The effect of occupational exposure on pulmonary function: a longitudinal evaluation of fire fighters and nonfire fighters.

To examine the chronic effect of fire fighting on pulmonary function, we undertook a longitudinal analysis of 168 fire fighters and 1,474 nonfire fighters enrolled in a study of normal aging. Spirometric measurements (FVC and FEV1) were obtained on all subjects over a 5-yr intake period (1963 to 1968) and these subjects were reexamined 5 yr later (1968 to 1973). Questionnaire information about smoking habits, respiratory symptoms, and illness was also obtained. Fire fighters had a greater loss of pulmonary function (FVC and FEV1) than nonfire fighters (p = 0.007 and p = 0.054). This occupational effect could not be explained by differences in age, height, smoking status, or initial level of pulmonary function between the two occupational groups. Although respiratory symptoms were greater among current cigarette smokers, they were not significantly different between either occupational group. However, fire fighters generally reported more symptoms when smoking was controlled for. These results confirm earlier reports of a chronic effect of fire fighting on pulmonary function and suggest an association of this occupational with increased respiratory symptoms and disease independent of cigarette smoke.