Embargoed until 11 a.m. ET Tuesday, September 8, 2015

Smoking tobacco is well established as a risk factor for multiple sclerosis (MS). Now a new study suggests that people who continue to smoke after their diagnosis convert to secondary progressive MS (SPMS) more rapidly than those who quit (JAMA Neurol doi:10.1001/jamaneurol.2015.1788).  

The authors enrolled 728 people in Sweden who smoked when diagnosed with MS. Each year that patients continued to smoke after diagnosis accelerated the time to conversion to SPMS by about 4.7%. So, smokers and quitters converted to SPMS at an average of 48 and 56 years respectively. In other words, quitting delayed SPMS by approximately 8 years.

To the authors’ knowledge, the study is the first to establish that smoking after being diagnosed with MS reduces the time to SPMS. The authors “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”.