Table 2.

Descriptive statistics for analysis samples.

Variable	NLSY79-YA (n = 9408)		UKHLS (n = 1204)		P-Valuea
	Categories	%	Categories (where different)	%
Poverty Exposure
Early Life Poverty		65.2		63.4	0.211
Mid-Childhood Poverty		58.6		49.2	<0.001
Early Adolescent Poverty		55.1		45.2	<0.001
Early upward mobility		15.9		22.5	<0.001
Early downward mobility		9.2		8.3	0.338
Later upward mobility		13.5		18.5	<0.001
Later downward mobility		10.1		14.6	<0.001
Cumulative Poverty (# of periods of poverty)	0	21.1		21.8	<0.001
	1	19.9		24.8
	2	18.4		27.2
	3	40.7		26.2
Persistent poverty		40.7		26.2	<0.001
Any poverty		79.2		78.2	0.452
Adolescent Outcomes
Current smoker		12.1		12.5	0.676
Health limits activities		3.6		10.6	<0.001
Poor mental healtha		16.2		22.4	<0.001
Covariates
Gender	Male	51.4		51.9	0.759
	Female	48.6		48.1
Race/Ethnicity	Hispanic	7.7	White	95.9	n/a
	Black	16.2	Other	4.1
	Other	76.1
Family structure at birth	Married Couple	74.8	Couple	87.8	<0.001
	Other	25.2	Single	12.2
Year of birth	1979–1984	33.4	1991	23.9	n/a
	1985–1990	39.8	1992	19.7
	1991–1996	26.8	1994	17.9
			1995	13.8
			1996	11.5
			1997	13.1
Mother's age at birth	15–19	6.9		6.1	<0.001
	20–24	31.9		18.3
	25–29	35.2		29.7
	30–34	22.1		28.3
	35+	3.9		17.6
Mother's education (years)	11 or less	5.8		45.4	<0.001
	12–14	70.4		31.5
	15 or more	23.9		23.1
Maternal Smokingb		32.5		25.3	<0.001
Maternal mental health difficultiesc		22.3		32.9	<0.001
Mother foreign born		4.1		n/a	n/a

^aChi-Square test for difference.

^bIn NLSY79-YA mothers self-reported whether they had smoked prior to pregnancy. In UKHLS mothers self-reported their smoking status when the child was aged 0.

^cPoor mental health was indicated by CES-D short-form scores of 8 + in NLSY79-YA and by GHQ scores of 3 + in UKHLS.