Kindergarteners' Exposure to Passive Smoking at Home in Japan and China

Background : This study aimed to clarify the characteristics and actual conditions in the home environments of children who are exposed to passive smoking in China and Japan. Methods : Participants included 3- to 5-year-old kindergarteners (including children attending nursery schools) who lived in Osaka, Japan (975 children) and Beijing, China (1,021 children). We conducted a questionnaire survey of their guardians. Results : The questionnaires were collected from 583 households (59.8%) in Japan and 632 households (61.9%) in China. There were at-home smokers in 323 households (55.4%) in Japan and 318 households (50.3%) in China. Passive smoking by children at home was observed in 106 households (18.2%) in Japan and 97 households (15.3%) in China. Conclusions : The results of this survey suggest that a common factor to both countries was that the "number of cigarettes consumed per day" is correlated with an increase in the percentage of children who are exposed to passive smoking. Moreover, the findings suggest that the "number of at-home smokers" in Japan and "children aged 5 years old or older" in China increase the percentage of children who are exposed to passive smoking.