title: Bidirectional association between depression and metabolic syndrome: a systematic review and meta-analysis of epidemiological studies.
abstract: OBJECTIVE
  Epidemiological studies have repeatedly investigated the association between depression and metabolic syndrome (MetS). However, the results have been inconsistent. This meta-analysis aimed to summarize the current evidence from cross-sectional and prospective cohort studies that evaluated this association.
  
  
  METHODS
  MEDLINE, EMBASE, and PsycINFO databases were searched for articles published up to January 2012. Cross-sectional and cohort studies that reported an association between the two conditions in adults were included. Data on prevalence, incidence, unadjusted or adjusted odds ratio (OR), and 95% CI were extracted or provided by the authors. The pooled OR was calculated separately for cross-sectional and cohort studies using random-effects models. The I(2) statistic was used to assess heterogeneity.
  
  
  RESULTS
  The search yielded 29 cross-sectional studies (n = 155,333): 27 studies reported unadjusted OR with a pooled estimate of 1.42 (95% CI 1.28-1.57; I(2) = 55.1%); 11 studies reported adjusted OR with depression as the outcome (1.27 [1.07-1.57]; I(2) = 60.9%), and 12 studies reported adjusted OR with MetS as the outcome (1.34 [1.18-1.51]; I(2) = 0%). Eleven cohort studies were found (2 studies reported both directions): 9 studies (n = 26,936 with 2,316 new-onset depression case subjects) reported adjusted OR with depression as the outcome (1.49 [1.19-1.87]; I(2) = 56.8%), 4 studies (n = 3,834 with 350 MetS case subjects) reported adjusted OR with MetS as the outcome (1.52 [1.20-1.91]; I(2) = 0%).
  
  
  CONCLUSIONS
  Our results indicate a bidirectional association between depression and MetS. These results support early detection and management of depression among patients with MetS and vice versa.
authors.affiliation: Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts, USA. apan@hsph.harvard.edu
authors.forename: An
authors.initials: A
authors.lastname: Pan
authors.forename: Nana
authors.initials: N
authors.lastname: Keum
authors.forename: Olivia I
authors.initials: OI
authors.lastname: Okereke
authors.forename: Qi
authors.initials: Q
authors.lastname: Sun
authors.forename: Mika
authors.initials: M
authors.lastname: Kivimaki
authors.forename: Richard R
authors.initials: RR
authors.lastname: Rubin
authors.forename: Frank B
authors.initials: FB
authors.lastname: Hu
mesh_terms: D003430:Cross-Sectional Studies; D003863:Depression / Q000453:epidemiology* / Q000503:physiopathology; D006801:Humans; D024821:Metabolic Syndrome / Q000453:epidemiology* / Q000503:physiopathology