Objective: To examine the association of body weight, body fatness, and body fat distribution with osteoarthritis (OA) of the knee.
Methods: Bilateral standing knee radiographs, taken between 1985 and 1991, of 465 Caucasian men and 275 Caucasian women subjects aged 40 and above in the Baltimore Longitudinal Study of Aging were read by one investigator for grade of OA using Kellgren-Lawrence scales. Measures of obesity, assessed at same visit as the last radiograph during this interval, included body mass index, percent body fat, and body fat distribution.
Results: Both men and women with definite knee OA had higher age adjusted mean levels of body mass index, while women only had higher age adjusted mean levels of percent body fat. Both women and men in the highest tertile of body mass index had significantly increased odds of both definite and bilateral knee OA; women in the middle and highest tertile of percent body fat had significantly increased odds of both definite and bilateral knee OA, and men in the highest tertile of waist-hip ratio had significantly increased odds of bilateral knee OA. After adjusting for body mass index, however, the association of percent body fat and waist-hip ratio with knee OA in women and men, respectively, was no longer significant.
Conclusion: These data further extend observations that body weight is associated with both definite and bilateral knee OA in both sexes, and support a stronger contribution of mechanical as opposed to systemic factors to explain this association.