Iron Homeostasis and Manganese Exposure Occupational Cross-Sectional Study of a Welder Population

Abstract

Manganese exposure is a serious occupational health hazard for many welders, smelters, and miners. Manganese exposure may result in Parkinson-like symptoms. It has been hypothesized that altered iron concentrations in the brain could also lead to neurological symptoms similar to what appears in those with chronic exposer to manganese. Th erefore, the goal of this project is to explore the relationship between manganese and hepcidin as an indicator of altered iron homeostasis. Population demographics were collected from semi-trailer factory workers in a cross-sectional study via a questionnaire. Demographic information includes age, race, and weight. Toenail clippings and questionnaires were collected on the same day; blood and air concentrations were sampled on a diff erent day within a short time period. Statistical analyses include descriptive statistics and regression analyses. Multiple linear regressions were run that utilized hepcidin and transferrin as dependent variables, with air, toenail, and blood manganese and welder status as independent variables. Mean air concentrations for the metals were below recommended exposure limits. Manganese toenail concentrations were 5.23 μg/g (standard deviation [SD] = 2.53 μg/g) while iron toenail concentrations were 183.93 μg/g (SD = 124.06 μg/g). Results showed a statistically signifi cant association between natural log (ln)(hepcidin) and welding status (p = 0.042); no statistically signifi cant relationship was found between ln(hepcidin) with air manganese (p = 0.313) or toenail manganese (p = 0.672). Th ere was no association found between transferrin and air manganese, toenail manganese, or welder status. Continued research is needed to investigate these relationships further.