A longitudinal study of the effects of long-term exposure to lead among lead battery factory workers in Taiwan ž1989 1999/

The objective of this study was to assess the relationship between blood-lead levels ŽBLL., hematological, liver and renal indicators among workers in a lead battery factory in Taiwan over a 10-year period. Blood samples were taken periodically from 30 workers and BLL, HGB Žhemoglobin., RBC Žred blood cells., WBC Žwhite blood cells. and HCT Žhematocrit. were measured. Levels of GPT Žalanine aminotransferase. and Crea Žcreatinine. in the blood were assessed to indicate liver and renal function, respectively. The results showed that there was a general decrease in BLL over the 10-year period Žexcept for 1993.. There was a similar trend for HCT, RBC and Crea. There was no significant trend for the other health indicators. Four generalized estimating equation ŽGEE. models correlation model ŽA., threshold correlation model ŽB., instant change model ŽC. and lag change model ŽD. were set up to demonstrate the causal relationship between BLL and the other health indicators. Models A and C showed that BLL correlated positively with RBC, but negatively with Crea. Model B showed that BLL correlated positively with GPT. There were no significant correlations of BLL with the other indicators. Models C and D, ŽGEE with logit link function to analyze the association between changes BLL and the other health indicators. showed that when BLL increased, RBC and HCT increased, both longitudinally and cross-sectionally. The authors conclude that long-term exposure to lead stimulates production of RBC and HCT, but the effect on liver and renal function was unclear.