Dr. Axe Wire · Study decoded · health

Early Pet And Farm Animal Exposure Shows No Link To IBD

A 24-year Danish cohort study of over 90,000 children found no connection between early pet or farm exposure and inflammatory bowel disease risk.

By Dr. Axe Editorial Team · October 18, 2026 · 1 source · Watch

Photo: Pexels

A nationwide Danish birth cohort study published October 13, 2026 in Clinical Gastroenterology and Hepatology found that early-life exposure to pets or farm animals was not associated with a child's risk of developing inflammatory bowel disease.

90,306offspring tracked

615developed IBD

24-yearmedian follow-up

Researchers drew on the Danish National Birth Cohort to track 90,306 children from birth, using maternal reports of prenatal pet or farm animal exposure. Forty-six percent of mothers reported pet exposure during pregnancy and 7% reported farm animal exposure. Over a median follow-up of 24 years, 615 offspring were diagnosed with inflammatory bowel disease through national health registries. Pet exposure showed no link to IBD risk (adjusted hazard ratio 1.05, 95% confidence interval 0.89 to 1.24), and neither did farm animal exposure (adjusted hazard ratio 1.00, 95% CI 0.73 to 1.37). The pattern held for Crohn's disease and ulcerative colitis analyzed separately. In a smaller group of 63,958 offspring with both pregnancy and early-childhood exposure data, no link emerged for exposure limited to pregnancy (hazard ratio 1.10, 95% CI 0.75-1.63) or limited to the first 18 months of life (hazard ratio 0.73, 95% CI 0.46-1.15).

The hygiene hypothesis holds that early contact with microbes carried by pets and farm animals helps train a child's immune system and may be linked to lower rates of immune-related disease. This study tested that idea directly for IBD in one of the largest birth cohorts available, and the numbers did not show animal exposure linked to higher or lower risk either way.

Adjusted Hazard Ratios for IBD: Pet vs Farm Animal Exposure

Clinical Gastroenterology and Hepatology, 2026, Balmer et al.

Exposure was based on maternal memory, not direct measurement of contact, which can blur a true signal. The abstract does not say whether diet, antibiotic use or rural versus urban living were accounted for, and each may shape IBD risk independently. This shows a lack of a link, not proof that animal exposure has no effect through pathways the study did not measure.

Dr. Axe’s Take

This is a useful reality check. Pets and farm animals didn't track with higher or lower IBD risk over 24 years in 90,000 kids, and I think that's a fair reading of the data. I still believe early microbial diversity matters for immune development broadly, but IBD looks driven more by gut barrier integrity, diet quality and the community of microbes living in your gut than by whether a child grew up around animals. For families, I'd put the energy into real food, fermented foods and outdoor time rather than treating pet ownership as an IBD lever.

— Dr. Axe

Take the Cellular Health Quiz →

Study summary

Who: 90,306 Danish offspring, followed median 24 years
Design: Birth cohort; maternal-reported pet/farm exposure; registry diagnoses; Cox hazards models
Dose: Not applicable; exposure was animal contact, not a dose
Primary result: 615 developed IBD; pet exposure aHR 1.05 (CI 0.89-1.24); farm exposure aHR 1.00 (CI 0.73-1.37)
Secondary: In 63,958 with pre/postnatal data: pregnancy-only exposure HR 1.10 (CI 0.75-1.63); childhood-only HR 0.73 (CI 0.46-1.15)
Funding / conflicts: Funders listed in the journal record: Danish National Research Foundation; Novo Nordisk Foundation. Conflicts not reported in the abstract.
Date: Oct 13, 2026