Table 2.

Comparison of ADDM Network Indicators of Autism Spectrum Disorder Using Previous and New Case Definitions at ADDM Network Sites^a, Surveillance Years 2014 and 2016

Finding or Indicator	ADDM Network Surveillance Year
	2014				2016
	Previous Case Definition	95% CI	New Case Definition	95% CI	Previous Case Definition	95% CI	New Case Definition	95% CI
ASD prevalence, no. of cases/1,000 children aged 8 years
Total	17.3	16.8, 178	17.2	16.7, 177	18.5	18.0, 19.1	17.3	16.8, 17.8
By sex
Male	27.7	26.8, 28.7	27.7	26.7, 28.6	29.7	28.8, 30.6	27.8	270, 28.7
Female	6.4	6.0, 6.9	6.3	5.9, 6.8	6.9	6.5, 74	6.3	5.9, 6.7
By race/ethnicity
Non-Hispanic White	17.3	16.6, 18.1	17.1	16.3, 179	18.5	178, 19.3	17.0	16.4, 177
Non-Hispanic Black	16.1	15.1, 171	16.2	15.2, 172	18.3	172, 19.4	16.8	15.8, 179
Hispanic	15.0	13.9, 16.2	14.2	13.1, 15.4	15.4	14.4, 16.4	14.3	13.4, 15.3
ASD prevalence ratio
Male:female	4.30	3.97, 4.66	4.37	4.03, 4.74	4.27	3.99, 4.59	4.42	4.10, 4.76
White:Black	1.08	1.00, 1.16	1.06	0.98, 1.14	1.01	0.94, 1.09	1.01	0.94, 1.09
White:Hispanic	1.15	1.05, 1.26	1.20	1.10, 1.32	1.20	1.12, 1.30	1.19	1.10, 1.28
Hispanic:Black	0.93	0.85, 1.03	0.88	0.79, 0.97	0.84	0.77, 0.92	0.85	0.78, 0.93
Other indicators
Age at first evaluation, monthsb,c	41	40, 42	41	39, 42	40	39, 41	40	39, 41
Age at ASD diagnosis, monthsb,d	52	51, 53	53	51,54	51	50, 53	52	51, 53
% with known IQ ≤70e	33	32, 35	34	32, 36	33	32, 35	35	33, 37

Abbreviations: ADDM, Autism and Developmental Disabilities Monitoring; ASD, autism spectrum disorder; CI, confidence interval; IQ, intelligence quotient.

^aEight ADDM Network study areas (Arkansas, Georgia, Maryland, Minnesota, New Jersey, North Carolina, Tennessee, and Wisconsin) were included in 2014, and 11 areas (Arizona, Arkansas, Colorado, Georgia, Maryland, Minnesota, Missouri, New Jersey, North Carolina, Tennessee, and Wisconsin) were included in 2016.

^bValues are expressed as median and bootstrap 95% CI.

^cCalculated among children with linked in-state birth certificates.

^dHistorically, the ADDM Network reports the median age of ASD diagnosis among children who have a diagnosis—children who do not have a diagnosis are excluded. In 2014, 25.4% of children meeting the previous case definition and 23.0% of children meeting the new case definition did not have a known age of ASD diagnosis and were excluded. In 2016, 26.3% and 19.0% were excluded, respectively.

^eChildren with unknown or missing cognitive function data were excluded. In 2014, 21.8% of children meeting the previous case definition and 25.5% of children meeting the new case definition were excluded. In 2016, 22.7% and 25.0% were excluded, respectively.