[Effects of indoor exposures on respiratory and allergic disorders]

Several studies have shown that indoor pollution increases the risk for chronic pulmonary diseases and acute respiratory symptoms in children/adolescents. Some associations have been confirmed by studies. Other relations are still unclear, such as those regarding dog and cat ownership. In this study we assessed the relationships of the exposure to mould and dog/cat ownership with respiratory/allergic symptoms/diagnoses, such as wheezing, asthma, rhinoconjunctivitis, eczema, and cough/phlegm in 20,016 children (6-7 yrs old) and 13,266 adolescents (13-14 yrs old) from 12 Italian areas. Early mould exposure (in the first year of life) was positively related to all considered symptoms/diagnoses (significantly for wheezing, asthma, rhinoconjunctivitis in both children and adolescents, and for cough/phlegm among children); current exposure (in the last year) was a significant risk factor for wheeze, among children. In the latter, dog exposure only in the first year of life increased the risk for wheezing and cough/phlegm, whereas the presence of a dog lifetime seemed a protective factor (though not significant) for all symptoms/diagnoses; negative relations (but not significant) suggested a protective effect by the cat for asthma, independently of exposure period. Among adolescents, the presence of a dog both lifetime and only in the first year of life was significantly related to cough/phlegm; except for rhino-conjunctivitis, all symptoms/diagnoses were negatively related to the presence of a cat lifetime (though not significantly). In conclusion, our results confirmed the effects of mould exposure, especially when it occurs early, on the prevalence of respiratory disorders such as asthma, rhinitis and cough in the pediatric age. The complex relations between keeping a dog or cat at home and respiratory/allergic symptoms/diseases in childhood warrants further studies.