Electrocardiographic conduction disturbances in association with low-level lead exposure (the normative aging study)
Journal
American Journal of Cardiology
Journal Volume
82
Journal Issue
5
Pages
594-599
Date Issued
1998
Author(s)
Abstract
Recent research indicates that cumulative exposure to lead may be more toxic than previously thought. This study was undertaken to examine the relation of lowlevel lead exposure to electrocardiographic (ECG) conduction disturbances among 775 men who participated in the Normative Aging Study (average age 68 years; range 48 to 93). We used K-x-ray fluorescence to measure lead levels in the tibia and patella, and graphite furnace atomic absorption spectroscopy to measure blood lead levels. The mean (SD) values for blood lead, tibia lead, and patella lead were 5.8 (3.4) μg/dl, 22.2 (13.4) μg/g, and 30.8 (19.2) μg/g, respectively. Bone lead levels were found to be positively associated with heart rate-corrected QT and QRS intervals, especially in younger men. Specifically, in men <65 years of age, a 10 μg/g increase in tibia lead was associated with an increase in the QT interval of 5.03 ms (95% confidence interval [Cl], 0.83 to 9.22) and with an increase in the QRS interval of 4.83 ms (95% Cl, 1.83 to 7.83) in multivariate regression models. In addition, an elevated bone lead level was found to be positively associated with an increased risk of intraventricular block in men <65 years of age and with an increased risk of atrioventricular (AV) block in men ≥65 years of age. After adjustment for age and for serum high-density lipoprotein (HDL) level, a 10 μg/g increase in tibia lead was associated with an odds ratio (OR) of 2.23 (95% Cl, 1.28 to 3.90) for intraventricular block in men <65 years of age and with an OR of 1.22 (95% Cl, 1.02 to 1.47) for AV block in men ≥65 years of age. Blood lead level was not associated with any of the ECG outcomes examined. The results suggest that cumulative exposure to lead, even at low levels, may depress cardiac conduction. © 1998 by Excerpta Medica, Inc.
SDGs
Publisher
Elsevier Inc.
Type
journal article