Heavy metals, organic solvents, and multiple sclerosis: An exploratory look at gene-environment interactions

ABSTRACT

Exposure to heavy metals and organic solvents are potential etiologic factors for multiple sclerosis (MS), but their interaction with MS-associated genes is under-studied. The authors explored the relationship between environmental exposure to lead, mercury, and solvents and 58 single-nucleotide polymorphisms (SNPs) in MS-associated genes. Data from a population-based case-control study of 217 prevalent MS cases and 496 age-, race-, gender-, and geographically matched controls were used to fit conditional logistic regression models of the association between the chemical, gene, and MS, adjusting for education and ancestry. MS cases were more likely than controls to report lead (odds ratio [OR] = 2.03; 95% confidence interval [CI]: 1.07, 3.86) and mercury exposure (OR = 2.06; 95% CI: 1.08, 3.91). Findings of potential gene-environment interactions between SNPs in TNF-α, TNF-β, TCA-β, VDR, MBP, and APOE, and lead, mercury, or solvents should be considered cautiously due to limited sample size.

KEYWORDS:

• Autoimmune diseases
• case-control
• epidemiology
• gene-environment interaction
• heavy metal exposure
• organic solvents; multiple sclerosis

Acknowledgments

The authors thank the individuals who participated in the study as well as Carolyn Harris, Sara Hatch, Janine Trottier, Laurie Wagner, the Michigan Public Health Institute, and McKing Consulting.

Funding

This study was supported by the Agency for Toxic Substances and Disease Registry (contract no. 200-2003-01396). Disclaimer: The results and conclusions in this article are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.   Dr. Marrie receives research funding from the Canadian Institutes of Health Research, Public Health Agency of Canada, Manitoba Health Research Council, Health Sciences Centre Foundation, Multiple Sclerosis Society of Canada, Multiple Sclerosis Scientific Foundation, and Rx & D Health Research Foundation and has conducted clinical trials funded by Sanofi-Aventis. Ms. Napier and Drs. Poole, Satten, Ashley-Koch, and Williamson have no conflicts of interest regarding this paper.