Causal association between adiposity and hemorrhoids: a Mendelian randomization study

Jian Huang; Ying Gui; Hongping Qin; Yubo Xie

doi:10.3389/fmed.2023.1229925

Causal association between adiposity and hemorrhoids: a Mendelian randomization study

Front Med (Lausanne). 2023 Oct 6:10:1229925. doi: 10.3389/fmed.2023.1229925. eCollection 2023.

Authors

Jian Huang¹, Ying Gui¹, Hongping Qin¹, Yubo Xie^{2

3}

Affiliations

¹ Clinical Laboratory Center, The First Affiliated Hospital of Guangxi Medical University, Nanning, China.
² Department of Anesthesiology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China.
³ Guangxi Key Laboratory of Enhanced Recovery After Surgery for Gastrointestinal Cancer, The First Affiliated Hospital of Guangxi Medical University, Nanning, China.

Abstract

Background: Hemorrhoids are a very common anorectal disorder affecting a large number of individuals throughout the world. This study aimed to evaluate the causal effects of four adiposity traits including body mass index (BMI), body fat percentage, waist circumference, and waist-to-hip ratio on hemorrhoids by Mendelian randomization (MR).

Methods: We used summary statistics of BMI (N = 461,460), body fat percentage (N = 454,633), waist circumference (N = 462,166), waist-to-hip ratio (N = 212,244), and hemorrhoids (N = 337,199) from large-scale genome wide association studies of European ancestry. Univariable and multivariable MR were carried out to infer causality. The MR Steiger directionality test was used to test the causal direction.

Results: The primary MR analysis using the inverse variance weighted (IVW) method showed that there were positive effects of genetically determined BMI [odds ratio (OR) = 1.005, 95% confidence interval (CI): 1.003-1.008, per standard deviation (SD), p = 7.801 × 10^-5], body fat percentage (OR = 1.005, 95% CI: 1.001-1.008, per SD, p = 0.008), waist circumference (OR = 1.008, 95% CI: 1.005-1.011, per SD, p = 1.051 × 10^-6), and waist-to-hip ratio (OR = 1.010, 95% CI: 1.003-1.017, per SD, p = 0.003) on hemorrhoids. These findings were robust in multivariable MR adjusting for physical activity. The Steiger directionality test showed evidence against reverse causation.

Conclusion: Our MR study supports a causal role of adiposity in the development of hemorrhoids. Adiposity prevention may be an important strategy for reducing hemorrhoids risk.

Keywords: Mendelian randomization; adiposity; body mass index; hemorrhoids; risk.

Grants and funding

This study was supported in part by the Special Fund of Neurotoxicity of General Anesthetics and Its Prevention and Treatment Innovation Team of the First Affiliated Hospital of Guangxi Medical University (No. YYZS2022001), Guangxi Clinical Research Center for Anesthesiology (No. GK AD22035214), and the Key Project of Natural Science Foundation of Guangxi (No. 2020GXNSFDA238025). The funding sources had no role in study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the article for publication.