Joint associations of diet quality and physical activity with healthcare utilization among adults in South Korea: a cross-sectional study, 2014-2021.

Objective: Little is known about the joint associations of diet quality and physical activity with healthcare utilization. We examined these associations in a nationally representative sample of Korean adults. Methods: This cross-sectional study analyzed 37,059 adults aged 20 years or older in the Korea National Health and Nutrition Examination Survey, South Korea, 2014-2021. Participants were cross-classified into four groups by the sample median of the Korean Healthy Eating Index (KHEI) and physical activity level (≥150 moderate-equivalent minutes/week). Inpatient visits (past 12 months) and outpatient visits (past two weeks) were self-reported. Survey-weighted two-part models adjusted for sociodemographic and clinical covariates. Results: The High KHEI & Active group showed a lower probability of inpatient visits (OR, 0.89; 95% CI, 0.79, 0.99) than the Low KHEI & Inactive reference. The High KHEI & Inactive group showed a higher probability of outpatient visits (1.19; 1.09, 1.30). Inpatient associations were strongest among women, older adults, and adults with chronic diseases. Conclusions: Combined high diet quality and sufficient physical activity was associated with a lower probability of inpatient healthcare utilization, particularly among women, older adults, and those with chronic diseases. These findings support integrated health promotion strategies targeting both diet quality and physical activity.