Abdominal obesity and risk of hip fracture: a meta-analysis of prospective studies

A Summary We conducted a meta-analysis to qualitatively summarize the evidence of the association between abdominal obesity and hip fracture risk. The results indicated that abdominal obesity as measured by waist circumference and waist-hip ratio might be associated with an increased risk of hip fracture. Introduction Epidemiological investigations evaluating the association of abdominal obesity with hip fracture risk have yielded conflicting results. Therefore, a meta-analysis was conducted to qualitatively summarize the evidence of the associations between waist circumference, waist-hip ratio, and hip circumference and the risk of hip fracture, respectively. Methods PubMed, Embase, and Web of Science were searched for relevant articles published up to March 2017. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated with a random-effects model. Dose-response relationship was assessed by restricted cubic spline. Results Seven studies involving 180,600 participants for hip circumference, six studies involving 199,828 participants for waist-hip ratio, and five studies involving 170,796 participants for waist circumference were finally included in this meta-analysis. The combined RRs with 95% CIs of hip fracture for the highest versus lowest category of waist circumference, waist-hip ratio, and hip circumference were 1.58 (95% CI 1.20-2.08), 1.32 (95% CI 1.15-1.52), and 0.87 (95% CI 0.74-1.02), respectively. For dose-response analysis, a nonlinear relationship was found (P (nonlinearity) < 0.001) between waist circumference and the risk of hip fracture, and a linear relationship (P (nonlinearity) = 0.911) suggested that the risk of hip fracture increased about 3.0% (1.03 (1.01-1.04)) for each 0.1 unit increment of waist-hip ratio. Conclusions This meta-analysis suggested that abdominal obesity as measured by waist circumference and waist-hip ratio might be associated with an increased risk of hip fracture. From a public health perspective, indicators of abdominal obesity may be usable predictors of hip fracture risk.