Smoking associated with accelerated disease progression in MS

Continued smoking after a diagnosis of multiple sclerosis (MS) appears to be associated with accelerated disease progression compared with those patients who quit smoking, according to a new study by researchers from Karolinska Institutet. The findings are being published online in JAMA Neurology.

“There are of course a number of health risks connected to smoking, but for people diagnosed with a such a severe disease as MS, it is especially important to quit smoking immediately”, says study leader Jan Hillert, MD, PhD, Professor of Neurology at Karolinska Institutet’s Department of Clinical Neuroscience.

MS is a neurogenerative disease and smoking is one of its known risk factors. While MS begins with an initial course of irregular and worsening relapses, it usually changes after about 20 years into secondary progressive (SP) disease. The time that passes from onset to conversion to SPMS is a frequently used measure of disease progression.

The current study included 728 patients in Sweden with MS who smoked at diagnosis, of whom 216 converted to SP. Among the smokers, 332 were classified as 'continuers' who smoked continuously from the year after diagnosis, and 118 were 'quitters' who stopped smoking the year after diagnosis. Data on 1,012 never smokers also were included. Nearly 60 percent of patients with MS were smokers in the present study cohort and in a Swedish cohort of new cases, according to study background.

Each additional year

Analysis by the authors suggests each additional year of smoking after diagnosis accelerated the time to SP conversion by 4.7 percent. Other analysis suggested that those patients who continued to smoke each year after diagnosis converted to SP faster (at age 48) than those who quit (at age 56).

Funding this study was provided by Neuroförbundet, the Swedish Research Council, the Knut and Alice Wallenberg Foundation, the AFA foundation, the Swedish Brain Foundation, Margareta af Ugglas Stiftelse, EU FP7 Neurinox, the Bibby and Nils Jensen Foundation, and the Karolinska Institutet Research fund. This news article is an edited version of a press release from JAMA Network.

Publication

Effect of Smoking Cessation on Multiple Sclerosis Prognosis
Ryan Ramanujam, Anna-Karin Hedström, Ali Manouchehrinia, Lars Alfredsson, Tomas Olsson, Matteo Bottai, Jan Hillert
JAMA Neurology, doi:10.1001/jamaneurol.2015.1788, online September 8, 2015