Dietary patterns among Japanese adults: findings from the National Health and Nutrition Survey, 2012

Background and Objectives: Recent studies have analyzed dietary patterns to assess overall dietary habits, but there have been no studies of dietary patterns among the contemporary Japanese population nationwide. The objective of this study was to identify dietary patterns based on consumption of food items among Japanese adults, and to examine whether these dietary patterns were associated with nutrient intake, demographic characteristics, and lifestyle factors. Methods and Study Design: The study population included 25,754 Japanese adults aged 20 years and older registered in the nationwide National Health and Nutrition Survey database in 2012. Dietary patterns were analyzed by factor analysis of 29 food items from the dietary intake survey and household-based semi-weighed dietary records. Results: Five dietary patterns were identified: high-bread and low-rice, high-meat and low-fish, vegetable, wheat-based food, and noodle and alcohol patterns. The lowest quartile of factor scores for high-meat and low-fish, wheat-based food, and noodle and alcohol patterns had higher nutrient intakes, and the highest quartile of factor scores for the vegetable pattern had a higher nutrient intake overall (all p<0.01). Dietary pattern scores were associated with demographic and lifestyle factors such as sex, age, region, smoking status, and alcohol intake. Conclusions: Five major dietary patterns among Japanese adults were identified by factor analysis. Dietary pattern scores were associated with differences in nutrient intakes and demographic and lifestyle factors. These patterns were further used for examining the association between Japanese diets and health outcomes.