(HealthDay News) – Exposure to secondhand smoke during early childhood is associated with decreased lung function, and allergic sensitization affects this association, particularly among girls.

Kelly J. Brunst, of the University of Cincinnati College of Medicine, and colleagues performed a study involving 486 participants from the Cincinnati Childhood Allergy and Air Pollution birth cohort study. A skin prick test (SPT) was performed when children were age 2, 4, and 7 to assess their allergen sensitization, and lung function was assessed when children were age 7. The children’s exposure to secondhand smoke was measured based on the quantity of hair cotinine at age 2 and/or 4 years.

The researchers found that children exposed to secondhand smoke had significantly reduced lung function, as demonstrated by forced expiratory volume in one second, peak expiratory flow, and forced expiratory flow between 25–75% of forced vital capacity (FEF25-75%). Girls with two or more positive SPTs at age 2 exhibited the greatest deficits in FEF25-75%, compared with non-sensitized boys and girls. Compared with boys with the same degree of allergic sensitization, girls with two or more positive SPTs had a two-fold greater decrease in FEF25-75%, although this difference was not significant.

“Based on our results, and those of others, gender and the extent of allergic sensitization are significant factors in susceptibility to secondhand smoke. Our study identified sensitized girls as being a high-risk group for the damaging effects of secondhand smoke on FEF25-75%,” the authors write.

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