Shedding new light on the pets and asthma debate
Published: February 9, 2022
It has long been debated whether growing up with a cat or dog affects a child’s risk of developing allergy or asthma. On the one hand children can become sensitised to cat and dog allergens, which can be a trigger for asthma symptoms; on the other, early exposure to cat and dog allergens may induce immune tolerance, and their associated microbiota may be beneficial to the developing immune system. Studies investigating the influence of early-life cat and dog exposure on later risk of asthma have produced conflicting results, making it difficult to determine what advice should be offered to new or expectant parents regarding cat and dog ownership.
In a recent study published in The Journal of Allergy and Clinical Immunology (JACI), Pinot de Moira et al. use data from over 77,000 mother-child pairs from nine birth cohorts participating in the EU Child Cohort Network to shed some light on this debate. The study examines how cat and dog ownership in the first three years of life affects the risk of asthma at around 7 years, including the influence of timing of ownership and the number of cats or dogs owned. It also uses data from a smaller sample of children to analyse how ownership influences the risk of cat- and dog-specific allergic sensitisation at around 7 years, and whether the risk of asthma associated with having a cat or dog in early-life differs in children who develop allergic sensitisation compared with children who do not.
Between 12 and 45% and 7 and 47% of children included in the study had a cat or dog before the age of three years, respectively, and prevalence of asthma in the birth cohorts ranged between 2 and 20%. The authors observe no overall association between having a cat or dog in early life and later risk of asthma, and this was not strongly influenced by timing of ownership or the number of cats or dogs owned. The authors also do not observe an association between having a cat or dog and later risk of cat- or dog-specific allergic sensitisation. They do, however, observe a strong association between cat- and dog-specific allergic sensitisation and increased risk of asthma, which was stronger among children who had a cat or dog in early life. In contrast to this, however, among children who did not develop cat- or dog-specific allergic sensitisation, having a cat or dog was associated with slightly reduced risk of asthma.
These findings suggest that having a cat or dog in early-life in itself is unlikely to increase the risk of school-age asthma or cat- or dog-specific allergic sensitisation. It may even offer some protection among children who do not develop sensitisation. Having a cat or dog in early-life may, however, increase the risks associated with cat- and dog-specific allergic sensitisation.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.
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