. 2015 Sep 30;15:435. doi: 10.1186/s12913-015-1095-6

Table 1.

Summary statistics of participants and non-participants^a

	Condition	Participants			Non-participants^b
Age		Mean	SD	n	Mean	SD	n	p value¹
	ASD	16.1	1.3	118	16.0	1.3	99	0.68
	CP	16.5	1.9	106	16.5	1.4	293	0.80
	Diabetes	16.2	1.3	150	15.9	1.2	67	0.14
	Total	16.2	1.3	374	16.3	1.3	459	0.40
		Male	Female	Total	Male	Female	Total
Gender		n (%)	n (%)	n (%)	n (%)	n (%)	n (%)	p value²
	ASD	82 (69)	36 (31)	118 (32)	81 (76)	25 (24)	106 (23)	0.24
	CP	60 (57)	46 (43)	106 (28)	181 (62)	112 (38)	293 (62)	0.35
	Diabetes	77 (51)	73 (49)	150 (40)	31 (45)	38 (55)	69 (15)	0.38
	Total	219 (59)	155 (41)	374 (100)	293 (63)	175 (37)	468 (100)	0.23
SES		Median	IQR	n	Median	IQR	n	p value³
IMD	ASD	19.9	9.7-31.1	118	22.6	15.9-37.8	96	0.01
	CP (NECCPS)	17.5	13.2-30.4	60	27.4	12.7-39.9	164	0.05
	Diabetes	12.1	7.3-20.8	150	14.3	10.3-23.2	67	0.11
	Total	15.5	8.6-28.0	328	21.6	12.2-36.8	327	<0.001
MDM	CP (NICPR)	15.3	10.7-26.8	46	17.7	8.4-34.8	128	0.58

^aYoung people approached who declined to take part or did not respond

^bData missing from one diabetes site

¹t-test of a significant difference in means between participants and non-participants

²Chi-squared test of a difference in the gender distribution between participants and non-participants

³Mann-Whitney rank sum test of a difference in deprivation measure between participants and non-participants

SD Standard Deviation

IQR Interquartile Range

SES Socio-economic status as captured for England by index of multiple deprivation (IMD) [27] and for Northern Ireland by multiple deprivation measure (MDM) [28]

ASD Autism Spectrum Disorder

CP Cerebral Palsy

NECCPS North of England Collaborative Cerebral Palsy Survey