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Environmental lead exposure and cognitive function in community-dwelling older adults.
Shih-RA; Glass-TA; Bandeen-Roche-K; Carlson-MC; Bolla-KI; Todd-AC; Schwartz-BS
Neurology 2006 Nov; 67(9):1556-1562
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.
Environmental-exposure; Exposure-levels; Age-groups; Humans; Men; Women; Lead-absorption; Lead-poisoning; Analytical-methods; Blood-analysis; Blood-samples; Nervous-system; Neurological-system; Epidemiology; Statistical-analysis; Demographic-characteristics
Dr. Brian S. Schwartz, Division of Occupational and Environmental Health, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Room W7041, Baltimore, MD 21205
Issue of Publication
Johns Hopkins University
Page last reviewed: May 5, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division