Abstract
OBJECTIVE: To investigate an 8-year change in waist circumference (WC) with the risk of incident low physical function over 1 year in adults with, or at risk of, knee osteoarthritis (OA). METHODS: Data from the Osteoarthritis Initiative 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 (< 5cm gain). We identified World Health Organization (WHO) risk category based on WC at study enrollment as Large WC (males ≥ 102 cm, females ≥ 88 cm) or Small WC (males < 102 cm, females < 88 cm). The outcome was incident low physical function (≥ 28 Western Ontario and McMaster Universities Osteoarthritis Index 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% 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 (95% CI 1.04-1.96) times the risk of incident low physical function compared to adults in the Maintain WC group. Adults with a Large WC at baseline who increased WC had 1.55 (95% CI 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 (95% CI 0.84-4.63) times the risk compared to those 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.