Adult Antibiotic Use Not Linked to Early-Onset Colorectal Cancer Risk
A large case-control study spanning more than 2 decades found no significant association between oral antibiotic use in adulthood and the risk of early-onset colorectal cancer (EOCRC), addressing a question that has fueled scientific debate amid rising cancer rates among younger adults.
“Prior antibiotic use may be a factor in the rising incidence of colorectal cancer seen in those under 50 years of age (EOCRC),” the authors explained in Clinical Gastroenterology and Hepatology. “However, the few studies to examine this link have reported conflicting results.”
Researchers examined health records from Kaiser Permanente Northern California for adults aged 18–49 who were diagnosed with EOCRC—defined as adenocarcinoma of the colon or rectum—between 1998 and 2020. Eligible participants had at least 2 years of continuous pharmacy benefits before their cancer diagnosis. Each case (n = 1359) was matched with 4 controls (n = 4711) on sex, race and ethnicity, birth year, medical facility, and pharmacy coverage duration.
Exposure to oral antibiotics more than one year before diagnosis was assessed using detailed prescribing records. The analysis revealed no significant link between prior antibiotic use and EOCRC risk. In both unadjusted and adjusted models, the adjusted odds ratio was 1.04 (95% CI, 0.94–1.26)—a statistically non-significant result. Researchers also found no association when evaluating the cumulative number of antibiotic prescriptions or timing of use.
A sensitivity analysis limited to individuals with ≥10 years of continuous pharmacy data confirmed these findings.
“In a large US healthcare setting, there was no conclusive evidence of an association between oral antibiotic use in adulthood and risk of EOCRC,” the authors concluded.
Reference
Kane KJ, Jensen CD, Yang J, et al. Oral antibiotic use in adulthood and risk of early-onset colorectal cancer: a case-control study. Clin Gastroenterol Hepatol. 2025;23(8):1440-1447.e5. doi:10.1016/j.cgh.2024.09.002
