Objective: Several epidemiological studies have evaluated the associations between dietary magnesium (Mg) and calcium (Ca) intake and the risk of depression. However, the results of these studies remain controversial. Thus, we performed a meta-analysis to explore these associations and to investigate the possible dose-response relationship between dietary Mg intake and risk of depression.
Methods: MEDLINE, Web of Science, Embase, Cochrane CENTRAL, CINAHL database, Chinese National Knowledge Infrastructure, Wan fang databases and Databases of Chinese Scientific and Technical Periodicals were searched for eligible publications up to September 2016. Pooled relative risks with 95% confidence intervals were calculated using random-effects model. Publication bias was estimated using Egger's test and the funnel plot. Dose-response relationship was assessed by restricted cubic spline functions.
Results: A total of 17 epidemiological studies from 12 articles were included in the present meta-analysis. Among these studies, 11 studies evaluated the association between dietary Mg intake and risk of depression and 6 studies evaluated the association between dietary Ca intake and risk of depression. When comparing the highest with the lowest intake, the pooled relative risks of depression were 0.81 (95% confidence interval = [0.70, 0.92]) for Mg and 0.66 (95% confidence interval = [0.42, 1.02]) for Ca. Dietary Mg intake was significantly associated with a reduced risk of depression among studies conducted in Asia (relative risk = 0.57; 95% confidence interval = [0.44, 0.74]) and in studies adjusting for energy intake (relative risk = 0.73; 95% confidence interval = [0.58, 0.92]). For dose-response analysis, evidence of a nonlinear relationship was found between dietary Mg intake and risk of depression, and the largest risk reductions were observed for 320 mg/day.
Conclusion: This meta-analysis indicated that moderate Mg intake may be inversely associated with the risk of depression, which still needs to be confirmed by larger prospective cohort studies.
Keywords: Magnesium; calcium; depression; meta-analysis and dose–response analysis.