Association between metabolic syndrome and osteoporosis: a meta-analysis.

Metabolic syndrome (MetS) consists of several independent clinically recognisable features that have their own independent effects on bone metabolism, and even a single disease could have apparently contradictory effects on bone metabolism. This meta-analysis aimed to detect a relationship between MetS and osteoporosis. The PubMed, Embase, and Cochrane library databases were searched for relevant studies published before April 1, 2013. On June 22, 2013, the databases were searched again for additional studies. Studies clearly reporting a comparison of bone mineral density (BMD) in subjects with or without MetS were selected for our analysis. From these results, we analysed the crude BMD and the BMD adjusted for all covariates (age, weight, height, alcohol intake, cigarette smoking and exercise). Weighted mean differences were calculated using a random-effects model. Nine studies were included in this meta-analysis. No significant differences were found when analysing the crude lumbar spine BMD and the femoral neck BMD. However, the MetS (-) group showed a significantly higher BMD when all covariates were adjusted for femoral neck BMD (0.02, p=0.0002) and lumbar spine BMD (0.01, p=0.007). Subgroup analysis suggested a negative effect of MetS on BMD in men but not in women. These findings suggest that MetS is a risk factor for developing osteoporosis in men.