Several Risk Factors Linked to Adult-Onset Asthma

September 19, 2008

Factors associated with asthma diagnosed in adulthood include persistent wheezing in early life, bronchial hyper-responsiveness at 6 years of age, and allergic or non-allergic rhinitis in adulthood, according to the results of two studies published in the Sept. 20 issue of The Lancet.

FRIDAY, Sept. 19 (HealthDay News) -- Factors associated with asthma diagnosed in adulthood include persistent wheezing in early life, bronchial hyper-responsiveness at 6 years of age, and allergic or non-allergic rhinitis in adulthood, according to the results of two studies published in the Sept. 20 issue of The Lancet.

In the first study, Debra A. Stern, of the Arizona Respiratory Center in Tucson, and colleagues analyzed data from 849 adults who had been tracked since infancy for asthma-related issues and had follow-up data available at the age of 22. The investigators found that factors predicting newly diagnosed asthma at this age included bronchial hyper-responsiveness and low airway function at age 6 and persistent wheezing early in life.

In the second study, Rafea Shaaban, M.D., of the National Institute of Health and Medical Research in Paris, France, and colleagues analyzed data from 6,461 participants between the ages of 20 and 44 who were free of asthma at baseline. Subjects were classified into four groups based on presence or absence of rhinitis and atopy, assessed by questionnaire and skin-prick testing, respectively. At follow-up, roughly nine years later, the cumulative incidence of asthma was 2.2 percent, the researchers report. The adjusted relative risk for asthma was 2.71 and 3.53 in the groups with non-allergic rhinitis and allergic rhinitis, respectively, the investigators found.

"Several mechanisms might be responsible for the interaction between the upper and lower airways. Two main pathways could be involved in the nasobronchial cross-talk: respiratory and systemic pathways. For the respiratory pathway, the simplest explanation is the loss of protective functions of the nose. The inhalation of cold and dry air is associated with a decreased FEV1 value in asthmatic patients and cold air can be used as a provocative agent in bronchoconstriction tests," Shaaban and colleagues write. "Another possible explanation is the aspiration of nasal secretions towards the lower airways (post-nasal drip), which is related to cough."

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