Pet ownership at a young age does not trigger asthma

Early-life ownership of cats or dogs among children does not increase the risk of developing asthma by school age, reports a new meta-analysis. However, such pet ownership may exacerbate related allergic risks.

Drawing from nine birth cohorts in the EU Child Cohort Network, the researchers examined 77,434 mother-child dyads. Pet ownership was determined from parental reports of having a cat or dog during early pregnancy or early childhood. Outcomes included current asthma, allergic sensitization, and lung function at school age.

Early-life cat ownership ranged from 12.2 percent to 45.1 percent, while that for dogs ranged from 7.4 percent to 47.4 percent. Current asthma at school age was detected in 2.3 percent to 19.5 percent of children; the corresponding prevalence range for sensitization was from 6 percent to 12 percent for cats, and from 3 percent to 5 percent for dogs.

There was no strong evidence to support the influence of early-life cat or dog ownership on school-age asthma. Wheezing during infancy, child sex, and parental asthma likewise had no effect on such outcome. Pet ownership was likewise unrelated to school-age lung function. Moreover, early-life pet ownership did not increase the risk of cat- or dog-specific allergic sensitization.

However, allergic sensitization to pets was a strong and significant risk factor for school-age asthma, increasing its odds by around sixfold (cat-specific sensitization: odds ratio [OR], 6.69, 95 percent confidence interval [CI], 4.91–9.10; dog-specific sensitization: OR, 5.98, 95 percent CI, 3.14–11.36).

“Cat and dog ownership in themselves are unlikely to increase the risk of school-age asthma and cat- and dog-specific allergic sensitization, but may exacerbate the risks associated with cat- and dog-specific allergic sensitization,” the researchers said.