CHICAGO -- Cigarette smoking is a risk factor for developing multiple sclerosis among first-degree relatives of confirmed MS patients, according to an ongoing study of more than 2,600 such individuals.
The study, based on a model combining genetic and environmental risk factors to identify likelihood of developing MS, found in 1,696 first-degree relatives of MS patients (113 with MS themselves) that smoking is associated with MS susceptibility (P=0.0096), said lead study author Zongqi Xia, MD, PhD, of Brigham and Women's Hospital in Boston.
The work, presented here at the American Neurological Association's annual meeting, did not find an association between infectious mononucleosis and risk of MS (P=0.39) -- of interest because past studies have linked MS to exposure to Epstein-Barr virus, which causes infectious mononucleosis.
The investigators found the incidence of MS in this population to be 123 per 100,000 -- a rate that is 20 to 30 times higher than that of the general population, Xia said. Consequently, the model holds promise for identifying individuals at the highest risk of developing MS who could be good candidates for prevention efforts.