Epidemiology of Chronic Airways Diseases in Japan: Passive smoking
No correlation between prevalence of symptoms aiid air pollution Was observed among children who had no allergic disposition (Thble 5). Allergic disposition is defined here as children who have the anamnesis of allergic disease (nettle rash, allergic coryza, or eczema) or family history of allergic disease (asthma or allergic coryza). On the Other hand, it was shown that children who have allergic disposition were profoundly influenced by air pollution. Slight effects of passive smoking were observed ohly in the prevalence of wheezing but not in persistent cough, phlegm, or asthma-like symptoms. No clear correlation was observed in this survey between the prevalence of respiratory symptoms among the children and nutrition, dwelling conditions, or heating apparatus.
Surveys oil respiratory symptoms and related factors were also carried out ainong the parents of the schoolchildren mentioned above. The total number surveyed was 204,265. The results shown here were obtained from 89,042 mothers who had lived for 3 years or more at the survey area. The results from fathers were excluded, because the prevalence of respiratory symptoms was markedly influenced by smoking, and the results from nonsmokers have not yet been reported separately. Even among the women, 12.5% were present smokers and 2.1% were exsmokers, but as 58.1% smoked fewer than 20 cigarettes per day and 61.1% had a smoking index of less than 200 (number of cigarettes x smoking years), it was thought that the influence of smoking was not as marked in women. read
Prevalences of persistent cough, persistent phlegm, persistent cough and phlegm, and asthma-like symptoms were 1.7%, 2.9%, 0.9%, and 1.0%, respectively, among women. They were deeply influenced by the level of air pollution. Almost all the pollutants correlated significantly with the prevalence of symptoms (Table 6). However, the prevalence of the symptoms was strongly influenced by the family history of allergic disease, anamnesis of the previous disease such as pneumonia, allergic coryza, empyema nasi, and so on, as shown in Table 7.
Discussion and Conclusion
1. The trend of mortality from CAD is being watched with keen interest because of the high concentration of SOa in the air before the 1970s, because of the long-term air pollution by NOa, NO, and NO, and because of the high rate of cigarette smoking in Japan. However, so far no direct correlation between air pollution and mortality, or an increase of age-adjusted mortality from CAD has been observed, except a slight increase of mortality from pulmonary emphysema in men.
2. It is true that the prevalence of respiratory syqigtoms among adult women rises with increased concentration of air pollution where they live. However, the prevalence of symptoms is much more profoundly influenced by the previous history of respiratory diseases such as pneumonia, allergic cqryza, empyema nasi, and so on.
3. Although the prevalence of respiratory symptoms in schoolchildren correlates significantly with the concentration of alinost all kinds of air pollution, no correlation was observed in schoolchildren who have no allergic disposition. The prevalence of respiratory symptoms is very high among children with allergic disposition.
4. In spite of unfavorable environmental circumstances, the mortality from chronic airways disease is rather low in Japan. Genetic factors appear to contribute to the development of CAD.
Table 5—Pfevatence of Persistent Rhohchi titidJor Phlegm by Allergic Disposition and iVO, Concentration in the Area (the Environmental Agency)
|Total||Allergic Disposition, %|
Table 6—Prevalence of Respiratory Symptoms by Concentration ofNOt, NO, NO„ SO, and SP in the Area (Women) (the Environmental Agency)
|ppbTotal||PersistentCough1.7%||PersistentPhlegm2.9%||Persistent Cough and Phlegm0.9%||Asthma-likeSymptoms1.0%|
Table 7—Prevalence of Respiratory Symptoms Among Adult Women by Family History, Previous History of Respiratory Disease and Smoking Habit (the Environmental Agency)
|No.Observed||PersistentCough||PersistentPhlegm||Persistent Cough and Phlegm||Asthma-likeSymptoms||Wheezing|
|Family history of allergy|