Serum total adiponectin level and risk of cardiovascular disease in Han Chinese populations: a meta-analysis of 17 case-control studies

Objective To systematically evaluate low serum adiponectin level as a risk factor for cardiovascular disease (CVD). A meta-analysis was performed to quantitatively analyse the association of serum total adiponectin level with CVD using previous casecontrol studies in Han Chinese populations. Methods Several electronic databases were searched for relevant articles up to July 2011. A total of nine (n = 933), eight (n = 939) articles were included in each meta-analysis regarding the association of serum adiponectin level with coronary heart disease (CHD) and ischaemic stroke, respectively. Publication bias was examined by the Eggers linear regression test. Sensitivity analysis was performed by omitting one study at a time, and the pooled standardized mean difference (SMD) was estimated using fixed-effects model and random-effects model, respectively. Results Serum total adiponectin concentrations were lower in patients with CHD and ischaemic stroke, with pooled SMD of -1.41 (95% CI -1.69, -1.12, P < 0.00001) and -1.69 (95% CI -2.04, -1.33, P < 0.00001), respectively. By performing a meta-regression analysis, homeostasis model assessment of insulin resistance, study size, adiponectin measurement assays, gender and mean body mass index of cases failed to account for heterogeneity for comparisons between lower adiponectin level and ischaemic stroke. However, study size had significant effect on the association of lower adiponectin level with CHD and accounted for 96.72% of the between-study variance. No publication bias was detected. No single study was found to affect the overall result of each analysis by sensitivity testing. Conclusions The accumulated evidence suggested that low serum adiponectin level increased the risk of a first cardiovascular event in the Han Chinese population. Further study is recommended with larger sample size to explore the role of hypoadiponectinemia in the causation of CVD.