A longitudinal study of risk factors in asthma and chronic bronchitis in childhood.

The prevalence, persistence, incidence and remission rates of reported diagnosed asthma and chronic bronchitis has been studied longitudinally over ten years in a representative community sample of children and adolescents. The objectives are to evaluate the rates of change over time, the role of family history of disease, and the social risk factors in the longitudinal course of disease. The relationship between the two reported diagnoses is very high, about half of each group having the other diagnosis. Each diagnosis has specific symptoms with which it is associated. Remission of clinical disease is associated with continuing symptoms in about half of such cases. The incidence rates and remissions of cases as they have occurred over time were associated with different symptoms and risk factors. A family history of lung disease and family social characteristics are significant risk factors affecting the presence of these diseases, and how they change. Discussion suggests these factors may affect possible precursors, such as lower respiratory tract illnesses, as well as personal habits (such as smoking), which are related to both diagnoses. Further, the interactions of these risk factors appear to significantly influence impairments of lung function at the beginning of adult life, and potential subsequent disease.