Exhaled nitric oxide in a population‐based study of asthma and allergy in schoolchildren

Abstract

Exhaled nitric oxide (NO) reflects inflammation in the lower airways and is well adapted for use in children. The aims of this study were to investigate the distribution of the fraction of expired NO (FENO) in school children and to compare FENO and spirometry in relation to the International Study of Asthma and Allergies in Childhood questionnaire. The study was performed in 959 randomly selected 13-14-year-old school children in Uppsala, Sweden. Exhaled NO was measured at an inhalation rate of 0.1 l/s (FENO0.1) and a spirometric test was performed and data from these measurements were related to questionnaire data. Exhaled NO was measured according to American Thoracic Society recommendations, except the use of a mouth wash and an exhalation flow rate of 0.1 l/s. The distribution of the mean FENO0.1 values was skewed, with a preponderance of very low levels and a widespread tail of values ranging up to 102 parts per billion (ppb). Boys exhibited significantly higher mean FENO0.1 values than girls, 5.2 (4.7-5.7) vs 4.4 (4.0-4.8) ppb (geometric mean and 95% CI), P <0.01). Children who reported wheezing in the last year had higher FENO0.1 values than children that had not, 8.5 (7.1-10.2) vs 4.3 (4.0-4.6) ppb, P <0.001). The same association was found to most symptoms indicating hay fever and eczema. In contrast to this, only weak or inconsistent associations were found between asthma and spirometric indices. Exhaled NO levels were found to be independently related to male gender, wheeze and rhinoconjuctivitis but not to current eczema. In conclusion, exhaled NO was closely associated with reported asthma and allergy symptoms whereas spirometric indices such as percent predicted forced expiratory volume in 1 s were not. As most asthma cases in a population are mild, the findings suggest that exhaled NO is a sensitive marker of asthma and allergy.

Factors that influence exhaled nitric oxide in Italian schoolchildren

“…This result is in agreement with the works of Barreto et al 4 and Wong et al, 16 who recently demonstrated a sex difference in eNO levels in schoolchildren. Similarly, Nordvall et al, 17 in a large population sample, found a significantly higher eNO in boys than in girls. The authors attributed this finding to a possible role of larger lung volumes in boys.…”

Profiling allergic asthma volatile metabolic patterns using a headspace-solid phase microextraction/gas chromatography based methodology

“…Studies have been developed using HS-SPME in order to establish the volatile composition of human exhaled breath [8] or for a specific type of disease, for example diabetes [14], lung cancer [15] and cystic fibrosis [16] or for chemical substances exposure monitoring [17]. Studies concerning non invasive monitoring of allergic airway inflammation have been made using exhaled nitric oxide [18] or breath condensate [19]. The lack of a prominent HS-SPME study in allergic asthma exhaled breath led us to develop an experimental design by combining HS-SPME with gas chromatography-quadrupole mass spectrometry (GC-qMS) to assess information from allergic asthma metabolomic patterns.…”

Óxido nítrico em criança com asma persistente

“…[15][16][17] There was no agreement as to whether the presence of symptoms was higher in the atopic patient. In the present study, no statistically significant difference was observed between the groups; however, some authors have described such significance.…”

“…16 These levels are elevated in asthmatic patients, with rates 1.6 to 4.4 times greater than those found in healthy individuals. 17 During treatment with inhaled or systemic corticosteroids, these levels decrease or even return to normal.…”