August 20, 2009
Smoking Linked to Brain Damage in MS Patients
People with multiple sclerosis (MS) who smoked for as little as six months during their lifetime exhibited more destruction of brain tissue and more brain atrophy than MS patients who had never smoked, according to a study at the University of Buffalo.
Research showed that "ever-smokers" had more brain lesions and greater loss of brain volume, as well as higher scores on the Expanded Disability Status Scale (EDSS), than MS patients who had no history of smoking.
The EDSS score is derived from measures of various functions of the central nervous system. It has a scale from 0 to 10, with 10 representing greatest disability. Nonsmokers recorded an average EDSS score of 2.5, compared to 3.0 for ever-smokers.
"Cigarette smoking is one of the most compelling environmental risk factors linked to the development and worsening of MS," Robert Zivadinov, M.D., Ph.D., UB professor of neurology, director of the Buffalo Neuroimaging Analysis Center (BNAC) and first author on the study was quoted as saying.
"The biological basis of the potential link between smoking and MS has not yet been fully elucidated," Zivadinov continued. "In addition to nicotine, cigarette smoke contains hundreds of potentially toxic components, including tar, carbon monoxide and polycyclic aromatic hydrocarbons. In MS patients, smoking was associated with higher increased lesion burden and greater brain atrophy. Our results indicate that a wide range of quantitative brain MRI markers are affected by smoking in MS patients."
The study involved 368 patients who were seen at the Baird Multiple Sclerosis Center of the Jacobs Neurological Institute (JNI), UB School of Medicine and Biomedical Sciences. Of the 368 patients, 128 had a history of smoking. Ninety-six were active smokers who had smoked more than 10 cigarettes per day in the three months prior to the beginning of the study, and 32 were former smokers who had smoked for at least six months sometime in their lives. The remaining 240 participants were lifelong nonsmokers.
Nearly 80 percent in both groups were female, and nearly 75 percent were diagnosed with progressive MS, characterized by a steadily increasing disability.