Thursday, April 8, 2010 (Last Updated: 04/09/2010)
THURSDAY, April 8 (HealthDay News) -- Smoking may increase the risk of multiple sclerosis (MS) in people who have high levels of antibodies to Epstein Barr virus, another risk factor for MS, according to research published online April 7 in Neurology.
Claire Simon, of the Harvard School of Public Health in Boston, and colleagues conducted an analysis of 442 cases and 865 controls from three MS case-control studies to establish the association between smoking, serum antibody titers to Epstein-Barr virus nuclear antigen (anti-EBNA), the HLA-DR15 gene, and MS risk.
The researchers found that, among the patients with MS, anti-EBNA titers were significantly higher in ever smokers compared to never smokers, and that, among those who had high levels of anti-EBNA, ever smokers had a stronger increased risk of MS than never smokers (odd ratios, 3.9 versus 1.8). The association was not found in people with low antibody levels, and the increased risk of MS associated with smoking disappeared after adjustment for anti-EBNA titers. There was no modification or confounding by HLA-DR15.
"In this investigation we found the well-established association between anti-EBNA Ab titers and MS risk varied based on smoking history," the authors write. "The association between increasing standardized anti-EBNA Ab titer and increased MS risk appeared to be approximately two-fold greater among ever smokers compared to never smokers."
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