Those with high levels of Epstein-Barr antibodies double their chances if they smoke, study found
WEDNESDAY, April 7 (HealthDay News) -- Smoking appears to enhance the link between an existing risk factor and multiple sclerosis, nearly doubling the chances of getting the disabling neurologic disease, according to a new study.
The existing risk factor is having high levels of antibodies to the Epstein-Barr virus (EBV), a common herpes virus that infects most people but is associated with multiple sclerosis (MS) in a small fraction of those who have it. Previous research has found a link between high levels of EBV antibodies and the disease, said the study's lead author, Kelly Claire Simon, a research associate at the Harvard School of Public Health in Boston.
"Although higher antibody titers to EBV are associated with an increased risk of MS, an individual's absolute risk of MS associated with high antibody titers to EBV is still small," she added.
Even so, she and her research team decided to see whether smoking, which has been linked to increasing the risk of getting MS, would boost the risk even more when a person had high antibody levels of EBV.
The researchers also looked at whether smoking also boosted the risk of MS in those people who have an immune system-related gene called the HLA-DR15, which is also linked to an increased MS risk. The gene, which is present in about 20 percent of the general population, is evident in about 60 percent of MS patients.
For this new study, the researchers wanted to focus on "how these different risk factors may be related to each other and whether they acted together or independently," Simon said. Her study is published in the April 7 online edition of the journal Neurology.
Simon and her colleagues evaluated 442 people with MS and 865 healthy people without the disease who had been participants in three large studies: The Nurses' Health Study
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