Cumulative lead dose and cognitive function in adults: a review of studies that measured both blood lead and bone lead.
OBJECTIVE
We review empirical evidence for the relations of recent and cumulative lead dose with cognitive function in adults.


METHODS
A systematic search of electronic databases resulted in 21 environmental and occupational studies from 1996 to 2006 that examined and compared associations of recent (in blood) and cumulative (in bone) lead doses with neurobehavioral outcomes.


METHODS
Data were abstracted after consideration of exclusion criteria and quality assessment, and then compiled into summary tables.


CONCLUSIONS
At exposure levels encountered after environmental exposure, associations with bio-markers of cumulative dose (mainly lead in tibia) were stronger and more consistent than associations with blood lead levels. Similarly, in studies of former workers with past occupational lead exposure, associations were also stronger and more consistent with cumulative dose than with recent dose (in blood). In contrast, studies of currently exposed workers generally found associations that were more apparent with blood lead levels; we speculate that the acute effects of high, recent dose may mask the chronic effects of cumulative dose. There is moderate evidence for an association between psychiatric symptoms and lead dose but only at high levels of current occupational lead exposure or with cumulative dose in environmentally exposed adults.
Shih
Regina A
RA
Division of Epidemiology, Statistics, and Prevention Research, National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Rockville, Maryland 20892, USA.
Hu
Howard
H
Weisskopf
Marc G
MG
Schwartz
Brian S
BS
D000328:Adult; D001842:Bone and Bones / Q000378:metabolism; D003071:Cognition / Q000187:drug effects*; D004785:Environmental Pollutants / Q000032:analysis / Q000097:blood / Q000633:toxicity*; D006801:Humans; D007854:Lead / Q000032:analysis / Q000097:blood / Q000633:toxicity*
D004785:Environmental Pollutants; D007854:Lead