Antonia Sardella

Impact of Chlorinated Swimming Pool Attendance on the Respiratory Health of Adolescents

OBJECTIVE: The goal was to estimate the burden of allergic diseases associated with chlorinated pool exposure among adolescents. METHODS: We examined 847 students, 13 to 18 years of age, who had attended outdoor or indoor chlorinated pools at various rates. Of them, 114 had attended mainly a copper-silver pool and served as a reference group. We measured total and aeroallergen-specific immunoglobulin E (IgE) levels in serum and screened for exercise-induced bronchoconstriction. Outcomes were respiratory symptoms, hay fever, allergic rhinitis, and asthma that had been diagnosed at any time (ever asthma) or was being treated with medication and/or was associated with exercise-induced bronchoconstriction (current asthma). RESULTS: Among adolescents with atopy with serum IgE levels of >30 kIU/L or aeroallergen-specific IgE, the odds ratios (ORs) for asthma symptoms and for ever or current asthma increased with the lifetime number of hours spent in chlorinated pools, reaching values of 7.1 to 14.9 when chlorinated pool attendance exceeded 1000 hours. Adolescents with atopy with chlorinated pool attendance of >100 hours had greater risk of hay fever (OR: 3.3-6.6), and those with attendance of >1000 hours had greater risk of allergic rhinitis (OR: 2.2-3.5). Such associations were not found among adolescents without atopy or with copper-silver pool attendance. The population attributable risks for chlorinated pool-related ever-diagnosed asthma, hay fever, and allergic rhinitis were 63.4%, 62.1%, and 35.0%, respectively. CONCLUSION: Chlorinated pool exposure exerts an adjuvant effect on atopy that seems to contribute significantly to the burden of asthma and respiratory allergies among adolescents.

Infant swimming in chlorinated pools and the risks of bronchiolitis, asthma and allergy

Recent studies suggest that swimming in chlorinated pools during infancy may increase the risks of lower respiratory tract infection. The aim of the present study was to assess the influence of swimming in chlorinated pools on the risks of bronchiolitis and its late consequences. A total of 430 children (47% female; mean age 5.7 yrs) in 30 kindergartens were examined. Parents completed a questionnaire regarding the child’s health history, swimming practice and potential confounders. Attendance at indoor or outdoor chlorinated pools ever before the age of 2 yrs was associated with an increased risk of bronchiolitis (OR 1.68; 95% CI 1.08–2.68; p = 0.03), which was exposure-dependent for both types of pool (p-value for trend <0.01). Associations persisted, and were even strengthened, by the exclusion of other risk factors. Among children with no parental antecedents of atopic disease or no day-care attendance, odds ratios for bronchiolitis amounted to 4.45 (1.82–10.9; p = 0.001) and 4.44 (1.88–10.5; p = 0.007) after >20 h spent in chlorinated pools during infancy. Infant swimmers who developed bronchiolitis also showed higher risks of asthma and respiratory allergies later in childhood. Swimming pool attendance during infancy is associated with a higher risk of bronchiolitis, with ensuing increased risks of asthma and allergic sensitisation.

Interactions between domestic water hardness, infant swimming and atopy in the development of childhood eczema.

AIM Recent studies suggest that domestic water hardness and swimming in chlorinated pools may increase the prevalence of childhood eczema. The combined influence of these two factors as well as their interaction with atopic status has not been investigated. METHODS We conducted a cross-sectional study on 358 children aged 5-6 years (54% of boys) in 30 kindergarten schools. Parents completed a questionnaire about the childs health, chlorinated pool attendance and potential confounders. Data about tap water quality were provided by water companies. Atopy was defined as a sensitization to at least one aeroallergen or as a medication for allergy. The effect of water hardness and infant swimming practice were assessed by multivariate logistic models. In addition, the effects of these risk factors combined with atopy were evaluated using two measures of biological interaction: the attributable proportion of interaction (AP) and the synergy index (S). AP>0 and S>1 indicate biological interaction between the two risk factors. RESULTS Water hardness was linearly associated to the prevalence of eczema whereas the relationship of eczema with infant swimming was not linear. We observed a biological interaction between hard water (>150 mg/L CaCO(3)L(-1)) and atopic status that increases the prevalence of eczema with an odds ratio (OR) of 3.30 and a 95% confidence interval (CI) of 1.34-8.15 (AP, 0.41; 95% CI 0.15-0.66 and S, 2.4; 95% CI 0.96-6.01). Infant swimming practice combined with atopy also increased the prevalence of eczema (OR, 2.72; 95% CI 1.29-5.74) although none of the interaction measures was significant. However, when water hardness and infant swimming were combined, there was no further increase of the eczema prevalence due to some form of antagonistic interaction between these two factors (AP, -0.56; 95% CI -1.12 to -0.01 and S, 0.54; 95% CI 0.33-0.87). CONCLUSIONS Our study shows that exposure to hard water and infant swimming interact with atopic status to increase the prevalence of childhood eczema. A breaching of the epidermal barrier by detergents or salts in hard water and by chlorine-based oxidants in swimming pool water might explain these interactions.

