Analysis of the association of plasma lead levels and markers of calcium homeostasis among occupational lead-exposure workers

INTRODUCTION: Lead (Pb) is one of the occupational toxicants and is used as a petrol additive to reduce engine spark knock. Pb in the environment may result from natural or industrial sources. In humans, leaded petrol can cause various biological effects depending on the level and duration of the exposure. The aim of this study was to explore the effect of occupational Pb-exposure on calcium homeostasis markers and to verify the possible correlation.METHODS: One hundred petrol station workers were selected for the Pb-exposed group, with an equal number of non-exposed subjects chosen as control group. Venous blood samples were collected from both groups and standard procedures were used to measure the biochemical parameters.RESULTS: The study most relevant results were: the Pb-exposed group showed higher plasma Pb and parathyroid hormone (PTH) levels, and lower levels of total calcium, vitamin D, calcitonin, phosphorus, albumin, and total protein compared to the control group. The results of multivariate general linear model (GLM) analysis showed a significant total variability (all dependent variables) attributable to Pb-exposure (partial η2=0.707, P<0.001). Between-subjects effects test showed the largest effect of plasma Pb on PTH and vitamin D (partial η2=1.00, P<0.001).DISCUSSION: The results suggest that elevation in the plasma levels of Pb is associated in the Pb-exposed subjects to decreased levels of all studied markers of calcium homeostasis, except PTH compared to the control group.