What is Epidemiology? Asthma is a highly prevalent disease that affects the quality of life of many people. o The prevalence is rising China:0.5-1.0%, about 20 millionWhat is Epidemiology? • Asthma is a highly prevalent disease that affects the quality of life of many people. • The prevalence is rising. • China: 0.5- 1.0%, about 20 million