The Association of an Increasing Waist Circumference and Risk of Incident Low Physical Function in Adults with Knee Osteoarthritis.

OBJECTIVE: To investigate an eight-year change in waist circumference (WC) with the risk of incident low physical function over one-year in adults with or at risk of knee osteoarthritis (OA). METHODS: Data from the Osteoarthritis Initiative (OAI) were used. Change in WC was measured from study enrollment (0-month) to the 96-month visit and classified as Increase (>/= 5cm gain) or Maintain ( /= 102cm, females >/= 88cm) or Small WC (males /= 28 WOMAC physical function subscale) at the 108-month visit. To investigate the association of the 8-year change in WC with the risk of low physical function, we calculated risk ratios 95% confidence intervals [95%CI and adjusted for potential confounders. We repeated the analyses stratified by the WHO disease risk category. RESULTS: The Increase WC group had 1.43 [1.04, 1.96] times the risk of incident low physical function compared to adults in the Maintain WC group. Adults with a Large at baseline WC, who increased WC, had 1.55 [1.00, 2.37] times the risk of incident low physical function compared to those who maintained WC. Adults with a Small WC at baseline, who increased WC, had 1.97 [0.84, 4.63] times the risk compared to the who maintained WC. CONCLUSION: Increasing WC increases the risk of incident low physical function in the following year. Maintaining WC may mitigate developing low physical function.