Respiratory effects associated with wood fuel use: A cross-sectional biomarker study among adolescents

The use of wood as heating and cooking fuel can result in elevated levels of indoor air pollution, but to what extent this is related to respiratory diseases and allergies is still inconclusive. Here, we report a cross‐sectional study among 744 school adolescents (median age 15 years) using as main outcomes respiratory symptoms and diseases, exhaled nitric oxide, total and aeroallergen‐specific IgE in serum, and two epithelial biomarkers in nasal lavage fluid (NALF) or serum, that is, Clara cell protein (CC16) and surfactant‐associated protein D (SPD). Information about the wood fuel use and potential confounders was collected via a personal interview of the adolescent and a questionnaire filled out by the parents. Two approaches were used to limit the possible influence of confounders, that is, multivariate analysis using the complete study population or pairwise analysis of matched sub‐populations obtained using an automated procedure. Wood fuel use was associated with a decrease of CC16 and an increase of SPD in serum, which resulted in a decreased serum CC16/SPD ratio (median −9%, P = 0.001). No consistent differences were observed for the biomarkers measured in exhaled breath or NALF. Wood fuel use was also associated with increased odds for asthma [odds ratio (OR) 2.2, 95% CI: 1.1–4.4, P = 0.02], hay fever (OR = 2.4, 95% CI: 1.4–4.3, P = 0.002), and sensitization against pollen allergens (OR = 2.1, 95% CI: 1.3–3.4, P = 0.002). The risks of respiratory tract infections, self‐reported symptoms, and sensitization against house‐dust mite were not increased by wood fuel use. The increased risks of asthma, hay fever and aeroallergen sensitization, and the changes of lung‐specific biomarkers consistently pointed towards respiratory effects associated with the use of wood fuel. Pediatr Pulmonol. 2012; 47:358–366.

Biomarkers of early respiratory effects in smoking adolescents

Noninvasive biomarkers can be used to evaluate airways damage caused by tobacco smoke, but studies so far have only involved adult smokers. In this study, we evaluated whether such biomarkers can detect early respiratory effects in adolescents passively or actively exposed to tobacco smoke. In a cross-sectional study of 845 adolescents (mean age 16 yrs), we measured exhaled nitric oxide (NO) and various epithelial markers in nasal lavage fluid (NALF) and serum, including Clara cell protein (CC16) and surfactant protein (SP)-D. Information about smoking habits and potential confounders was collected by questionnaire. Four groups of equal size (n=36), of nonsmokers, passive smokers, light smokers (<5 cigarettes·day−1, median 0.08 pack-yrs) and heavy smokers (≥5 cigarettes·day−1, median 0.35 pack-yrs), were matched using an automated procedure. The levels of exhaled NO and of CC16 in NALF were significantly decreased in the group of heavy smokers. A trend towards lower levels of CC16 in NALF was observed in passive smokers. There were no significant changes in serum CC16 and SP-D, which suggests that the deep lung epithelium had not yet been affected by smoking. In conclusion, tobacco smoke can cause early changes in the airways of adolescents with a cumulative smoking history of <1 pack-yr.

