Prospective Evaluation of Airways Reactivity

BACKGROUND:

Epidemiologic models for growth and decline in lung function have been developed from longitudinal studies in adults. The development of chronic obstructive lung disease appeared to be the result of both an abnormally rapid rate of decline in level of lung function in early adult life. Thus factors in early childhood influenced adult pulmonary function in either of two ways. First, it was hypothesized that childhood factors diminished the maximally attained level of lung function in early adult life, thus increasing the likelihood that, with a fixed rate of decline in adult life, these individuals would be more likely to develop symptoms. Alternatively, childhood events might act directly to increase the risk of developing a more rapid rated decline in pulmonary function in adult life. The above theory had a plausible patho-anatomic basis. The lung is one of the last organs in the body to mature and children continue to make alveoli up until the age of six or seven. Thus risk factors both environmental, such as respiratory illness, active and passive cigarette smoke, and host airways responsiveness and atopy, could adversely influence lung growth and lead to less maximal lung growth and/or increased sensitivity to cigarette smoking in adult life.

This study was a subproject in a Specialized Center of Research in Chronic Diseases of the Airways. The East Boston cohort was developed in 1975 under contract issued by the Division of Lung Diseases.

DESIGN NARRATIVE:

In 1975 a stratified, random sample of propositus children ages 5-9 living in the East Boston area of Boston, Massachusetts was selected as were their family members to form the cohort. In the longitudinal study, each member of the propositus cohort and all family members five years of age and older residing in the household were visited at home annually by study personnel. Data collected included: a respiratory illness history; demographic data on type of heating, fuel for cooking, types of air-purifying devices, and area of residence; cigarette smoking history; disability from cardiac disease; age of puberty in female children; pulmonary function tests; and anthropometric data. The study helped to determine the extent to which airways responsiveness was a risk factor for chronic airflow obstruction, was acquired as a result of other exposures or as a consequence of chronic symptoms or lower levels of pulmonary function.