RESPIRATORY MORBIDITY IN MERSEYSIDE SCHOOLCHILDREN EXPOSED TO COAL-DUST AND AIR-POLLUTION

A cross sectional study was carried out to determine whether schoolchi ldren in a specific locality exposed to pollution from steam coal dust have an excess of respiratory symptoms compared with children in cont rol areas. A total of 1872 primary schoolchildren (aged 5-11 years) fr om five primary schools in the Bootle dock area of Liverpool (exposed area), five primary schools in South Sefton (control area), and five p rimary schools in Wallasey (control area) were studied. A questionnair e was distributed through the schools and was completed by the parents of the children. The questionnaire inquired about respiratory symptom s (cough, wheezing, and shortness of breath), allergy, atopy, smoking, and socioeconomic factors. Height, weight, and peak expiratory flow w ere measured. Compliance was good (92%) and similar in the three study areas. The children in the three areas were of similar mean age (7.5 years), height (1.24 m), sex ratio, and had a similar prevalence of pa ternal (6.2%) and maternal (7%) asthma. The exposed zone contained mor e unemployed parents (41, 29, and 29% respectively), more rented housi ng (64, 45, 34%), and more smoking parents (71, 60, 59%) than the cont rol areas. Respiratory symptoms were significantly more common in the exposed area, including wheeze (25.0, 20.6, and 17.5%), excess cough ( 40.0, 23.4, and 25.1%), and school absences for respiratory symptoms ( 47.5, 35.9, and 34.9%). These differences remained significant even if the groups were subdivided according to whether or not parents smoked or were employed. Multiple logistic regression analysis confirmed the exposed zone as a significant risk factor for absenteeism from school due to respiratory symptoms (odds ratio 1.55, 95% confidence interval 1.17 to 2.06) after adjusting for confounding factors. Standard dust deposit gauges on three schools confirmed a significantly higher dust burden in the exposed zone. An increased prevalence of respiratory sym ptoms in primary schoolchildren exposed to coal dust is confirmed. Alt hough the association with known coal dust pollution is suggestive, a cross sectional study cannot confirm a causal relation and further stu dies are needed.