Longitudinal change in magnetopneumographic measurements in Japanese arc welders, in relation with working conditions, pulmonary function, and chest x-ray findings

Welding work is associated with the inhalation of fumes and accumulation of particulates in welders' lungs. It is assumed that particulates deposited in the respiratory system, mainly consisting of iron oxides, are eliminated by several mechanisms, such as muco-ciliary transport and macrophage phagocytosis. In their cross-sectional study of 42 Finnish shipyard arc welders, Kalliomäki et al. indicated that from 10 to 20 % of total accumulated welding particulates from fumes was eliminated annually from welders' lungs [1]. However, longitudinal changes in the lung deposition of welding particulates have not yet been fully described. We previously reported a cross-sectional distribution of magnetopneumographic (MPG) measurements of Japanese electric arc welders [2]. Follow-up examination of those welders was conducted five years after the baseline survey. The purpose of this study is to investigate the longitudinal changes in MPG measurements over five years in individual welders, as an index of welding particulate accumulation in the lungs, in relation to several aspects of working conditions and pulmonary function.