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Environ Health Perspect. 2009 Jan;117(1):80-5. doi: 10.1289/ehp.11559. Epub 2008 Aug 22.

Iron metabolism genes, low-level lead exposure, and QT interval.

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  • 1Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan 48109, USA. sungkyun@umich.edu

Abstract

BACKGROUND:

Cumulative exposure to lead has been shown to be associated with depression of electrocardiographic conduction, such as QT interval (time from start of the Q wave to end of the T wave). Because iron can enhance the oxidative effects of lead, we examined whether polymorphisms in iron metabolism genes [hemochromatosis (HFE), transferrin (TF) C2, and heme oxygenase-1 (HMOX-1)] increase susceptibility to the effects of lead on QT interval in 613 community-dwelling older men.

METHODS:

We used standard 12-lead electrocardiograms, K-shell X-ray fluorescence, and graphite furnace atomic absorption spectrometry to measure QT interval, bone lead, and blood lead levels, respectively.

RESULTS:

A one-interquartile-range increase in tibia lead level (13 mug/g) was associated with a 11.35-msec [95% confidence interval (CI), 4.05-18.65 msec] and a 6.81-msec (95% CI, 1.67-11.95 msec) increase in the heart-rate-corrected QT interval among persons carrying long HMOX-1 alleles and at least one copy of an HFE variant, respectively, but had no effect in persons with short and middle HMOX-1 alleles and the wild-type HFE genotype. The lengthening of the heart-rate-corrected QT interval with higher tibia lead and blood lead became more pronounced as the total number (0 vs. 1 vs. >/=2) of gene variants increased (tibia, p-trend = 0.01; blood, p-trend = 0.04). This synergy seems to be driven by a joint effect between HFE variant and HMOX-1 L alleles.

CONCLUSION:

We found evidence that gene variants related to iron metabolism increase the impacts of low-level lead exposure on the prolonged QT interval. This is the first such report, so these results should be interpreted cautiously and need to be independently verified.

KEYWORDS:

gene–environment interaction; heme oxygenase-1; hemochromatosis; iron; lead; transferrin

PMID:
19165391
PMCID:
PMC2627870
DOI:
10.1289/ehp.11559
[PubMed - indexed for MEDLINE]
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