Cumulative lead exposure and cognitive performance among elderly men.
BACKGROUND
Recent evidence suggests that cumulative lead exposure among adults in nonoccupational settings can adversely affect cognitive function. Which cognitive domains are affected has not been explored in detail.


METHODS
We used nonlinear spline regressions and linear repeated-measures analysis to assess the association between scores on a battery of cognitive tests over time and both blood and bone lead concentrations in the Normative Aging Study, a cohort of community-dwelling elderly men. Bone lead was measured from 1991 through 1999 with K-shell x-ray fluorescence. A total of 1089 men with a mean (+/-standard deviation) age of 68.7 (+/-7.4) years with blood lead measurements, 761 of whom also had valid bone lead measurements, completed at least one of a battery of cognitive tests. Approximately 3.5 years later, 69% of the men had at least one repeat test. Cognitive testing was performed from 1993 through 2001.


RESULTS
On a cross-sectional basis, there was little association between blood or bone lead and cognitive test scores. Change in performance over time on virtually all tests worsened as bone lead increased, with the most robust effects on performance and reaction time scores on visuospatial/visuomotor tests.


CONCLUSIONS
Low-level cumulative exposure to lead in nonoccupational settings may adversely affect cognitive function, particularly in the visuospatial/visuomotor domain.
Weisskopf
Marc G
MG
Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts 02215, USA. mweissko@hsph.harvard.edu
Proctor
Susan P
SP
Wright
Robert O
RO
Schwartz
Joel
J
Spiro
Avron
A
Sparrow
David
D
Nie
Huiling
H
Hu
Howard
H
D000367:Age Factors; D000368:Aged; D001842:Bone and Bones / Q000737:chemistry; D001900:Boston / Q000453:epidemiology; D003071:Cognition; D003072:Cognition Disorders / Q000453:epidemiology / Q000209:etiology*; D015331:Cohort Studies; D004781:Environmental Exposure / Q000009:adverse effects; D006801:Humans; D007854:Lead / Q000097:blood / Q000633:toxicity*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests
D007854:Lead