Table 4.9.

Percentages of patients with a progressive initial course of multiple sclerosis according to age at onset: data from the literature

Age at onset of multiple sclerosis (years)	McAlpine and Compston 1952 n = 414	Confavreux 1977 n = 349	S. Poser et al 1982b n = 1529	Weinshenker et al 1989a n = 1099	Phadke 1990 n = 1055
<20	0	3	9	18	3
20–29	5	10	13	19	4
30–39	14	25	27	38	5
40–49	24	24	41	63	14
≥50	29	45		74	27