Causal relationship between hypertension and risk of constipation: A 2-way 2-sample Mendelian randomization study

Patients with hypertension have a higher risk of having constipation and vice versa. The causal association between these 2 variables is not proven. We performed a retrospective Mendelian randomization analysis to determine the causal association between constipation and hypertension. Two-sample 2-way Mendelian randomization analysis was used. Genetic variants for constipation were derived from genome-wide association study data of European origin (15,902 cases and 395,721 controls). Corresponding genetic associations for hypertension were derived from European ancestry GWAS data (54,358 cases and 408,652 controls). Genetic susceptibility to hypertension was associated with an increased risk of constipation (OR: 3.459, 95% CI: 1.820-6.573, P < .001). In an inverse Mendelian randomization analysis, no causal effect of constipation on hypertension was found (OR: 0.999, 95% CI: 0.987-1.011, P = .834). In sensitivity analyses, these associations persisted and no multiple effects were found. This study suggests that there is a causal relationship between hypertension and constipation and that hypertension may increase the risk of developing constipation.