Search

The objective of this study was to investigate the spatial distribution of respiratory morbidity and asthma in children in relation to high levels of airborne dust pollution. A cross-sectional survey of 2035 children (aged 5-11 yr) by parent-completed questionnaire, with concurrent monitoring of dust deposition rates in the vicinity of children's homes, was performed in 15 primary schools (5 in each of 3 areas of Merseyside). The main outcome measures were (1) doctor-diagnosed asthma, (2) parent-reported respiratory symptoms of recent excess cough, wheeze, and breathlessness, and (3) school absenteeism due to respiratory ill health. Proximity to the source of dust pollution was associated with increased prevalence of excess cough, breathlessness, school absence due to respiratory ill health, and doctor-diagnosed asthma, after adjusting for a range of socioeconomic, environmental, and other confounding factors. The adjusted odds for excess cough and breathlessness for children living within 2 km of the source (dock area) are estimated to be almost twice those for children living more than 2 km away: excess cough 1.9 (95% CI 1.4-2.6); breathlessness 1.9 (1.3-2.7); school absence 1.5 (1.2-1.9); and doctor-diagnosed asthma 1.5 (1.1-2.0). Excess cough was significantly associated with the mean annual dust deposition recorded in the vicinity of the child's home. The adjusted odds ratio for excess cough corresponding to an increase in mean annual dust deposition of 50 mg/m2/d was 3.1 (95% CI 1.1-8.2). These results suggest that airborne dust was associated with respiratory morbidity in these children, which could relate to the high prevalence of childhood doctor-diagnosed asthma in this community.

Objectives: (1) To determine the prevalence of cough, wheeze, and breathlessness, both as single symptoms and in combination, in primary schoolchildren and their relation to doctor diagnosed asthma. (2) To identify in areas with different levels of dust pollution whether questionnaire reported 'cough alone' (without wheeze or breathlessness) had similar risk factors to the questionnaire reported triad of 'cough, wheeze, and breathlessness'., Subjects and Methods: Two cross sectional community surveys of primary schoolchildren (5-11 years) were performed in 1991 and 1993. Parent completed questionnaires related to socioeconomic and respiratory factors were distributed through 15 schools in three areas of Merseyside, one of which had a relatively high level of dust pollution. Data were analysed to determine the prevalence of different respiratory symptom patterns. Univariate and multiple logistic regressions were used to investigate the associations between respiratory symptom profiles and potential risk factors., Results: The proportions of completed questionnaires that were returned were similarly high in both surveys, 92% in 1991 (1872 of 2035) and 87% in 1993 (3746 of 4288). The proportions of children with different respiratory symptom patterns were similar in the two surveys: in 1991, asymptomatic children 70.1% (1109 of 1583), those with cough alone 8.9% (141 of 1583), and children with the symptom triad of cough, wheeze, and breathlessness 8.3% (132 of 1583); the figures for 1993 were 69.5% (2144 of 3083), 9.2% (284 of 3083), and 7.3% (224 of 3083) respectively. The prevalence of doctor diagnosed asthma increased from 17.4% in 1991 to 22.1% in 1993. The symptom of cough alone was associated with going to school in an area of increased air pollution. The symptom triad of cough, wheeze, and breathlessness was associated with reported allergies, familial history of atopy and preterm birth. In 1991, of children with the symptom of cough alone one in eight were diagnosed asthmatic; twice as many doctors made the diagnosis on this basis in 1993., Conclusion: The respiratory symptom of cough alone and cough, wheeze, and breathlessness represent clinical responses to different specific risk factors. Cough alone was associated with the environmental factors of school in the dust exposed zone and dampness in the home, whereas cough, wheeze, and breathlessness related to allergic history and preterm birth, and may be the best surrogate of asthma. Diagnosis of asthma on the basis of cough alone partly explains the increased prevalence of doctor diagnosed asthma, especially in dust polluted areas.

Background: A study was carried out to analyse the impact of maternal asthma on the risk of preterm delivery and the contribution of preterm delivery to the development of childhood asthma., Methods: Two cross sectional community studies of 1872 children (5-11 years) in 1991 and 3746 children in 1993 were performed. A respiratory health questionnaire was distributed throughout 15 schools in Merseyside and completed by the parents of the children., Results: Asthmatic mothers were more likely to have a preterm delivery than non-asthmatic mothers (odds ratio (OR) 1.49; 95% CI 1.10 to 2.02). Smoking was a separate risk factor for preterm delivery (OR 1.35; 95% CI 1.10 to 1.65). Asthmatic mothers did not have an increased risk of delivering small, growth retarded babies. Maternal asthma, paternal asthma, and premature birth, in that order, increased the risk of later childhood respiratory morbidity (OR 3.13, 95% CI 2.36 to 4.16; 2.23, 95% CI 1.62 to 3.05; 1.40, 95% CI 1.10 to 1.79). Conversely, babies who were small for gestational age appeared less likely to develop doctor diagnosed asthma or the symptom triad of cough, wheeze, and breathlessness in childhood, although this was not statistically significant (OR 0.63, 95% CI 0.28 to 1.41)., Conclusions: Maternal smoking during pregnancy and maternal asthma are independent risk factors associated with preterm delivery. Asthma in mothers predisposes to preterm delivery but not fetal growth retardation. Preterm birth, but not growth retardation, predisposes the child to the development of subsequent asthma.