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.