ABSTRACT
Epidemiology is the study of the causes, distributions, occurrences, and patterns of disease in populations. Several epidemiological study designs and data sources can be used to try and estimate the frequency and patterns of asthma, and to understand the etiology of the disease. The key measures of disease frequency include: the incidence of the disease, which is the rate of occurrence of new cases and the point, period, or lifetime prevalence. The potential of using information from routine data sources to establish the accurate prevalence of a disease has also emerged. The frequency of asthma is highest during childhood and usually peaks in presentation at approximately 5 years of age with a secondary peak during adolescence. The role of genetic variants as risk factors in the population in determining the geographical distribution of asthma prevalence should be noted. For clinicians, improving outcomes for patients with asthma is the main goal.
