Abstract
Fractional exhaled nitric oxide (FENO50), a marker of allergic airway inflammation, is used in respiratory research and asthma clinical care; however, its trajectory with increasing age during childhood has not been well characterised. We examined FENO50 longitudinally during a period of important somatic growth to describe trajectories across childhood and adolescence in healthy participants and evaluate clinical factors as potential determinants of trajectories.
FENO50 was collected at six visits over 8 years in a population-based cohort of 1791 schoolchildren without asthma (median age at entry 8.4 years). Smooth sex-specific FENO50 trajectories were estimated using generalised additive mixed models, with participant-level random effects. We evaluated whether sex-specific trajectories were influenced by race/ethnicity, body mass index (BMI) percentile, allergic rhinitis or puberty.
Different FENO50 patterns were observed by sex in later childhood and several factors were associated with either FENO50 level or change in FENO50 as participants aged. FENO50–age trajectories were similar by sex until age ∼11.5 years, after which males had greater FENO50 change than females. This divergence in FENO50–age trajectories coincides with puberty. Males with higher starting BMI percentile had attenuated FENO50–age slopes. Among males, FENO50 levels were lower in non-Hispanic white subjects. Among both sexes, participants with rhinitis had higher FENO50. FENO50 levels within individuals tracked over time; however, there was considerable variation in FENO50 patterns across participants.
FENO50 trajectories from longitudinal data provide evidence of sex differences coinciding with puberty, suggesting potential hormone link. Improved understanding of determinants of FENO50 trajectories is needed to realise the potential for using individualised predicted FENO50 trajectories.
Abstract
Longitudinal FENO50 trajectories in healthy children aged 8–16 years displayed a similar upward trend in males and females until age 11.5, after which males had higher FENO50. Males with higher starting BMI percentile had attenuated FENO50 slopes with age. https://bit.ly/2UMb8mI
Footnotes
This article has supplementary material available from erj.ersjournals.com
Conflict of interest: E. Garcia has nothing to disclose.
Conflict of interest: Y. Zhang reports grants from NIH, AHRQ, VA and CDC, outside the submitted work.
Conflict of interest: E.B. Rappaport has nothing to disclose.
Conflict of interest: K. Berhane reports grants from NIH, during the conduct of the study.
Conflict of interest: P. Muchmore reports grants from National Institute of Environmental Health Sciences, USA (grant number T32ES013678), during the conduct of the study; and has a patent PCT/US2018/042316 pending.
Conflict of interest: P.E. Silkoff has nothing to disclose.
Conflict of interest: N. Molshatzki has nothing to disclose.
Conflict of interest: F.D. Gilliland has nothing to disclose.
Conflict of interest: S.P. Eckel reports grants from NIH, during the conduct of the study.
Support statement: This work was supported by the National Heart, Lung, and Blood Institute (grants R01HL61768 and R01HL76647); the Southern California Environmental Health Sciences Center (grant P30ES007048) funded by the National Institute of Environmental Health Sciences; the Children's Environmental Health Center (grants P01ES009581, R826708-01 and RD831861-01) funded by the National Institute of Environmental Health Sciences and the Environmental Protection Agency; the National Institute of Environmental Health Sciences (grants P01ES011627, R01ES023262, R01ES027860, and T32ES013678); the James H. Zumberge Research and Innovation Fund, and the Hastings Foundation. Funding information for this article has been deposited with the Crossref Funder Registry.
- Received June 25, 2019.
- Accepted March 24, 2020.
- Copyright ©ERS 2020