Dlamini, Wendy Wandile2018-08-162018-08-162018https://hdl.handle.net/10539/25403A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science in Epidemiology & Biostatistics. February 2018.Background Manganese is an essential micronutrient for humans, but excessive levels are harmful. Manganese neurotoxicity is associated with parkinsonism and the associated motor deficits can affect an individual’s daily activities and quality of life (QoL) in manganese–exposed persons. Objectives In this study, we sought to investigate the associations between manganese, parkinsonism and QoL in South African manganese mine workers, in the period 2010–2014. Methods This was a secondary analysis of data from 418 South African manganese mine workers already recruited into a prospective study of the association between Mn mining exposure and parkinsonism. Parkinsonism, the primary outcome, was defined as a Unified Parkinson’s Disease Rating Scale motor subsection part 3 score (UPDRS-3) ≥15. The 39–item Parkinson’s Disease Questionnaire (PDQ-39) was used to assess miners’ health status or QoL, the secondary outcome. Cumulative manganese exposure in mg/m3-year (measured as inhalable dust) was estimated using an exposure matrix from participants’ job histories. We used Mann-Whitney and Pearson’s Chi-Square tests to compare participants’ parkinsonism status with regard to baseline continuous and categorical characteristics. Multiple linear and logistic regression modeling was used to quantify associations. Results The mean age of the manganese mine workers was 41.5 years (SD=11.9); 97.6% were male. Average manganese exposure was estimated as 3.7 mg/m3-years (SD=5.8) at baseline with mean duration of 13.5 years (SD=11.7). The prevalence of parkinsonism was 29.4%. Participants’ characteristics, stratified by parkinsonism status, differed significantly by age, education, and comorbid disease. Parkinsonism prevalence decreased significantly with increasing miners’ education status, p=0.029 and was higher (36.4% vs 25.9%, p=0.042) in those with comorbidities. Parkinsonism participants were generally older (mean age 45.3 vs 39.6, p<0.0001). QoL sub-scores and total scaled PDQ-39 score means were higher in mine workers with parkinsonism compared to those without. We found no evidence of a monotonic dose-response relationship between cumulative manganese exposure and parkinsonism. Similarly, there was no statistically significant association between QoL and cumulative manganese exposure. Being aged 40 years or older was an independent risk factor for having parkinsonism (OR=2.11, 95% CI: 1.18, 3.78). Parkinsonism (β=0.63, p=0.004) and age (β= -0.48, p=0.031) were strong predictors of QoL. Conclusion We found a strong association between parkinsonism and QoL in manganese mine workers, confirming previous reports in manganese–exposed welders. There was no evidence of an association between parkinsonism and manganese exposure. The lack of a monotonic dose–response relationship between parkinsonism and manganese exposure may be due to the healthy worker survivor effect, a non-linear relationship, or exposure misclassification.enQuality of LifeParkinsonian DisordersThesis