Swimming in chlorinated outdoor pools may boost child's asthma risk

London, September 25: For kids, swimming pool makes a good place to cool off on a sizzling summer day. But, swimming in outdoor chlorinated pools can increase children’s risk of developing asthma, warns a new study.

Several earlier researches have suggested that chlorinated indoor swimming pools can cause asthma in swimmers. And, it was thought that outdoor pools are safer than indoor pools. But, researchers in Belgium debunked all those claims, saying that swimming even in outdoor chlorinated pools could do more harm than good.

The study, conducted by Prof Alfred Bernard, of the Catholic University of Louvain, Brussels, Belgium and colleagues, warned that children who regularly swim in chlorinated pools are 'five times' more likely to develop asthma, a chronic allergic inflammatory disease of the airways that affects more than 300 million people worldwide.

"The more you swim, the higher the risk," said Bernard. "What is new in this study is that we looked at outdoor pools for the first time."

In their study, Bernard and his team, who reported their findings in the European Respiratory Journal, expressed the potential harms of swimming in outdoor pools. They warned that despite their natural ventilationdefine outdoor pools could be riskier than indoor ones because harmful chlorine fumes remain at the pool surface.

The chlorine vapors floating around the surface of the pool may trigger the respiratory effects by penetrating the upper airways, the researchers said. And children are highly vulnerable to develop asthma, because they tend to spend hours playing and swimming in the pool.

To detect the effects of swimming in outdoor pools regularly, Bernard and his team examined 847 secondary school students with an average age of 15. They asked their parents to fill a questionnaire, consisting questions about the respiratory health of their child and their exposure to common risk factors of asthma and allergies.

The questionnaire also asked about the children’s swimming pool attendance that allowed experts to estimate the total amount of time each child had spent during his life in outdoor chlorinated pools.

The researchers found that adolescents with highest pool attendance- one hour a week for ten years (more than 500 hours in total) - were five times more likely to have the wheezing condition than children who had never swum in outdoor pools.

And, those with a predisposition to allergies were up to ten times more likely to be asthmatic if they had swum for more than 500 hours in an outdoor pool, the researchers said.

"In summary, the present study shows that the attendance at outdoor chlorinated swimming pools, at home or during holidays, is associated with an exposure-dependent increase in the risk of asthma," the authors of the study concluded.

Asthma is an allergic inflammatory disease of the airways, in which the airways in the lungs become inflamed, excess airway mucus is produced, and airways narrow when muscles within the airway walls contract causing wheezing and breathlessness, sometimes to the point where the patient gasps for air.

Although Asthma is a chronic respiratory disease, sometimes worrisome and inconvenient, at the same time it is a manageable condition. With proper understanding, good medical care, and monitoring, the disease can be kept under control

Asthma, also known as reactive airway disease, affects more than 2 million people in Canada, and more than 22 million people in America, including 7million children under 18. In Britain, more than five million patients suffer from asthma and around 70,000 are admitted to hospital each year with life-threatening attacks.