Exploring Obesity Management as a Novel Approach for Preventing Inguinal Hernias: Evidence from a Mendelian Randomization Study and Systematic Review

Abstract

Background: The relationship between obesity and the risk of developing inguinal hernias (IH) is still unclear. This study aimed to examine the role of different types of obesity in IH risk, with the potential for obesity management as a new approach to preventing IH. Methods: A two-sample Mendelian randomization (MR) analysis and replicated MR analysis were conducted to assess the causal effect of obesity on IH risk. Summary data on genetically determined obesity-related traits, including body mass index (BMI), waist circumference (WC), hip circumference (HC), and waist-to-hip ratio (WHR), were collected from large-scale consortia. Multivariable MR was performed to estimate the independent effects on IH risk. Additionally, a systematic review of observational studies identified from PubMed, Embase, and Web of Science databases was conducted to evaluate the associations between different obesity types and IH, covering the period from inception to November 22, 2023. Results: The findings revealed that increased BMI, WC, and HC (P < 0.05) were associated with a lower risk of IH. The replicated and multivariable MR analyses consistently indicated that BMI exhibited a similar direction and magnitude of effect as observed in the univariable MR analysis [odds ratio (OR) = 0.940-0.989], while WC was associated with a higher risk of IH (OR = 1.018-1.099). The systematic review results supported BMI as a protective factor against inguinal hernia. However, there was limited evidence supporting the causal role of HC and WHR in IH risk. Conclusion: Genetically determined BMI and WC demonstrate a causal relationship with IH risk, providing new insights into potential underlying mechanisms. These results suggest that increasing overall or reducing abdominal obesity may be beneficial for preventing IH.