Paracelsus Medical University Salzburg and Nuremberg, Salzburg, Austria, and La Trobe University, Bundoora, Victoria, Australia.
Boston University School of Medicine, Boston, Massachusetts, and University of Manchester and Central Manchester NHS Foundation Trust, Manchester, UK.
Arthritis Care Res (Hoboken). 2017 Aug;69(8):1266-1270. doi: 10.1002/acr.23182.
To determine whether lower thigh muscle specific-strength increases the risk of incident radiographic knee osteoarthritis (RKOA), and whether there exists a sex-specific relationship between thigh muscle specific-strength and body mass index (BMI).
A total of 161 Osteoarthritis Initiative participants (62% female) with incident RKOA (Kellgren/Lawrence grade 0/1 at baseline, developing an osteophyte and joint space narrowing grade ≥1 by year 4) were matched to 186 controls (58% female) without incident RKOA. Thigh muscle anatomical cross-sectional areas (ACSAs) were determined at baseline using axial magnetic resonance imaging scans. Isometric extensor and flexor muscle strength was measured at baseline, and specific strength (strength ÷ ACSA) was calculated. Logistic regression assessed the risk of incident RKOA associated with muscle specific-strength (with and without adjustment for BMI).
Lower knee extensor- and flexor-specific strength significantly increased the risk of incident RKOA in women but not in men (odds ratio 1.47 [95% confidence interval (95% CI) 1.10-1.96] and 1.41 [95% CI 1.06-1.89], respectively). The significant relationship in women was lost after adjustment for BMI. Lower specific strength was associated with higher BMI in women (r = -0.29, P < 0.001), but not in men, whereas absolute strength was associated with BMI in men (r = 0.28, P = 0.001), but not in women.
Lower thigh muscle specific-strength predicts incident RKOA in women, with this relationship being confounded by BMI. The sex-specific relationship between muscle specific-strength and BMI provides a possible explanation why women with muscle-strength deficits typically have a poorer prognosis than men with similar strength deficits.
确定大腿肌肉比力量是否会增加膝关节骨关节炎（KOA）的发病风险，以及大腿肌肉比力量与体重指数（BMI）之间是否存在性别特异性关系。
共纳入 161 名（62%为女性）患有膝关节骨关节炎（OAI）的患者（基线时 Kellgren/Lawrence 分级为 0/1，4 年内出现骨赘和关节间隙狭窄分级≥1），将他们与 186 名（58%为女性）未患有膝关节骨关节炎的对照者进行匹配。使用轴位磁共振成像扫描，在基线时确定大腿肌肉解剖横截面积（ACSA）。在基线时测量等距伸肌和屈肌力量，并计算比力量（力量÷ACSA）。使用 logistic 回归评估肌肉比力量与膝关节骨关节炎发病风险之间的关系（是否调整 BMI）。
女性的膝关节伸肌和屈肌比力量显著增加了膝关节骨关节炎的发病风险，但男性则没有（比值比 1.47[95%置信区间（95%CI）为 1.10-1.96]和 1.41[95%CI 为 1.06-1.89]）。女性的这种显著关系在调整 BMI 后消失。在女性中，较低的比力量与较高的 BMI 相关（r=-0.29，P<0.001），但在男性中则没有，而绝对力量与 BMI 相关在男性中（r=0.28，P=0.001），但在女性中则没有。
较低的大腿肌肉比力量预测女性膝关节骨关节炎的发病风险，这种关系受 BMI 的影响。肌肉比力量与 BMI 之间的性别特异性关系可能解释了为什么肌肉力量不足的女性通常比具有类似力量不足的男性预后更差。
