Interaction Between Vitamin D Status and Aerobic Physical Activity in Relation to Cardiometabolic Risk Clustering Among Rural Older Adults

Background/Objectives: This study investigated whether serum 25-hydroxyvitamin D (25(OH)D) modifies the association between meeting WHO aerobic physical activity guidelines and cardiometabolic risk clustering among rural older adults in South Korea. Methods: This cross-sectional study analyzed 2023 Korea National Health and Nutrition Examination Survey (KNHANES) data for rural-dwelling adults aged ≥65 years with complete data (n = 441). Cardiometabolic risk clustering (CMRC) was defined as the presence of ≥3 of five risk factors (abdominal obesity, elevated blood pressure, low HDL-cholesterol, elevated triglycerides, and hyperglycemia). Exposures were continuous serum 25-hydroxyvitamin D (25(OH)D) and adherence to the WHO aerobic physical activity guidelines (yes/no). Multivariable logistic regression models tested the 25(OH)D × physical activity interaction, adjusting for sex, age (≥75 vs.