Cancer Epidemiology Unit, University of Oxford, Oxford, United Kingdom.
J Bone Miner Res. 2011 Jun;26(6):1330-8. doi: 10.1002/jbmr.315.
Hip fracture risk is known to increase with physical inactivity and decrease with obesity, but there is little information on their combined effects. We report on the separate and combined effects of body mass index (BMI) and physical activity on hospital admissions for hip fracture among postmenopausal women in a large prospective UK study. Baseline information on body size, physical activity, and other relevant factors was collected in 1996-2001, and participants were followed for incident hip fractures by record linkage to National Health Service (NHS) hospital admission data. Cox regression was used to calculate adjusted relative risks of hip fracture. Among 925,345 postmenopausal women followed for an average of 6.2 years, 2582 were admitted to hospital with an incident hip fracture. Hip fracture risk increased with decreasing BMI: Compared with obese women (BMI of 30+ kg/m(2) ), relative risks were 1.71 [95% confidence interval (CI) 1.47-1.97)] for BMI of 25.0 to 29.9 kg/m(2) and 2.55 (95% CI 2.22-2.94) for BMI of 20.0 to 24.9 kg/m(2). The increase in fracture risk per unit decrease in BMI was significantly greater among lean women than among overweight women (p < .001). For women in every category of BMI, physical inactivity was associated with an increased risk of hip fracture. There was no significant interaction between the relative effects of BMI and physical activity. For women who reported that they took any exercise versus no exercise, the adjusted relative risk of hip fracture was 0.68 (95% CI 0.62-0.75), with similar results for strenuous exercise. In this large cohort of postmenopausal women, BMI and physical activity had independent effects on hip fracture risk.
髋部骨折风险已知会随身体活动减少和肥胖增加而增加，但关于它们联合作用的信息较少。我们报告了在一项大型英国前瞻性研究中，绝经后妇女的身体质量指数（BMI）和身体活动对髋部骨折住院的单独和联合影响。1996-2001 年收集了身体大小、身体活动和其他相关因素的基线信息，并通过与国民保健服务（NHS）住院数据的记录链接，对髋部骨折的发病情况进行随访。Cox 回归用于计算髋部骨折的调整相对风险。在随访平均 6.2 年的 925345 名绝经后妇女中，有 2582 人因髋部骨折入院。随着 BMI 的降低，髋部骨折风险增加：与肥胖女性（BMI 为 30+kg/m²）相比，BMI 为 25.0 至 29.9kg/m²的相对风险为 1.71（95%可信区间 1.47-1.97），BMI 为 20.0 至 24.9kg/m²的相对风险为 2.55（95%可信区间 2.22-2.94）。BMI 每降低一个单位，骨折风险的增加幅度在瘦弱女性中明显大于超重女性（p<0.001）。对于每个 BMI 类别的女性，身体活动不足与髋部骨折风险增加相关。BMI 和身体活动的相对作用之间没有显著的交互作用。与不运动的女性相比，报告有任何运动的女性髋部骨折的调整相对风险为 0.68（95%可信区间 0.62-0.75），剧烈运动的结果相似。在这项大型绝经后妇女队列中，BMI 和身体活动对髋部骨折风险有独立的影响。
