increased risk of colorectal adenoma cancer but not hyperplastic polyp among Japanese populations living in São Paulo, Brazil: Results from a cross-country colorectal cancer project in Japan, Hawaii, and Brazil

Introduction: Brazil and Hawaii are two countries beside Japan where there are large numbers of Japanese populations. Unlike Japanese populations in Hawaii and Japan, populations in Brazil do not show increasing colorectal cancer incidence. The aim of this study was to determine the major dietary patterns through a quantitative food frequency questionnaire among the Japanese Brazilian population and identify associations between the identified dietary patterns and risks for colorectal cancer, adenoma, and hyperplastic polyp.Methods: Participants were recruited from patients undergoing colonoscopy in two hospitals in São Paulo. Eligible individuals had lived in the state of São Paulo for over six months prior to recruitment, were between 40 and 79 years old, had at least three grandparents of Japanese ancestry, and underwent colonoscopy between May 2007 and August 2013. A trained interviewer collected information on demographics, personal and family medical history, anthropometric measurements, physical activity, supplement use, smoking and alcohol, medication use, reproductive factors, and dietary intake using a validated quantitative food frequency questionnaire. Principal components analysis of 48 food groups identified three dietary patterns. Multivariable-adjusted odds ratios (ORs) for colorectal cancer risk were estimated with logistic regression modelling considering the presence of hyperplastic polyps or colorectal cancer/adenoma, and the size and location of colorectal adenoma. Results: Of 1132 recruited subjects, we analysed data from 842 subjects (403 controls, 316 adenoma, and 123 Hyperplastic) and identified three major dietary patterns: ‘fruit and vegetables’, ‘meat’, and ‘alcohol (moderate user)’ patterns. The risk of colorectal cancer or adenoma was negatively associated with the ‘fruit and vegetables’ (OR: 0.53; 95% CI: 0.33, 0.85; P=0.007) and ‘alcohol’ (OR: 0.46; 95% CI: 0.28, 0.76; P=0.006) dietary patterns, but positively associated with the ‘meat’ pattern (OR: 1.75; 95% CI: 1.07, 2.85; P=0.04). Subgroup analyses showed that the negative association between ‘fruit and vegetables’ pattern and ‘alcohol’ pattern remained significant for large adenoma (≥ 5mm) and adenoma for the rectum.Conclusion: Diets high in fruit and vegetables and moderate alcohol consumption have a strong inverse relationship with the risk of colorectal cancer whereas diets high in meat have a positive relationship with colorectal cancer risk among Japanese population in Brazil.