Table 2.

Kaplan–Meier estimates of the time to EDSS scores 4 and 6 and the results of Cox hazard regression model by smoking status

Smoking status	n	Median time to EDSS 4 from onset (95%CI)	Median time to EDSS 4 from birth (95%CI)	Hazard ratio (95%CI)
Non-smokers	417	16 (14–19)	50 (48–51)	Reference
Stopped before onset	58	11 (9–18)	52 (47–58)	1.01 (0.7–1.46)
Stopped after onset	107	18 (14–20)	50 (47–52)	1.03 (0.8–1.34)
Current smokers	231	11 (9–12)	45 (42–47)	1.64 (1.33–2.02)
	n	Median time to EDSS 6 from onset (95%CI)	Median time to EDSS 6 from birth (95%CI)	Hazard ratio (95%CI)
Non-smokers	439	22 (19–25)	54 (53–55)	Reference
Stopped before onset	64	15 (10–19)	56 (50–60)	0.97 (0.66–1.4)
Stopped after onset	111	23 (20–25)	54 (51–55)	1.04 (0.78–1.38)
Current smokers	241	16 (13–20)	50 (47–53)	1.49 (1.18–1.86)