Appendectomy, acute appendicitis, and gastrointestinal diseases: A Mendelian randomization study.

BACKGROUND

Appendectomy is the standard treatment for acute appendicitis. However, the effects of appendectomy and acute appendicitis on gastrointestinal diseases are not fully understood.

METHODS

Genetic variants associated with appendectomy and acute appendicitis at a genome-wide significance level (P ​< ​5.0E-08) were selected as instrumental variables. Two-sample univariate and multivariate Mendelian randomization (MR) analyses were performed to examine the independent effects of appendectomy and acute appendicitis on related gastrointestinal diseases.

RESULTS

Appendectomy was linked to an increased risk of colon cancer (odds ratio [OR], 1.54; 95 ​% confidence interval [CI], 1.15-2.07; P ​= ​0.004; FDR-corrected P ​= ​0.016) and a decreased risk of primary sclerosing cholangitis (OR, 0.57; 95 ​% CI, 0.38-0.84; P ​= ​0.004; FDR-corrected P ​= ​0.016). Acute appendicitis was associated with a higher risk of cholelithiasis (OR, 1.16; 95 ​% CI, 1.06-1.27; P ​= ​0.002; FDR-corrected P ​= ​0.016).

CONCLUSION

This study suggested that appendectomy and acute appendicitis might affect the risk of several gastrointestinal diseases in European populations.