Household Triggers: Asthma’s Smoking Guns


Vol. 19 •Issue 16 • Page 15
Household Triggers: Asthma’s Smoking Guns

Research on Dust Mites et al. Enhances Asthma Rx

Want to learn why parents should put baby’s teddy bear in the freezer? Want to hear about the possible return to fashion of the smoking jacket?

Then travel to Grand Rapids, Mich., on Aug. 7 for a Train-the-Trainer workshop for respiratory therapists and nurses, offered free of charge by the U.S. Environmental Protection Agency (EPA) and the American Respiratory Care Foundation (ARCF).

The subject: indoor environmental asthma triggers. “We will talk about the five most common triggers of asthma in the indoor environment: smoking, dust mites, warm-blooded pets, molds and cockroaches,” said Thomas Kallstrom, RRT, one expert slated to speak. “And we’ll talk about what we as RTs and nurses need to impart to our patients to make them better understand what they can do at home.”

There are a number of ways to control dust mites, which collect on bedspreads, curtains, couches and fuzzy children’s toys such as teddy bears, Kallstrom continued. “One is to control the humidity level,” he said. “Another is washing sheets in hot water. And, yes, there is some evidence you can freeze them up and kill them. Put teddy bears in the freezer for two hours.”

Also promised are some strategies smoking parents can adopt to avoid inflaming their children’s sensitive airways with second-hand smoke. “If they must smoke, they should smoke outdoors,” Kallstrom said. “And put some type of clothing over you so the residue lands on that and not on your clothes. Remember smoking jackets? Maybe it’s time to bring them back.”

Easier Said Than Done

Smoking in the house remains one of the most common and most modifiable triggers threatening the health of asthmatic children, according to Esmeralda Morales, MD, of the Arizona Respiratory Center at the University of Arizona in Tucson. “It’s such an easy thing to not smoke around children who have asthma,” Morales told ADVANCE. “We usually say, if you’re allergic to something and it triggers your asthma, it shouldn’t be around your house. But I guess that’s easier said than done.”

Morales and several associates are investigating asthma triggers as part of a comprehensive, NIH-funded epidemiological study called the Infant Immune Study, now in its seventh year.

Their latest preliminary findings, presented this year at the American Thoracic Society conference, suggests that exposure to cats soon after birth is associated with increased prevalence of eczema, especially among children of non-asthmatic mothers.

In eczema, which often develops in those with asthma, inflammation of the skin can produce itching followed by small blisters that release fluid and form a crust. Morales et al. found that of 128 children with a cat in their household, 34 of them (26.6 percent) had eczema by age one compared to 47 (17.3 percent) of the 272 children with no cats in their homes.

“We can say that, in our population, there is an association between eczema and children in households with cats, as compared to children without cats,” she explained. “But you can’t, on the basis of this, say, ‘Get rid of your cats if you don’t want to get eczema.’ You can’t infer any causation from it. Epidemiological studies raise more questions and don’t really give a lot of answers.”

Airway Hyper-Responsiveness

However, another recent study found that exposure during infancy to pets, dust mites and the like does not seem to increase the likelihood a child will develop airway hyper-responsiveness (AHR), a hallmark of asthma.

Ongoing exposure to aeroallergens, not just early-life exposure, more determines the likelihood of developing AHR, according to Elizabeth TePas, MD, et al., from the Channing Laboratory, Brigham and Women’s Hospital in Boston.1

TePas and colleagues tested 131 children at high risk for atopy and found that more than half of them had at least one positive skin-prick test response, while 37 subjects (28 percent) had AHR as determined by methacholine challenge testing.

AHR was strongly associated with sensitization to at least four aeroallergens, they learned. However, no association was seen between AHR and early life exposure to a pet in the home or to tobacco smoke.

Meanwhile, a new international study of more than 20,000 children confirms a commonly held belief: Exposure to cigarette smoke before and after birth impairs lung function.2 “Considering the high number of children exposed to maternal smoking in utero and the even higher number exposed to passive smoking after birth,” the authors wrote, “this risk factor for reduced lung function growth remains a serious pediatric and public health issue.”

References:

1. TePas E, Litonjua A, Celed—n J, et al. Sensitization to aeroallergens and airway hyperresponsiveness at 7 years of age. Chest. (2006; 129: 1500-1508).

2. Moshammer H, Hoek G, Luttmann-Gibson H, et al. Parental smoking and lung function in children: An international study. AmJRespirCritCareMed. (173: 1255-1263).

You can reach Michael Gibbons at mgibbons@merion.com.

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