[Cohort study of respiratory tract diseases and lung function in school children in southwest Germany. 2. Regional influences on respiratory tract diseases in Mannheim and the Freiburg area].

A prospective cohort study on 8124 schoolchildren aged 8 to 16 was conducted during the years 1977, 1979 and 1985 in Mannheim and two regions near Freiburg (Breisgau and the Black Forest). The objective of this part of the analysis was to investigate the regional differences in respiratory symptoms due to air pollution. Results are presented of 5726 children who had been living in those regions for at least five years at the times of interview. We have analysed 11 respiratory symptoms and two scores, measuring the tendency to infectious and asthmatic diseases, by logistic regression. Comparing the children living 1977 in Mannheim or the Breisgau to those living in the Black Forest the Relative Risks (Odds Ratios) of respiratory symptoms are in the range of 1.26-1.85 and 1.21-1.96 respectively. The results for the year 1979 are similar. In 1985 the regional effect has become smaller and no difference can be observed between Breisgau and the Black Forest. The infect score comprises bronchitis, inflamed throat with fever and sinusitis. The Relative Risk of an increased score decreases from 1.67 in 1977 to 1.65 in 1979 and 1.35 in 1985 in Mannheim and from 1.40 to 1.28 and 1.05 respectively in the Breisgau. The results of asthma and asthma symptoms are not homogeneous. In the Breisgau 1977 and 1979 the Relative Risk of an increased asthma score is slightly higher compared to the Black Forest. Allergies of the skin are reported more often in Mannheim than in the other areas. The Relative Risks of infectious respiratory symptoms and diseases agree spatially and temporarily well with the pattern of SO2 concentration. SO2 may be interpreted as an indicator for air pollution by power plants, industry and domestic heating.