Table 2.

Adjusted relative risk ratio (95% confidence intervals) for determinants of the timing of diagnosis for autism spectrum disorder.

	Timing of diagnosis for autism spectrum disorder
	During primary schoola	During secondary schoola
Female sex	1.02 (0.53–1.97)	1.23 (0.61–2.48)
Cognitive delay	1.12 (0.50–2.53)b	0.49 (0.19–1.30)b
Low parental education (below A-level)	0.42 (0.24–0.74)	0.68 (0.39–1.18)
Low household income	1.90 (1.03–3.53)	2.15 (1.05–4.42)
Having parental concerns over the child’s socio-behavioural difficulties at age 5	0.32 (0.15–0.70)b	0.19 (0.09–0.43)b
Teacher-evaluated social developmental delay	0.50 (0.27–0.90)	0.75 (0.39–1.44)
Neighbourhood health deprivation	1.65 (0.82–3.32)	1.90 (0.68–5.27)

^aThe Before school group is taken as reference.

^bSignificant difference between During primary school group and During secondary school group. All analyses adjusted for multiple birth indicator.