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 an article published online by JAMA Neurology.
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 from onset to conversion to SPMS is a frequently used measure of disease progression.
Jan Hillert, M.D., Ph.D., of the Karolinska Institutet at Karolinska University Hospital Solna, Stockholm, and coauthors studied patients in Sweden with MS who smoked at diagnosis (n=728), of whom 216 converted to SP. Among the 728 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.
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). The authors note it is impossible to rule out other confounding factors.
“This study demonstrates that smoking after MS diagnosis has a negative impact on the progression of the disease, whereas reduced smoking may improve patient quality of life, with more years before the development of SP disease. Accordingly, evidence clearly supports advising patients with MS who smoke to quit. Health care services for patients with MS should be organized to support such a lifestyle change,” the study concludes.
Source: Jan Hillert, M.D., Ph.D. – JAMA Network
Image Source: The image is credited to Mikael Häggström and is in the public domain
Original Research: Full open access research for “Effect of Smoking Cessation on Multiple Sclerosis Prognosis” by Ryan Ramanujam, PhD; Anna-Karin Hedström, MD; Ali Manouchehrinia, PhD; Lars Alfredsson, PhD; Tomas Olsson, MD, PhD; Matteo Bottai, PhD; and Jan Hillert, MD, PhD in JAMA Neurology. Published online September 8 2015 doi:10.1001/jamaneurol.2015.1788
Abstract
Effect of Smoking Cessation on Multiple Sclerosis Prognosis
Importance Smoking tobacco is a well-established risk factor for multiple sclerosis (MS), a chronic inflammatory disorder of the central nervous system usually characterized by bouts and remissions and typically followed by a secondary progressive (SP) course. However, it is not clear whether smoking after diagnosis is detrimental.
Objective To determine whether smoking after MS diagnosis is associated with a change in time to SP disease.
Design, Setting, and Participants Cross-sectional study of patients with prevalent MS who smoked at diagnosis (n = 728) taken from the Genes and Environment in Multiple Sclerosis Study, which consists of patients from the Swedish National MS Registry. The study entrance date was at time of first-year smoking. The study was conducted between November 2008 and December 2011, with patient environmental data collected from November 2009 to March 2011 via questionnaire. Study participants were from all counties in Sweden diagnosed as having MS at the time of the Genes and Environment in Multiple Sclerosis Study and registered in the Swedish National MS Registry. Patients with MS with relapsing-remitting disease course or SP were included. These patients’ conditions were diagnosed according to the McDonald criteria and the patients responded to recruitment letters with detailed questionnaires.
Exposure Smoking, considered yearly after diagnosis and combined into a time-invariant covariate before diagnosis.
Main Outcomes and Measures Time to SPMS, measured using an accelerated failure time model, with smoking as a time-varying covariate. Other covariates included sex, age at diagnosis, snuff use, and smoking before diagnosis.
Results The optimized model illustrated that each additional year of smoking after diagnosis accelerated the time to conversion to SPMS by 4.7% (acceleration factor, 1.047; 95% CI, 1.023-1.072; P < .001). Kaplan-Meier plots demonstrated that those who continued to smoke continuously each year after diagnosis converted to SPMS faster than those who quit smoking, reaching SP disease at 48 and 56 years of age, respectively.
Conclusions and Relevance This study provides evidence that continued smoking is associated with an acceleration in time to SPMS and that those who quit fare better. Therefore, we propose that patients with MS should be advised to stop smoking once a diagnosis has been made, not only to lessen risks for comorbidities, but also to avoid aggravating MS-related disability.
“Effect of Smoking Cessation on Multiple Sclerosis Prognosis” by Ryan Ramanujam, PhD; Anna-Karin Hedström, MD; Ali Manouchehrinia, PhD; Lars Alfredsson, PhD; Tomas Olsson, MD, PhD; Matteo Bottai, PhD; and Jan Hillert, MD, PhD in JAMA Neurology. Published online September 8 2015 doi:10.1001/jamaneurol.2015.1788
