title: Blood lead is a predictor of homocysteine levels in a population-based study of older adults.
abstract: Lead and homocysteine are both associated with cardiovascular disease and cognitive dysfunction. We evaluated the relations among blood lead, tibia lead, and homocysteine levels by cross-sectional analysis of data among subjects in the Baltimore Memory Study, a longitudinal study of 1,140 randomly selected residents in Baltimore, Maryland, who were 50-70 years of age. Tibia lead was measured by (superscript)109(/superscript)Cd K-shell X-ray fluorescence. The subject population had a mean +/- SD age of 59.3 +/- 5.9 years and was 66.0% female, 53.9% white, and 41.4% black or African American. Mean +/- SD blood lead, tibia lead, and homocysteine levels were 3.5 +/- 2.4 microg/dL, 18.9 +/- 12.5 microg/g, and 10.0 +/- 4.1 micromol/L, respectively. In unadjusted analysis, blood lead and homocysteine were moderately correlated (Pearson's r = 0.27, p < 0.01). After adjustment for age, sex, race/ethnicity, educational level, tobacco and alcohol consumption, and body mass index using multiple linear regression, results revealed that homocysteine levels increased 0.35 micromol/L per 1.0 microg/dL increase in blood lead (p < 0.01). The relations of blood lead with homocysteine levels did not differ in subgroups distinguished by age, sex, or race/ethnicity. Tibia lead was modestly correlated with blood lead (Pearson's r = 0.12, p < 0.01) but was not associated with homocysteine levels. To our knowledge, these are the first data to reveal an association between blood lead and homocysteine. These results suggest that homocysteine could be a mechanism that underlies the effects of lead on the cardiovascular and central nervous systems, possibly offering new targets for intervention to prevent the long-term consequences of lead exposure.
authors.affiliation: Department of Environmental Health Sciences, Division of Occupational and Environmental Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205, USA.
authors.forename: Jyme H
authors.initials: JH
authors.lastname: Schafer
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Glass
authors.forename: Joseph
authors.initials: J
authors.lastname: Bressler
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Todd
authors.forename: Brian S
authors.initials: BS
authors.lastname: Schwartz
mesh_terms: D000368:Aged; D002318:Cardiovascular Diseases / Q000209:etiology* / Q000503:physiopathology; D002490:Central Nervous System / Q000187:drug effects / Q000473:pathology; D003072:Cognition Disorders / Q000209:etiology* / Q000503:physiopathology; D003430:Cross-Sectional Studies; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007854:Lead / Q000097:blood*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged
chemical_list: D006710:Homocysteine; D007854:Lead