FEBRUARY 01, 2007

Put Down the Cigarettes

Adolescents who smoke cigarettes regularly may increase the risk of developing asthma during the teen years, compared with nonsmokers the same age, according to the latest results of the Children's Health Study reported in the American Journal of Respiratory and Critical Care Medicine (November 15, 2006).

Over the course of 5 to 8 years (depending on a participant's age at the study's onset), the researchers annually collected data on demographic factors, medical histories, household exposures, cigarette smoking, and newly diagnosed asthma through interviews and questionnaires with 2609 children. The data were used to estimate a child's relative risk for new-onset asthma.

The researchers identified 255 cases of new-onset asthma. The participants who reported smoking ≥300 cigarettes per year had nearly a 4-fold increased risk for new-onset asthma, compared with nonsmokers. The researchers noted the increased risk was greater in nonallergic children, compared with children with a history of allergies.

Lead investigator Frank D. Gilliland, MD, PhD, noted that the adolescents with the greatest risk for developing asthma were those who were exposed to cigarette smoke while in the womb and who later picked up the habit (7 or more cigarettes daily). The researchers concluded this combination led to a >8-fold increased risk of asthma, compared with unexposed nonsmokers.

Is Asthma Misdiagnosed?

A weight problem may increase the odds of being misdiagnosed with asthma when other health problems are actually the reason for shortness of breath and wheezing, concluded a study reported recently at the American College of Chest Physicians annual meeting.

Study author Chirag Mehta, MD, explained that individuals who are overweight or obese can produce symptoms similar to asthma, such as shortness of breath from being out of shape or wheezing from acid reflux disease. To evaluate the accuracy of asthma diagnoses in the overweight or obese, the researchers recruited 20 individuals. The participants had been diagnosed with asthma, but their lung-function tests suggested they might not have the disease. The researchers administered a bronchoprovocation test with a substance called methacholine. In this test, the airways of patients with asthma will overact or become hyperresponsive when provoked with a known irritant.

The findings indicated that only 39% of those overweight or obese individuals tested positive on this test. This means that nearly 2 of every 3 study participants had been misdiagnosed with the disease. "A lot of times with increased body mass, you have deconditioning or you have reflux," said Dr. Mehta.

Flu Spray Works for Asthmatic Kids

Two new studies found that the nasal-spray flu vaccine is more effective than the inactivated flu-vaccine shot for children with asthma and recurrent respiratory tract infections. The first study evaluated the outcomes of 2220 children with asthma, aged 6 to 17 years.

The children were randomly selected to receive the live attenuated nasal-spray flu vaccine or the inactivated flu shot during the 2002-2003 influenza season.

The findings showed that the influenza rate in the nasalspray flu-vaccine group was 4.1%, considerably lower than the 6.2% noted in the flu-shot group. The rate of asthma flare-ups and other asthma-related episodes did not differ drastically between the 2 groups.

The second study assessed the efficacy of both vaccines in 2187 younger children, aged 6 to 71 months, with a history of recurrent respiratory tract infections. The researchers found that the nasal-spray flu vaccine was linked with fewer flu cases due to viral strains similar to the vaccine, compared with the flu shot. Furthermore, respiratory tract-related health care visits were fewer in the nasal-spray group, and the children missed fewer days of school or day care. (The findings were reported in The Pediatric Infectious Disease Journal, October 2006.)

Work Environment Raises Asthma Risk

Exposure to certain types of surface materials in the workplace may increase adults' odds of developing asthma, according to a study reported in the American Journal of Epidemiology (October 15, 2006).

Studies have linked certain materials, pollutants, and even renovations to asthma in children. Yet, there has been no evidence on how such exposure may impact adults' asthma risk. For the study, the researchers compared 521 adults newly diagnosed with asthma over a 21/2-year period and a control group of 932 adults without asthma. The group was questioned about the materials they were exposed to at home and at work as well as whether they had renovated their homes in the past year.

The study results indicated exposure to plastic wall coverings on the job raised the asthma risk 2.43-fold. Individuals who worked in offices with wall-to-wall carpeting were 1.73 times more likely to have developed asthma. The risk more than quadrupled when mold problems were present at the workplace with wall-to-wall carpeting. While home renovation has no connection with asthma, the researchers noted that individuals living in homes where plaster had been used to level floors faced an 80% increased risk of developing asthma.