Chlorinated Pool Attendance, Atopy, and the Risk of Asthma during Childhood

The pool chlorine hypothesis postulates that the rise in childhood asthma in the developed world could result at least partly from the increasing exposure of children to toxic gases and aerosols contaminating the air of indoor chlorinated pools. To further assess this hypothesis, we explored the relationships between childhood asthma, atopy, and cumulated pool attendance (CPA). We studied 341 schoolchildren 10–13 years of age who attended at a variable rate the same public pool in Brussels (trichloramine in air, 0.3–0.5 mg/m(3)). Examination of the children included a questionnaire, an exercise-induced bronchoconstriction (EIB) test, and the measurement of exhaled nitric oxide (eNO) and total and aeroallergen-specific serum IgE. CPA by children (range, 0–1,818 hr) emerged among the most consistent predictors of asthma (doctor diagnosed or screened with the EIB test) and of elevated eNO, ranking immediately after atopy and family history of asthma or hay fever. Although the risk of elevated eNO increased with CPA [odds ratio (OR) = 1.30; 95% confidence interval (CI), 1.10–1.43] independently of total or specific serum IgE, the probability of developing asthma increased with CPA only in children with serum IgE > 100 kIU/L (OR for each 100-hr increase in CPA = 1.79; 95% CI, 1.07–2.72). All these effects were dose related and most strongly linked to pool attendance before 6–7 years of age. Use of indoor chlorinated pools especially by young children interacts with atopic status to promote the development of childhood asthma. These findings further support the hypothesis implicating pool chlorine in the rise of childhood asthma in industrialized countries

Les risques sanitaires des produits dérivés de la chloration des eaux de bassins de natation

Swimming pools are attended by a lot of people worldwide, to swim or to relax. However, the chlorinated atmosphere of swimming pools may be responsible for health problems. Indeed, the majority of swimming pools are disinfected by chlorine based products –leading to the formation of potentially toxic derivatives- and studies have recently drawn attention to health risks linked to the attendance of swimming pools. It has been suggested among other things that the increasing and earlier exposure of children to swimming pools chlorination by-products could, in association with other factors, be implicated in the increasing incidence of asthma and allergies. For the moment, prevention measures should be taken to decrease the risk linked to the exposure to these derivatives (reduction in their formation or in their accumulation at least)

Les risques sanitaires des produits dérivés de la chloration des eaux de bassins de natation

Les piscines sont fréquentées par de nombreuses personnes à travers le monde, pour y nager ou pour s’y délasser. Cependant, l’atmosphère chlorée des piscines pourrait être responsable de problèmes de santé. En effet, la majorité des piscines sont désinfectées par des produits à base de chlore –menant à la formation de dérivés potentiellement toxiques- et des études ont récemment attiré l'attention sur les risques pour la santé liés à la fréquentation des piscines. Il a entre autres été suggéré que l’exposition croissante et plus précoce des enfants aux produits de chloration des piscines pourrait, en association avec d’autres facteurs, être impliquée dans l’incidence croissante de l’asthme et des allergies. Pour le moment, des mesures de prévention devraient être prises pour diminuer le risque lié à l'exposition à ces dérivés (réduction de leur formation ou du moins de leur accumulation).Swimming pools are attended by a lot of people worldwide, to swim or to relax. However, the chlorinated atmosphere of swimming pools may be responsible for health problems. Indeed, the majority of swimming pools are disinfected by chlorine based products –leading to the formation of potentially toxic derivatives- and studies have recently drawn attention to health risks linked to the attendance of swimming pools. It has been suggested among other things that the increasing and earlier exposure of children to swimming pools chlorination by-products could, in association with other factors, be implicated in the increasing incidence of asthma and allergies. For the moment, prevention measures should be taken to decrease the risk linked to the exposure to these derivatives (reduction in their formation or in their accumulation at least).En todo el mundo, mucha gente frecuenta las piscinas, para nadar o relajarse. No obstante, la atmósfera clorada de las piscinas podría dar lugar a problemas de salud. En efecto, la mayoría de las piscinas están desinfectadas con productos a base de cloro -lo que conduce a la formación de derivados potencialmente tóxicos- y varios estudios han puesto de relieve, en los últimos tiempos, los riesgos para la salud derivados de la frecuentación de piscinas. También se ha sugerido que la exposición creciente y a una edad más temprana a productos de cloración de piscinas podría, en conjunción con otros factores, tener relación con la creciente incidencia de asma y alergias. Por el momento, deberían tomarse medidas de prevención para reducir los riesgos conectados con la exposición a estos derivados (reducción de su formación o, al menos, de su acumulación)

