Serum mercury concentration and the risk of ischemic stroke: The REasons for Geographic and Racial Differences in Stroke Trace Element Study.

Abstract

BACKGROUND:

Although biologically plausible, epidemiological evidence linking exposure to methylmercury with increased risk of ischemic stroke is limited. The effects of methylmercury may be modified by selenium, which is an anti-oxidant that often co-exists with mercury in fish.

OBJECTIVES:

To examine the association between serum mercury levels with the incidence of ischemic stroke and to explore the possible effect modifications by serum selenium levels and demographic and geographic factors.

METHODS:

A case-cohort study was designed nested in the REasons for Geographic and Racial Differences in Stroke cohort, including 662 adjudicated incident cases of ischemic stroke and 2494 participants in a randomly selected sub-cohort. Serum mercury was measured using samples collected at recruitment. Multivariable-adjusted hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) were estimated using the Barlow-weighting method for the Cox proportional hazards regression model.

RESULTS:

No statistically significant association was observed between serum mercury concentration and the incidence of ischemic stroke (the highest vs. lowest quintile of mercury levels: HR = 0.82; 95% CI = 0.55-1.22; P for linear trend = 0.42). Sex (P for interaction = 0.06), but not serum selenium levels, modified the association; a more evident trend toward lower incidence of ischemic stroke with higher mercury levels was observed among women.

CONCLUSION:

This study does not support an association between mercury and the incidence of ischemic stroke within a population with low-to-moderate level of exposure. Further studies are needed to explore the possibility of mercury-induced ischemic stroke toxicity in other populations at higher exposure levels.

• Authors: Cheng Chen, Pengcheng Xun, Leslie A McClure, John Brockman, Leslie MacDonald, Mary Cushman, Jianwen Cai, Lisa Kamendulis, Jason Mackey, Ka He
• Journal: Environment international (Environ Int) Vol. 117 Pg. 125-131 (08 2018) ISSN: 1873-6750 [Electronic] Netherlands
• PMID: 29738916 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2018 Elsevier Ltd. All rights reserved.

Chemical References

• Methylmercury Compounds
• Selenium

Topics

• Brain Ischemia (blood, epidemiology)
• Cohort Studies
• Female
• Humans
• Male
• Methylmercury Compounds (blood)
• Selenium (blood)
• Stroke (blood, epidemiology)