Body composition is more closely related to the development of knee osteoarthritis in women than men: A cross-sectional study using the Fifth Korea National Health and Nutrition Examination Survey (KNHANES V-1, 2)

Objective: To evaluate the association between knee osteoarthritis (OA) and body composition parameters, and to analyze the correlations of both obesity and lower extremity muscle mass with radiographic knee OA in relation to sex. Methods: This was a cross-sectional study using data on body composition parameters measured using dual energy X-ray absorptiometry in 4246 participants in the Fifth Korea National Health and Nutrition Examination Survey. The relationships between knee OA and body composition parameters were evaluated. The associations between knee OA and the four subgroups corresponding to obesity and muscle mass percentage in both lower extremities were analyzed separately for each sex. Results: The lower extremity muscle mass showed a decreasing trend, while fat parameters showed an increasing linear trend (P for trend <0.05) with increasing severity of knee OA in women. The odds ratio of each quarter percentile group (25 percentile) for fat parameters showed an increasing trend, while that of the lower extremity muscle mass showed a decreasing linear trend in relation to knee OA in women (P for trend < 0.05). In women, low percentage of lower extremity muscle mass was more associated with knee OA regardless of obesity (P < 0.05). However, there were no associations between all body composition parameters and knee OA in men. Conclusion: In women, high fat mass and low lower extremity muscle mass were associated with presence and severity of knee OA. Lower extremity muscle mass was more closely correlated with knee OA than obesity in women.