In vivo bone lead measurements: A rapid monitoring method for cumulative lead exposure

Abstract

Lead concentrations (microgram/g wet weight) in human bone (tibia) were measured noninvasively in vivo employing an X-ray fluorescence technique. Forty-five workers who had been subjected to chronic industrial exposure were found to have a mean bone lead content of 52.9 micrograms/g wet weight (0 to 198 micrograms/g). In addition to bone lead content, blood lead, body burden of lead as assessed by urinary lead excretion after EDTA chelation, zinc protoporphyrin, and unstimulated urinary lead excretion were evaluated. The results suggest that the in vivo measurement of tibia lead content may serve as an acceptable indicator of body lead burden and provide a practical technique for lead screening purposes. The correlation coefficient between X-ray fluorescence findings and lead excretion following Ca-EDTA administration is 0.69; p less than 0.001.

Chelated lead and bone lead.

“…As noted in the introduction, there have been studies examining the relationship between chelated urinary lead and vertebral lead (14) and cortical surface lead (12). In the former study, the correlation observed was r =0.81 (N= II) for active workers and r=0.91 (N = 12) for retired workers; for the combined data set the value was r = 0.53 (N = 23).…”

“…In the former study, the correlation observed was r =0.81 (N= II) for active workers and r=0.91 (N = 12) for retired workers; for the combined data set the value was r = 0.53 (N = 23). In the latter study, Wielopolski et al (12) found a correlation coefficient of 0.69 (N = 34) for active workers. These correlations are both much stronger than were observed for our complete data set for any of the bones measured.…”

Current issues in the epidemiology and toxicology of occupational exposure to lead.

“…For evaluation of these effects a marker of chronic absorption is needed. A most promising approach to development of such a measure is offered by X-ray fluorescence analysis, a technology that permits rapid, noninvasive assessment of the lead burden in bone (51)(52)(53). Application of this technology in epidemiologic studies which also use newly developed biological markers of subclinical impairment offers the possibility of reliable early detection of lead-induced nephropathy in lead workers who are not yet clinically impaired.…”

“…Again, the most promising approach to this measure appears to be noninvasive X-ray fluorescence analysis of lead in bone (51,53).…”

Bone Lead Measured by X-Ray Fluorescence: Epidemiologic Methods

“…The software that runs the instrument and analyzes the resultant spectra is algorithm-driven, allowing the instrument to be operated by a trained technician rather than a physicist (17 (2,(19)(20)(21), in studies comparing lead burden estimated by XRF with lead burden estimated by chelation and cumulative indices of blood lead (22)(23)(24), and in pilot studies of control subjects with no known lead exposure (10,12,25). One group of investigators has been using an L-X-ray fluorescence technique to measure lead burden in children (26); the same investigators also conducted a survey of lead burden among factory workers (27).…”