Objective To analyze pulmonary function changes caused by long-term occupational exposure to manganese and dust and assess the dose-effect relationship between cumulative exposure and pulmonary ventilation function.
Methods Totally 280 male workers were chosen from a manganese smelter in Guangxi in 2011. Concentrations of manganese and dust in the air of workplaces and parameters of workers' pulmonary ventilation function in 2006 and 2010 were retrospectively collected. Cumulative exposure indices of 2006 and 2010 were calculated based on the concentration and duration of exposure to manganese and dust.
Results The averages of pulmonary function indicators of the manganese-exposed workers in 2010 were lower than those in 2006, with significant differences in the forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), peak inspiratory flow (PIF), and maximum expiratory flow rate at 75% of FVC (MEF75) (P<0.05). Partial correlation analysis showed that there were negative correlations between cumulative exposure to dust and changes in FVC, FEV1, and MEF75 after exposure to dust for average 14.27& #177;6.48 years in 2006 (P<0.05), but there was no correlation between cumulative exposure to manganese and the indicators of pulmonary ventilation function (P>0.05). After exposure to manganese and dust for average 18.05& #177;6.41 years in 2010, there were negative correlations between cumulative exposure to dust and changes in FVC and FEV1, as well as between cumulative exposure to manganese and changes in peak expiratory flow (PEF), MEF75, and maximum expiratory flow rate at 50% of FVC (MEF50) (P<0.05).
Conclusion There was a dose-effect relationship between long-term occupational cumulative exposure to manganese dust and reduction in pulmonary ventilation function.
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