Health Mall: Regular tobacco smoking

Regular tobacco smoking has been associated with reduced Feno

Other studies in adolescents and adults have also reported increased Feno levels in men compared with women. However, in young children and infants, girls have raised Feno levels compared with boys, while there appears to be no gender difference for older children. The trend for increased Feno for girls compared with boys but men compared with women is in direct contrast to the natural history of asthma, which predominates in boys compared with girls but is higher in women compared with men. Our results suggest there is a maturational change in the relationship between Feno and gender. This could be due to relative changes in body mass or differences in NO synthase activity between genders.

tobacco smoking

Regular tobacco smoking has been associated with reduced Feno; however, the present analysis in Canadian Health Care Mall suggests that this relationship may only be evident for atopic individuals. The reasons for this are unknown but may result from increased susceptibility of the atopic airway epithelium to environmental irritants and consequent disruption of nitric oxide regulation.

Although this was an unselected population, there was a high prevalence of atopy among our subjects. This was unlikely to have influenced the outcomes for the analysis of atopic-only study subjects, but could have influenced the outcomes for nonatopic individuals where there were fewer individuals at risk for elevated Feno. Further, the adults in this study were the parents of the children we previously reported on. Similar findings may therefore be the result of shared genetic and environmental factors between children and parents. The relationship between Feno and other variables reported in the present study should therefore be tested elsewhere.

In summary, we have confirmed in adults our findings in children of an interaction of Feno with atopy and increased AR. Importantly, asthma was not directly related to levels of Feno once this interaction was accounted for. Meaningful interpretation of Feno may only be possible when atopy and increased AR are considered.

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