The relationship between gluten free diet adherence and depressive symptoms in adults with coeliac disease: A systematic review with meta-analysis

Purpose: Depressive symptoms are common in patients with coeliac disease (CD) and may represent a barrier to gluten free diet (GFD) adherence. The aims of this meta-analysis were: (1) to synthesise the evidence on the relationship between depression or depressive symptoms and degree of adherence to a GFD in patients with CD who are already attempting a GFD (i.e., post-diagnosis and onset of GFD), and (2) to summarise the direction of causation of any observed relationship. Methods: A random effects meta-analysis of 8 cross-sectional studies (N = 1644) was conducted. Included studies measured self-reported depressive symptoms and GFD adherence using either a dietitian interview or validated self-report questionnaire that considered unintentional gluten consumption. Results: There was a moderate association between poorer GFD adherence and greater depressive symptoms (r = 0.398, 95% CI = 0.321-0.469), with marked heterogeneity in the effects (I-2 = 66.8%). A sensitivity analysis excluding studies with a moderate/high (k = 1) or unclear risk of bias (k = 1) did not change the results. Conclusion: The low number of studies meeting inclusion criteria limits the strength of the conclusions. Available evidence suggests there is an association between poorer GFD adherence and self-reported depressive symptoms; however, studies using longitudinal and prospective designs, and reliable measures, particularly for adherence, are needed to confirm this association. The direction of causation between depression and adherence remains unclear. (C) 2017 Elsevier Ltd. All rights reserved.