Table 2.

Demographic features and index events

FeatureMonophasicRelapsingp Value*
* Chi-square tests were used for statistical analysis except for year and age at onset (Wilcoxon rank sum test), and immunization (two-tailed Fisher’s exact test).
p Value given is for the entire distribution of index events in each group (exact chi-square test for pooled data).
ON = optic neuritis.
n2348
Sex (F:M)11:1240:80.008
Median year of onset197519860.003
Median onset age (range)29 (1–54)39 (6–72)0.009
Antecedent event (%)
Viral illness7 (30)11 (23)0.437
Immunization2 (9)00.090
Autoimmune disease015 (30)0.003
Index events (%)
ON6 (26)23 (48)0.001
Myelitis5 (22)20 (42)
Bilateral ON4 (17)4 (8)
Myelitis + ON1 (4)1 (2)
Bilateral ON + myelitis7 (31)0