OBJECTIVE: To investigate the correlation of asthma incidence with environmental pollution. METHODS: We performed stratified-cluster-disproportional-random-sampling survey in the occupational populations from 10 professional systems by using an uniform protocol, questionnaire and procedure in this multicenter study. Original data were processed and statistically analyzed with SPSS 8.0 for windows. Prevalence rates were compared by chi(2) test. RESULTS: A total of 50,558 people supposed to cover more than 200,000 staff and workers were sampled. Six hundred and thirty asthmatics were identified and the overall prevalence rate in Beijing area was 1.25%. The incidence of asthma in occupational populations from urban commercial and trade circles, common chemical plants, and a certain petrochemical works was 0.51%, 1.06% and 2.81% respectively. The morbidity of asthma in the latter two populations was significantly higher than that in peasants (0.43%) in the remote outskirts of Beijing city (P < 0.01). The relative risk (RR) of asthma incidence in occupational populations from the commercial and trade circles, common chemical plants, the petrochemical works and the students in elementary and middle schools was 1.88, 2.79, 5.19 and 3.05 respectively as compared to peasants, the differences being statistically significant. CONCLUSION: The results suggest that the difference in asthma incidence in occupational populations may be attributable to environmental pollution.
OBJECTIVE: To investigate the correlation of asthma incidence with environmental pollution. METHODS: We performed stratified-cluster-disproportional-random-sampling survey in the occupational populations from 10 professional systems by using an uniform protocol, questionnaire and procedure in this multicenter study. Original data were processed and statistically analyzed with SPSS 8.0 for windows. Prevalence rates were compared by chi(2) test. RESULTS: A total of 50,558 people supposed to cover more than 200,000 staff and workers were sampled. Six hundred and thirty asthmatics were identified and the overall prevalence rate in Beijing area was 1.25%. The incidence of asthma in occupational populations from urban commercial and trade circles, common chemical plants, and a certain petrochemical works was 0.51%, 1.06% and 2.81% respectively. The morbidity of asthma in the latter two populations was significantly higher than that in peasants (0.43%) in the remote outskirts of Beijing city (P < 0.01). The relative risk (RR) of asthma incidence in occupational populations from the commercial and trade circles, common chemical plants, the petrochemical works and the students in elementary and middle schools was 1.88, 2.79, 5.19 and 3.05 respectively as compared to peasants, the differences being statistically significant. CONCLUSION: The results suggest that the difference in asthma incidence in occupational populations may be attributable to environmental pollution.