Early age of dog exposure is negatively associated with atopic dermatitis: A comprehensive analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational cohort studies
PubMed 39837990 · doi:10.1038/s41390-025-03864-x
What was done
The authors conducted a systematic review and meta-analysis following PRISMA guidelines, searching PubMed, Cochrane Library, and EMBASE for cohort studies assessing early-life pet exposure (ages 0–12 years) and incident atopic dermatitis (AD). Quality of included studies was evaluated using the Newcastle-Ottawa Scale (NOS), and publication bias was examined using funnel plots. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were synthesized across 23 studies.
What was found
Based on 23 studies with participant cohort sizes ranging from 3,174 to 25,527, dog exposure was significantly associated with a decreased risk of incident AD (RR = 0.82, P = 0.002). No statistically significant association was found for exposure to cats (RR = 1.08, P = 0.490) or other pets (RR = 0.94, P = 0.550). In subgroup analysis, the negative association with dog exposure was stronger in North American populations (RR = 0.60, P < 0.001). Funnel plots showed no evidence of publication bias.
Why it matters
This meta-analysis helps resolve conflicting findings regarding pet ownership and eczema by demonstrating that the protective association is specific to dogs rather than other domestic animals, with notable geographic variation.
Limits
The findings are based solely on observational cohort studies, which are subject to residual confounding such as family history of atopy and pet-avoidance behavior in at-risk families. The abstract does not report pooled confidence intervals, heterogeneity statistics (such as I²), or definitions of pet exposure intensity and timing within the 0–12 age window.
Cited by
- partial Children who grow up in households with dogs have a lower incidence of autoimmune diseases and allergies.