Analysis of GP records of 642 eight-year-old children alongside the childhood records of their parents has ruled out the basis of the hygiene hypothesis.
This states that reduced exposure to early life infections and antibiotic treatment in childhood is detrimental to the immune system, increasing the risk of atopy.
But the latest study demonstrated that 97 per cent of the children had at least three infections by the age of five, compared with 69 per cent of their parents.
Antibiotic use before the age of five was also higher among the children, with 98 per cent having a record of an antibiotic scrip compared with 76 per cent of their parents.
The children had been followed up annually since birth. By the age of eight 19 per cent had atopy, 13 per cent suffered from wheeze and 21 per cent had seasonal rhinitis.
When parental atopy and birth order were considered, no association was found between infection counts and atopy, with an odds ratio of 1.01 per infection. Positive associations were found for wheeze and seasonal rhinitis, with the risk of current wheeze increasing by 7 per cent for each antibiotic scrip.
But lead researcher Dr Paul Cullinan, an expert in respiratory epidemiology at Imperial College London, said that this was probably due to asthmatic children often having wheeze in early life, a symptom that can increase prescribing for antibiotics.
‘There are some people who worry that if you give kids a lot of antibiotics, you’re likely to upset their system. I don’t think people need to worry about that.’
But other reasons, such as the emergence of drug-resistant pathogens, do suggest that careful prescribing of antibiotics is warranted, said Dr Cullinan.
‘The thing about the hygiene hypothesis is that, although it’s very attractive, there isn’t very much evidence for it. I suspect in a contemporary UK population, it’s not very important any more,’ he added.