职业铅接触对工人骨密度和骨代谢的影响

目的探讨职业铅接触对工人骨密度和骨代谢的影响。方法以上海某蓄电池厂298名铅作业工人为职业接触对象，同时选取该厂无职业铅接触史的办公室工作人员81名作为对照。血铅（BPb）、尿铅（UPb）为接触标志物；代表骨质疏松的Z评分、尿羟脯氨酸（HYP）、血清碱性磷酸酶（ALP）、血清骨碱性磷酸酶（BALP）、血清骨钙素（BGP）为效应标志物。应用单光子骨密度仪（SPA-4）测定工人骨密度。结果职业铅接触组人群BPb、UPb、HYP、ALP、BALP均高于对照组，其中男性差异有统计学意义（P〈0．01）；接触组BGP高于对照组，差异无统计学意义（P〉0．05）；接触组骨密度低于对照组，差异无统计学意义（P〉0．05）。与UPb 0-μg／gCr组比，各人群UPb10-μg／gCr组的骨密度均明显降低，差异有统计学意义（P〈0．01）；与BPb0～μg／L组比，男性BPb300-μg／L组的骨密度明显下降，差异有统计学意义（P〈0．01）。分别与UPb0-μg／gCr组、BPb0-μg／L组比，各人群UPb20-μg／gCr组、BPb300-μg／L组的HYP、ALP、BALP、BGP均明显升高，差异有统计学意义（P〈0．05）。随着体内铅接触水平的升高，人群骨质疏松的患病率和各骨代谢指标的异常率均随之明显升高，差异有统计学意义（P〈0．01），并呈线性相关（P〈0．01），但BGP的异常率与UPb无明显联系（P〉0．05）。计算得到基准剂量（BMD），推出基准剂量的95％低限水平（BMDL）。铅所引起的骨质疏松指标的BPb、UPbBMDL值均高于铅致骨代谢指标改变的BMDL值。结论职业铅接触能引起人群骨密度降低而导致骨质疏松，并且可以影响工人骨代谢。

Effects of occupational lead exposure on bone mineral density and bone metabolism in workers

OBJECTIVE: To investigate the effects of occupational lead exposure on the bone mineral density and the bone metabolism in exposed workers. METHODS: Two hundred and ninety-eight lead-exposed workers in a storage battery plant in Shanghai were selected as the exposed subjects while eighty-one healthy officers in the plant who were not occupationally exposed to lead were treated as the control. The blood lead (BPb) and the urinary lead (UPb) were used as the exposure biomarkers while the Z score, the urinary hydroxyproline (HYP) the serum alkaline phosphatase (ALP) the serum alkaline phosphatase bone isoenzyme BALP and the serum osteocalcin BGP were used as the effect biomarkers for the bone effect caused by the lead. Bone mineral density (BMD) was measured by the monophoton absorptiometry (SPA-4). RESULTS: The BPb, UPb, HYP, ALP, BALP in the occupational lead exposure group were higher than those in the control group with significantly statistical difference in male (P < 0.01). The levels of BGP in the exposure group was higher than that in the control group without significantly statistical difference (P > 0.05). The BMD in the exposure group was lower than that in the control group without significantly statistical difference (P > 0.05). The BMD was significantly decreased in the groups of the UPb 10 approximately microg/g Cr level compared with the 0 approximately microg/g Cr group with the significant difference (P < 0.01). In males, the BMD was significantly decreased in the group of the BPb 300 approximately microg/L level compared with the 0 approximately microg/L group with the significant difference (P < 0.01). The levels of HYP, ALP, BALP, BGP in the UPb 20 approximately microg/g Cr group were significantly higher than those in the UPb 0 approximately microg/g Cr group (P < 0.05). The levels of HYP, ALP, BALP, BGP in the BPb 300 approximately microg/L group were significantly higher than those in the BPb 0 approximately microg/L group (P < 0.05). The prevalence of both osteoporosis and the abnormal bone metabolisms indexes would increase significantly with the increase of the lead exposure (P < 0.01) with the linear correlation (P < 0.01). But the prevalence of higher BGP had no significant correlation with UPb (P > 0.05). BMDs were calculated using BMDS Version 1.3.2 software and BMDLs were also determined. The BMDLs of BPb and UPb for lead-induced osteoporosis were higher than those representing the change of bone metabolism induced by lead. CONCLUSIONS: The occupational exposure to lead could cause the decrease of the bone mineral density, lead to the osteoporosis, and may affect the bone metabolism.