Dietary patterns and risk of dementia in an elderly Japanese population: the Hisayama Study

Background: To our knowledge, there are no previous reports that assessed the association between dietary patterns and risk of dementia in Asian populations. Objective: We investigated dietary patterns and their potential association with risk of incident dementia in a general Japanese population. Design: A total of 1006 community-dwelling Japanese subjects without dementia, aged 60-79 y, were followed up for a median of 15 y. The reduced rank regression procedure was used to efficiently determine their dietary patterns. Estimated risk conferred by a particular dietary pattern on the development of dementia was computed by using a Cox proportional hazards model. Results: Seven dietary patterns were extracted; of these, dietary pattern 1 was correlated with high intakes of soybeans and soybean products, vegetables, algae, and milk and dairy products and a low intake of rice. During the follow-up, 271 subjects developed all-cause dementia. Of these individuals, 144 subjects had Alzheimer disease (AD), and 88 subjects had vascular dementia (VaD). After adjustment for potential confounders, risks of development of all-cause dementia, AD, and VaD were reduced by 0.66 (95% Cl: 0.46, 0.95), 0.65 (95% Cl: 0.40, 1.06), and 0.45 (95% CI: 0.22, 0.91), respectively, in subjects in the highest quartile of score for dietary pattern 1 compared with subjects in the lowest quartile. Conclusion: Our findings suggest that a higher adherence to a dietary pattern characterized by a high intake of soybeans and soybean products, vegetables, algae, and milk and dairy products and a low intake of rice is associated with reduced risk of dementia in the general Japanese population. Am J Clin Nutr 2013;97:1076-82.