Nationwide cross-sectional population-based study on the prevalences of asthma and asthma symptoms among Japanese adults

Background: Asthma is a common respiratory disease worldwide. However, few reports are available on the prevalences of asthma and asthma symptoms among Asian subjects.

Methods: To determine the prevalences of asthma and asthma symptoms among Japanese subjects, we performed a nationwide cross-sectional, population-based study on Japanese adults aged 20-79 years. Ten areas spread throughout the country were randomly selected. Door-to-door or postal surveys were performed using a translated version of the European Community Respiratory Health Survey questionnaire.

Results: The survey was completed by 23,483 participants. The overall response rate was 70.6%. The prevalences of wheeze and current asthma among all participants aged 20-79 years were 10.1% (95% CI: 9.7-10.5%) and 4.2% (95% CI: 4.0-4.5%), respectively. The prevalences among young adults aged 20-44 years were 9.3% (95% CI: 8.7-9.9%) and 5.3% (95% CI: 4.8-5.8%), respectively. The prevalence of current asthma was highest in females aged 30-39 years in comparison with the other gender and age groups.

Conclusions: This nationwide study determined the prevalences of asthma and asthma symptoms among Japanese adults. The results provide fundamental information on the respiratory health of Japanese adults.