@article {Gilbody631, author = {Simon Gilbody and Tracy Lightfoot and Trevor Sheldon}, title = {Is low folate a risk factor for depression? A meta-analysis and exploration of heterogeneity}, volume = {61}, number = {7}, pages = {631--637}, year = {2007}, doi = {10.1136/jech.2006.050385}, publisher = {BMJ Publishing Group Ltd}, abstract = {Low folate has been causatively linked to depression, but research is contradictory. An association may arise due to chance, bias, confounding or reverse causality. A systematic review of observational studies which examined the association between depression and folate was conducted. 11 relevant studies (15 315 participants; three case{\textendash}control studies, seven population surveys and one cohort study) examining the risk of depression in the presence of low folate were found. Pooling showed a significant relationship between folate status and depression (odds ratio (OR)pooled unadjusted = 1.55; 95\% CI 1.26 to 1.91). This relationship remained after adjustment for potential confounding (OR)pooled adjusted = 1.42; 95\% CI 1.10 to 1.83). Folate levels were also lower in depression. There is accumulating evidence that low folate status is associated with depression. Much of this evidence comes from case{\textendash}control and cross-sectional studies. Cohort studies and definitive randomised-controlled trials to test the therapeutic benefit of folate are required to confirm or refute a causal relationship.}, issn = {0143-005X}, URL = {https://jech.bmj.com/content/61/7/631}, eprint = {https://jech.bmj.com/content/61/7/631.full.pdf}, journal = {Journal of Epidemiology \& Community Health} }