Decreased total and ionized calcium levels and haematological indices in occupational lead exposure as evidence of the endocrine disruptive effect of lead

Abstract

The multisystem and prime environmental and occupational toxin, lead (Pb) is seldom included in the list of endocrine disruptors group like bisphenols A, B and F, nonylphenol, benzoquine, equiline etc. <br>One hundred and thirty-seven subjects consisting of 86 lead workers and 51 unexposed individuals (as controls) participated in the study. Dietary intake including dairy products and micronutrients as assessed by 24-hour dietary recall was similar between lead workers and controls. Calcium homeostasis and haematological indices were evaluated in all subjects. <br>Blood lead level was significantly higher in the lead workers than in controls (P<0.001). Total and ionized calcium levels were in contrast significantly decreased in lead workers compared with controls (P<0.01, P<0.001 respectively). Inorganic phosphate level though slightly raised compared to controls did not reach statistical significance (P>0.05). <br>The haematological indices, haemoglobin, haematocrit, and mean cell haemoglobin concentration like calcium levels were all significantly reduced (P<0.001) in all cases. <br>Semi-quantitative assessment of erythrocyte protoporphyrin was trace (±) in both lead workers and controls (i.e. similar). Serum copper level was significantly higher in Pb workers than in controls (P<0.005). <br>These decreases are consistent with a repression of the endocrine systems regulating both erythropoiesis and calcium homeostasis resident in the proximal convoluted tubule(PCT) of the kidney; the most vulnerable site to Pb damage.<br>Our findings therefore, appear to provide evidence or a reminder that Pb satifies the conditions defining EDCs and should be recognized as one, especially in developing countries where high environmental Pb and malnutrition co-exist and may magnify this effect<br>