Global DNA (LINE‑1) methylation is associated with lead exposure and certain job tasks performed by electronic waste workers
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Date
2021
Journal Title
Journal ISSN
Volume Title
Publisher
International Archives of Occupational and Environmental Health
Abstract
Objective This study assessed the associations between blood and urine levels of toxic metals; cadmium (Cd) and lead (Pb),
and methylation levels of the LINE-1 gene among e-waste and control populations in Ghana.
Methods The study enrolled 100 male e-waste workers and 51 all-male non-e-waste workers or controls. The concentrations
of Cd and Pb were measured in blood and urine using inductively coupled plasma mass spectrometry, while LINE1 methyla tion levels were assessed by pyrosequencing of bisulfte-converted DNA extracted from whole blood. Single and multiple
metals linear regression models were used to determine the associations between metals and LINE1 DNA methylation.
Results Blood lead (BPb) and urine lead (UPb) showed higher median concentrations among the e-waste workers than the
controls (76.82 µg/L vs 40.25 µg/L, p≤0.001; and 6.89 µg/L vs 3.43 µg/L, p≤0.001, respectively), whereas blood cadmium
(BCd) concentration was lower in the e-waste workers compared to the controls (0.59 µg/L vs 0.81 µg/L, respectively,
p=0.003). There was no signifcant diference in LINE1 methylation between the e-waste and controls (85.16±1.32% vs
85.17±1.11%, p=0.950). In our single metal linear regression models, BPb was signifcantly inversely associated with
LINE1 methylation in the control group (βBPb=− 0.027, 95% CI − 0.045, − 0.010, p=0.003). In addition, a weak associa tion between BPb and LINE1 was observed in the multiple metals analysis in the e-waste worker group (βBPb=− 0.005,
95% CI − 0.011, 0.000, p=0.058).
Conclusion Continuous Pb exposure may interfere with LINE1 methylation, leading to epigenetic alterations, thus serving
as an early epigenetic marker for future adverse health outcomes.
Description
Research Article
Keywords
Electronic waste, Toxic metals, DNA methylation, LINE-1