Renal Haemodynamics and Tubular Function in Workers with Long-Term Exposure to Cadmium in Battery Manufacturing Plants in Lagos, South West Nigeria

Background: Cadmium is a nephrotoxic heavy metal that selectively damages renal proximal tubular cells, impairing tubular reabsorption and progressively compromising glomerular filtration at higher cumulative exposures. Battery manufacturing workers represent a high-risk occupational group for cadmium-induced nephrotoxicity. Nigerian occupational nephrology data addressing cadmium renal physiology are critically limited. Objectives: This study aims to assess renal haemodynamic indices, including estimated glomerular filtration rate, renal plasma flow, and filtration fraction, alongside tubular function markers such as urinary beta-2 microglobulin, N-acetyl-beta-D-glucosaminidase, and albumin-to-creatinine ratio, in battery plant workers in Lagos with varying years of cadmium exposure. Methods: Seventy battery manufacturing workers and thirty non-exposed administrative employees will be recruited. Blood cadmium will be quantified by atomic absorption spectrometry. Serum creatinine and cystatin C will estimate glomerular filtration rate. Urine will be collected for tubular biomarker analysis. Dose-response relationships between blood cadmium and renal function markers will be modelled using restricted cubic splines. Expected Outcomes: Workers with elevated blood cadmium and longer employment duration are anticipated to exhibit significantly impaired tubular reabsorption and reduced glomerular filtration rates, consistent with cadmium-induced nephropathy. Conclusion: Findings will contribute to the evidence base for occupational cadmium exposure limits and renal surveillance in Nigerian manufacturing industries. Keywords: cadmium nephrotoxicity, tubular function, glomerular filtration, battery workers, Lagos.