Association Between Vitamin D Deficiency and Cardiometabolic Risk Clustering Among Rural Community-Dwelling Older Adults: A Cross-Sectional Study

Background/Objectives: Cardiometabolic risk factor clustering is common in older adults and is associated with substantially increased cardiometabolic morbidity and mortality. This study aimed to examine the association between serum 25-hydroxyvitamin D [25(OH)D] status and cardiometabolic risk factor clustering among rural community-dwelling older adults. Methods: This cross-sectional study analyzed data from the 2022 Korea National Health and Nutrition Examination Survey (KNHANES) for 432 adults aged ≥65 years residing in rural areas. Cardiometabolic risk factor clustering was defined as the presence of ≥2 of the following: abdominal obesity, hypertension, type 2 diabetes mellitus, and dyslipidemia. Multivariable logistic regression was performed adjusting for sociodemographic and behavioral factors. Results: Cardiometabolic risk factor clustering was more prevalent among participants with vitamin D deficiency (<15 ng/mL) than among those with sufficient levels (66.0% vs. 44.9%, p = 0.006). After adjustment, vitamin D sufficiency (≥15 ng/mL), compared with vitamin D deficiency (<15 ng/mL), was associated with lower odds of clustering (aOR = 0.422, 95% CI: 0.219–0.811, p = 0.010). Meeting the WHO physical activity guideline was also associated with lower odds of clustering (AOR = 0.450, 95% CI: 0.226–0.897, p = 0.023). Conclusions: Lower vitamin D status was associated with a higher prevalence of cardiometabolic risk factor clustering. These findings support the consideration of vitamin D assessment and lifestyle-focused strategies within community health nursing practice to reduce cardiometabolic risk in rural aging populations.