[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 single-photon 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.
Sun
Yi
Y
Department of Occupational Health, School of Public Health, Fudan University, Shanghai 200032, China.
Jin
Tai-yi
TY
Sun
Dong-hong
DH
Zhu
Guo-ying
GY
Lei
Li-jian
LJ
Zhang
Hai-ying
HY
Shen
Guang-zu
GZ
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood / Q000652:urine; D015519:Bone Density / Q000187:drug effects*; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007854:Lead / Q000009:adverse effects* / Q000097:blood / Q000652:urine; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D010024:Osteoporosis / Q000139:chemically induced; D055815:Young Adult
D015415:Biomarkers; D007854:Lead