This is because the by-products of chlorination contaminate the air of indoor pools, irritating the airways and lungs and making them more vulnerable to allergens.
But asthma charities said the research was not conclusive enough to make them advise parents against indoor pools.
They said chlorine, added to kill germs, has saved hundreds of lives.
More than five million people are estimated to suffer from asthma in the UK.
The Belgian study, reported in the journal Pediatrics, compared the health of 733 teenagers between 13 and 18 who swam regularly in chlorinated pools with that of 114 who swam mostly in pools sanitised with a mix of copper and silver.
They found the highest proportion of asthma among the children who used the pools the most.
Toxicology professor Alfred Bernard, who led the research, said: ‘There is little doubt that pool chlorine is an important factor implicated in the epidemic of allergic diseases affecting the westernised world.
‘It is probably not by chance that countries with the highest prevalence of asthma and respiratory allergies are also those where swimming pools are the most popular.’
But Dr Elaine Vickers, of Asthma UK, said: ‘Asthma develops as a result of a complex mix of genetic and environmental factors, so more research is needed before we can make a conclusive link with the use of chemicals in swimming pools.
‘Swimming is an excellent form of exercise for children with asthma as it can help improve lung capacity and the warm, humid air of indoor pools is less likely to trigger asthma symptoms.
‘We would advise parents of children with asthma not to worry about letting their child go swimming, unless they develop asthma symptoms in the pool environment.’
Source: mail Online ; 16 Sept.’09
Related articles by Zemanta
- Pool chlorine raises kids’ asthma risk (cbc.ca)
- Chlorine in swimming pools linked to allergy risks: study (nationalpost.com)
- Chlorinated Swimming Pools: More Harm Than Good? (malepatternfitness.com)
- You: Eczema’s link to asthma uncovered (news.bbc.co.uk)
- Infection-allergy link questioned (news.bbc.co.uk)
- Stressed parents up asthma risk (news.bbc.co.uk)
- Chronic asthma study offers hope (news.bbc.co.uk)