Population-based study of antibiotics use and subsequent risk of colorectal cancer

A population-based study in Sweden investigated the association of antibiotics use and risk of colorectal cancer. The study included 40,545 CRC cases, and for each patient five controls matched for age, sex, and county (n=202,720). After exclusion of antibiotic use within two years from diagnosis (or index date for controls) there was a robust association between antibiotics use and higher risk of proximal colon cancer, and an inverse association with rectal cancer (driven by women).