Sleep-associated movement disorders and the risk of cardiovascular disease: A systematic review and metaanalysis

AIM:To investigate whether an association exists between sleep-associated movement disorders and cardiovascular disease(CVD).METHODS:Several studies have observed the relationship of sleep-associated movement disorders such as restless legs syndrome(RLS)and periodic limb movements during sleep with CVD,but the results were still contradictory.We performed an extensive literature search on Pub Med,Medline and Web of Science published from inception to December 2014.Additional studies were manually searched from bibliographies of retrieved studies.Meta-analyses were conducted with Stata version 12.0(Stata Corp,College Station,Texas).Pooled odds ratios(ORs)and 95%CIs were calculated to assess the strength of association using the random effects model.Sensitivity and subgroup analyses were performed to explore the underlying sources of heterogeneity.The publication bias was detected using Egger’s test and Begg’s test.RESULTS:A total of 781 unique citations were indentified from electronic databases and 13 articles in English were finally selected.Among these studies,nine are cohort studies;two are case-control studies;and two are cross-sectional studies.The results showed that the summary OR of CVD associated with sleepassociated movement was 1.51(95%CI:1.29-1.77)in a random-effects model.There was significant heterogeneity between individual studies(P for heterogeneity=0.005,I2=57.6%).Further analysis revealed that a large-scale cohort study may account for this heterogeneity.A significant association was also found between RLS and CVD(OR=1.54,95%CI:1.24-1.92).In a fixed-effects model,we determined a significant relationship between sleep-associatedmovement disorders and coronary artery disease(CAD)(OR=1.34,95%CI:1.16-1.54;P for heterogeneity=0.210;I2=30.0%).Our meta-analysis suggests that sleep-associated movement disorders are associated with prevalence of CVD and CAD.CONCLUSION:This finding indicates that sleep-associated movement disorders may prove to be predictive of underlying CVD.