Cohort studyindependent cross-checkabstract checked I-ABX-119 standard review
Infant antibiotics linked to later IBD, not explained by infections
Early-Life Infections, Antibiotics and Later Risk of Childhood and Early Adult-Onset Inflammatory Bowel Disease: Pooled Analysis of Two Scandinavian Birth Cohorts.
Overview
Mårild K et al.. Aliment Pharmacol Ther 2025 · PMID 39450871 · DOI 10.1111/apt.18358
Antibiotics in the first year were linked to 33% higher relative risk of IBD after accounting for infections.
Does the study support the specific claim? Partly · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Separate effects of infections and antibiotics on IBD
- How was the study done?
Two birth cohorts
- How many people, animals or samples were studied?
103,046 children
- What was actually found?
Antibiotics, not infections, linked to IBD
- How large was the observed effect?
aHR 1.33 (1.01-1.76)
- What do the results mean in everyday life?
Possible modest effect
- What are the study's limitations?
Few cases
- What does it say about Elawady's specific claim?
Supports a possible effect, not a doubling
- Do the results apply to Germany and Europe?
High
- What can explicitly not be concluded from this study?
Proof of cause
Scientific in-depth review
1. Full reference
- Authors
- Mårild K et al.
- Journal
- Aliment Pharmacol Ther
- Year
- 2025
- Identifier
- PMID 39450871 DOI 10.1111/apt.18358
- Verification
- verified – PubMed efetch 2026-10-26 + Crossref
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Swedish and Norwegian research funds (record); authors declare no conflicts.
2. Research question
Are early-life infections and antibiotics associated with IBD, independent of infection frequency?
3. Study design and population
- Study design
- Cohort study – Pooled analysis of two prospective birth cohorts
- Population
Children followed from birth (ABIS Sweden, MoBa Norway)
- Country
Sweden, Norway
- Period
Births 1997-2009, follow-up to 2021
- Sample size
103,046 children; 395 IBD cases
- Inclusion and exclusion criteria
Questionnaire data to age 3; IBD from registries
4. Methods and endpoints
- Exposure / intervention
Antibiotics to age 3
- Comparator
No antibiotics
- Endpoints
IBD, CD, UC
- Statistical methods
Cohort-specific Cox, random-effects pooling
5. Actual results
- Results
Infection frequency not associated with IBD (aHR 1.01 per infection). Adjusted for infections, any vs no antibiotics in first year aHR 1.33 (95% CI 1.01-1.76); per additional course 1.17 (0.96-1.44), penicillin per course 1.28 (1.02-1.60); non-penicillin at 1-<3 years and UC per course aHR 1.95 (1.38-2.75).
- Absolute risks
395 cases in 1,663,898 person-years
- Authors' conclusion
Early-life antibiotic use was a significant risk factor for childhood and early adult-onset IBD, independent of infection frequency.
6. Strengths
- Prospective
- Adjusts for infection frequency
7. Weaknesses
- Few cases; wide CIs
- Parent-reported exposures
8. Risk of bias
- Orienting tool
- ROBINS-E
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Partially addresses confounding by indication.
9. Assessment of the statistical interpretation
Borderline precision.
10. Relevance to the specific claim
Addresses the key alternative explanation (infections).
11. Independent contrary findings
Imprecise.
12. Transferability to Germany and Europe
High (Scandinavian).
13. Overall methodological judgement
Adds support for a possible effect; magnitude modest (HR 1.33).
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | low |
| Directness | direct |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Causality.