Association between Healthy Eating Index and Mental Health in Middle-Aged Adults Based on Household Size in Korea

This study examined the association between dietary lifestyle and mental health outcomes among middle-aged individuals (40-60-year-olds) living alone, using the Korean Healthy Eating Index (KHEI). The participants were selected (1334 men and 2185 women) from the Korea National Health and Nutrition Examination Survey 2016-2018 and categorized into single/multi-person households. The KHEI scores were calculated based on the 24 h recall data of dietary intake. Among both sexes, single-person households had significantly lower subjective health status scores (p = 0.015 for men; p < 0.001 for women), lower EuroQol-5D index scores (p = 0.011 for men; p = 0.003 for women), and higher Patient Health Questionnaire-9 index scores (p = 0.004 for men; p < 0.001 for women), compared to multi-person households. Men had a higher risk of depression in single-person households compared to multi-person households (OR, 3.5; 95% CI, 1.2-10.1). For women, the ORs for stress perception with the first tertile group of KHEI scores in single-person and multi-person households compared to the third tertile group were 3.5 (95% CI, 1.3-9.0) and 1.4 (95% CI, 1.0-1.8), respectively. The results of this study are expected to be used as baseline data to establish nutrition, healthy eating behavior, and health policies for the middle-aged living alone.