Table 4. Incidence Rate Ratio of Autism Spectrum Disorders in Persons with a Diagnosis of Obsessive-compulsive Disorder (OCD; 1994–2012).

		First Adjustment a		Second Adjustment b
Time Since OCD Diagnosis	Cases	Incidence Rate Ratio	95% CI	Incidence Rate Ratio	95% CI
< 1 year	135	8.32	6.98–9.83	9.64	8.09–11.38
1 year	42	3.38	2.45–4.51	3.90	2.83–5.20
2 years	29	2.91	1.97–4.10	3.45	2.34–4.87
3 years	31	2.29	1.58–3.20	2.84	1.95–3.96
5 years	30	2.30	1.57–3.24	2.87	1.96–4.02
≥ 10 years	14	2.08	1.17–3.38	2.87	1.61–4.65
Persons without OCD	17893	1	1	1	1

^aEstimates of relative risk were adjusted for calendar year, age, maternal and paternal age, sex, parental history of psychiatric illness, place of residence at time of birth and the interaction of age with sex

^bEstimates of relative risk were adjusted for calendar year, age, maternal and paternal age, sex, parental history of psychiatric illness, first psychiatric hospital contact for any other disorder, place of residence at time of birth and the interaction of age with sex