Determinants of Metabolic Syndrome Among Rural Older Adults: A Cross-Sectional Analysis of the 2023 Korea National Health and Nutrition Examination Survey

Metabolic syndrome (MetS) is common in later life and shaped by modifiable lifestyle and clinical factors, yet data specific to rural older adults are limited. This cross-sectional study analyzed rural Koreans aged ≥65 years (unweighted n = 467) from the 2023 Korea National Health and Nutrition Examination Survey, incorporating the complex survey design (strata, clusters, and weights). MetS was defined using National Cholesterol Education Program Adult Treatment Panel III criteria with Asian-specific waist cutoffs (≥3 of 5 components). Sociodemographic, behavioral, and clinical characteristics were compared by MetS status using design-based tests, and complex-sample logistic regression estimated adjusted odds ratios (aORs) with 95% confidence intervals (CIs). The survey-weighted prevalence of MetS was 42.8%. Compared with those without MetS, participants with MetS had higher body mass index (BMI) and waist circumference, more hypertension and diabetes, higher triglycerides, and lower high-density lipoprotein cholesterol; low-density lipoprotein cholesterol did not differ meaningfully. In multivariable models, BMI ≥25 kg/m2 (aOR 9.08; 95% CI 6.01–13.71, p ≤ 0.001), hemoglobin A1c ≥ 7.0% (aOR 4.42; 95% CI 1.75–11.16, p = 0.003), and vitamin D deficiency <20 ng/mL (aOR 2.32; 95% CI 1.23–4.35, p = 0.012) were independently associated with higher odds of MetS, whereas meeting the World Health Organization physical activity guideline was inversely associated (aOR 0.50; 95% CI 0.26–0.96, p = 0.039). These findings highlight adiposity, suboptimal glycemic control, and vitamin D deficiency as key, potentially modifiable correlates of MetS in rural older adults and support promotion of guideline-level physical activity as part of integrated cardiometabolic risk management in rural settings.