Differences and determinants of dietary intake according to living arrangements in older adults: a cross-sectional study using the 2019, 2021, and 2023 Korea National Health and Nutrition Examination Surveys

Background: The nutritional status of older adults is closely related to their living arrangements and reflects social support and food accessibility. This study aimed to compare dietary intake between older adults living alone and those living with others and to identify the key socioeconomic, behavioral, and psychosocial determinants influencing nutrient intake. Methods: Data were obtained from the 2019, 2021, and 2023 Korea National Health and Nutrition Examination surveys. Older adults aged ≥65 years were classified according to their living arrangements (living alone vs. living with others). Dietary intake was assessed using 24-hour dietary recall data. Group differences in daily energy and nutrient intake were analyzed using analysis of covariance, adjusted for age. Differences in energy and nutrient intake and their associated factors were examined according to the living arrangement (living alone vs. living with others). Results: Older adults living alone had significantly lower daily energy and carbohydrate, protein, fat, and calcium intake than those living with others (all P<0.05). In the non-living-alone group, smoking status, quality of life, and food abundance were the key determinants of energy and nutrient intake. Among adults living alone, economic activity, smoking status, and food abundance were the most influential factors. Conclusion: Living arrangements are a crucial contextual factor influencing dietary intake among older Koreans. Nutritional programs that improve food security and social participation may mitigate these disparities and support healthy aging.