Longitudinal relationship between dentin lead levels in childhood and bone lead levels in young adulthood

A retrospective cohort study was conducted to examine the relationship between tooth lead in children and bone lead levels in young adults. Members of a cohort of young adults were reassessed 13 y after initial examination at an ambulatory clinical research center. Dentin lead levels were measured by anodic stripping voltammetry during the years 1975-1978, and bone lead levels of the tibia and patella were measured by K-x-ray fluorescence technique during 1989 and 1990. A total of 63 subjects who had no history of chelation or had no missing information on potential confounders were studied. The median follow-up interval was 13.2 y. Dentin lead levels averaged 13.4 micrograms/g (standard deviation [SD] = 10.7 micrograms/g, range = 2.9-51.8 micrograms/g), and bone lead levels averaged 1.3 micrograms/g (SD = 4.4 micrograms/g, range = -9-13 micrograms/g) for tibia and 5.4 micrograms/g (SD = 8.4 micrograms/g, range = -10-25 micrograms/g) for patella. The authors controlled for age, sex, race, and mother's socioeconomic status, and dentin lead levels were predictive of higher tibia, patella, and mean bone lead levels in 32 subjects (follow-up interval of 11.8-13.2 y). A correction for measurement errors in dentin lead measurements was made, and it was determined that a 10-micrograms/g increase in dentin lead levels in childhood was predictive of a 1-microgram/g increase in tibia lead levels, a 5-micrograms/g increase in patella lead levels, and a 3-micrograms/g increase in mean bone lead levels among the young adults. It was concluded, therefore, that lead exposure in early life may be used to predict elevated body burden up to 13 y later.