Different relations of exhaled nitric oxide with age and ex-smoking in healthy middle-aged men and women

Abstract

Background: Exhaled nitric oxide (FeNO) is a marker of inflammation used in asthma. Current smokers have lower FeNO levels, but there are inconsistent reports of FeNO levels in ex-smokers. FeNO levels are stable in healthy younger adults and appear to increase later in life, with an earlier increase in women. We studied the effects of age and ex-smoking on FeNO in middle-aged men and women. Methods: FeNO was measured in 4206 subjects, aged 40-68 years, without asthma or recent use (previous year) of inhaled medicines. Smoking habits were questionnaire-assessed and serum IgE were measured for cat, mite and grass pollen allergens. Results: Males in the upper quartile of age (>60.2 years) had higher FeNO compared with males in the lower age quartile (≤ 48.4 years): 19.4 vs 17.8 ppb; p=0.005. In women, FeNO was higher for both third (aged 54.6 to 60.2 years) and fourth quartile vs lowest quartile: 15.2 and 16.7 vs 14.0 ppb; p=0.009 and p Conclusion: This cross-sectional analysis suggests that ex-smoking relates with lower FeNO in healthy middle-aged men, and that higher levels are observed in older people with this increase being more apparent at younger ages in women. These results may have practical consequences for the interpretation of FeNO levels in men and women with regard to age and smoking. Presented on behalf of ECRHS III (www.ecrhs.org).