Dietary patterns and abnormal glucose tolerance among Japanese: findings from the National Health and Nutrition Survey, 2012

Objective Previous studies have associated dietary patterns with diabetes risk in Western countries, but such studies among the Japanese population are scarce. The present study aimed to investigate dietary patterns associated with abnormal glucose tolerance determined by elevated glycated Hb (HbA1c) levels. Design The 2012 National Health and Nutrition Survey (NHNS) database was used for the cross-sectional study. Dietary patterns were analysed by factor analysis of twenty-five food items from the dietary intake survey and household-based semi-weighed dietary records. OR and 95 % CI for elevated HbA1c levels (>= 6 center dot 5 %) according to dietary patterns were estimated using logistic regression models. Setting Japan. Participants The study population comprised 9550 Japanese aged >= 40 years registered in the nationwide NHNS. Results Three dietary patterns were identified: (i) high-bread and low-rice; (ii) high-meat and low-fish; and (iii) vegetable. The high-bread and low-rice pattern, characterised by high frequent consumption of bread, milk and dairy products, and fruits, and low rice intake, was associated with marginally decreased prevalence of elevated HbA1c levels (P-trend=0 center dot 047). The vegetable pattern, characterised by vegetables, mushrooms, soyabeans and soybean products, was significantly inversely associated with elevated HbA1c levels (4th v. 1st quartile: multivariable OR=0 center dot 68; 95 % CI 0 center dot 49, 0 center dot 95; P-trend=0 center dot 007). Conclusions Our findings suggest that the vegetable pattern is associated with decreased prevalence of elevated HbA1c levels among Japanese.