Blood lead levels among the occupationally exposed workers and its effect on calcium and vitamin D metabolism: A case-control study

Introduction: Lead (Pb) is one of the major occupational pollutants present in the developed and developing countries including India. In humans, Pb can cause a wide range of biological effects depending upon the level and duration of exposure. The goal of this study was to evaluate the blood lead levels (BLLs) and its associated effects on vitamin D and calcium metabolism, among the workers occupationally exposed to Pb. Materials and Methods: This cross-sectional, case-control study was conducted for a period of 18 months (January 2017 to July 2018). A total of 160 subjects were included in the study (80 in each, Pb-exposed group and control group). The blood Pb levels were quantified by using an inductively coupled plasma mass spectrometry with triple quadrupole technology (iCAP™ TQ ICP-MS). Other biochemical parameters were estimated using fully automatic analyzer by RANDOX, RX-imola, Crumlin, UK and Johnson and Johnson, VITROS® ECi Q, Immunodiagnostic system, Ortho Clinical Diagnostics, New Jersey, USA. Results: Upon analysis it was observed that serum calcium, phosphorous, and vitamin D levels were significantly decreased (8.35 ± 0.42 mg/dl, 3.07 ± 0.34 mg/dl, and 28.82 ± 10.81 ng/ml respectively;P < 0.001), whereas the BLL and serum iPTH levels were significantly increased (38.02 ± 19.92 μg/dl and 116.78 ± 19.93 pg/ml respectively;P < 0.001) in Pb exposed subjects as compared to control subjects. Conclusion: Our study results demonstrated that high BLL significantly alter vitamin D and calcium metabolism. The data extrapolated from our study emphasizes the necessity of surveillance in exposed workers. As the associated deleterious effects of Pb-exposure can be serious, we propose that a routine-periodical screening of the workers exposed to lead should be conducted.