Effect of manganese on neural endocrine hormones in serum of welders and smelters.

Background: Although manganese (Mn)-induced neurotoxicity effects are well known among occupational Mn exposure, few reports have investigated the effects on endocrine systems among welders and smelters.

Objective: To determine the effect of high level occupational manganese (Mn) exposure on neuropsychological parameters and hormonal status.

Methods: We used a cross-sectional design with 52 welders, 48 smelters and 43 age-matched office workers from the same factory in China. We analyzed serum endocrine hormones level and airborne Mn concentrations. Erythrocyte and urine Mn levels were quantified using inductively-coupled plasma atomic emission spectroscopy.

Results: The geometric mean of air Mn concentrations for the welders and smelters were 19.7 and 273.1 μg/m, respectively. Mn concentrations in erythrocytes of smelters were markedly greater than those in controls and welders, but there was no difference between the erythrocytes Mn levels of Control and welders. We also found an increase of Mn levels in the urine of both welders and smelters vs. controls; Mn levels in urine of smelters were higher than in welders. Self-reported neurobehavioral symptoms were higher in welders and smelters than in controls. Finally, thyroid-stimulating hormone (TSH) levels of welders were significantly lower than in controls, whereas smelters had lower prolactin (PRL), testosterone (TST) and follicle-stimulating hormone (FSH) concentrations than either controls or welders.

Conclusions: These results show that smelters have higher Mn exposure than do welders, and that Mn levels in erythrocytes or urine can be a marker for exposure. Moreover, high level occupational Mn exposure increases adverse neurobehavioral effects, and also may disrupt endocrine systems.