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。     

铅对作业工人血清中热应激蛋白70水平的影响

为了观察职业铅接触人群血清热应激蛋白70的变化．探讨热应激蛋白作为职业铅接触敏感生物标志物的可能性．对铅作业工人进行血清中热应激蛋白70水平的调查。以其蓄电池厂铅接触工人72人为铅暴露组,不接触铅及其他职业有害因素工人41人作为对照组。用ELISA方法检测工人血清中热应激蛋白70的水平,血铅水平用原子吸收光谱法进行检测,尿铅水平用微分电位溶出法检测。结果显示．暴露组工人中血清热应激蛋白70及血铅的水平均明显高于对照组．差异均具有非常显著性（P〈0．01）,两组人群尿铅水平差异无显著性（P〉O．05）;血清中热应激蛋白的水平与血铅水平有相关性（r=0．501,P〈O．01）,而与尿铅无明显的相关性（r=0．181,P〉0．05）。提示,血清中热应激蛋白70的水平可反映职业铅接触的情况。作为生物标志物在铅作业工人健康监护中有一定的价值。     

铅作业工人血铅和氧化应激酶变化的研究

目的研究职业性铅接触者的氧化损伤,探讨血铅和氧化应激酶之间的变化关系,以探讨铅中毒的作用机制。方法采用火焰原子吸收分光光度法测定空气中的铅含量,用石墨炉原子吸收分光光度法测定血铅浓度,选择超氧化物歧化酶（SOD）和丙二醛脱氢酶（MDA）作为氧化应激损伤的效应指标,分析血铅与氧化效应指标的变化。结果共采集了车间内5个工作点的空气样品。接触组血铅浓度（244．274±124．59）μg／L,显著高于对照组（P〈0．01）;接触组SOD活性（61．27±6．97）KU／L,与对照组比较无统计学差异（P〉0．05）;接触组MDA含量（9．42±3．89）mmol／L,显著高于对照组（P〈0．01）;血清MDA含量与血铅之间存在正相关关系（r=0．3,P〈0．01）;吸烟、饮酒对SOD活性和MDA含量影响无统计学差异。结论职业性铅接触引起人体血铅升高,作业场所空气中铅浓度与血铅含量变化不一致,血铅是近期铅接触者的敏感内接触指标,且血铅浓度越高,SOD活性代偿性升高;MDA含量越高,氧化损伤越明显。     

铅染毒对大鼠体内铜元素的影响研究

目的：探讨铅染毒后对铜元素的影响和意义。方法：将SD大白鼠随机分为对照组和不同剂量醋酸铅染毒实验组。用醋酸铅饮用水染毒大白鼠8周，在第8周末处死全部动物，取血、骨、脑、肾、卵巢及睾丸组织，测定组织中铜、血铅、骨铅含量。结果：血铅和骨铅含量随铅染毒剂量增加而升高，组间差异均有统计学意义（P〈0．05）。骨、肾组织中的铜含量降低，组间差异均有统计学意义（P〈0．05）。脑组织中的铜含量升高，组间差异均有统计学意义（P〈0．05）。结论：铅染毒对大鼠体内组织中铜的含量有影响。     

两种冶炼工艺对作业工人健康影响的比较

目的探讨2种不同冶炼生产工艺下职业病有害因素对作业工人健康的影响。方法采用原子吸收分光光度计石墨炉法对尿铅含量进行测定,运用t和X^2检验对结果进行统计分析。结果传统工艺所测铅烟、二氧化硫浓度分别为（1．023±0．931）、（3．753±1．631）mg／m^3,新工艺则分别为（0．308±0．166）、（1．227±0．903）mg/m^3,传统工艺与新工艺所测铅烟、二氧化硫浓度差异均有统计学意义（P〈0．05）;在所调查的63个项目中有鼻干、腹痛、乏力、牙齿松动4项接触组明显高于对照组（P〈0．01）;职业健康检查中有贫血、慢性支气管炎、尿潜血、慢性鼻炎、慢性结膜炎、肝功能接触组明显高于对照组（P〈0．05）;2组炉前工的尿铅超标人数差异有统计学意义（P〈0．01）。结论通过技术改造后车间铅烟、二氧化硫等职业病危害因素浓度明显下降,职业病危害因素对作业工人的健康影响有明显改善。     

