Having a pet dog can cut a child’s risk of asthma

HAVING a pet dog reduces a child’s risk of asthma by 15 per cent, and contact with farm animals halves their likelihood of developing the condition, research has shown.

Scientists analysed health records of more than a million children in Sweden, a country where any pet or farm animal ownership has to be registered.

Regular exposure to dogs during the first year of a child’s life was associated with a 15 per cent lower likelihood of getting asthma, while living close to farm animals cut their risk by 52 per cent. The study, published in the journal JAMA Paediatrics, said the findings lent support to the ‘hygiene hypothesis’ – which suggests that living in clean conditions early in life increases susceptibility to allergies including asthma.

According to the hypothesis, a lack of early exposure to microbes and parasites prevents the immune system developing prop- erly. As a result, natural checks on unwanted immune responses that can lead to allergy are lacking.

Lead researcher Dr Tove Fall, from Uppsala University in Sweden, said: ‘Earlier studies have shown that growing up on a farm reduces a child’s risk of asthma to about half. We wanted to see if this relationship also was true also for children growing up with dogs in their homes.

‘Our results confirmed the farming effect, and we also saw that children who grew up with dogs had about 15 per cent less asthma than children without dogs. Because we had access to such a large and detailed data set, we could account for confounding factors such as asthma in parents, area of residence and socio-economic status.’

Researcher Professor Catarina Almqvist Malmros added: ‘We know that children with established allergy to cats or dogs should avoid them, but our results also indicate that children who grow up with dogs have reduced risks of asthma later in life.’