Associations of early-life pet ownership with asthma and allergic sensitization: A meta-analysis of more than 77,000 children from the EU Child Cohort Network.
Level 3 - non-randomized controlled study
Meta-analysis of observational prospective birth cohorts
PubMed 35150722 · doi:10.1016/j.jaci.2022.01.023
What was done
Researchers harmonized data from 77,434 mother-child dyads across 9 birth cohorts in the European Union Child Cohort Network. They assessed the association between early-life cat and dog ownership (evaluating pet type, timing [never, prenatal, or early childhood], and number of pets) and school-age asthma (ages 5 to 11 years) and allergic sensitization. Associations were modeled via adjusted logistic regression per cohort and pooled using random-effects meta-analysis.
What was found
Early-life pet ownership prevalence across cohorts ranged from 12% to 45% for cats and 7% to 47% for dogs, while asthma prevalence ranged from 2% to 20%. Overall, pet ownership was not associated with asthma (cat OR = 0.97, 95% CI = 0.87–1.09; dog OR = 0.92, 95% CI = 0.85–1.01), and timing or number of pets did not alter these associations. Pet ownership was also not associated with pet-specific allergic sensitization (cat OR = 0.92, 95% CI = 0.75–1.13; dog OR = 0.93, 95% CI = 0.57–1.54). However, pet sensitization was strongly associated with school-age asthma (cat-sensitized OR = 6.69, 95% CI = 4.91–9.10; dog-sensitized OR = 5.98, 95% CI = 3.14–11.36), with evidence of an interaction where ownership exacerbated asthma risk primarily in sensitized children.
Why it matters
This large-scale meta-analysis resolves conflicting smaller studies by showing that early-life cat or dog ownership alone does not increase the risk of childhood asthma or allergic sensitization.
Limits
Observational designs remain susceptible to unmeasured confounding and selective avoidance (e.g., atopic families avoiding pet ownership). Pet ownership was used as a surrogate measure rather than direct indoor allergen concentrations, and cohorts varied in their baseline prevalence and harmonization definitions.
Cited by
- contradicts Children who grow up in households with dogs have a lower incidence of autoimmune diseases and allergies.