驱铅治疗患者尿中总锌含量的分析

目的研究驱铅治疗患者尿中总锌的含量及变化,为对症治疗提供科学依据。方法选择2012年1月—2013年4月进行驱铅治疗的35名患者作为研究对象,采集其24h空白尿及不同治疗阶段的试排尿进行尿铅和尿锌含量的分析。结果比较24h空白尿,男女尿铅含量差异无统计学意义（P〉0．05）,男性尿锌含量高于女性,差异有统计学意义（P〈0．01）。轻度铅中毒的患者与铅吸收观察对象的空白尿锌含量间差异无统计学意义（P〉0．05）。尿锌含量与年龄不存在相关关系（P〉0．05）,与尿铅含量存在不密切的正相关（r=0．429,P〈0．05）;第1疗程第1、第2、第3针后的尿锌含量显著高于空白尿,差异有统计学意义（P〈0．01）;第1、第2针排出的尿铅与尿锌不存在相关性（P〉0．05）,而第3针后两者存在显著的正相关关系（r=0．667,P〈0．01）。空白尿锌与试排各个阶段的尿锌间均不存在相关关系（P〉0．05）。结论使用依地酸二钠钙进行驱铅治疗的患者尿中排出大量的锌,疗程后期尿锌会随铅排出的增加而增加,所以在治疗的过程中,尤其是在疗程后期要特别注意微量元素丢失出现的不良反应,及时对症治疗。     

职业性铅接触对作业人群的增龄效应

[目的]以职业性铅接触人群为研究对象，选用与年龄有关并可反映机体功能状态的生理、心理指标，同时应用工作能力指数（WAI）测定研究对象的工作能力，分析职业性铅接触对作业人群的增龄效应。[方法]以蓄电池制造企业铅接触工人为接触组，以同一企业非铅接触工人为对照组，应用工作能力指数调查表确定研究对象的WAI，使用生理功能测试仪器、CD-1型老化度仪、心理及临床老化征象调查表测试生理和心理功能并确定其生理年龄（PhA）和心理年龄（PsA），以观察职业性铅接触的增龄作用。根据工作能力、生理年龄、心理年龄提出衰老指数模型并结合血铅浓度测定结果进行验证。[结果]随着工人血铅水平的升高，WAI评分减少，接触组中WAI等级为“优”者血铅值相对较低，等级为“差”者血铅值相对较高（P=0．010），表明铅接触在一定程度上影响了工人的工作能力。接触组与对照组比较，握力、动作稳定度、敲击试验、心理老化测试结果差别均有统计学意义；配对t检验表明，〉40岁铅接触组作业工人的生理年龄和心理年龄均高于其日历年龄（CA），分别增高0．51岁和3．92岁（P〈0．05和P〈0．01）。建立衰老指数模型：衰老指数（AEI）=[（49／WAI）X1＋（PhA／CA）X2＋（PsA／CA）X3]·100，（X1、X2、X3分别是根据体力劳动、脑力劳动及体力与脑力混合比例来确定的权重系数）。〉40岁年龄段工人的年龄与衰老指数之间存在正相关关系（，=0．309，F=6．349，P=0．014）。接触组血铅值和衰老指数之间存在正相关关系（r=0．438，F=17．75，P=0．000）。按照衰老指数模型得出铅接触工人的衰老指数平均为1．13±0．074。[结论]长期铅接触作业可降低职业人群的工作能力，降低握力、动作稳定度、神经肌肉协调性，增加心理老化，〉40岁铅接触组作业工?     

