Table 3.

Logistic regression estimates (odds ratios) of displaying low cognitive scores at the 24 and 48 month assessments (N = 7,200)

	24 Mo assessment		48 Mo assessment
	Model 1	Model 2	Model 1	Model 2
Male	1.93***	2.00***	1.55***	1.66***
Child age (months)	0.66***	0.64***	0.86***	0.83***
Ethnic origin
Black	3.00***	1.92***	4.47***	1.97***
Hispanic	2.89***	2.04***	5.69***	2.61***
Asian	2.45***	2.74***	1.68*	1.61
Native American	1.96	1.46	4.45***	2.37***
Other	1.85*	1.49	2.40***	1.70*
White, non-hispanic	1.00 (ref)	1.00 (ref)	1.00 (ref)	1.00 (ref)
Mother’s education at corresponding assessment
Less than 9th grade		2.33**		13.65***
From 9th to 12th grade		2.45***		6.88***
High school graduate		1.97***		3.13***
Some training/college after high school		1.81**		1.83*
Four year college degree and above		1.00 (ref)		1.00 (ref)
Family income at corresponding assessment
Less than $10,000		1.43		7.01***
Between $10,001 and $20,000		1.56		5.13***
Between $20,001 and $40,000		1.31		3.92***
Between $40,001 and $75,000		1.10		2.52**
At or above $75,001		1.00 (ref)		1.00 (ref)
Maternal age = 35 or older		0.90		0.96
Marital status = unmarried, 48 month assessment		1.10		0.99
Medical risk factor(s)		0.98		0.89
Behavioral risk factor(s)		0.79		0.87
Obstetric procedure(s)		0.85		0.83*
Labor complication(s)		1.04		1.03
Multiple birth		1.52**		1.52*
Gestation
Very preterm ≤32 weeks		1.52		1.86
Moderately preterm 33–36 weeks		1.07		1.10
Birthweight
Very low birthweight		4.38***		1.10
Moderately low birthweight		1.70***		1.17
Congenital anomaly		1.19		1.27

* P ≤ 0.05, ** P ≤ 0.01, *** P ≤ 0.001

Literacy, math, color knowledge, and receptive vocabulary scores were converted into z-scores and summed to produce cognitive score at 48 months; lowest 10% were defined as low

Bayley mental score was used as cognitive score at 24 months; lowest 10% were defined as low

Sample size rounded to the nearest 50 in accordance with ECLS-B data confidentiality requirements (available at http://nces.ed.gov/ecls/birthdatainformation.asp)