Table 1.

Demographic characteristics.

	Q1		Q2		Q3		Q4		Q5		Group Comparison
	n	%	n	%	n	%	n	%	n	%
Sex (Female)	977	47.80	935	45.90	956	46.70	996	49.00	990	48.50	χ2 (4,10204) = 5.33, p = 0.026*
Household income											χ2 (36,9375) = 3008.68, p < 0.001*
Less than $5000	24	1.3	32	1.7	47	2.5	61	3.3	170	9.5
$5000–11999	19	1	30	1.6	49	2.6	83	4.4	172	9.6
$12000–15999	20	1.1	19	1	30	1.6	66	3.5	101	5.7
$16000–24999	26	1.4	42	2.2	67	3.5	89	4.8	203	11.4
$25000–34999	43	2.3	67	3.5	78	4.1	140	7.5	234	13.1
$35000–49999	72	3.8	95	4.9	143	7.5	231	12.4	249	13.9
$50000–74000	144	7.6	196	10.2	310	16.3	348	18.6	311	17.4
$75000–99999	186	9.8	315	16.4	354	18.6	342	18.3	180	10.1
$100000–199999	750	39.6	856	44.5	690	36.2	454	24.3	162	9.1
$200000+	608	32.1	271	14.1	136	7.1	55	2.9	5	0.3
	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD
Age (months)	119.34	7.49	119.44	7.44	118.88	7.58	119.06	7.53	118.49	7.41	F(4, 10200) = 5.27, p < 0.001*
Weight (inches)	80.42	21.12	81.65	22.11	83.49	23.18	86.09	25.81	90.08	29.61	F(4, 10200) = 50.25, p < 0.001*
Cognition total scorea	46.76	16.86	46.19	15.88	45.08	16.36	44	15.46	41.82	15.24	β = 0.11, t = 10.62, p < 0.001*
Parental education	17.71	2.17	17.23	2.32	16.57	2.6	16	2.54	14.79	2.52	F(4,10043) = 436.04, p < 0.001*
ADI index score	55.22	27.05	89.52	3.5	98.4	2.15	105.83	2.31	115.63	3.72	F(4,10200) = 7120.82, p < 0.001*