[Review of epidemiological studies on adult bronchial asthma in Japan]

The prevalence of adult asthma in Japan has tripled since the 1960 s (1.2%- > 3.14%). The number of young patients has increased more than the number of middle-aged patients. The asthma mortality rate was high (19.5 per 100,000) in 1950 but it gradually decreased, to 5.0 per 100,000 in 1980, and has since been unchanged. Annual asthma mortality among adult asthma patients was 0.29%. Nationwide research on adult asthma in Japan disclosed that: 1) the male/female ratio was 48.3%/51.7%. 2) 79.8% of adult asthma cases were adult onset, and 3) a total of 80% needed regular medications. Based on the above observations, a new classification of adult asthma, which includes child-onset asthma, adult-onset asthma and adult relapse asthma was proposed.