The association between occupational lead exposure and serum levels of vitamin D3 and a bone turnover biomarker in smelter workers

ObjectiveBone tissue is the chief target for lead (Pb) in chronic exposure. This study aimed to demonstrate the relation between the blood lead levels (BLL) and serum levels of 1,25 dihydroxy cholecalciferol (vitamin D3) and type I collagen cross-linked C-telopeptide (CTX-1) as a biomarker of bone turnover among some Egyptian workers occupationally exposed to Pb in the smelting process. The study also targeted to identify any clinical manifestations indicative of skeletal system affection and their association with the performed investigations.MethodsA total of 48 smelter workers and 48 administrative controls participated in the study. All subjects underwent comprehensive medical and occupational history taking and detailed clinical examinations, with a particular focus on symptoms indicative of skeletal system involvement. These symptoms included generalized bony aches, low back pain, joint pain, restricted joint movement, a history of fractures from minor trauma, and delayed fracture healing. BLL, as well as serum levels of vitamin D3 and CTX-1, were measured in all participants.ResultsSmelter workers exhibited significantly higher prevalence of bony aches, low back pain, joint pain, and past fractures from minor trauma compared to controls. The BLL and serum CTX-1 levels were significantly elevated in the exposed group, while serum vitamin D3 levels were notably lower. Logistic regression analysis revealed that BLL significantly predicted bony aches and low back pain. Additionally, serum vitamin D3 and CTX-1 levels were significant predictors of low back pain and joint pain, respectively, among exposed workers. The measured parameters were significantly correlated with one another and with the duration of employment in the exposed group.ConclusionSignificant associations between manifestations of skeletal system affection, BLL, and serum levels of vitamin D3 and CTX-1 were detected among smelter workers with chronic occupational exposure to Pb.