João Cavaleiro Rufo

Volatile organic compounds in asthma diagnosis: a systematic review and meta-analysis.

We aimed to assess the value and classification rate of exhaled volatile organic compounds (VOCs) in asthma diagnosis. A PRISMA‐oriented systematic search for published studies regarding exhaled VOCs in asthma diagnosis was conducted based on predefined criteria. Studies presenting sensitivity and specificity values for the test were included in the meta‐analysis. Pooled diagnosis odds ratios (DOR), area under the curve (AUC) and positive and negative likelihood ratios (LR) for exhaled VOC profiles were calculated; and publication bias, threshold effect and heterogeneity were estimated. Eighteen studies were selected for the qualitative analysis and six met the criteria for inclusion in the quantitative analysis. Mean (95% CI) pooled DOR, positive and negative LR were 49.3 (15.9–153.3), 5.86 (3.07–11.21) and 0.16 (0.10–0.26), respectively. The AUC value was 0.94. Only three of the 18 reviewed studies performed an external validation of the model using a different data set. The results from the revised studies suggest that exhaled VOCs are promising biomarkers for asthma diagnosis and that several compounds, mainly alkanes, may be significantly associated with asthma inflammation. However, there are still various constraints associated with standardization and externally validated studies are needed to introduce exhaled VOC profiling in a clinical scenario.

A systematic review of evidence and implications of spatial and seasonal variations of volatile organic compounds (VOC) in indoor human environments

ABSTRACT Many volatile organic compounds (VOC) are classified as known or possible human carcinogens, irritants, and toxicants, and VOC exposure has been associated with asthma and other respiratory symptoms/diseases. This review summarizes recent quantitative data regarding VOC in four categories of indoor environments (schools, housing, offices, and other indoor) and compares the types and concentration levels of individual VOC that were detected, measured, and reported according to season (cold and warm). The influence of outdoor air on concentrations of indoor VOC was also assessed as ratios of indoor versus outdoor. Papers published from 2000 onward were reviewed and 1383 potentially relevant studies were identified. From these, 177 were removed after duplication, 1176 were excluded for not meeting the review criteria, and 40 were included in this review. On average, higher mean concentrations of indoor VOC were found in housing environments, in offices, and in the cold season. Volatile organic compounds are commonly present in indoor air and specific compounds, and their concentrations vary among indoor environments and seasons, indicating corresponding differences in sources (indoors and outdoors). Actions and policies to reduce VOC exposures, such as improved product labeling and consumer education, are recommended.

Exposure of Children to Ultrafine Particles in Primary Schools in Portugal

Children spend a large part of their time at schools, which might be reflected as chronic exposure. Ultrafine particles (UFP) are generally associated with a more severe toxicity compared to fine and coarse particles, due to their ability to penetrate cell membranes. In addition, children tend to be more susceptible to UFP-mediated toxicity compared to adults, due to various factors including undeveloped immune and respiratory systems and inhalation rates. Thus, the purpose of this study was to determine indoor UFP number concentrations in Portuguese primary schools. Ultrafine particles were sampled between January and March 2014 in 10 public primary schools (35 classrooms) located in Porto, Portugal. Overall, the average indoor UFP number concentrations were not significantly different from outdoor concentrations (8.69 × 103 vs. 9.25 × 103 pt/cm3, respectively; considering 6.5 h of indoor occupancy). Classrooms with distinct characteristics showed different trends of indoor UFP concentrations. The levels of carbon dioxide were negatively correlated with indoor UFP concentrations. Occupational density was significantly and positively correlated with UFP concentrations. Although the obtained results need to be interpreted with caution since there are no guidelines for UFP levels, special attention needs to be given to source control strategies in order to reduce major particle emissions and ensure good indoor air quality.

Serum biomarkers in elderly asthma

Abstract Objective: Asthma is usually misdiagnosed and under-treated in the elderly population, resulting in complications and increased severity to the patient. In this review, we describe some of the most important serum markers of asthma studied so far, reporting their outcomes and possible prediction of asthma in the elderly population. Methods: The PubMed electronic database was used to search for promising serum biomarkers of asthma studied in original articles published in peer-reviewed journals from 2000 to January 2013. Results: A total of 13 relevant serum biomarkers were selected, including IgE, CRP, high sensitive CRP, IL-6, IL-8, IL-17, TNF-α, neopterin, serum amyloid A, eosinophil cationic protein, leukolysin, YKL-40 and soluble CD86. Conclusions: Although the major focus of treatment and research has been on allergic asthma, several forms of the disease are recognized, such as neutrophilic asthma, which is characteristic of older patients. Different phenotypes imply different treatments and so it becomes important to correctly determine which type of asthma the patient is suffering from. Serum markers capable of supporting a diagnosis of asthma are needed in order to counter mistreatment and misdiagnosis with other obstructive airways disease (OAD) in elderly patients. As convenient as serum markers may seem to be, a marker capable of accurately identifying asthma with sufficient specificity is yet to be found.

Indoor fungal diversity in primary schools may differently influence allergic sensitization and asthma in children

Childhood exposure to microbiologic agents may influence the development of allergic and respiratory diseases. Apart from home, children spend most of their time at school, which represents an environment of significant exposure to indoor air microbes. Therefore, we aimed to assess how the prevalence of allergic sensitization and asthma in schoolchildren is affected by microbiologic exposure within classrooms.

