1987 Volume 22 Issue 6 Pages 431-459
Epidemiological studies have been conducted from 1980 to 1984 to investigate health effect of air pollution in 53 areas whithin Japan showing different degrees of ais pollution (average NO2value of three years before the investigation was 5-43 ppb).
Self-admistrated questionnaires based upon the ATS-DLD standard were prepared by Research Team for Air Pollution Effect on Human Health in Japan Environment Agency and were distributed to 125. 728 school-children (boy: 64.218 girl: 61.510) in surveyed areas.
Effective collected questionnaires numbered 123.536 with response rate of 98.2%.
98. 965 cases from the responded who had been resided in the surveyed areas for more than three yearswere analyzed for further examination and following results were obtained:
1. Prevalences of respiratosy symptom of surveyed areas were:
Persistant cough...boy 1.8% girl 1.3%
Persistent congestion and/or phlegm...boy 1.2% girl 0.9%
Asthma-like symptom (existing)...boy 4.6% girl 2.9%
Wheezing...boy 6. 3% girl 5. 3%
Prevalence of each item showed higher for boy than girl.
Clear difference was found among the areas concerning the prevalence of asthma-like symptom (existing) and wheezing, i. e.
Asthma-like symptom (existing)...boy 2. 9% (min.) 8. 7% (max.)
girl 1. 4% (min.)-6. 9% (max.)
Wheezing...boy 3. 9% (min.)-9. 9% (max.)
girl 2. 9% (min.) 9. 0% (min.)
Prevalences of persistent cough and persistent congestion and/or phlegm were low enough so that difference among the areas decreased.
2. Concerning various factors relating to asthma-like symptom and whcezing, i. e. allergic disposition, medical anamnesis, infantile nutrition, smoking within family, dwelling condition, heating apparatus, all of which could be obtained from the questionnaires, were analyzed and result was as follows:
Concerning cases having medical anamnesis of allergic disease (nettle rash, allergic coryza, eczema, ) and cases having family history of asthma and/or allergic coryza, higher prevalence was revealed than the cases which had no such medical anamnesis and family history.
Influence of smoking whithin family could be seen a little in wheezing prevalence but it could not be found in the prevalence of asthma-like symptom.
Prevalence of asthma-like symptom (existing) showed a little higher tendency for the cases who used heating apparatus whithout ventiduct in reinforced concrete houses (air-tight structural house) than those who used heating apparatus with ventiduct in wooden houses with wooden sash (non-air-tight house). But this difference was not significant.
Allergic dispostion and medical anamnesis of allergic disease were found influential to prevalence but this did not explain the difference among the surveyed areas.
3. The surveyed areas were classified into four groups according to NO2concentration, i. e. under 10 ppb, 21-30 ppb, over 31 ppb. The higher was NO2value, the higher was the prevalence of each symptom (asthma-like, wheezing, persistent cough, persistent congestion and/or phlegm).
Such tendency was found in the cases having allergic dispostion and medical anamnesis of allergic disease mentioned above. Nevertheless as to the cases without said allergic dispostion and medical anamnesis of allergic disese, only girl cases showed higher increased.
Correlation coefficients between prvalence of asthma-like symptom (existing) and average NO2value of three years befor the investigation were significant for both sexes.
This investigation were cross sctional study mainly for respiratory symptoms and therefore other relating factors of asthma such as social, economical, or psychoanalystic factors have been left untouched.
