Persistence of self-injurious behaviour in autism spectrum disorder over 3 years: a prospective cohort study of risk markers

Table 4 Demographic variables for participants with self-injury and without self-injury at T₂

		Percentage of individuals with self-injury (N—point prevalence)	Percentage of individuals without self-injury (N—point prevalence)	Chi-square	P value^a	Relative Risk (95 % CI)
Gender	Male	82.1 (23)	89.7 (35)	N/A^b	0.474	–
Gender	Female	17.9 (5)	10.3 (4)	N/A^b	0.474	–
Age^c	<11 years	39.3 (11)	38.5 (15)`	0.590	0.745	–
	12–18 years	46.4 (13)	38.5 (15)
	≥19 years	14.3 (4)	20.5 (8)
Ability^c	Able/partly able	75.0 (21)	97.4 (38)	N/A^b	*0.008*	*2.4 (1.5–3.8)*
Ability^c	Not able	21.4 (6)	2.6 (1)	N/A^b	*0.008*	*2.4 (1.5–3.8)*
Speech^c	Verbal/partly verbal	78.6 (22)	100.0 (39)	N/A^b	*0.005*	*2.8 (2.0–3.9)*
Speech^c	Non-verbal	17.9 (5)	0.0 (0)	N/A^b	*0.005*	*2.8 (2.0–3.9)*
Mobility^c	Mobile	92.6 (26)	100.0 (39)	N/A^b	0.409	–
Mobility^c	Non-mobile/partly mobile	3.6 (1)	0.0 (0)	N/A^b	0.409	–
Vision	Normal	89.3 (25)	84.6 (33)	N/A^b	0.724	–
Vision	Poor vision/blind	10.7 (3)	15.4 (6)	N/A^b	0.724	–
Hearing	Normal	96.4 (27)	100.0 (39)	N/A^b	0.418	–
Hearing	Poor hearing/deaf	3.6 (1)	0.0 (0)	N/A^b	0.418	–

^aSignificant differences (p < 0.05) are highlighted in italics; variables for which significant differences at p < 0.05 were obtained at T₁ are set in bold (all tests are two-tailed apart from level of ability and speech)
^bFisher’s exact was calculated
^cOne case of missing data

ISSN: 1866-1955