Swimming and Asthma

All too often I hear in my allergy/asthma clinic about how a swimming pool affects the child’s breathing. The assumption is that the chlorine or mold is aggravating the respiratory tract. All too often the evaluation for mold allergy is negative and we would consider chlorine as a possible irritant for the inflamed, hyper-reactive airways. Hopefully, we will see the sun soon and those hot days of summer will be upon us. The kids will be in the pools!

 

I was intrigued to see a recent article in the American Journal of Respiratory and Critical Care Medicine (Volume 183. pages 582-588, 2011) that dealt with asthma and swimming pools. The title of the article was ‘Swimming Pool Attendance, Asthma, Allergies, and Lung Function in the Avon Longitudinal Study of Parents and Children Cohort’ written by Font-Ribera and others. What follows are a number of interesting points about swimming pools and asthma that appear in the article.

 

Background

There is the suggestion that swimming in chlorinated swimming pools is a risk factor for developing asthma. The theory was that cleaning products had an effect on the airway which could lead to the development of asthma. Studies were references showing increased asthma in lifeguards and a higher prevalence of asthma in elite swimmers.

 

These observations were also thought to be due to ‘reverse causation (where the effect preceded the cause)’- swimming is recommended for those with asthma.

 

There have been many epidemiologic studies done in Europe regarding swimming as a risk factor for asthma, however the results are conflicting. Of note is the statement “….there is agreement on the complexity of the potential role of swimming asthma etiology and the important public health implications.

 

Asthma is one of the most common chronic conditions in childhood and swimming is one of the most popular sports/activities. So, a study was done to address some of these issues

 

The purpose of the study

To examine whether swimming at different periods during early childhood is associated with the prevalence of asthma and allergy symptoms.

 

How they did it

This was part of a large cohort study. In such a study a group of children are recruited and watched over time for events to occur. This was done as part of the Avon Longitudinal Study of Parents and Children (ALSPAC) and comes from the United Kingdom. More than 5,700 children were evaluated. Asthma symptoms were reported using a standardized tool (the International Study of Asthma and Allergies in Children- ISAAC). Lung function was measured and a methacholine challenge was performed (measures airway hyper-reactivity)

 

Swimming frequency was asked at various times of the child’s life. There were a variety of possible confounding variables looked at as well; sex, birth weight, number of siblings, atopy, maternal education, maternal and paternal social class, maternal age at delivery, maternal asthma, allergy and hay fever, contact with pets, hours of TV watching, exposure to environmental smoke, and body mass.

 

What they found

The total number of children in the study was 5,738. Only 12% of the mothers had asthma. Positive allergy skin tests were seen in 21.4%. Asthma was present in 20%.

 

The crude and an adjusted model looked at using a variety of variables and both gave similar results. When all the confounders were accounted for, swimming was not associated with ever having asthma. Interestingly, swimming was associated with a lower prevalence of currently having asthma and currently using asthma medication at age 7 years. There was also no significant association seen between swimming and current wheezing, eczema, nasal symptoms, or eye symptoms at age 7 or at age 10 years.

 

The data was looked at from the perspective of the effect of swimming when there were previous respiratory tract symptoms at different ages. The protective effect of swimming was only seen among children who wheezed prior to age 3.5 years.

 

Of note, there was no significant association between swimming and bronchial hyper-reactivity.

 

Swimming also did not increase the risk of any respiratory tract symptom in children who were atopic.

 

Conclusions

This large prospective birth cohort study did not find that swimming increased the risk for asthma, atopy, or any respiratory/allergic symptom in British children. Swimming was associated with better lung function and decrease asthma prevalence in children who had previous respiratory tract symptoms.

 

The authors do point out a few problems with the study. The questionnaire asked about swimming and not swimming pool attendance. It was assumed that since this was done in the United Kingdom and the weather being what it is, the assumption was that the affirmative answer did refer to pools. Chlorine is the most commonly used disinfectant. However, no information was collected regarding the amount of chlorine exposure.

 

Reviewers Note

This was a large study and a prospective study that looked into a very practical question. The more children the study, the stronger the conclusions.
Swimming did not make things worse and in fact lung function was better and the risk of asthma symptoms and medication used was lower in those children who were known to have wheezing when they were younger.

Swimming is a good thing!

FEL

May 23, 2011 · fleickly · 2 Comments
Tags: , ,  · Posted in: Allergy in Children, Asthma, Interesting articles, Swimming and asthma

2 Responses

  1. pool leak detection in Canada - March 18, 2012

    pool leak detection in Canada…

    Good information on Complaints web Holland Swimming . As I have read other online views on the same I think the details are well reflected on this.It was a good way of spending evening on Sunday . I’ll visit again to read more on this website and hope…

  2. fleickly - March 19, 2012

    Thanks for the comments.
    FEL