铅暴露水平与主要生物监测指标的剂量-反应关系

目的分析2012年度无锡市14家铅蓄电池生产企业1134名铅作业人员的职业健康检查结果,了解铅暴露水平与主要生物监测指标的剂量-反应关系。方法健康监护结果按照血铅浓度不同分组,采用SPSS15．0统计软件分析不同浓度下血、尿常规主要生物指标与铅水平的剂量-反应关系。结果调查铅作业工人1134人,其中男性573人,女性561人;年龄19—66（38．2±8．87）岁,工龄1个月-35a。血铅浓度范围0．01—7．60μmol／L,以血铅浓度作为内暴露剂量分析不同暴露水平对主要生物监测指标的影响,结果显示,不同暴露水平组间血红蛋白减少异常率、红细胞减少异常率、血小板减少异常率、尿胆红素阳性率差异有统计学意义（P〈0．01）,不同暴露水平组间白细胞减少异常率、尿酮体阳性率、尿蛋白阳性率、尿胆原阳性率差异无统计学意义（P〉0．05）。结论铅作业工人体内铅水平的增高可导致血液系统、消化系统损伤的加重,导致血红蛋白、红细胞、血小板减少,尿胆红素阳性率增高。     

职业性镍接触工人外周血淋巴细胞微核率观察

[目的]探讨职业性镍接触对工人外周血淋巴细胞微核率的影响以及染色体损伤作用。[方法]根据生产工艺的不同,选取某钢铁企业男性炼钢工、轧钢工及钢渣处理工共231人作为镍接触组,同时选择该企业的男性水泵工75人为对照组。采用人外周血淋巴细胞胞质分裂阻滞微核试验检测各组淋巴细胞的微核率;采用丁二酮肟分光光度法检测尿中镍的含量。[结果]不同镍接触组细胞微核率分别与对照组相比,差异有统计学意义（P〈0．01）,相关分析显示淋巴细胞微核率与尿镍含量呈正相关性（r=0．971,P〈0．05）;不同工龄组细胞微核率分别和对照组相比较,差异也有统计学意义（P〈0．01）,相关分析．显示,工龄与细胞微核率和尿镍含量均呈正相关性（r微核率=0．923,P〈0．05;r尿镍=0．915,P〈0．05）;不同镍接触组尿镍含量分别与对照组相比,差异有统计学意义（P〈0．05）;不同工龄尿镍含量分别与对照组比较,除工龄“0年～”和“6年～”组以外,各组与对照组相比,差异均有统计学意义（P〈0．05）。[结论]职业性镍接触使工人外周血淋巴细胞微核率增加．对染色体有捐伤作用。     

铅作业工人血铅、尿铅和血常规检测结果分析

目的比较铅作业工人和非铅作业工人血铅、尿铅和血红蛋白浓度的差异。了解长期低铅作业工人的健康状况。方法对2009年天津市某蓄电池厂400例铅作业工人和120例非铅作业工人分别进行血铅、尿铅和血红蛋白浓度的测定,并对结果进行统计学处理。结果铅作业组血红蛋白浓度低于非铅作业组。而血铅、尿铅浓度均显著高于非铅作业组（P〈0.01）。并且血铅和血红蛋白浓度间呈负相关性（r=-0.442）,尿铅与血铅和血红蛋白间的相关性均不理想（r值分别为-0.026和-0.018）。结论长期低铅作业可导致人体血铅尿铅升高,血红蛋白降低,但尿铅浓度波动大,且影响因素多,不能精确反映体内铅积蓄量,结果与其他指标的相关性较差。     

