Mn exposure may be associated with decreased plasma BDNF levels and cognition impairment in this large cross-sectional study.

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ObjectiveTo determine the relationship between biomarkers of exposure, disease and susceptibility, and early health effects and long-term diseases related to occupational manganese (Mn) exposure.DesignBaseline survey of a longitudinal cohort study of workers in a ferromanganese refinery.ParticipantsA total of 1888 individuals (1197 men, 691 women; average seniority 15.34 years) were enrolled in the Guangxi manganese-exposed workers healthy cohort (GXMEWHC) study. Participants were between 18 and 60 years of age (mean 40.31 years), had worked in the ferromanganese refinery for at least 1 year and lived in the local area.ResultsThe GXMEWHC study included a baseline survey. Participants were divided into four groups according to manganese (Mn) cumulative exposure index (Mn-CEI) levels: an internal control group (Mn-CEI <1.0 mg/m3 year), a low exposure group (1.0 mg/m3 year≤Mn-CEI<2.0 mg/m3 year), a medium exposure group (2.0 mg/m3 year≤Mn-CEI<5.0 mg/m3 year) and a high exposure group (Mn-CEI≥5.0 mg/m3 year). Genome-wide association studies of quantitative trait loci and binary trait loci in 500 Mn-exposed workers were performed using Illumina Infinium HumanExome BeadChip arrays. Stored plasma, DNA, hair and urine are available for further study. Participants will be followed up every 3 years.ConclusionsThe GXMEWHC study provides abundant data for exploring the systemic health effects of occupational Mn exposure using biomarkers of exposure, disease and susceptibility.

PurposeThe aims of this study were to investigate the effects of manganese (Mn) dust exposure on lung functions and evaluate the potential synergistic effect between smoking and Mn dust exposure among refinery workers.MethodsA retrospective study including 1658 workers in a ferromanganese refinery was conducted, with subjects who were from the Guangxi manganese-exposed workers healthy cohort (GXMEWHC). Based on the Mn manganese cumulative exposure index (Mn-CEI), all subjects were divided into the low exposure group (n = 682) and the high exposure group (n = 976). A pulmonary function test was performed using an electronic spirometer, including the values and percentages of FVC, FEV1, FEV1/FVC, MMEF, PEFR, MVV, respectively.ResultsNo significant effect of Mn dust exposure on the pulmonary function was found in the female workers (all p>0.05). However, there was an obvious decrease in the male workers in the high exposure group compared with those in the low exposure group (FVC -60 ml, FEV1 -120 ml, MMEF -260 ml/s, MVV -5.06 L, all p<0.05). In the high exposure group, the reduction in FVC% predicted, MMEF and MMEF% predicted was 1.0%, 210 mL/s, and 4.9%, respectively. In particular, among the exposed subjects smokers had a statistically significant decrease in lung function compared with non-smokers and the reduction in FVC% predicted, MMEF and MMEF% predicted was 1.0%, 210 mL/s, and 4.9%, respectively (p<0.05). Partial correlation analysis showed that there was also negative correlation between Mn-CEI and decreased changes in MMEF (r = -0.159, p = 0.018) and also MMEF% predicted (r = -0.163, p = 0.015).ConclusionsMn dust can impair the pulmonary ventilation function of male workers but not females, and individual smoking habits and manganese exposure had a synergistic effect on the lung function decrease.

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