Some Renal Function Indices in Workers Occupationally Exposed to Lead

Nam, Je Sung; Kim, Yong Bae; Ahn, Hyun Cheol; Kim, Hwa Sung; Lee, Gap Soo; Hwang, Kyu Yoon; Lee, Sung Soo; Ahn, Kyu Dong; Lee, Byung Kook

Abstract

The influence of lead exposure on renal function was studied. Three hundred forty two male lead exposed workers who worked in 3 storage battery factories, 5 secondary smelting factories and 3 litharge making factories, and 60 male control workers who were not exposed to lead occupationally were chosen for this study. Blood lead (PbB), zinc protoporphyrin in whole blood (ZPP) and delta-aminolevulinic acid in urine (DALA) were selected as indicators of lead exposure. As indicators of renal function blood urea nitrogen(BUN) , serum creatinine(S-Cr), serum uric acid (S-UA), N-acetyl-beta-D-glucosaminidase in urine (NAG) and urine protein (U-TP) were selected. While the mean values of lead exposure indicators of lead workers were significantly different from non-exposed ones, the mean values of renal function indicators of exposed except S-UA were significantly different from non-exposed. The frequency of workers whose value of renal function indicators were over the nor mal criteria (BUN>20 mg/dl ; S-Cr>1.2 mg/dl ; S-UA>7.0 mg/dl ; NAG>8.0 U/liter; U-TP>8.0 mg/dl) by the level of lead absorption in terms of PbB, ZPP and DALA were calculated. Age adjusted odds ratio of over the normal value of BUN and NAG were statistically significant by the level of ZPP and that of BUN only showed the dose-dependant relationship. But the frequency of over the normal criteria of renal function indicators were not increased by the level of PbB and DALA. On stepwise multiple regression using renal function indicators as a dependent variable and each lead exposure indicator and age as independent variables, only BUN, NAG and U-TP were contributed by the lead exposure indicators. It was found that only NAG of renal function indices was most reliable indicator who showed dose-response relationship with lead exposure and the measurement of NAG for lead workers whose relatively high exposure is highly recommended.