职业铅接触致肾损伤的危险度评定

目的 通过职业流行病学调查和基准剂量计算,对职业性铅接触所造成的肾损伤进行危险度评定.方法 以浙江某蓄电池生产工厂239名工人为接触组,同地区某厨具厂工人76名为对照组,对工人开展问卷调查与体格检查,采集生物样本.收集车间空气中铅监测资料,计算工人在车间中接触的铅的总量,考查铅外剂量与内剂量之间的关系;以外剂量(铅参考接触剂量)、血铅、尿铅为接触标记,以尿中N-乙酰-β-D-氨基葡萄糖苷酶(UNAG)和尿白蛋白(UALB)(均以尿肌酐进行校正)为效应标记.采用基准剂量计算软件(BMDS 11311)计算基准剂量反应为5%时,各效应标记的血铅、尿铅基准剂量.结果 铅的外剂量与内剂量呈正相关(血铅:r=0.466,P<0.01;尿铅:r=0.383,P<0.01),铅接触组的血铅、尿铅水平分别为654.03μg/L、143.45μg/g Cr,明显高于对照组(分别为57.12μg/L、7.20μg/gCr),且呈剂量-效应关系;按照对照组效应指标的95%上限为参考值上限,求得各效应指标的异常发生率与接触指标呈剂量-反应关系;UALB、UNAG的血铅BMDL-05分别为607.76、362.56μg/L,UALB、UNAG的尿铅BMDL-05分别为117.79、78.79 μg/Cr.结论 职业铅接触可致肾损伤,且呈剂量-反应关系;使用计算血铅、尿铅BMD的方法能进行职业铅接触的肾损害危险度评定.     

Influence of the delta-aminolevulinic acid dehydratase (ALAD) polymorphism on biomarkers of lead exposure in Turkish storage battery manufacturing workers

BACKGROUND: The relationship between delta-aminolevulinic acid dehydratase polymorphism (ALAD) and biomarkers of exposure was investigated in Turkish lead workers in this study. METHODS: Seventy two male lead battery manufacturing workers were selected for the study. Blood lead (BPb) and urinary lead (UPb) concentrations were determined by atomic absorption spectrometry. Erythrocyte ALAD activity and urinary 5-aminolevulinic acid (UALA) were measured spectrophotometrically. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was used to determine the genotype of the ALAD gene. RESULTS: In total, 51 workers (70.8%) had the ALAD 1-1 genotype, whereas 21 workers (29.2%) had the ALAD 1-2 genotype. No significant relationships were found between the two genotypes and BPb, UPb, and ALAD activity. ALAD1 homozygotes showed significantly higher levels of UALA in comparison with those ALAD2 carriers. CONCLUSIONS: ALAD 1-1 individuals might be an increased risk compared to ALAD2 carriers to disturbance in heme biosynthetic pathway in high lead exposure.     

Serum Calmodulin Activity in Male Lead-exposed Workers

Abstract

Serum calmodulin (CaM) activity was studied in 75 lead exposed and 21 non-exposed male workers. The lead-exposed workers were divided into groups with low blood lead (BPb < 50 μg/dL) and high blood lead (BPb ≥ 50 μg/dL). The concentrations of lead, calcium, magnesium, copper, zinc, and free erythrocytic protoporphyrin (FEP) in blood were determined. Serum samples were heated in a water bath (100° C) for 3 minutes arid centrifuged for 15 minutes at 4° C (18,000 × g). The supernatants obtained were used to measure CaM activity. The results showed that: 1) Average blood lead concentrations in workers with both low and high levels of exposure were significantly higher than those in controls (p < 0.05). 2) Serum CaM activity in the high-exposure group (31.09 ± 7.84 μg/dL) was significantly lower than that in controls (78.11 ± 15.13 μg/dL,p < 0.05). The biological threshold of BPb inhibition of CaM activity was less than 50 μg/dL. 3) Multiple correlation analysis showed a negative dose-response relationship between BPb and CaM activity. The step wise regression procedure indicated that lead had negative, and calcium and magnesium positive, effects on serum CaM activity. The regression equation was Y = 66.1383 – 1.0857 X_l + 2.9676 X₂ + 5.2222 X₃ (Y:CaM; X_l:Pb; X₂: Ca; X₃:Mg). These results of the first such study carried out in male lead-exposed workers suggest that lead can inhibit CaM activity in humans.     

