Diet quality of Japanese adults with respect to age, sex, and income level in the National Health and Nutrition Survey, Japan

OBJECTIVE: Although several studies in Western countries show that higher socioeconomic status is associated with higher diet quality, no study has observed this association in Japan. In the current study, we examined the association between diet quality and the combinations of age, sex, and household income, and also compared the dietary intake between diet quality levels according to household income. DESIGN: Cross-sectional study. SETTING: National Health and Nutrition Survey, Japan in 2014. PARTICIPANTS: 2785 men and 3215 women. RESULTS: Higher Japanese Food Guide Spinning Top scores (better diet quality) were observed in older women, especially those with higher household income, whereas lower scores were observed in younger men with lower household income. Those having low quality diet, especially in low income households, had higher odds of not meeting the recommended amounts of the Japanese dietary guidelines, than those having high quality diet. CONCLUSIONS: Diet quality in Japanese adults differed by age and sex as well as by household income level. A different approach to diet quality improvement is needed according to population characteristics including not only age and sex but also social economic status.