Cigarette Smoking and Secondary Progressive Multiple Sclerosis

Smoking has been identified as a modifiable environmental risk factor associated with the development and worsening of multiple sclerosis (MS). To determine whether smoking after MS diagnosis is associated with time to secondary progressive (SP) disease, researchers conducted a population-based, case-control study involving MS patients in Sweden.

Of 2358 participants, 1725 had relapsing-remitting disease and 633 had converted to SPMS. Based on self-report, 728 participants were smokers at the time of diagnosis, 1012 were never-smokers, and 618 were past-smokers. Of the 728 who smoked at diagnosis, 118 had subsequently quit, 332 had continued, and 278 had smoked intermittently.

Each successive year of smoking after diagnosis was associated wit…