Thursday, April 14, 2011

Childhood Asthma Study: Part 2 - Carpet, No Carpet? No Difference

Childhood Asthma Study: Part 2 - Carpet, No Carpet? No Difference

Childhood Asthma Study Concludes: No Difference in Symptom Improvement, Allergen Levels in Carpeted vs. Uncarpeted Homes - Part 2

[Part 1 of this two-part series describes the original Childhood Asthma Study.]

If you buy into the widespread current thinking in the medical community and popular media on the effect of carpet on patients with asthma and allergies, you would expect that, all other variables being equal, asthmatic children who live in homes without carpet on the floors would suffer fewer symptoms. A major medical study indicates that this is not the case.

Titled, “Results of a Home-Based Environmental Intervention among Urban Children with Asthma”, the study was published in the September 9, 2004 edition of the New England Journal of Medicine. It describes the results of a project called “The Inner-City Asthma Study.” Because children with asthma who live in the inner city are exposed to multiple indoor allergens and environmental tobacco smoke in their homes, the objective of the study was to determine “whether an environmental intervention tailored to each child’s allergic sensitization and environmental risk factors could improve asthma-related outcomes.” In other words, if making healthy changes in an asthmatic child’s home would help him or her live more symptom-free.

Childhood Asthma Study Details

The study followed 937 children from seven major U.S. cities over the course of a year. Of the participants, more than 50% of the children had positive skin tests to three or more allergen groups. Other common elements of the group were that they were from families whose incomes were at or close to the poverty level, as well as these factors:

“Cockroaches were reported in 58% of homes, wall-to-wall carpeting in the child's bedroom in 55%, a smoker in 48%, mice or rats in 40%, and furry pets in 28%. "

Trained instructors worked with each subject family, educating and motivating them to make changes in as many as six different areas, according to each child’s needs: establishing an allergen-free sleeping zone, eliminating environmental tobacco smoke, cockroach and rodent allergens, pet dander, and mold.

Families were given HEPA-filter vacuum cleaners, and in some instances, freestanding air filters. Professional pest exterminators were called in where needed. Children’s beds were encased in dust-mite-blocking covers, and caretakers were given cleaning products and instructed in how best to clean and maintain the home to remove allergens. Study sponsors supplied the families with cleaning products – even the cost of the additional electricity the household would need to run the vacuum or air filter was provided through the study.

Another article about the Inner City Study, published in 2002 in Environmental Health Perspectives (peer-reviewed journal published by the National Institute of Environmental Health Sciences) tells how, at the outset of the study, researchers wanted to remove carpet from the children’s’ bedrooms, but for various reasons could not. “Because wall-to-wall carpeting is known to be a major allergen reservoir, we would have preferred to remove it from the child’s bedroom. However, expense and apartment rental contracts prevented us from relying on this approach.” Still, caregivers were instructed to, “whenever possible, remove the carpet from their children’s bedrooms.”

Childhood Asthma Study Results

The interventions took place over one year, but the households in the study were monitored every six months for a period of two years. Children’s symptoms were assessed every two months during the first year.

The interventions resulted in more symptoms-free days for the study group throughout the study. Children missed fewer days of school, slept through the night more, and made fewer trips to the emergency room. Here’s an interesting fact mentioned in the study: contrary to what was expected, “Carpeting in the home did not modify the effect of the intervention on symptoms.” In other words, children with carpet in their bedrooms improved as much and did just as well as children who had hard surface floors.

In addition, the interventions produced marked declines in the measured levels of allergens in the home, including in the bed, and on the floor. Indeed, the study reported, “There was no difference in allergen reduction between homes with carpets and those without carpeting.”

I am certainly no medical expert, but it seems to me that this large-scale, multi-faceted and randomized study, sponsored by the nation’s most well-respected institutions in asthma and allergy research (National Institute of Allergy and Infectious Diseases, National Institute of Environmental Health Sciences, and National Center for Research Resources, National Institutes of Health), goes a long way towards refuting the widely-held notion that patients with asthma and/or allergies must remove their carpet, and seems to confirm the Carpet and Rug Institute’s (CRI) assertion that clean, dry carpet is a healthy flooring choice for everyone, including children and adults with asthma and allergies. CRI’s position is based on a body of sponsored as well as independent research, but the Inner City study is significant in that it comes from the medical community.

According to published disclosure statements, no carpet manufacturer contributed to or was in any way involved in this research, and none of the researchers were affiliated with or sponsored by any representative of the carpet industry.

Do you consider this information useful? I’d like to know your thoughts.

N.B.: Some of you may find this August 2007 chart significant. It is from the National Heart, Lung and Blood Institute website and represents a synopsis of the Childhood Asthma Study and its findings.

Synopsis of the Childhood Asthma Study and its findings
Click on the image for a larger view.
You can also access the chart by clicking on this link to an 11 page pdf document.  This particular chart on the Childhood Asthma Study is on page 11.


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