Key clinical point: Patients with multiple sclerosis who smoke regularly have a significantly higher risk of elevated plasma neurofilament light levels.

Major finding: Being a current smoker was associated with much higher odds of having plasma neurofilament light levels above C99, compared with never smokers (odds ratio, 1.52; 95% confidence interval, 1.12-2.05; P = .007) and past smokers (OR, 1.42; 95% CI, 1.01-1.99; P = .043).

Study details: A retrospective, population-based cohort study of 2,572 Swedish multiple sclerosis patients with a self-reported history of cigarette smoking.

Disclosures: The authors reported several potential conflicts of interest, including receiving research grants and lecture honoraria and serving on advisory boards for various pharmaceutical companies.