Oral antibiotic use and early-onset colorectal cancer: findings from a case-control study using a national clinical database

Ronald McDowell, Sarah Perrott, Peter Murchie, Christopher Cardwell, Carmel Hughes, Leslie Samuel

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27 Citations (Scopus)
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Background: Antibiotic-induced gut dysbiosis has been associated with colorectal cancer (CRC) in older adults. This study will investigate whether an association exists between antibiotic usage and early-onset colorectal cancer (CRC), and also evaluate this in later-onset CRC for comparison. Methods: A case-control study was conducted using primary care data from 1999–2011. Analysis were conducted separately in early-onset CRC cases (diagnosed < 50 years) and later-onset cases (diagnosed ≥ 50 years). Conditional logistic regression was used to calculate odds ratios and 95% confidence intervals (CI) for the associations between antibiotic exposure and CRC by tumour location, adjusting for comorbidities. Results: Seven thousands nine hundred and three CRC cases (445 aged <50 years) and 30,418 controls were identified. Antibiotic consumption was associated with colon cancer in both age-groups, particularly in the early-onset CRC cohort (<50 years: adjusted Odds Ratio (ORadj) 1.49 (95% CI 1.07, 2.07), p = 0·018; ≥50 years (ORadj (95% CI) 1.09 (1.01, 1.18), p = 0·029). Antibiotics were not associated with rectal cancer (<50 years: ORadj (95% CI) 1.17 (0.75, 1.84), p = 0.493; ≥50 years: ORadj (95% CI) 1.07 (0.96, 1.19), p = 0.238). Conclusion: Our findings suggest antibiotics may have a role in colon tumour formation across all age-groups.

Original languageEnglish
Pages (from-to)957-967
Number of pages11
Issue number6
Early online date17 Dec 2021
Publication statusPublished (in print/issue) - 4 Jan 2022

Bibliographical note

Publisher Copyright:
© 2021, The Author(s).

Data Access Statement

The datasets analysed in this study are not publicly available and were used under license. Requests for PCCIUR data should be directed in the first instance to Katie Wilde (Research Manager), email: k.wilde@abdn.ac.uk.


  • cancer epidemiology
  • Colon cancer


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