Exhaled breath condensate pH determinants in school-aged children: A population-based study

The mediating role of exhaled breath condensate metabolites in the effect of particulate matter on pulmonary function in schoolchildren: A crossover intervention study

The role played by metabolites in exhaled breath condensate (EBC) in the effect of PM on schoolchildren's pulmonary function has received little attention. Accordingly, we examined whether metabolites in EBC mediated the effect of PM10, PM2.5, and PM1 on the pulmonary function of schoolchildren at a residential primary school who had received an air-cleaner cross-over intervention. Samples of EBC were collected from a total of 60 schoolchildren and subjected to metabolomics analysis. We found that the effect of PM on six pulmonary function indicators was mediated by the following nine lipid peroxidation-related and energy metabolism-related metabolites present in EBC: 4-hydroxynonenal, arachidoyl ethanolamide, dl-pyroglutamic acid, 5-deoxy-d-glucose, myristic acid, lauric acid, linoleic acid, l-proline, and palmitic acid. However, while all nine of these metabolites mediated the effects of PM on boys' pulmonary function, only 4-hydroxynonenal, arachidoyl ethanolamide, and dl-pyroglutamic acid mediated the effects of PM on girls' pulmonary function. Overall, our results show that (1) short-term exposure to PM affected the schoolchildren's pulmonary function by causing an imbalance between lipid peroxidation and glutathione-based antioxidant activity and by perturbing energy metabolism in respiratory system and (2) there was a sex-dependent antioxidant response to PM exposure, with boys being less resistant than girls.

Exhaled Breath Condensate and Respiratory Sequelae in Children Post-COVID-19

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes an acute respiratory illness. A substantial proportion of adults experience persistent symptoms. There is a paucity of data on respiratory sequelae in children. Exhaled breath condensate (EBC) is a non-invasive tool used to assess airway inflammation.

OBJECTIVES

This study aimed to evaluate EBC parameters, respiratory, mental and physical ability among children post COVID-19 infection.

METHODS

Observational study of confirmed SARS-CoV-2 infection cases among children, aged 5-18 years, evaluated once, 1-6 months post positive SARS-CoV-2 PCR testing. All subjects performed spirometry, 6-min walk test (6MWT), EBC (pH, interleukin-6), and completed medical history questionnaires, Depression, Anxiety, and Stress Scale (DASS-21), and physical activity scores. Severity of COVID-19 disease was classified according to WHO criteria.

RESULTS

Fifty-eight children were included and classified asymptomatic (n = 14), mild (n = 37), and moderate (n = 7) disease. The asymptomatic group included younger patients compared to the mild and moderate groups (8.9 ± 2.5y vs. 12.3 ± 3.6y and 14.6 ± 2.5y, respectively, p = 0.001), as well as lower DASS-21 total scores (3.4 ± 4 vs. 8.7 ± 9.4 and 8.7 ± 0.6 respectively, p = 0.056), with higher scores in proximity to positive PCR (p = 0.011). No differences were found between the 3 groups regarding EBC, 6MWT, spirometry, body mass index percentile, and activity scores.

CONCLUSIONS

COVID-19 is an asymptomatic-mild disease in most young healthy children, with gradually diminishing emotional symptoms. Children without prolonged respiratory symptoms revealed no significant pulmonary sequelae as evaluated by EBC markers, spirometry, 6MWT, and activity scores. Larger studies are required to assess long-term pediatric consequences of post SARS-CoV-2 infection, to assess the need for pulmonology surveillance.

Issue 2 - "Update on adverse respiratory effects of indoor air pollution" Part 1): Indoor air pollution and respiratory diseases: A general update and a Portuguese perspective

OBJECTIVE

To quantify the impact of different air pollutants on respiratory health based on robust estimates based on international data and to summarise the evidence of associations between indoor exposure to those pollutants and respiratory morbidity in the Portuguese population.

RESULTS

Several systematic reviews and meta-analyses (MA) at the world level demonstrate the impact of indoor air quality on respiratory health, with indoor particulate matter and gasses exerting a significant effect on the airways. Volatile organic compounds (VOC) have been related to asthma and lung cancer. However, only meta-analyses on biomass use allowed documentation of long-term respiratory effects. While early publications concerning Portuguese-based populations mainly focused on indoor exposure to environmental tobacco smoke, later studies relocated the attention to relevant exposure environments, such as day care buildings, schools, residences and nursing homes. Looking at the pooled effects from the reviewed studies, high levels of carbon dioxide and particulate matter in Portuguese buildings were significantly associated with asthma and wheezing, with VOC and fungi showing a similar effect in some instances.

CONCLUSIONS

Despite the significant reduction of indoor air pollution effects after the 2008 indoor smoking prohibition in public buildings, studies show that several indoor air parameters are still significantly associated with respiratory health in Portugal. The country shares the worldwide necessity of standardisation of methods and contextual data to increase the reach of epidemiological studies on household air pollution, allowing a weighted evaluation of interventions and policies focused on reducing the associated respiratory morbidity.

Diet Quality and Exhaled Breath Condensate Markers in a Sample of School-Aged Children

Exhaled breath condensate (EBC) analysis is a recently developed, non-invasive method used to identify and quantify biomarkers, mainly those coming from the lower respiratory tract. It seems that diet can influence the airway's inflammation and change the exhaled breath composition. This study aimed to assess the association between diet quality intake and markers in EBC among school-aged children. A cross-sectional analysis included 150 children (48.3% females, aged 7-12 years, mean age: 8.7 ± 0.8 years) from 20 schools across Porto, Portugal. We assessed diet quality through the Healthy Eating Index (HEI)-2015, which was estimated based on a single 24 h food recall questionnaire. EBC samples were collected, and we assessed their ionic content (Na⁺, K⁺) and conductivity. The association between diet quality and Na⁺, K⁺, Na⁺/K⁺ ratio and conductivity was estimated using logistic regression models adjusted for potential confounders. After adjustment, a higher quality diet score increases the odds of higher conductivity values of the EBC (aOR = 1.04, 95%CI 1.00; 1.08). Our findings suggest that a higher diet quality in school-aged children is associated with higher conductivity levels of the EBC.