THE LEFT-SIDED PREDOMINANCE OF ASBESTOS-RELATED PLEURAL DISEASE

In a series of 406 subjects with a diagnosis of asbestos-related pleur al disease (ARPD), the left-right symmetry of radiographically diagnos ed ARPD was assessed using the International Labour Organization (ILO) system for classifying radiographic abnormalities and three different statistical models for testing the degree of symmetry. The extent of chest disease was found to be greater on the left than on the right fo r a number of parameters of pleural disease, including the width and e xtent of localized pleural thickening, the extent of enface pleural th ickening, and the extent of diaphragmatic and chest wall calcification . Current cigarette smoking significantly enhanced the observed asymme try, with the most pronounced effect being in diaphragmatic calcificat ion. Using a composite scale for each subject's pleural disease, the l eft side had 1.6 times more localized disease than did the right (p < 0.001). Asymmetry in one parameter was associated with asymmetry in an other for a number of pairs. The most significant of these association s was between enface pleural thickening and chest wall calcification ( Kendall's tau B = 0.42). The pathophysiologic mechanisms that explain these findings remain elusive and need further investigation.