OBJECTIVETo investigate the association of the haplotypes and genotype combinations of vitamin D receptor (VDR) BsmI (rs1544410), Tru9I (rs757343), ApaI (rs7975232), and TaqI (rs731236) with the susceptibility to elevated blood lead in Chinese Han population.

METHODSAccording to Diagnostic Criteria of Occupational Chronic Lead Poisoning (GBZ 37-2002) and Occupational Exposure Limits for Hazardous Agents in the Workplace Part 1: Chemical Hazardous Agents (GBZ 2.1-2007), the workers were divided into high-exposure group (lead dust ≥ 0.05 mg/m(3), lead fume ≥ 0.03 mg/m(3)) and low-exposure group based on the concentrations of lead fume and lead dust in the workplace. The high-exposure group was further divided into normal-blood lead subgroup and high-blood lead subgroup. Fasting peripheral venous blood (5 ml) was collected using a heparin tube; genomic DNA was extracted from the peripheral blood cells with a Qiagen kit; single nucleotide polymorphisms were detected by allelic discrimination assay using TaqMan probes (carrying fluorescent dyes); haplotypes were analyzed and compared by Haploview.

RESULTSVDR BsmI, Tru9I, ApaI, and TaqI were in Hardy-Weinberg equilibrium between the normal-blood lead subgroup and high-blood lead subgroup (P > 0.05). Compared with haplotype CCCA which had the highest distribution frequency, haplotypes CCAA and CTCA were the high-risk factors for elevated blood lead (OR = 1.814, 95%CI = 1.055 ∼ 3.119; OR = 1.919, 95%CI = 1.040 ∼ 3.540). Compared with genotype combination CC + CC + CC + AA which had the highest distribution frequency, genotype combination CC + CC + AC + AA was the high-risk factor for elevated blood lead (OR = 2.800, 95%CI = 1.282 ∼ 6.116).

CONCLUSIONAs for VDR BsmI, Tru9I, ApaI, and TaqI, haplotypes CCAA and CTCA and genotype combination CC + CC + AC + AA are associated with the susceptibility to elevated blood lead.