Respiratory effects associated with the attendance at chlorinated swimming pools

Swimming pools are mainly disinfected by chlorination, which leads to the formation of unwanted harmful products. In a first sudy initially planned to evaluate the respiratory effects of air pollution in children living in Brussels, attendance at chlorinated pools appeared to be associated with lung hyperpermeability. A retrospective analysis of data on asthma prevalence in children brought to light an increased risk of asthma with cumulative attendance at the chlorinated school pool. To further investigate these findings, several studies were carried out. Chronic studies specifically designed to investigate the relationship between chlorinated pool attendance and the risk of asthma confirmed the association. Whilst the risk of lung inflammation assessed by the measurement of exhaled nitric oxide increased with cumulated chlorinated pool attendance in all children, the risk of developing asthma was only increased in atopic children (with a level of serum IgE >100 kIU·L-1). These effects were strongly linked to pool attendance before the age of 6-7 years. Infant swimming practice was identified as a high risk activity, leading to airway changes that seem to promote the onset of asthma and recurrent bronchitis later in childhood. Short-term studies in recreational and trained swimmers also revealed an increased permeability of the lung epithelium. This finding was confirmed in mice acutely exposed to a controlled concentration of nitrogen trichloride. Inflammatory effects were also studied in trained swimmers. The physiological lung inflammation normally observed during exercise and assessed by exhaled nitric oxide was inhibited in chlorinated atmosphere. No change was detected in lung function or in lung epithelium permeability in this study where levels of trichloramine were low (<300 ìg/m³). In conclusion, attendance at chlorinated pools clearly acts as an adjuvant in the development of asthma in atopic subjects. Infant swimming practice is also detrimental to respiratory health. Therefore, it is recommended not to take children too early to swimming pools and to be particularly cautious in case of atopic children. At least, children should only attend well-managed pools, to avoid jeopardizing their respiratory health.(MED 3) -- UCL, 200

House cleaning with chlorine bleach and the risks of allergic and respiratory diseases in children.

Chlorine bleach or sodium hypochlorite can inactivate common indoor allergens. In this cross-sectional study we evaluated to what extent regular house cleaning with bleach can influence the risks of respiratory and allergic diseases in children. We studied a group of 234 schoolchildren aged 10-13 yr among whom 78 children were living in a house cleaned with bleach at least once per week. Children examination included a questionnaire, an exercise-induced bronchoconstriction test and the measurement of exhaled nitric oxide (NO) and of serum total and aeroallergen-specific immunoglobulin (Ig)E, Clara cell protein (CC16) and surfactant-associated protein D (SP-D). Children living in a house regularly cleaned with bleach were less likely to have asthma (OR, 0.10; CI, 0.02-0.51), eczema (OR, 0.22; CI, 0.06-0.79) and of being sensitized to indoor aeroallergens (OR, 0.53; CI, 0.27-1.02), especially house dust mite (OR, 0.43; CI, 0.19-0.99). These protective effects were independent of gender, ethnicity, previous respiratory infections, total serum IgE level and of family history of allergic diseases. They were however abolished by parental smoking, which also interacted with the use of bleach to increase the risk of recurrent bronchitis (OR, 2.03; CI, 1.12-3.66). House cleaning with bleach had effect neither on the sensitization to pollen allergens, nor on the levels of exhaled NO and of serum CC16 and SP-D. House cleaning with chlorine bleach appears to protect children from the risks of asthma and of sensitization to indoor allergens while increasing the risk of recurrent bronchitis through apparently an interaction with parental smoking. As chlorine bleach is one of the most effective cleaning agent to be found, these observations argue against the idea conveyed by the hygiene hypothesis that cleanliness per se increases the risk of asthma and allergy

Clinical trials design and treatment tailoring: General principles applied to breast cancer research

Nowadays tailored therapy tends to replace standard cancer treatment approaches. Tailoring treatment is possible thanks to clinical trials results that identified subgroups of patients benefiting most from some treatments. Treatment can be tailored on the basis of specific clinical characteristics of the population or on the basis of predictive or prognostic markers. Finally treatment can be tailored for specific molecular targets. This evolution in cancer treatment has triggered the development of innovative trial designs to validate these new hypotheses. The real challenge of the next coming years resides in recruiting large number of patients from specific subgroups to validate tailored therapies. (c) 2006 Published by Elsevier Ireland Ltd

Infant swimming practice, pulmonary epithelium integrity, and the risk of allergic and respiratory diseases later in childhood.

OBJECTIVE: Irritant gases and aerosols contaminating the air of indoor swimming pools can affect the lung epithelium and increase asthma risk in children. We evaluated the impact of infant swimming practice on allergic status and respiratory health later in childhood. METHODS: Clara cell protein, surfactant-associated protein D, and total and aeroallergen-specific immunoglobulin E were measured in the serum of 341 schoolchildren aged 10 to 13 years, among whom 43 had followed an infant swimming program. Asthma was defined as doctor-diagnosed asthma and/or positive exercise-induced bronchoconstriction (15% decrease in postexercise forced expiratory volume). RESULTS: There were no significant differences between the infant swimming group and the other children regarding the levels of exhaled nitric oxide and total or aeroallergen-specific serum immunoglobulin E. Children who swam as infants showed, by contrast, a significant decrease of serum Clara cell protein and of the serum Clara cell protein/surfactant-associated protein D ratio integrating Clara cell damage and permeability changes of the lung epithelial barrier. These effects were associated with higher risks of asthma and of recurrent bronchitis. Passive exposure to tobacco alone had no effect on these outcomes but seemed to interact with infant swimming practice to increase the risk of asthma or of recurrent bronchitis. CONCLUSIONS: Our data suggest that infant swimming practice in chlorinated indoor swimming pools is associated with airways changes that, along with other factors, seem to predispose children to the development of asthma and recurrent bronchitis

Cuticular lobes in the Tetranychus urticae complex (Acari : Tetranychidae): a reliable taxonomic character?

Taxonomic work on spider mites has mostly been based on morphological characters. The shape of lobes on dorsal integumentary ridges of summer females was used in the past as an additional morphological character to discriminate between the green and the red forms of the two-spotted spider mite Tetranychus urticae. However, we showed that lobes were not always present or were not completely formed in some females, presumably because of micro-environmental conditions. No clear-cut differences were put forward between green and red forms concerning that ridge structure. This underlines the care needed when this criterion is used. The possible role of lobes in adaptation to water balance is discussed