Childhood asthma linked to chemicals in swimming pools

Published on 18/07/2006 02:08

SOARING rates of childhood asthma in the UK could be linked to exposure to chemicals from swimming pools, researchers believe.

Cases of asthma have increased steeply in the past 30 years, with one study showing Scotland has the worst rates among children aged 13 and 14 in the world.

Now research involving almost 190,000 teenagers from 21 European countries has found that more visits to indoor swimming pools may be part of the reason for the rise in asthma cases.

The researchers, from the Catholic University of Louvain in Brussels, analysed rates of wheezing, asthma, hay fever and other allergies compared with the number of indoor chlorinated swimming pools per 100,000 of the population.

The UK had the most pools - about five per 100,000 people, compared with about three or four in countries such as Spain, Germany and France. In eastern Europe, with much lower rates of asthma, there was just one pool per 300,000 people.

The researchers, led by Professor Alfred Bernard, found that the rate of wheezing increased by 3.39 per cent for every extra indoor swimming pool in a country, while rates of asthma rose by 2.73 per cent.

Writing in the journal Occupational and Environmental Medicine, they concluded that the rise of asthma in western Europe could at least be partly due to children being exposed to the byproducts of chlorine in the air and water of indoor pools.

Prof Bernard said the study had also probably underestimated the availability of swimming pools in the UK, where children have increased access to pools in school.

It is estimated that the UK has about 2,300 school pools compared with 1,700 public ones. In other European countries children tend to use public pools.

Prof Bernard said: "Sometimes privately managed pools are not as well-managed as municipal pools."

The researchers said they had been surprised by the association they found between asthma and public pools and that it was important to study this further.

Prof Bernard also highlighted the importance of ventilation.

"In a well-managed pool with good ventilation there should be hardly any chlorine smell. There can be some smell but not the kind that has irritating effects. But ventilation is very, very expensive. My concern is that it will become increasingly difficult to afford such costs in the future," Prof Bernard said.

Ian Wakefield, of the Institute of Sport and Recreation Management, said that as long as pools were properly managed there should not be a problem with chlorine and asthma. But he said there might not always be proper ventilation.

"There are plenty of pools that don't follow the guidance and it is a message that we need to get across to the industry," he said.

A spokeswoman for the charity Asthma UK said: "Swimming is an excellent form of exercise for children with asthma as the warm humid air in the swimming pool is less likely to trigger asthma symptoms.

"We do recognise, however, that the chemicals present in heavily chlorinated pools may be important in making the airways more irritable and further research is needed to understand this association."