Study after study is finding that having pets in early childhood or living on a farm with lots of exposure to animals is associated with a lower incidence of allergies. Pets with all their "germs" (bacteria and other microbes) appear to have beneficial effects on children's developing immune systems. One study from the Univ. of Gothenburg (in Sweden) actually found that the more pets a child lives with in the first year of life, the lower the incidence of later allergies in children. The results were dose-dependent - with each additional pet, the incidence of allergies is a little lower.
The numbers are amazing - allergies decreased from 49% in those with no pets to zero in those with five or more pets. The researchers suggest that there is a “mini-farm” effect, with exposure to a number of cats and dogs protecting against all allergy development (animal, food, and pollen allergies). What an about face in medical views in a few decades! It used to be viewed that if you wanted to prevent allergies in children, then avoid pets such as dogs and cats. Hah!
From Medical Xpress: Pet-keeping in early life reduces the risk of allergy in a dose-dependent fashion
A team of researchers at the University of Gothenburg has found that when infants live with pets, they grow up to have fewer allergies and other diseases. In their paper published on the open access site PLOS ONE, the group describes their study of datasets that held information on children's health and whether they had lived with pets as infants, and what they found.
It is commonly believed that allowing infants and children to come into contact with germs helps their immune system to grow stronger, offering them more protection later in life. In this new effort, the team in Sweden sought to learn more about the possible benefits of germ exposure to infants living with pets in their home.
The study by the team consisted of analyzing data from databases built around two previous studies that involved tracking children's health and which also held information about pets in their homes. One of the datasets included information for 1,029 children that were either seven or eight years old. In that dataset, the researchers found that the incidence of allergies (which in this study included asthma, eczema, hay fever and allergic rhinoconjunctivitis) was 49 percent for children who had not been exposed to pets as infants. That number fell to 43 percent for children who had lived with a single pet as an infant and to 24 percent for children who had lived with three pets.
The second dataset held information on 249 children— it showed that the allergy rate for children growing up without a pet was 48 percent, 35 percent for children with one pet and just 21 percent for children who had grown up with multiple pets.
The researchers suggest that taken together, the two datasets show that the more exposure infants have to pets, they less likely they are to develop allergies later in life. They also note that having pets is just one way to reduce allergy risk, other factors such as being born vaginally, living on a farm and having more siblings have also been shown to reduce the risk—as has parents sucking on a baby's pacifier before handing it to them.