The Risk of Atopic Dermatitis in Children Exposed to Pets During Pregnancy
Vasu N, Wegienka G, Havstad S, Johnson CC, and Zoratti E. The Risk of Atopic Dermatitis in Children Exposed to Pets During Pregnancy. Breast 2019; 44:S15.
Background: Although the mechanism is uncertain, some studies have linked prenatal and early-life pet exposure to a decreased risk of atopic dermatitis (AD). Methods: 675 participants in a southeast Michigan population-based birth cohort were evaluated at age 2 to 4 years. Based on medical history and examination, a study physician was asked to determine whether there was evidence of current AD or a past history consistent with AD. Information regarding the presence of indoor dogs or cats was prospectively collected from the participants’ mothers during pregnancy. Results: Of 675 maternal-child pairs, 255 (37.7%) mothers reported living with a pet during pregnancy and 150 children (22%) were diagnosed with either current or prior atopic dermatitis by age 2 to 4 years. Compared to mothers not exposed to indoor pets during pregnancy, the risk of AD was lower among offspring of 255 mothers that lived with an indoor pet prenatally [OR = 0.6, 95% CI, (0.4-0.9), P = 0.01]. The lower risk was seen primarily among 137 mothers reporting indoor dogs only [OR = 0.5, (0.3, 0.8), P = 0.009] or 43 that had lived with both indoor cat(s) and dog(s) [OR = 0.4 (0.1, 1.0), P = 0.05]. There did not appear to be a similar effect among 75 mothers with cat only prenatal exposure [OR = 0.9 (0.5, 1.6), P = 0.79]. When analyses were restricted to the presence or absence of dog exposure (not considering cat co-exposure), offspring were also less likely to have had current or prior AD [OR 0.5(0.3, 0.8), P = 0.002]. Results of analyses further restricted to dog exposure and “current AD” (AD present at the 2–4 year evaluation) were similar [OR 0.5 (0.3, 0.9), P = 0.013]. These results were not substantially different in logistic regression models adjusting for the child's total IgE level or the presence of atopy as assessed by positive allergen-specific IgE tests or positive skin prick tests to a panel of common allergens. Conclusions: Prenatal dog exposure is associated with a lower risk of AD in young children. The mechanism(s) responsible for this relationship require further study.