US EPA

194212 

Journal Article 

Editorial 

Cumulative effect of lead on cognition: Is bone more revealing than blood? 

Weisskopf, MG; Myers, G 

2006 

1 

Neurology
ISSN: 0028-3878
EISSN: 1526-632X 

67 

9 

1536-1537 

English 

17101881 

10.1212/01.wnl.0000246111.21148.ee 

WOS:000241991400001 

OBJECTIVE: To determine if long-term exposure to high levels of lead in the environment is associated with decrements in cognitive ability in older Americans.

METHODS: We completed a cross-sectional analysis using multiple linear regression to evaluate associations of recent (in blood) and cumulative (in tibia) lead dose with cognitive function in 991 sociodemographically diverse, community-dwelling adults, aged 50 to 70 years, randomly selected from 65 contiguous neighborhoods in Baltimore, MD. Tibia lead was measured with (109)Cd induced K-shell X-ray fluorescence. Seven summary measures of cognitive function were created based on standard tests in these domains: language, processing speed, eye-hand coordination, executive functioning, verbal memory and learning, visual memory, and visuoconstruction.

RESULTS: The mean (SD) blood lead level was 3.5 (2.2) microg/dL and tibia lead level was 18.7 (11.2) microg/g. Higher tibia lead levels were consistently associated with worse cognitive function in all seven domains after adjusting for age, sex, APOE-epsilon4, and testing technician (six domains p <or= 0.01, one domain p <or= 0.05). Blood lead was not associated with any cognitive domain. Associations with tibia lead were attenuated after adjustment for years of education, wealth, and race/ethnicity.

CONCLUSIONS: Independent of recent lead dose, retained cumulative dose resulting from previous environmental exposures may have persistent effects on cognitive function. A portion of age-related decrements in cognitive function in this population may be associated with earlier lead exposure. 

Adult; *Blood Chemical Analysis/st [Standards]; *Bone and Bones/ch [Chemistry]; Bone and Bones/de [Drug Effects]; Bone and Bones/me [Metabolism]; Brain/de [Drug Effects]; Brain/me [Metabolism]; Brain/pp [Physiopathology]; Cognition Disorders/bl [Blood]; *Cognition Disorders/di [Diagnosis]; Cognition Disorders/pp [Physiopathology]; Environmental Exposure; Humans; *Lead/an [Analysis]; Lead/to [Toxicity]; Lead Poisoning, Nervous System, Adult/bl [Blood]; *Lead Poisoning, Nervous System, Adult/di [Diagnosis]; Lead Poisoning, Nervous System, Adult/pp [Physiopathology]; Neuropsychological Tests; Predictive Value of Tests; Socioeconomic Factors; *Spectrometry, X-Ray Emission/st [Standards]; Time; 7439-92-1 (Lead)