A prospective study of asthma in a rural community.

Changes in symptoms and pulmonary function among asthmatic subjects in the general population remain poorly characterized. We studied 1,303 white residents aged seven years and older in Lebanon, Conn, a rural community largely unaffected by air pollution or major occupational exposures. These residents were examined in 1972 and again in 1978. There were 73 asthmatic subjects seen in 1972 who were followed. In addition, we identified 278 persons in 1972 who complained of wheezing who were also seen in 1978. Of the original asthmatic subjects, 50 (68 percent) were in remission; and from the original nonasthmatic population, 19 (1.4 percent) new asthmatic subjects were identified. Similarly, the condition of 215 (77 percent) of those who initially complained of wheeze had improved, whereas 56 (4.6 percent) of those initially studied either developed new wheeze or saw their wheezing worsen. When the groups of persons complaining of wheeze and the asthmatic subjects were analyzed for the presence of chronic bronchitis, we found a significant correlation between wheeze and chronic bronchitis in individuals aged 18 years and older (p less than 0.001) for both men and women, and a significant correlation (p less than 0.001) between asthma and chronic bronchitis in women aged 18 years and older. Loss of pulmonary function over time measured in terms of the forced expiratory volume in one second and the forced expiratory flow at 50 percent of total lung capacity was consistently greater for asthmatic adults than for nonasthmatic adults. Furthermore, when individuals were studied by the severity and duration of their asthmatic symptoms, a trend of worse pulmonary function was seen in those individuals with chronic asthma. We conclude that remission rates among asthmatic subjects and persons with wheeze are high in individuals aged seven years and older, that chronic bronchitis is frequently associated with wheezing and a history of asthma in adults, and that significant abnormalities in pulmonary function as well as accelerated loss of pulmonary function are associated with asthma.