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

Abstract

BackgroundEndurance 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.MethodsA 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.ResultsCurrent 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.ConclusionsConcluding, swimming pool attendance appears to be associated with autonomic changes and increased baseline airway smooth muscle constriction even in children without asthma.

Development and validation of exhaled breath condensate microRNAs to identify and endotype asthma in children

“…Study population was drawn from a cross sectional survey conducted between January 2014 and March 2015, that enrolled 1602 children aged 7 to 12 years old attending the 3 rd and 4 th grades from 20 primary schools in Porto, Portugal [11]. The participation rate of the study was 57% (n = 916).…”

Health effects of exposure to chlorination by‐products in swimming pools

“…Associations between asthma and recreational swimming in chlorinated pools were also reported in Ireland, 86 Italy, 87 and Portugal 88 . Several other studies, however, provided no evidence of an increased asthma risk in recreational swimmers 89–92 .…”

“…Swimming in indoor chlorinated pools during infancy has also been associated with a higher risk of bronchiolitis or recurrent respiratory infection mainly in children with family antecedents of atopic diseases 7,95,96 . Associations have also been reported between indoor chlorinated pool attendance and the risks of allergic rhinitis, 83,97 autonomic changes, 88 and airway inflammation assessed by FeNO 43 . Further complicating the issue, some studies suggest that early swimming in chlorinated pools may increase the risks of allergic sensitization in particular to perennial allergens 61,92,98 .…”

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

“…Air sampling was performed at the classrooms of selected children, during regular classroom activities and under representative conditions at the breathing zone, for 5 school days. Data on classroom air quality included room temperature, relative humidity, and CO 2 , O 3 , NO 2 , particulate matter (PM) 10 and PM 2.5, ultrafine particles (UFP), total volatile organic compounds (VOC), and gram‐negative endotoxin concentrations (Table 2), which were assessed as previously described 23–25 …”