The epidemiology of asthma.

Significant strides have been made in recent years in the epidemiologic study of obstructive lung diseases including asthma. Community population samples are being evaluated prospectively and followed up longitudinally to document the appearance of morbidity and clinical diagnoses. Also, a variety of environmental, physiologic, and immunologic variables are being collected on a serial basis to correlate changes with the appearance (or disappearance) of recognizable disease. Unfortunately, until the semantics and diagnostic labeling of airway abnormalities becomes more precise, especially in the older population, the incidence and prevalence of disease will lack the precision it should have.