title: Type 2 diabetes mellitus as a risk factor for the onset of depression: a systematic review and meta-analysis.
abstract: OBJECTIVE
  An earlier meta-analysis showed that diabetes is a risk factor for the development and/or recurrence of depression. Yet whether this risk is different for studies using questionnaires than for those relying on diagnostic criteria for depression has not been examined. This study examined the association of diabetes and the onset of depression by reviewing the literature and conducting a meta-analysis of longitudinal studies on this topic.
  
  
  METHODS
  EMBASE, MEDLINE and PsycInfo were searched for articles published up to September 2009. All studies that examined the relationship between type 2 diabetes and the onset of depression were included. Pooled relative risks were calculated using fixed and random effects models.
  
  
  RESULTS
  Eleven studies met our inclusion criteria for this meta-analysis. Based on the pooled data, including 48,808 cases of type 2 diabetes without depression at baseline, the pooled relative risk was 1.24 (95% CI 1.09-1.40) for the random effects model. This risk was significantly higher for studies relying on diagnostic criteria of depression than for studies using questionnaires. However, this difference was no longer significant when controlled for year of publication.
  
  
  CONCLUSIONS
  Compared with non-diabetic controls, people with type 2 diabetes have a 24% increased risk of developing depression. The mechanisms underlying this relationship are still unclear and warrant further research.
authors: School of Psychology, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK. a.nouwen@bhm.ac.uk
authors: A
authors: A
authors: Nouwen
authors: K
authors: K
authors: Winkley
authors: J
authors: J
authors: Twisk
authors: C E
authors: CE
authors: Lloyd
authors: M
authors: M
authors: Peyrot
authors: K
authors: K
authors: Ismail
authors: F
authors: F
authors: Pouwer
mesh_terms: D017668:Age of Onset; D003863:Depression / Q000453:epidemiology / Q000209:etiology*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000453:epidemiology; D006801:Humans; D008137:Longitudinal Studies / Q000706:statistics & numerical data; D012307:Risk Factors