Risks of new-onset allergic sensitization and airway inflammation after early age swimming in chlorinated pools

RATIONALE Irritant chlorination products in swimming pools can cause respiratory problems in swimmers but their possible implication in allergies development is still unclear. OBJECTIVES To assess prospectively whether early-life attendance at chlorinated pools increases the risks of IgE sensitization and of airways inflammation later during childhood. METHODS We conducted a two-year prospective study among 196 kindergarten children (mean age of 5.7 years, 54% of boys). We measured exhaled nitric oxide (eNO) and aeroallergen-specific IgE in nasal mucosa. Parents completed a questionnaire about the childs health, chlorinated pool attendance and potential confounders. MAIN RESULTS Ever swimming at indoor or outdoor chlorinated pools before the age of three years was associated with higher odds for new-onset IgE sensitization to house dust mite (adjusted odds ratio [aOR] 2.93, 95% confidence interval [CI] 1.14-7.55) and for new-onset increased eNO (>15 ppb; aOR, 4.54, 95% CI 1.48-13.9). For both outcomes, aORs increased dose-dependently with time spent in chlorinated pools with values reaching, respectively, 3.60 (95% CI 1.21-10.7) and 5.92 (95% CI 1.72-20.5) when the cumulative pool attendance exceeded 60 h These risks appeared independently of each other, of parental history of allergies and of pre-existing diseases, including eczema, which at baseline was more prevalent in early swimmers (aOR, 2.91; 95% CI 1.23-6.89). Such associations were not seen with IgE sensitization to pollen or cat allergens. CONCLUSION Attendance at chlorinated swimming pools in early life is associated with higher risks of new-onset airways inflammation and IgE sensitization to house dust mite, independently of other risk factors.

Nasal epithelium integrity, environmental stressors, and allergic sensitization: A biomarker study in adolescents

Changes in the airways epithelium caused by environmental insults might play a role in the development of allergic rhinitis. We measured albumin and Clara cell protein (CC16) in the nasal lavage fluid (NALF) from 474 adolescents (263 girls and 211 boys). The NALF CC16/albumin ratio, integrating the permeability and cellular integrity of the nasal epithelium, decreased mostly with time spent in chlorinated pools. In boys, a lower CC16/albumin ratio in NALF was associated with an increased risk of house dust mite sensitization. The results suggest that the CC16/albumin ratio in NALF can be used to detect nasal epithelium alterations linked to allergic sensitization.

Nasal epithelium biomarkers in young children: Associations with allergic sensitization and environmental stressors

Recent studies suggest that allergic diseases might have their onset in early epithelial barrier defects. To test this hypothesis, we assessed associations between nasal epithelium biomarkers, environmental stressors, and the risks of allergic sensitization.

Nasal epithelium injury by chlorination products and other stressors predicts persistent sensitization to aeroallergens in young schoolchildren

Background Allergic sensitization during childhood is a dynamic process with a substantial rate of remission. Factors influencing this process are largely unknown. Methods We conducted a two‐year prospective study among 121 schoolchildren (mean age, 5.8 years; 64 boys). We measured urea, club cell protein (CC16), &bgr;2‐microglobulin and albumin in nasal lavage fluid (NALF) and IgE to cat, pollen or house dust mite (HDM) in nasal mucosa fluid. Results Odds of persistent sensitization to any aeroallergen increased across baseline ascending tertiles of urea‐adjusted &bgr;2‐microglobulin or albumin and descending tertiles of albumin‐ or &bgr;2‐microglobulin‐adjusted CC16 (P‐trend = 0.006, 0.02, 0.044 and 0.006, respectively). Persistent HDM sensitization also increased with baseline descending tertiles of raw or urea‐adjusted CC16 (both P‐trend = 0.007). Such strong associations were not observed with new‐onset or remitted sensitization to any aeroallergen or with raw NALF concentrations of urea, albumin or &bgr;2‐microglobulin. At baseline, house cleaning with bleach and chlorinated pool attendance emerged among the strongest and most consistent determinants of NALF biomarkers, being both associated with higher urea and lower CC16 in NALF. Conclusion In young children, a defective nasal epithelium attributable to immaturity or stressors such as chlorination products is predictive of more persistent aeroallergen sensitization. HighlightsFactors influencing allergic sensitization during childhood are largely unknown.We used biomarkers in nasal lavage fluid to assess the nasal epithelium integrity.A defective nasal epithelium was predictive of a persistent sensitization to any aeroallergen.Chlorination products emerged among the most consistent stressors on nasal epithelium.