Abstract
Introduction: In September 2022, the Serenje district health office reported cases of lower limb weakness, difficulty walking, and impaired sexual function among workers at a manganese smelting plant. To investigate, we conducted a case-control study.
Methods: Cases were identified as individuals with confirmed neurological symptoms, elevated blood manganese levels, and neurologist-validated brain imaging reports. The study included 20 cases and 42 controls, selected at random but balanced for their duration of employment.
Results: Symptoms among cases included difficulty walking (90%), joint pain (90%), impaired sexual function (90%) and difficulty talking (75%). Blood manganese levels among cases were exceptionally elevated, exceeding 20 times the normal range (0.116 to 0.623 ppm), compared to the reference range (0.005-0.02 ppm). Each additional day of overtime worked per week was associated with a 2.40-fold increased risk (95% CI = 1.05-6.35) of developing manganese toxicity. Notably, individuals using respirators had a 93% lower risk of adverse outcomes compared to non-users (OR = 0.07, 95% CI 0.01-0.51).
Conclusion: Our study highlights the association between overtime work and manganese toxicity risk. To prevent future occurrences of heavy metal toxicity among industrial workers, we emphasize the need for enhanced monitoring, adherence to safety protocols, and vigilant toxic exposure surveillance.
To Read or Download the Article PDF