BUFFALO, N.Y. -- Persons with multiple sclerosis who smoked for a little as six months during their lifetime had more destruction of brain tissue and more brain atrophy than MS patients who never smoked, a study by neuroimaging specialists at the University at Buffalo has shown.
Research published in the Aug. 18, 2009, issue of Neurology®, the medical journal of the American Academy of Neurology, 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 an average number derived from measures of various functions of the central nervous system. It is based on 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," said Robert Zivadinov, M.D., Ph.D., UB professor of neurology, director of the Buffalo Neuroimaging Analysis Center (BNAC) where the research was conducted and first author on the study.
"The biological basis of the potential link between smoking and MS has not yet been fully elucidated," Zivadinov said. "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 consecutive patients who were seen at the Baird Multiple Sclerosis Center of the Jacobs Neurological Institute (JNI), UB's Department of Neurology, UB School of Medicine and Biomedical Sciences.
Within the study cohort, 128 had a history of smoking: 96 were active smokers who had smoked more than 10 cigarettes-per-day in the three months prior to the study start and 32 were former smokers who had smoked cumulatively for at least six months sometime in the past. 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.
All participants were evaluated by a clinician, were rated by disability using the EDSS scale and underwent a variety of high-resolution magnetic resonance imaging (MRI) scans conducted by MRI analysts who were blinded to the patient's clinical status and characteristics.
Results showed that smokers with MS had a greater breakdown of the blood-brain barrier, had nearly 17 percent more brain lesions -- patches of inflammation in the sheath surrounding the nerve fibers that impair their function -- than nonsmokers with MS, and also had less brain volume. Smoking also was associated with increased physical disability, as measured by the EDSS score.
Bianca Weinstock-Guttman, M.D., director of the Baird MS Center, UB associate professor of neurology and a principal co-author on the study, said:
"The findings underscore the detrimental effect of smoking, providing a link between smoking and a more severe brain injury in MS patients.
"Increased antismoking education in schools and more targeted smoking cessation programs for patients with MS should be encouraged further and supported."
Murali Ramanathan, Ph.D., associate professor of pharmaceutical sciences in the UB School of Pharmacy and Pharmaceutical Sciences, is senior author on the study. Additional authors, all from UB, are Komal Hashmi, M.D., Nadir Abdelrahman, M.D., Milena Stosic, M.D., Michael G. Dwyer, Sara Hussein and Jackie Durfee.
The research was funded by an independent grant from the BNAC, by the National Multiple Sclerosis Society and by a Pediatric MS Center of Excellence Center Grant. The Pediatric MS Center of Excellence is located in Women and Children's Hospital of Buffalo. The BNAC is located in Buffalo General Hospital. Both hospitals are part of Kaleida Health.
The University at Buffalo is a premier research-intensive public university, a flagship institution in the State University of New York system and its largest and most comprehensive campus. UB's more than 28,000 students pursue their academic interests through more than 300 undergraduate, graduate and professional degree programs. Founded in 1846, the University at Buffalo is a member of the Association of American Universities.