Table 1.

Characteristics of the four groups of interest stratified according to demographics and features known to be associated with risk of early-onset dementia, including sample compositions used for the prevalence analysis and for the incidence analyses sample

	Prevalence analyses sample				Incidence analyses sample
	ASD only	ASD + ID	ID only	GP	ASD only	ASD + ID	ID only	GP
N	12,648	26,168	406,570	798,828	7,573	22,229	310,059	145,081
Age at First Enrollment 1 (%)
30–50	80.42	81.33	69.04	74.74	82.29	82.30	71.08	65.20
51–64	19.58	18.67	30.96	25.26	17.71	17.70	28.92	34.80
Sex Male (%)	67.39	69.60	53.41	37.94	68.08	70.08	52.88	36.32
Race/Ethnicity (%)
White	73.25	72.07	69.11	45.05	72.84	71.88	69.27	48.74
Black	13.12	17.30	18.97	20.47	14.26	17.41	18.84	25.09
Asian/Pacific Islander	1.79	1.68	1.64	5.02	1.90	1.72	1.68	5.37
Hispanic/Latino	5.09	3.99	5.58	22.65	4.87	4.07	5.68	15.25
Other	6.74	4.96	4.70	6.81	6.13	4.92	4.53	5.55
Urbanicity
Urban	81.72	82.10	77.65	83.49	81.71	82.01	77.14	80.92
Suburban	10.56	10.69	13.29	9.32	10.70	10.77	13.67	10.57
Rural	7.50	6.86	8.68	6.88	7.36	6.86	8.81	8.36
Missing	0.22	0.35	0.38	0.32	0.24	0.35	0.38	0.15
Medicaid Eligibility Category 2 (%)
Poverty	4.25	0.28	0.40	30.10	1.65	0.09	0.15	13.40
Disability	88.46	98.15	98.47	39.32	96.17	98.73	99.20	72.69
Other	7.29	1.57	1.13	30.59	2.18	1.18	0.66	13.90
Depression (%)	42.93	24.81	27.88	19.60	37.46	23.65	26.75	34.52
Any Other Mental Disorder(s) (%)	73.77	75.50	58.90	33.86	72.80	75.32	58.61	54.84
Cardiovascular Disease Risk Factor(s) (%)	42.98	39.23	43.27	33.32	42.63	39.01	43.02	56.39

^1.Age at first observed Medicaid enrollment, starting in 2008.

^2.The most common Medicaid eligibility category for the enrolled period.