LEAD IN FINGERBONE - A TOOL FOR RETROSPECTIVE EXPOSURE ASSESSMENT

Exposure to inorganic lead may cause many adverse health effects. When absorbed, lead is accumulated in large part in bone. In this study, w e investigated the relationship between lead concentration in fingerbo ne, exposure time, and Lead in blood. We also sought to design a model that made it possible to use fingerbone lead as an indicator of earli er exposure. The study comprised 137 active workers from a secondary l ead smeltery. Workers had undergone regular determinations of blood le ad (i.e., up to 6 times/y) for up to 24 y. In addition, during the per iod 1979-1992, workers underwent up to four fingerbone lead assessment s via noninvasive x-ray fluorescence. We calculated cumulative blood l ead, adjusted for time-related reduction of bone lead according to a t ransfer of lead from bone to blood, for each worker. We obtained the b est fit of bone lead to cumulative adjusted blood lead when we assumed a 14-y half-time for the transfer coefficient This half-time was simi lar to the terminal half-time far lead in bone in retired smelters, wh om we studied earlier by longitudinal in vivo measurements. We describ ed models for the accumulation of bone lead on blood lead and exposure time. The combined data on bone lead and exposure time may be used to estimate a mean blood lead during previous exposure. Such estimates w ill be valuable in epidemiological studies aimed at evaluating the tox ic effects of long-term lead exposure in lead workers for whom data on previous blood lead levels are lacking.