This study aims to assess whether older adults with low muscle mass or strength, in the presence of obesity, have an increased risk of knee (TKR) and hip replacement (THR) over 13 years. 1082 community-dwelling older adults (51% women; mean age 62.9 ± 7.5 years) were studied at baseline and multiple time points over 13 years. The incidence of TKR and THR was determined by data linkage to National Joint Replacement Registry. Appendicular lean and fat mass were measured using DXA. Lower-limb muscle strength (LMS) was assessed by dynamometer. Low muscle mass and strength were defined as the lowest sex-specific tertiles for appendicular lean mass (adjusted for height and total body fat mass) and lower-limb strength, respectively. Obesity was defined as the highest sex-specific tertile for total body fat mass. Competing risk regression models were used to estimate the sub-distribution hazard ratio (SHR) for TKR and THR. Over 13 years of follow-up, 6.8% (n = 74/1082) of the participants had a TKR and 4.7% (n = 50/1066) had THR. Participants with the combination of obesity and low muscle strength (SHR 3.36, 95% CI 1.50, 7.53) but low muscle mass (SHR 1.11, 95% CI 0.52, 2.40) had a significantly increased risk of TKR, compared to individuals with neither obesity nor low muscle mass/strength. However, obesity with low muscle strength did not lead to a significantly greater risk of TKR compared to having low muscle strength or obesity alone. There was no evidence for an association between obesity with low muscle mass or strength and THR (all p > 0.05). This finding suggests that combining muscle and fat assessments to predict the future risk of TKR is no better than each condition on its own.

这项研究旨在评估在肥胖的情况下，肌肉质量或强度低的老年人在13年内是否会增加膝关节（TKR）和髋关节置换（THR）的风险。在基线和13年中的多个时间点研究了1082名社区居住的老年人（51％的女性；平均年龄62.9±7.5岁）。TKR和THR的发病率是通过与国家联合置换登记处的数据链接确定的。使用DXA测量附录瘦肉和脂肪量。通过测力计评估下肢肌肉强度（LMS）。低肌肉质量和力量分别被定义为最低性别特异性阑尾瘦肉（针对身高和总身体脂肪质量进行调整）和下肢力量。肥胖被定义为身体总脂肪量最高的性别特异性三分位数。使用竞争风险回归模型来估计TKR和THR的子分布风险比（SHR）。在13年的随访中，6.8％（n  = 74/1082）的参与者具有TKR，4.7％（n  = 50/1066）的患者具有THR。与既没有肥胖者相比，肥胖和低肌力量（SHR 3.36，95％CI 1.50，7.53）但低肌肉质量（SHR 1.11，95％CI 0.52，2.40）合并的参与者TKR风险显着增加也不低的肌肉质量/强度。但是，与仅具有低肌肉强度或肥胖的人相比，具有低肌肉强度的肥胖症不会导致TKR风险显着增加。没有证据表明肥胖与低肌肉质量或力量与THR之间存在关联（所有p  > 0.05）。这一发现表明，结合肌肉和脂肪评估来预测TKR的未来风险并不比每种情况都要好。