Chronic effects of welding exposure on pulmonary function tests and respiratory symptoms.

OBJECTIVES The respiratory effects of exposure to welding fumes have been investigated in numerous studies; but results of these studies have not been consistent. The aim of the present study was to investigate the respiratory effects of welding exposure in a large group of manual are welders exposed primarily to mild steel welding processes in confined spaces without respiratory protection. METHODS Respiratory symptoms and spirometry were studied in 110 welders and 55 controls. The welders and controls were of similar average age and height; smoking habits of the groups were similar. Chest x ray films were taken to exclude people with radiological abnormalities that may influence pulmonary function tests. Welders were grouped according to smoking habits and duration of employment (< 20 years or > 20 years). RESULTS No gross radiological abnormalities were found. Respiratory symptoms and chronic bronchitis were more prevalent in welders (P < 0.05). Welders who were smokers showed a higher frequency of chronic bronchitis than controls who smoked (P < 0.05). No significant difference in the occurrence of chronic bronchitis was found between welders who smoked and welders who were non-smokers or exsmokers. Compared with the controls, forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow (PEF), and maximum midexpiratory flow (MMEF) were significantly lower in welders (mean values of FVC for welders and controls were 86.06 (25.74) and 96.40 (13.03); and values for FEV1 were 87.54 (13.70) and 95.36 (12.40) respectively; P < 0.01). There was no significant difference in pulmonary function tests between welders who were non-smokers and controls who were non-smokers; whereas FVC, FEV1, PEF, and MMEF were significantly lower in welders who smoked than controls who smoked (P < 0.01). There were no significant differences in pulmonary function tests and occurrence of chronic bronchitis between welders with more or less than 20 years at work. CONCLUSION Welders working in conditions of inadequate ventilation, have increased risk of chronic bronchitis and impairment of pulmonary function.