The association between metabolic syndrome and bone mineral density: a meta-analysis

Previous researches demonstrate uncertainty about the effect of metabolic syndrome (MS) on bone. We performed a meta-analysis to investigate the association of MS with bone mineral density (BMD) of spine and femoral neck (FN). In this meta-analysis, searches of Medline, Embase, Cochrane Library, Chinese biological medical database and China national knowledge infrastructure were undertaken to identify studies in humans of the association between MS and BMD. Random effects model was used for this meta-analysis. The results of our research were reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A total of 11 studies (including an outlier study) with 13,122 subjects were included in our research. We detected a significant overall association of MS with increased BMD of spine (weighted mean difference, WMD = 0.027, 95 % confidence interval, CI [0.011, 0.042]) and no significant overall association of MS with BMD of FN (WMD = 0.008, CI [-0.011, 0.026]). Subgroup analyses indicated significant association between MS and increased BMD of spine in subjects whose BMD was measured by dual-energy X-ray absorptiometry (DXA) scanner manufactured by Hologic Inc., subjects diagnosed by International Diabetes Federation criteria and subjects diagnosed by National Cholesterol Education Program's Adult Treatment Panel III (NCEP-ATP III) criteria. And significant association between MS and increased BMD of FN in Caucasian subjects, subjects whose BMD was measured by DXA scanner manufactured by Hologic Inc. and subjects diagnosed by NCEP-ATP III criteria was also found. Our meta-analysis suggests that MS has no clear influence on BMD, or its influence maybe beneficial.