Association of Weight Change and Physical Activity with Knee Pain and Health-Related Quality of Life in East Asian Women Aged 50 Years and Older with Knee Osteoarthritis: A Population-Based Study

Abstract

Objectives This study aimed to investigate the association of self-reported weight change and physical activity with 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 (K-L) grade ≥ 2) were included in the data analyses from the fifth Korea National Health and Nutrition Examination Survey. Data regarding the radiographic grade, self-reported 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 associated with 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/m<sup>2</sup>). Results In the whole group, the level of knee pain was significantly associated with K-L grade ( P < 0.001), and EQ-5D was negatively associated with age ( P < 0.001), the level of knee pain ( P < 0.001), and weekly hours of vigorous-intensity activity ( P = 0.026). In the subgroup analysis, weight gain showed significant association with the level of knee pain only in women with 22.5 kg/m<sup>2</sup> < BMI ≤ 27.5 kg/m<sup>2</sup> ( P = 0.006). Weight gain showed significant association with EQ-5D in women with BMI ≤ 22.5 kg/m<sup>2</sup> ( P = 0.047) whereas weekly hours of moderate-intensity activity was negatively associated with EQ-5D in women with BMI > 27.5 kg/m<sup>2</sup>. Conclusions The association of weight change and physical activity with knee pain and health-related quality of life might 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 strictly control physical activity, diet, and weight changes.