Considering the high number of children exposed to maternal smoking in utero and the even higher number exposed to passive smoking after birth, this risk factor for reduced lung function growth remains a serious pediatric and public health issue.

Objectives:Adverse effects have been reported of prenatal and/or postnatal passive exposure to smoking on children’s health. Uncertainties remain about the relative importance of smoking at different periods in the child’s life. We investigate this in a pooled analysis, on 53 879 children from 12 cross-sectional studies—components of the PATY study (Pollution And The Young).Methods:Effects were estimated, within each study, of three exposures: mother smoked during pregnancy, parental smoking in the first two years, current parental smoking. Outcomes were: wheeze, asthma, “woken by wheeze”, bronchitis, nocturnal cough, morning cough, “sensitivity to inhaled allergens” and hay fever. Logistic regressions were used, controlling for individual risk factors and study area. Heterogeneity between study-specific results, and mean effects (allowing for heterogeneity) were estimated using meta-analytical tools.Results:There was strong evidence linking parental smoking to wheeze, asthma, bronchitis and nocturnal cough, with mean odds ratios all around 1.15, with independent effects of prenatal and postnatal exposures for most associations.Conclusions:Adverse effects of both pre- and postnatal parental smoking on children’s respiratory health were confirmed. Asthma was most strongly associated with maternal smoking during pregnancy, but postnatal exposure showed independent associations with a range of other respiratory symptoms. All tobacco smoke exposure has serious consequences for children’s respiratory health and needs to be reduced urgently.

Background:The results of studies on the effect of nutrition on respiratory diseases are inconsistent. The role of nutrition in children's respiratory health was therefore analysed within the cross sectional Central European Study on Air Pollution and Respiratory Health (CESAR). Method: A total of 20 271 children aged 7-11 were surveyed in six European countries. Respiratory health and food intake were assessed using questionnaires. Associations between four symptoms and nutritional factors were evaluated using logistic regression, controlling for area plus other potential confounders.Results: All symptoms showed initial associations with nutritional factors. Low consumption of fish and of summer and winter fruit were the most consistent predictors. In a fully adjusted model low fish intake remained a significant independent predictor of persistent cough (OR=1.18; 95% CI 1.04 to 1.34), wheeze ever (OR=1.14; 95% CI 1.03 to 1.25) and current wheeze (OR=1.21; 95% CI 1.06 to 1.39) and a weaker predictor of winter cough (OR=1.10; 95% CI 0.99 to 1.23). Low summer fruit intake was a predictor of winter cough (OR=1.40; 95% CI 1.10 to 1.79) and persistent cough (OR=1.35; 95% CI 1.01 to 1.82). Low winter fruit intake was associated with winter cough (OR=1.28; 95% CI 1.09 to 1.51). Associations between symptoms and vegetable intake were inconsistent. Low summer intake was significantly associated with winter cough (OR=1.23; 95% CI 1.03 to 1.47) but, overall, winter intake had inverse associations with both coughs. Associations between winter vegetable intake and wheeze varied considerably between countries. Conclusion: A number of associations were found between respiratory symptoms and low intake of fish, fruit and vegetables in children. Low fish intake was the most consistent predictor of poor respiratory health. Fruit and vegetable intake showed stronger associations with cough than with wheeze.

Indoor mould exposure was consistently associated with adverse respiratory health outcomes in children living in these diverse countries.

Studies of the impact of long-term exposure to outdoor air pollution on the prevalence of respiratory symptoms and lung function in children have yielded mixed results, partly related to differences in study design, exposure assessment, confounder selection and data analysis.We assembled respiratory health and exposure data for .45,000 children from comparable crosssectional studies in 12 countries. 11 respiratory symptoms were selected, for which comparable questions were asked. Spirometry was performed in about half of the children. Exposure to air pollution was mainly characterised by annual average concentrations of particulate matter with a 50% cut-off aerodynamic diameter of 10 mm (PM10) measured at fixed sites within the study areas.Positive associations were found between the average PM10 concentration and the prevalence of phlegm (OR per 10 mg?m -3 1.15, 95% CI 1.02-1.30), hay fever (OR 1.20, 95% CI 0.99-1.46), bronchitis (OR 1.08, 95% CI 0.98-1.19), morning cough (OR 1.15, 95% CI 1.02-1.29) and nocturnal cough (OR 1.13, 95% CI 0.98-1.29). There were no associations with diagnosed asthma or asthma symptoms. PM10 was not associated with lung function across all studies combined. Our study adds to the evidence that long-term exposure to outdoor air pollution, characterised by the concentration of PM10, is associated with increased respiratory symptoms.