Effects of weight change and physical activity on knee pain and health-related quality of life in East Asian women aged 50 years and older with knee osteoarthritis: a population-based study

Background This study aimed to investigate the effects of weight change and physical activity on the level of knee pain and health-related quality of life in East Asian women with knee osteoarthritis using population-based data. Methods A total of 564 women (mean age, 68.2 years, standard deviation, 8.9 years) aged 50 years or older with knee osteoarthritis (Kellgren-Lawrence grade ≥2) were included in the data analyses from the fifth Korea National Health and Nutrition Examination Survey. Data regarding the radiographic grade, weight change during the past year, physical activity, level of knee pain, and health-related quality of life (EuroQOL five-dimension [EQ-5D] index) were collected. Multiple regression analysis was performed to identify factors significantly affecting the level of knee pain and health-related quality of life in subgroups according to the body mass index (BMI) range (≤22.5, between 22.6 and 27.5, and >27.5 kg/m2). Result In women with 22.5 kg/m227.5 kg/m2, weekly hours of moderate-intensity activity showed significant negative correlation with EQ-5D. Conclusions The effects of weight change and physical activity on knee pain and health-related quality of life could be different according to BMI ranges. Well-designed interventions to improve both knee pain and health-related quality of life need to be investigated in future studies that would assess physical activity, diet, and weight changes.