Exhaled NO among inner-city children in New York City

Abstract

Background. Fractional exhaled nitric oxide (FeNO) has been proposed as a biomarker of airway inflammation for cohort studies of asthma. Objectives. To assess the association between FeNO and asthma symptoms among 7-year-old children living in an inner-city community. To test the association between environmental tobacco smoke (ETS) exposure (previous and current) and FeNO among these children. Methods. As part of a longitudinal study of asthma, children recruited in Head Start centers at age 4 had offline FeNO and lung function testing at age 7. Children with allergen-specific immunoglobulin E (IgE) (≥0.35 IU/mL) at age 7 were considered seroatopic. ETS exposure at ages 4 and 7 was assessed by questionnaire. Results. Of 144 participating children, 89 had complete questionnaire data and achieved valid FeNO and lung function tests. Children with reported wheeze in the previous 12 months (n = 19) had higher FeNO than those without wheeze (n = 70) (geometric means 17.0 vs. 11.0 ppb, p = .005). FeNO remained significantly associated with wheeze (p = .031), after adjusting for seroatopy and forced expiratory volume in 1 second (FEV₁) in multivariable regression. FeNO at age 7 was positively associated with domestic ETS exposure at age 4 (29%) (β = 0.36, p = .015) but inversely associated with ETS exposure at age 7 (16%) (β = −0.74, p < .001). Conclusions. Given its association with current wheeze, independent of seroatopy and lung function, FeNO provides a relevant outcome measure for studies in inner-city communities. While compelling, the positive association between ETS exposure at age 4 and a marker of airway inflammation at age 7 should be confirmed in a larger study.

• exhaled nitric oxide
• IgE
• inner-city
• wheeze
• environmental tobacco smoke

Acknowledgments

The authors thank the participating mothers and children. This work would not have been possible without the hard work and dedication of the research workers and field technicians. The authors thank the directors and staff of the Head Start centers. This study was funded by the National Institutes of Health, National Heart, Lung, and Blood Institute (NHLBI) grant HL068236 and the National Institutes of Environmental Health Sciences grant P30 ES009089.

Declaration of Interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.