Uppsala University uses cookies to make your website experience as good as possible. Read more about cookies. OK 

 Image copyright SCIENCE PHOTO LIBRARY 
 
 Young children who have a pet dog in the home are less likely to go on to develop asthma, a large Swedish study has found. 
 
 Exposure to a dog in the first year of life was linked to a 13% lower risk of asthma in later childhood among the 650,000 children the authors tracked. 
 
 The findings, in JAMA Pediatrics, support the idea that pets can bolster the immune system and prevent allergy. 
 
 More evidence is still needed - past studies have found conflicting results. 
 
 Certainly, for a child who is already allergic to dogs, buying a puppy would not be a good idea, say the Swedish researchers. 
 
 Man's best friend? 
 
 Pets are a common cause of allergy, with half of all asthmatic children allergic to cats and 40% allergic to dogs, according to the charity Allergy UK. 
 
 When animals groom themselves, they lick. Skin cells covered in saliva - animal dander - are shed along with loose fur. It's the dander to which some people become sensitised. 
 
 The findings of this latest study suggest exposure to dog dander in infancy might actually be beneficial. 
 
 Children who had grown up with a dog in their home were less likely to have asthma at the age of seven than children without dogs. 
 
 Living on a farm with lots of animals seemed to confer even more protection, cutting the risk of asthma by about 50%. 
 
 Lead scientist Prof Tove Fall, from Uppsala University in Sweden, said: "Our results confirmed the farming effect and we also saw that children who grew up with dogs had about 15% less asthma than children without dogs." 
 
 She said this fits with the hygiene hypothesis which favours exposure to dust and dirt to improve our tolerance of common allergens. The findings should also provide some reassurance for parents. 
 
 "That's important information for parents who are pregnant or are planning to have a baby, that they should not worry about getting a dog or a puppy if they would like to. 
 
 "But if you have an allergic child you should not get a dog to cure your child. It won't work and will probably make the allergy worse." 
 
 If you are allergic and live with pets, there are things you can do to cut your risk of having an allergic reaction. 
 
 Asthma UK advises: 
 
 Try to keep pets out of your bedroom and where possible living area 
 
 Regular grooming and bathing of cats and dogs can help 
 
 You could try using air filters and an efficient vacuum cleaner. This might be helpful for people who have cat allergies; however the evidence on the benefit of these remains unclear 
 
 No breed of dog is completely "non-allergic" because they all shed dander 
 
 Amena Warner of Allergy UK said: "There have been a few studies that have alluded to this but not such a longitudinal study with so many children so from that point of view this is quite a powerful study. It's very welcome." 
 
 Erika Kennington of Asthma UK, said more research was needed to better understand the effects so that it could be turned into practical advice for parents of young children. 

 Importance The association between early exposure to animals and childhood asthma is not clear, and previous studies have yielded contradictory results. 
 
 Objective To determine whether exposure to dogs and farm animals confers a risk of asthma. 
 
 Design, Setting and Participants In a nationwide cohort study, the association between early exposure to dogs and farm animals and the risk of asthma was evaluated and included all children born in Sweden from January 1, 2001, to December 31, 2010 (N = 1 011 051), using registry data on dog and farm registration, asthma medication, diagnosis, and confounders for parents and their children. The association was assessed as the odds ratio (OR) for a current diagnosis of asthma at age 6 years for school-aged children and as the hazard ratio (HR) for incident asthma at ages 1 to 5 years for preschool-aged children. Data were analyzed from January 1, 2007, to September 30, 2012. 
 
 Exposures Living with a dog or farm animal. 
 
 Main Outcomes and Measures Childhood asthma diagnosis and medication used. 
 
 Results Of the 1 011 051 children born during the study period, 376 638 preschool-aged (53 460 [14.2%] exposed to dogs and 1729 [0.5%] exposed to farm animals) and 276 298 school-aged children (22 629 [8.2%] exposed to dogs and 958 [0.3%] exposed to farm animals) were included in the analyses. Of these, 18 799 children (5.0%) in the preschool-aged children’s cohort experienced an asthmatic event before baseline, and 28 511 cases of asthma and 906 071 years at risk were recorded during follow-up (incidence rate, 3.1 cases per 1000 years at risk). In the school-aged children’s cohort, 11 585 children (4.2%) experienced an asthmatic event during the seventh year of life. Dog exposure during the first year of life was associated with a decreased risk of asthma in school-aged children (OR, 0.87; 95% CI, 0.81-0.93) and in preschool-aged children 3 years or older (HR, 0.90; 95% CI, 0.83-0.99) but not in children younger than 3 years (HR, 1.03; 95% CI, 1.00-1.07). Results were comparable when analyzing only first-born children. Farm animal exposure was associated with a reduced risk of asthma in both school-aged children and preschool-aged children (OR, 0.48; 95% CI, 0.31-0.76, and HR, 0.69; 95% CI, 0.56-0.84), respectively. 
 
 Conclusions and Relevance In this study, the data support the hypothesis that exposure to dogs and farm animals during the first year of life reduces the risk of asthma in children at age 6 years. This information might be helpful in decision making for families and physicians on the appropriateness and timing of early animal exposure.
– In perhaps the largest study of its kind, researchers from Uppsala University in Sweden are reporting in the journal JAMA Pediatrics that early childhood exposure to dogs and farm animals is linked to lower asthma rates. The team was uniquely poised to study the question in Sweden, where every citizen has a unique identification number that helps track every visit to a physician, every prescription, and even dog ownership registration, which became mandatory in 2001. (Once the data is de-identified, it's free for researchers to use in, say, large longitudinal studies.) In this massive study, researchers followed all 11 million children born in Sweden from 2001 through 2010. Previous research has been conflicting, but as many other studies have already suggested, this one finds that early exposure to dogs, at least in Sweden, results in a 13% lower risk of asthma in later childhood. The link was dramatically stronger in farm animals—where exposure in early childhood resulted in a 50% lower risk of asthma later. Still, that doesn't mean that kids who have an animal allergy should be further exposed; in fact, that can exacerbate the allergy, the researchers say. "There have been a few studies that have alluded to this but not such a longitudinal study with so many children, so from that point of view this is quite a powerful study," a rep from Allergy UK tells the BBC. "It's very welcome." (Canines might have a probiotic effect on us.)