Swimming pool exposure is associated with autonomic changes and increased airway reactivity to a beta-2 agonist in school aged children: A cross-sectional survey

Background Endurance swimming exercises coupled to disinfection by-products exposure has been associated with increased airways dysfunction and neurogenic inflammation in elite swimmers. However, the impact of swimming pool exposure at a recreational level on autonomic activity has never been explored. Therefore, this study aimed to investigate how swimming pool attendance is influencing lung and autonomic function in school-aged children. Methods A total of 858 children enrolled a cross sectional survey. Spirometry and airway reversibility to beta-2 agonist, skin-prick-tests and exhaled nitric oxide measurements were performed. Pupillometry was used to evaluate autonomic nervous function. Children were classified as current swimmers (CS), past swimmers (PS) and non-swimmers (NS), according to the amount of swimming practice. Results Current swimmers group had significantly lower maximum and average pupil constriction velocities when compared to both PS and NS groups (3.8 and 5.1 vs 3.9 and 5.3 vs 4.0 and 5.4 mm/s, p = 0.03 and p = 0.01, respectively). Moreover, affinity to the beta-2 agonist and levels of exhaled nitric oxide were significantly higher in CS when compared to NS (70 vs 60 mL and 12 vs 10 ppb, p<0.01 and p = 0.03, respectively). A non-significant trend for a higher risk of asthma, atopic eczema and allergic rhinitis was found with more years of swimming practice, particularly in atopic individuals (β = 1.12, 1.40 and 1.31, respectively). After case-case analysis, it was possible to observe that results were not influenced by the inclusion of individuals with asthma. Conclusions Concluding, swimming pool attendance appears to be associated with autonomic changes and increased baseline airway smooth muscle constriction even in children without asthma.

Meal-exercise challenge and physical activity reduction impact on immunity and inflammation (MERIIT trial)

Background The effect of a pre-exercise meal as countermeasure to exercise induced immunodepression is poorly known. Also, sedentary behavior is associated with increased cardiometabolic risk but studies on immune changes are lacking. Therefore, we aimed to assess: 1) the impact of a pre-exercise Mediterranean meal (MdM) compared with a fast-food type meal (FFM) on exercise-induced immunological changes and 2) the impact of an induced acute period of sedentary behavior on neuro-immune-endocrine status. Methods /Design: This is a two steps clinical trial including: (a) randomized crossover clinical trial, comparing the effect a high-fat/low-nutrient dense meal, FFM, with an isoenergetic similar high-nutrient dense meal, MdM, in the immune response to an exercise challenge (EC) and (b) a pilot trial assessing the neuro-immune-endocrine change induced by acute decreasing by half the usual physical activity level. Results A total of 46 participants (26 females), median aged 25 years were included. Of those 39-completed protocol, including overweight, physical active and inactive and participants with asthma. There were no differences in the EC between interventions. Dietary factors and physical activity were closely monitored during interventions and kept similar. During physical inactivity induction, 31% reached the target of 50% reduction in mean step number and 77% reached a 30% reduction. Conclusion The use of a pre-exercise meal to modulate immune response and the understanding of the immunological impact of physical inactivity might help to establish future recommendations on how to practice exercise in a safer way and to recognize the potential impact of inactivity.

Exhaled breath condensate volatilome allows sensitive diagnosis of persistent asthma

The diagnosis and phenotyping of paediatric asthma are particularly complex due to the lack of currently available sensitive diagnostic tools. This often results in uncertainties associated with inhaled steroid therapy prescription. Therefore, this study aimed to investigate whether volatile organic compounds measured in exhaled breath condensate can be used as biomarkers for asthma diagnosis in the paediatric population.

Spirometry-adjusted fraction of exhaled nitric oxide increases accuracy for assessment of asthma control in children

Spirometry and exhaled nitric oxide are two important complimentary tools to identify and assess asthma control in children. We aimed to determine the ability of a new suggested spirometry‐adjusted fraction of exhaled nitric oxide (NO) index in doing that. A random sample of 1602 schoolchildren were screened by a health questionnaire, skin prick tests, spirometry with bronchodilation and exhaled NO. A total of 662 children were included with median (IQR) exhaled NO 11(14) ppb. Receiver operating characteristic (ROC) curves using exhaled NO equations from Malmberg, Kovesi and Buchvald, and spirometry‐adjusted fraction of exhaled NO values were applied to identify asthmatic children and uncontrolled asthma. Receiver operating characteristic (ROC) curves failed to identify asthmatic children (all AUC < 0.700). Spirometry‐adjusted fraction of exhaled NO/FEV1 (AUC = 0.712; P = .010) and NO/FEF25%‐75% (AUC = 0.735 P = .004) had a fair and increased ability to identify uncontrolled disease compared with exhaled NO (AUC = 0.707; P = .011) or the Malmberg equation (AUC = 0.701; P = .014). Sensitivity and specificity identifying non‐controlled asthma were 59% and 81%, respectively, for the cut‐off value of 9.7 ppb/L for exhaled NO/FEV1, and 40% and 100% for 15.7 ppb/L/s for exhaled NO/FEF25%‐75%. Exhaled NO did not allow to identify childhood asthma. Spirometry‐adjusted fraction of exhaled NO performed better‐assessing asthma control in children. Thus, although more validation studies are needed, we suggest its use in epidemiological studies to assess asthma control.