Lead effect on blood pressure in moderately lead-exposed male workers

BACKGROUND: The effect of lead (Pb) and potential confounding variables on blood pressure was examined in healthy male industrial workers 20-43 years of age. METHODS: In 100 Pb workers and 51 reference subjects, the following variables were measured: blood Pb (BPb), activity of delta-aminolevulinic acid dehydratase (ALAD), erythrocyte protoporphyrin (EP), blood cadmium (BCd), serum zinc (SZn), serum copper (SCu), hematocrit (Hct), body mass index (BMI), and blood pressure. The inter-relationship of biomarkers of Pb (BPb, ALAD, EP) and BCd, SZn, SCu, Hct, BMI, age, smoking, and alcohol to systolic and diastolic blood pressure was calculated by forward stepwise multiple regression. RESULTS: There was no significant difference in blood pressure between the two groups, possibly because the reference subjects had relatively high BPb levels and significantly higher BMI (P < 0.05) as compared to the Pb workers. According to the multiple regression results in Pb workers, an increase in systolic blood pressure was significantly associated with increasing EP (P = 0.001) and BMI (P < 0.002), or alternatively with increasing BMI (P < 0.004) and decreasing ALAD (P < 0.04) and BCd (P < 0.05). An increase in diastolic blood pressure was significantly associated with increasing BMI (P < 0.009) and EP (P = 0.05) and decreasing BCd (P < 0.04). With respect to the EP range of 0.73-13.94 micromol/l erythrocytes in 100 Pb workers, an increase of 17 mm Hg in systolic and 6 mm Hg in diastolic blood pressure was found. CONCLUSIONS: Long-term cumulative Pb exposure, which is better reflected by EP than by ALAD or current BPb level, can significantly increase blood pressure in moderately Pb-exposed male workers (long-term average BPb <400 microg/l; exposure duration 2-21 years).     

职业接触铅工人血细胞参数变化的调查

目的　对 5 98名工人的血铅及血细胞参数进行测定 ,以了解职业铅接触对工人造血系统的影响以及血细胞参数的变化。方法　据血铅测定水平将 5 98名职业接触铅工人分为 2组 :铅接触组 (血铅小于 2 .4 1μmol/ /L) 32 5名和铅吸收组 (血铅大于或等于 2 .4 1μmol/L) 2 73名。血铅测定采用石墨炉原子吸收法 ;血细胞参数的测定采用全自动血细胞分析仪进行测定。结果　铅吸收组的血红蛋白 (Hb) [男 :(12 9.3± 12 .3)g/L ,女 :(112 .2± 9.4 )g/L]、红细胞压积 (HCT) [男 :(0 .338± 0 .0 30 )L/L ,女 :(0 .30 2± 0 .0 2 8)L/L]明显低于正常组和铅接触组 ,差异均有显著性 (P <0 .0 5 ,P <0 .0 1) ;并且随血铅水平增高 ,Hb和HCT水平降低 ,血铅与Hb和HCT有弱的负相关关系。铅吸收组的红细胞平均分布宽度 (RDW) (男 :16 .6 8%± 0 .80 % ,女 :16 .98%± 0 .98% )明显高于正常组和铅接触组 ,铅接触组的RDW(男 :14 .77%± 0 .83% ,女 :14 .92 %± 1.13% )也明显高于正常组 ,差异均有显著性 (P <0 .0 5 ,P <0 .0 1) ;血铅与RDW有弱的正相关关系。结论　用Hb、HCT和RDW 3个指标可以反映铅作业工人是否贫血和贫血程度。     

接触铅工人骨密度与接铅工龄、血铅、血钙关系的研究

目的探讨接触铅工人骨密度与接铅工龄、血铅、血钙之间的相互关系,为慢性铅中毒防治提供科学依据。方法采用Lexxos型双能X射线骨密度仪(DEXA,法国DMS公司生产),测量男性接触铅工人220例(20～60岁)的骨密度,并测定血铅、血钙含量;另选择男性非接触铅工人109例(20～60岁)作为对照组。结果接触铅工人各年龄组中的骨密度值明显低于对照组(P<0.05);接触铅工龄与骨密度值呈明显的负相关关系(P<0.05或P<0.01)。血铅值的高低与骨密度值部分呈正相关关系(P<0.05)。结论低骨密度的发生与职业接触铅可能有关。     

Loss of hip bone mineral density over time is associated with spine and hip fracture incidence in osteoporotic postmenopausal women

