Causal relationship of obesity and adiposity distribution on risk of ventral hernia.

Purpose: Ventral hernia (VH) is a common surgical disease. Previous studies suggested that obesity is an important risk factor for VH. However, the causal relationship between fat distribution and the risk of VH is still unclear. This study used Mendelian randomization (MR) to evaluate their causal relationship.

Methods: We used the body mass index (BMI), body fat percentage, and body fat mass to represent general obesity and utilized the volume of abdominal subcutaneous adiposity tissue, visceral adiposity tissue, waist circumference, hip circumference, and waist-to-hip ratio to represent abdominal adiposity. The data were extracted from the large-scale genome-wide association study of European ancestry. We used two-sample MR to infer causality, using multivariate MR to correct the effects of confounding factors.

Results: Increased BMI, body fat percentage, body fat mass, visceral adiposity tissue, waist circumference, and hip circumference rather than subcutaneous adiposity tissue or waist-to-hip ratio, were causally associated with a higher risk of VH. The results of multivariate MR suggested that body fat percentage was causally associated with a higher risk of VH after adjusting for body mass index, diabetes, and smoking.

Conclusion: General obesity, increased visceral adiposity tissue, waist circumference, and hip circumference rather than subcutaneous adiposity tissue or the waist-to-hip ratio were causally associated with a higher risk of VH. These findings provided a deeper understanding of the role that the distribution of adiposity plays in the mechanism of VH.