Table 2.

Descriptive and inferential statistical indices of clinical characteristics between participants with early onset (EOMS), adult onset (AOMS) and late onset Multiple Sclerosis (LOMS).

			Samples			Statistics (between Groups)
		Whole sample	Early onset of MS (EOMS)	Adult onset of MS (AOMS)	Late onset of MS (LOMS)		Post-hoc tests
N		2627	127	2416	84
		n (%)	n (%)	n (%)	n (%)
Autoimmune comorbidity (yes vs. no)		440 (16.7%)	31 (24.4%)	402 (16.6%)	7 (8.3%)	X2(N = 440, df = 2) = 3.42
MS familial history	First degree (yes vs. no)	250 (9.5%)	15 (11.8%)	227 (9.4%)	8 (9.5%)	X2(N = 632, df = 3) = 2.45
	Second degree (yes vs. no)	382 (14.5%)	14 (11.0%)	362 (15.0%)	6 (7.1%)
Family history of other autoimmune disorder (first degree) (yes vs. no)		125 (4.8%)	4 (3.1%)	115 (4.8%)	6 (7.1%)	X2(N = 125, df = 1) = 1.95
Current disease course	Relapsing remitting MS	2129 (81.0%)	109 (85.8%)	1971 (81.6%)	49 (58.3%)	X2(N = 2627, df = 4) = 71.83 ***
	Secondary progressive MS	415 (15.8%)	18 (14.2%)	377 (15.6)	20 (23.8%)		POMS: more RRMS, less SPMS, low PPMS AOMS: more LOMS: more sPMS and PPMS
	Primary progressive MS	83 (3.2%)	-	68 (2.8%)	15 (17.9%)
Number of patients with relapse in the first two years	0/1/2/3$\ge$	1981/508/122/16	81/32/14/0	1831/463/106/16	69/13/2/0	X2(N = 2627, df = 6) = 19.57 ***	POMS: 1 and 2 relapses $\uparrow$ AOMS: zero and 3$\ge$ relapsaes $\uparrow$ LOMS: 0 relapses $\uparrow$
		Median (range)	Median (range)	Median (range)	Median (range)
EDSS at first visit		2.0 (1.0–2.5)	2.0 (0.0–2.0)	2.0 (1.0–2.5)	2.25 (2.0–3.0)	H(N = 2608, df = 2) = 31.38 ***	LOMS > POMS; AOMS
EDSS at last follow-up		1.0 (0.0–2.5)	0.0 (0.0–2.0)	1.0 (0.0–2.5)	2.25 (0.75–5.0)	H(N = 2608, df = 2) = 27.69 ***	LOMS > POMS; AOMS
First inter-attack interval (years)		3.0 (1.0–5.0)	2.0 (1.0–4.0)	3.0 (1.0–5.0)	2.0 (1.0–5.0)	H(N = 2608, df = 2) = 4.54
		n (%)	n (%)	n (%)	n (%)
Prevalent symptoms at onset	Sensory	786 (29.9%)	19 (15.0%)	741 (30.7%)	26 (31.0%)	X2(N = 2627, df = 10) = 70.75 ***
	Visual	688 (26.2%)	45 (35.4%)	632 (26.2%)	11 (13.1%)
	Motor	417 (15.9%)	19 (15.0%)	366 (15.1%)	32 (38.1%)		POMS: visual $\uparrow$; brain stem $\uparrow$; other $\uparrow$
	Brainstem	299 (11.4%)	21 (16.5%)	277 (11.5%)	1 (1.2%)		AOM: sensory $\uparrow ;$ LOMS: motor $\uparrow$ celebellar $\uparrow$; visual $\downarrow$
	Cerebellar	161 (6.1%)	3 (2.4%)	148 (6.1%)	10 (11.9%)
	Others	97 (3.7%)	6 (4.7%)	90 (3.7%)	1 (1.2%)
Disease modifying treatments at the last visit	First line	1709 (65.1%)	63 (49.6%)	1585 (65.6%)	61 (72.6%)	X2(N = 2627, df = 4) = 28.14 ***	POMS: first $\downarrow$; second $\uparrow$; switch $\uparrow$
	Second/third line	918 (34.9%)	64 (50.4%)	831 (34.4%)	23 (27.4%)		AOMS: first $\uparrow$
	switch						LOMS first $\uparrow$; second $\downarrow$

Notes: *** = p < 0.001. $\uparrow$ = higher than; $\downarrow$ = lower than.