An accelerated disease progression was seen in patients who continued smoking after being diagnosed with multiple sclerosis (MS) compared to patients who quit smoking, a new study published in JAMA Neurology has shown.

Disease progression is often measured by the time from onset to conversion to secondary progressive (SP) MS. Researchers from the Karolinska University hospital, Solna, Stockholm, and colleagues evaluated patients in Sweden with MS who smoked at diagnosis (n=728); 216 of which converted to SP. A total of 332 patients were classified as “continuers’ who smoked continuously from the year after diagnosis, and 118 patients were “quitters” who stopped smoking the year after diagnosis. Researchers also included data on 1,012 patients who never smoked.

RELATED: Relapsing MS Resource Center

Study analysis showed that each year of smoking after the diagnosis sped up the time to SP conversion by 4.7%. Patients who kept smoking each year after diagnosis accelerated to SP faster than those who quit (age 48 vs. age 56).

Researchers concluded that reduced smoking may improve the patient’s quality of life by delaying the onset of SPMS. Smoking is an important modifiable risk factor for MS and healthcare services should be organized to help support MS patients with this lifestyle change.

For more information visit