Prevalence and features of advanced asbestosis (ILO profusion scores above2/2)

In this study, the author addressed the following question: Do workers with advanced asbestosis have a restrictive pulmonary physiology, and, alternat ely, do those who have restrictive physiological tests have advanced asbest osis? One group was identified by obvious radiographic measurements, and th e other group was defined via physiologic measurements. Total lung capacity , vital capacity, and flows were measured in 12,856 men exposed to asbestos , of whom 3,445 had radiographic signs of asbestosis, as defined by the Int ernational Labour Off ice criteria. Radiographically advanced asbestosis-In ternational Labour Office criteria profusion greater than 2/2 was present i n 85 (2.5%) of men. An additional 52 men had physiologically restrictive di sease. The author, who compared pulmonary flows and volumes of these two gr oups, used mean percentage predicted, adjusted for height age, and duration of cigarette smoking. Men with radiographically advanced asbestosis had no rmal total lung capacity (i.e., 105.5% predicted), reduced forced vital cap acities (i.e., 82.7% predicted), air trapping (i.e,, residual volume/total lung capacity increased to 54.4%), and reduced flows (i.e., forced expirato ry flow [FEF25-75] = 60.6% predicted, forced expiratory volume in 1 s = 78. 0% predicted and forced expiratory volume in 1 s/forced vital capacity = 65 .5%). In contrast men selected from the same exposed population for restric tive disease (i.e., reduced total lung capacity [72.6% predicted] and force d vital capacity [61.5% predicted]) also had airflow obstruction (i.e;, for ced expiratory volume in I s/forced vital capacity of 74.5% predicted) and air trapping (i.e., residual volume/total lung capacity of 46.7%). Only hal f of these men had asbestosis-and it was of minimal severity. In summary, a dvanced asbestosis was characterized by airway obstruction and air trapping , both of which reduced vital capacity but not total lung capacity; therefo re, it was not a restrictive disease. In contrast, restrictive disease was rare and was associated with minimal asbestosis.