Heat, Humidity May Trigger Asthma
Therapists looking for discussion topics for young asthma patients and their parents might look at the results of a study published in the September edition of Annals of Allergy, Asthma and Immunology.
Could atmospheric conditions play a part?
That actually may be the case, according to Alan Baptist, MD, director of the University of Michigan asthma program in Ann Arbor and the senior study author. His group reported temperature changes of more than 10 degrees and humidity change factors of 10 percent could be factors in asthma exacerbations.
In the study, researchers looked at the records of youngsters hospitalized for asthma exacerbations at the Children's Hospital of Michigan in Detroit. The facility recorded more than 25,000 asthma admissions in a two-year span from Jan. 1, 2004, to Dec. 31, 2005.
The hospitalization records were then mapped against weather data during this time frame along with data on airborne allergens and air pollution. Their statistical model was designed to control for those factors, Baptist noted.
An increase of 10 percent in humidity two days before the admission date was associated with one additional visit to the emergency department, noted Baptist. "For temperature, an interday change of 10 degrees one day before the admission resulted in two additional visits." The facility averaged 35 asthma visits per day.
But wait! Doesn't the daily temperature change vary generally by 10 degrees or more? And how frequently do the relative humidity levels change? Aren't these sometimes by the hour?
"It's really unknown why temperature and humidity changes exacerbate asthma, and it should be looked at further," noted Baptist. "Asthma at its core is inflammation of the airways, and maybe these changes could be triggering more inflammation."
The results are not enough to encourage major changes in clinical practice, suggested Shean Aujla, MD, a pediatric pulmonologist at the Children's Hospital of Pittsburgh.
The take-home lesson for discussion: Most parents watch the weather forecasts daily so they know how their children should be dressed for school. Perhaps parents of school-age children with asthma should make it a point of stressing the importance of peak-flow tests and taking asthma medications, especially on those days when rapid climate changes can be expected. In addition, outdoor activities may need to be tailored to accommodate changes in temperature and humidity.
Kids are told to come in out of the rain. Further advice to asthma patients may be: on rainy days, be sure to check your peak flows when you come in out of the rain.
At least these are points that might be discussed in asthma management sessions.