Investigation of children health problems in relation to indoor environmental factors in Japan Part 1: Design of investigation and outcome of allergic symptoms

In Japan, there is an increase in allergic diseases such as asthma, respiratory symptom, particularly prevails among the young generation. The reasons why the prevalence of allergic diseases is increasing are still not yet well understood. However, it is deemed that indoor environmental factors are one of the essential sources. Therefore an epidemiology type of survey was investigated to 4th and 5th grade school students in Japan. The survey was divided into three phases: The first phase was a survey of the prevalence of adverse health problems, among school students, the second phase was a case-control study and the final phase was a field measurement for case- control. This paper described its survey protocol and outcomes from the first phase questionnaire survey. The results found that the ratio of children with current allergic symptoms was more than 50%, and indicated that environmental factors such as pollen and house dust could influence allergic symptoms. This survey also revealed the possibility of the relationship between adverse health effect and indoor environmental factors.