AUTHOR=Zhang Xue , Zhang Yingying , Zhou Yan , Yin Dongning , Lv Chengjian , Lin Jinwang , Bao Wuping , Zhang Min 

TITLE=Age-related circadian rhythm and variability of large- and small-airway function in healthy non-smoking adults: Data from 7-day diurnal and nocturnal home monitoring using an electronic portable spirometer

JOURNAL=Frontiers in Public Health

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2022.946988

DOI=10.3389/fpubh.2022.946988

ISSN=2296-2565

ABSTRACT=<sec><title>Background</title><p>The aim of the study was to investigate the possible influencing factors of the large- and small-airway function variation in healthy non-smoking adults.</p></sec><sec><title>Methods</title><p>Healthy non-medical non-smoking adults were enrolled in this prospective cohort study. Each participant took the portable spirometer test relying only on video teaching. Then conventional spirometry and bronchodilation test were conducted using a Jaeger spirometer, followed by 7-day diurnal and nocturnal home monitoring using a portable spirometer.</p></sec><sec><title>Results</title><p>A drop in both large- and small-airway function began at about 25 years of age, and a rapidly decline at about 50 years. The CV of FEV<sub>1</sub> (<italic>r</italic> = 0.47, <italic>P</italic> = 0.0082) and small-airway function variables correlated with age (<italic>r</italic> ≥ 0.37, <italic>P</italic> &lt; 0.05 for both MEFs and MEFs/FVC), especially for evening small-airway function variables. The CV of large (4.666 ± 1.946, <italic>P</italic> = 0.002 for FEV<sub>1</sub>; 4.565 ± 2.478, <italic>P</italic> = 0.017 for FEV<sub>3</sub>) and small airways (10.38 ± 3.196, <italic>P</italic> = 0.031 for MEF50 and 11.21 ± 4.178, <italic>P</italic> = 0.023 for MMEF) was higher in the 45- to 60-year subgroup than in the 30- to 45-year and 18- to 30-year subgroups.</p></sec><sec><title>Interpretation</title><p>Age was the main influencing factor of both central and peripheral airway function variability, especially for the small-airway function in the evening. The LLN of small-airway variables varies depending on the age and circadian rhythm. People older than 45 years should pay more attention to monitoring small-airway function in the evening, which will be helpful for early clinical detection of those at high risk for asthma.</p></sec><sec><title>Trial registration number</title><p>ChiCTR2100050355.</p></sec>