The objective of the study assess the relationship between bone mineral density (BMD) loss over time and fracture incidence in postmenopausal women. This is a posthoc analysis that includes women from the placebo group of two large randomized controlled trials having assessed the efficacy of a new anti-osteoporotic drug. BMD was assessed every 6 months during 3 years at the lumbar spine, the femoral neck and the total proximal femur. Vertebral fractures were assessed using a semiquantitative method. Hip fractures were based on written documentation. All patients received calcium and vitamin D. In the present study that included 1,775 patients (with complete data at baseline and after 3 years), the logistic regression analysis, adjusted for covariates, showed that 3-year change in lumbar BMD was not statistically associated with the new vertebral fractures after 3 years. However, femoral neck and total proximal femur BMD changes was statistically correlated with the incidence of new vertebral fractures (P < 0.001). When considering change in BMD after the first year of follow-up, a decrease in total proximal femur BMD was statistically associated with an increase in the incidence of new vertebral fractures during the last 2 years of follow-up (P = 0.048). The 3-year change in femoral neck and total proximal BMD was statistically correlated with the incidence of hip and fragility fracture after 3 years (all P < 0.001). In this elderly osteoporotic population receiving calcium and vitamin D, a decrease in hip BMD after 1 or 3 year of follow-up, is associated with an increased risk of fracture incidence. However, spine BMD changes do not influence vertebral fracture incidence.     

The association between environmental lead exposure and bone density in children

Osteoporosis is a decrease in bone mineral density (BMD) that predisposes individuals to fractures. Although an elderly affliction, a predisposition may develop during adolescence if a sufficient peak BMD is not achieved. Rat studies have found that lead exposure is associated with decreased BMD. However, human studies are limited. We hypothesized that the BMD of children with high lead exposure would be lower than the BMD of children with low lead exposure. We collected data on 35 subjects; 16 had low cumulative lead exposure (mean, 6.5 microg/dL), and 19 had high exposure (mean, 23.6 micro g/dL). All were African American; there was no difference between the groups by sex, age, body mass index, socioeconomic status, physical activity, or calcium intake. Significant differences in BMD between low and high cumulative lead exposure were noted in the head (1.589 vs. 1.721 g/cm2), third lumbar vertebra (0.761 vs. 0.819 g/cm2), and fourth lumbar vertebra (0.712 vs. 0.789 g/cm2). Contrary to our hypothesis, subjects with high lead exposure had a significantly higher BMD than did subjects with low lead exposure. This may reflect a true phenomenon because lead exposure has been reported to accelerate bony maturation by inhibiting the effects of parathyroid hormone-related peptide. Accelerated maturation of bone may ultimately result in a lower peak BMD being achieved in young adulthood, thus predisposing to osteoporosis in later life. Future studies need to investigate this proposed model.     

Critical dose of lead affecting postural balance in workers

BACKGROUND: The threshold blood lead (BPb) level for nervous system dysfunction in adults has been estimated to be 30-40 microg/dl. This study was carried out to estimate the critical dose of lead affecting the neuromotor function in workers by introducing the benchmark dose (BMD) approach, as well as to identify the specific postural sway to lead exposure. METHODS: Postural sway parameters with spectral analysis were compared between 121 lead workers with BPb levels of 6-89 (mean 40) microg/dl and 60 unexposed controls. RESULTS: All sway parameters, except for sagittal sways with eyes open, were significantly larger in the lead workers than in the controls; also, the Romberg quotient for sagittal sway was significantly higher in the lead workers. The BPb level in the lead workers was significantly related to sagittal sways at 1-2 Hz and 2-4 Hz with eyes open, and sagittal and transversal sways at 1-2 Hz and 2-4 Hz with eyes closed. The BMD levels of BPb (i.e., lower 95% confidence limits of BMD) were estimated to be 12.1-17.3 (mean 14.4) microg/dl for postural sway. CONCLUSIONS: Neuromotor dysfunction in lead workers may be initiated at BPbs below the level previously accepted as effectless, and be characterized mainly by an increased sway of high frequency (1-4 Hz) in the sagittal direction with eyes closed (high Romberg quotient).