Table 1.

Characteristics of the study population by age 5–19 physical activity, The Sister Study

		<1 hour per week N=34,193 (68%)		1–6 hours per week N=14,513 (29%)		7+ hours per week N=1,700 (3%)
		N	%	N	%	N	%
Age at baseline (mean, sd)		56.3	8.7	54.1	9.3	54.3	9.2
Age at menarche (mean, sd)		12.6	1.5	12.7	1.6	12.7	1.8
Race/Ethnicity
Non-Hispanic white		28,459	83.2	12,304	84.8	1,404	82.6
Non-Hispanic black		2,963	8.7	1,282	8.8	172	10.1
Hispanic		1,912	5.6	517	3.6	65	3.8
Other		854	2.5	407	2.8	58	3.4
Highest education in the household at age 13
Less than high school		7,151	21.2	1,848	12.8	233	13.8
High school graduate		12,462	37.0	4,856	33.7	517	30.7
Some college		6,223	18.5	2,868	19.9	329	19.5
College degree or higher		7,892	23.4	4,840	33.6	607	36.0
Family income while growing up
Poor		3,056	9.0	859	5.9	114	6.8
Low income		9,619	28.2	3,090	21.3	338	20.0
Middle income		19,773	57.9	9,242	63.8	1,015	60.1
Well off		1,680	4.9	1,292	8.9	222	13.1
Residence type
Urban		7,924	23.5	3,002	20.9	390	23.3
Suburban		8,958	26.5	4,446	30.9	480	28.6
Small town		8,421	25.0	3,950	27.5	460	27.4
Rural		8,363	24.8	2,950	20.5	341	20.3
Other		87	0.3	39	0.3	6	0.4
Smoked before age 20
No		22,876	66.9	9,540	65.7	1,082	63.7
Yes		11,311	33.1	4,972	34.3	617	36.3
Age 10 fruit and vegetable intake
<1 serving per week		282	0.9	54	0.4	4	0.3
1–6 servings per week		4,831	14.7	1,474	10.6	158	9.9
1–<2 servings per day		14,383	43.6	5,503	39.5	532	33.2
2+ servings per day		13,464	40.9	6,886	49.5	908	56.7
Relative weight to peers at age 10
Lighter		11,680	34.3	5,239	36.2	690	40.7
Same		16,072	47.2	6,693	46.2	760	44.8
Heavier		6,323	18.6	2,556	17.6	246	14.5