[Association between employment status, family structure, and nutrient adequacy in Japanese working-age adults]

Objectives　The aim of this study was to analyze the association between employment status, family structure, and nutrient adequacy in working-age Japanese adults (aged 20-64 years).Methods　Data from the 2019 National Health and Nutrition Survey and the Comprehensive Survey of Living Conditions, conducted by the Ministry of Health, Labour and Welfare, were used to examine the associations between nutrient adequacy and employment status (full-time, part-time, unemployed, or not applicable) and family structure (single, couple only, two-parents and child [parent, child], single parent and child [parent, child], three-generations [parent, child], and other family structures). Logistic regression analysis was performed with nutrient deficiency as the dependent variable and employment status and family structure as independent variables, controlling for age, municipality size, and prefecture of residence.Results　The association between employment status and nutrient adequacy, as assessed by the chi-squared test, showed statistically significant differences in the percentage of nutrient inadequacy across employment status categories among women for three nutrients, but not among men. The chi-squared test between family structure and nutrient adequacy showed statistically significant differences for 10 nutrients for men and 14 nutrients for women. Among men, parents in three-generation families had higher inadequacy rates; among women, those living alone showed higher inadequacy rates. Logistic regression revealed that, compared with those in full-time employment, men in part-time employment had statistically higher inadequacy in total fiber, folic acid, potassium, and magnesium. For women, employment status was associated with inadequacy of n-6 fatty acids, total fiber, vitamin A, vitamin C, salt equivalents, and magnesium. Furthermore, nutrient inadequacy differed significantly by family structure for 14 nutrients in men and 16 nutrients in women. For men, single individuals, and parents in three-generation families showed statistically higher inadequacy rates for some nutrients, while for women, of the 16 nutrients showing statistically significant differences, children in "two-parent and child families" and women in "couple-only families" showed lower rates of nutrient inadequacy for 9 and 8 nutrients, respectively.Conclusion　Nutritional disparities among working-age adults are associated with employment patterns and family structure. In addition, nutrient excesses and deficiencies were identified in groups previously overlooked, such as parents in two-parent and child households and three-generation households, highlighting the need for policies that address these diverse factors.