Association Between Chronic Obstructive Pulmonary Disease and Low Muscle Mass in Korean Adults

Background/Objectives: Chronic obstructive pulmonary disease (COPD) and restrictive pulmonary disease (RPD) are prevalent in older adults and are associated with systemic inflammation, oxidative stress, and reduced physical activity, all of which may contribute to low muscle mass (LMS)-a loss of skeletal muscle mass and function. This study investigates the association between COPD, RPD, and sarcopenia using data from the Korea National Health and Nutrition Examination Survey (KNHANES). Methods: A cross-sectional analysis was conducted with 8980 participants aged 40 years and older from the 2008-2011 KNHANES. LMS was defined using the Asian Working Group for Sarcopenia (AWGS) criteria, based on appendicular skeletal muscle mass adjusted for height squared (ASM/height²). Pulmonary diseases were identified via spirometry, and logistic regression models were used to assess associations, adjusting for demographic, lifestyle, and clinical factors. Results: The prevalence of LMS was highest among participants with COPD (37.3%), compared to those with RPD (25.3%) and normal pulmonary function (25.9%). COPD was significantly associated with LMS after adjusting for confounders (OR: 1.543, 95% CI: 1.246-1.910). However, no significant association was observed between RPD and LMS (OR: 1.225, 95% CI: 0.997-1.505). Conclusions: This study demonstrated that LMS was independently associated with COPD but not with RPD, even after adjusting for confounding variables.