Can depression lead to chronic constipation, or does chronic constipation worsen depression? NHANES 2005-2010 and bidirectional mendelian randomization analyses.

Background: Depression and chronic constipation often co-occur, but the reciprocal influence between the two remains unclear. The purpose of this study is to explore the potential association between depression and chronic constipation.

Methods: This study initially utilized data from National Health and Nutrition Examination Survey (NHANES) 2005-2010 to explore the correlation between depression scores and chronic constipation, assessing the non-linear relationship between the two. Subsequently, we conducted a two-sample Mendelian randomization (MR) analysis to evaluate the causal relationship between depression and major depression with chronic constipation. The Inverse Variance Weighting (IVW) method served as the primary reference, supplemented by sensitivity tests. Finally, a reverse MR analysis was performed to assess the presence of any reverse causation. The STROBE-MR checklist for the reporting of MR studies was used in this study.

Results: In the NHANES analysis, survey-weighted logistic regression revealed a significantly positive correlation between depression scores and chronic constipation (OR = 1.04, 95% CI = 1.02-1.07, p = 0.002), even after adjusting for the included covariates. The nonlinear analysis using Restricted Cubic Splines (RCS) enhanced the robustness of the association (P-non-liner = 0.01). The MR analysis also confirmed the causal relationship between depression (OR = 11.43, 95% CI = 1.85-70.67, p = 0.008) and major depression (OR = 1.12, 95% CI = 1.03-1.22, p = 0.007) with chronic constipation, passing rigorous sensitivity tests. No evidence of reverse causation was observed in the reverse MR analysis (P > 0.05).

Conclusions: Depression is positively correlated with the risk of chronic constipation. Therefore, enhancing attention to chronic constipation in patients with depression may be effective in clinical practice.