Predictors of DMSA chelatable lead, tibial lead, and blood lead in 802 Korean lead workers

Objectives - To examine the interrelations among chelatable lead (by dimerc aptosuccinic acid, DMSA), tibial lead, and blood lead concentrations in 802 Korean workers with occupational exposure to lead and 135 employed control s with only environmental exposure to lead. Methods - This was a cross sectional study wherein tibial lead, DMSA chelat able lead, and blood lead were measured. Linear regression was used to iden tify predictors of the three lead biomarkers, evaluating the influence of a ge, job duration, sex, education level, alcohol and tobacco use, creatinine clearance rate, and body mass index. Results - DMSA chelatable lead concentrations ranged from 4.8 to 2102.9 mug and were positively associated with age, current smoking, and creatinine c learance rate. On average, women had 64 mug less DMSA chelatable lead than men. When blood lead and its square were added to a model with age, sex, cu rrent smoking, body mass index, and creatinine clearance rate, blood lead a ccounted for the largest proportion of the variance and sex became of borde rline significance. Tibial lead concentrations ranged from -7 to 338 mug/g bone mineral and were positively associated with age, job duration, and bod y mass index. Women had, on average, 9.7 mug/g less tibial lead than men. B lood lead concentrations ranged from 4.3 to 85.7 mug/dl and were positively associated with age and tibial lead, whereas current smokers had higher bl ood lead concentrations and women had lower blood lead concentrations. Conclusions - The data suggest that age and sex are both predictors of DMSA chelatable lead, blood lead, and tibial lead concentrations and that tibia l lead stores in older subjects are less bioavailable and may contribute le ss to blood lead concentrations than tibial lead stores in younger subjects . Although blood lead concentrations accounted for a large proportion of th e variance in DMSA chelatable lead concentrations, suggesting that measurem ent of both in epidemiological studies may not be necessary, the efficacy o f each measure in predicting health outcomes in epidemiological studies awa its further investigation.