Combined healthy lifestyle and depressive symptoms: a meta-analysis of observational studies

Background: To systematically summarize the association between combined lifestyle (at least three factors, including but not limited to smoking, drinking, physical activity, body mass index, diet) and depressive symptoms by a meta-analysis in general populations. Methods: Multiple electronic databases were searched for observational studies investigating combined lifestyle factors and depressive symptoms published before September 2020. Pooled risk estimates were calculated using random-effects models. Publication bias was conducted using the Egger's and Begg's tests. Results: A total of 12 studies with 185,899 participants were included. The pooled OR of depressive symptoms in meta-analysis of 7 cross-sectional studies was 0.53 (0.39, 0.72), I2 = 83.6%, P for heterogeneity <0.001 and the pooled RR was 0.33 (0.12, 0.89), I2 = 95.3%, P for heterogeneity <0.001 in meta-analysis of 5 cohort studies for people with the highest versus lowest score of heathy lifestyles. In sensitivity analyses, the heterogeneity was significantly reduced in cross-sectional studies (pooled OR = 0.74 [0.65, 0.85], I2 = 21.7%, P for heterogeneity = 0.27) and cohort studies (pooled RR = 0.53 [0.38, 0.74], I2 = 15.2%, P for heterogeneity = 0.32). The publication bias corrected by "trim-and-fill" analysis yielded unchanged results. Limitations: Limitations included residual confounding in original studies, heterogeneity between studies, and potential publication bias in the analysis of cross-sectional studies. Conclusion: The healthy lifestyle was associated with a reduced risk of depressive symptoms. Adherence to overall healthy lifestyles is essential for the primary prevention of depression in general populations.