Table 4.

Linear regression assessing nighttime sleep (7 PM - 7 AM) and individual, behavioral, and environmental characteristics

	Model 1 N=89			Model 2 N=88			Model 3 N=86
	β	SE	p	β	SE	p	β	SE	p
Intercept	317.003	62.204	<0.001	314.800	57.233	<0.001	413.273	79.549	<0.001
Physical activity a	4.701	1.450	0.002	3.976	1.327	0.004	3.323	1.408	0.021
Physical activity2	−0.020	0.008	0.016	−0.016	0.007	0.026	−0.015	0.008	0.051
Sleep location
Crib in own room				56.247	17.084	0.002	53.401	19.592	0.008
Bed sharing				−30.006	23.429	0.204	−34.876	23.74	0.147
Other				−15.828	17.898	0.379	−29.211	19.404	0.137
Crib in parent’s room				Ref			Ref
Bedtime
Stays the same				43.726	16.549	0.010	43.688	17.758	0.016
Changes				Ref			Ref
Sleep position
Prone				−10.528	16.751	0.532	−3.874	18.055	0.831
Side				−14.985	19.366	0.441	−8.075	20.143	0.690
Mixed/Other				−4.878	24.236	0.841	−2.041	25.581	0.937
Supine				Ref			Ref
Male							28.081	13.726	0.045
Race/Ethnicity
Black							−31.146	17.914	0.087
Hispanic							−18.298	21.139	0.390
Other							−77.629	33.309	0.023
White							Ref
Age (weeks)							−1.734	1.647	0.296
No college degree							−9.407	18.312	0.609
BMI z-score							1.136	5.624	0.841
Adjusted R2		0.192			0.403			0.441

^aTotal ankle vector magnitude counts/1000 (7 AM to 7 PM)

Physical activity² was entered into the model to account for the curvilinear relationship between physical activity and sleep.

Ref = Reference category

Model 1 independent variables include physical activity and physical activity²

Model 2 independent variables include physical activity, physical activity², sleeping location, bedtime consistency, and sleeping position

Model 3 independent variables include physical activity, physical activity², sleeping location, bedtime consistency, sleeping position, sex, race/ethnicity, age, BMI z-score and maternal education