Does an Animal a Day Keep the Doctor Away?



By Harriet Gallegos, MRes Biochemistry

Following a recent report published by researchers at the University of Gothenburg, Sweden, Harriet Gallegos reports on the link between having a pet in your infancy and an absence of allergies in later life.

For those of you lucky enough to have grown up with a childhood pet, whether that is a dog, a cuddly rabbit or a not-so-cuddly reptile, you’ll understand the great friendship an animal can provide. For many, a pet is a silent confidant, the provider of endless company and the ultimate companion; but could early introduction to pets provide additional health benefits?

boy holding dog
Photo by Alicia Jones / Unsplash

Published data has demonstrated that exposure to farm animals and farm-living as a child has a protective effect against the risk of developing allergies such as asthma, eczema and hay fever. However, studies considering whether the same can be said for owning household pets present conflicting evidence. Despite some support for this notion, how pets might contribute to immunological tolerance and whether or not this relationship is dose-dependent has remained undetermined.

Bill Hesselmar at the University of Gothenburg, Sweden, and colleagues attempted to answer these questions. They analysed data from two previous studies: a cross-sectional questionnaire-based study of 1029 children aged 7-8 and a birth-cohort of children clinically evaluated up to the age of 8-9 years. Specifically, the number of household dogs and cats owned during the first year of life was investigated in relation to the development of the allergies: asthma, allergic rhinoconjunctivitis (ARC) and eczema.

In the cross-sectional questionnaire, the incidence of allergies was 49% in children who had spent their first year of life with no pets. This dropped to 43% for those with one pet, 24% for those with three pets and 0% for the two children who had lived with five pets. In support of this, data from the birth-cohort demonstrated similar results. The rate of allergies was 48% for children with no exposure to pets in the first 12 months of life, falling to 35% for those with one pet and 21% for those with two or more.

Any possibility that the results were due to selection bias, where parental allergies influence the number of pets they own, was eradicated: there was no significant difference in the frequency of positive Phadiatop tests, an allergy screening check, from parents with no household pets versus parents with increasing numbers of animals.

Thus a dose-dependent relationship was revealed: exposure to more pets resulted in a lower incidence of allergies! Good news for all of you animal-lovers out there. Given the results, why might this be the case and how can we explain this association? Well Hesselmar suggests that having multiple pets could be similar to living on a ‘mini-farm’. Living in close proximity to more animals results in exposure to a greater number of allergens, microbes and endotoxins which in turn provides immense immune stimulation and allergy prevention. This would equate the relationship to that found with farm-living where animals are diverse and numerous.

So does this mean we should all be growing up with two dogs, three cats a hamster and leopard gecko? Or perhaps we can embrace our inner Mowgli and be shipped off to the jungle for a week or two? Perhaps not, but it seems to be becoming increasingly clear that those childhood companions can provide heaps of benefits – both physically and emotionally.

Featured Image: Picsea/ Unsplash

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