Table 3.

Relationship between sleep and body fat percentage, BMI z-score, and being overweight

	Malesa						Femalesa
	Grade level						Grade level
	5th to 8th (n = 173)			9th to 12th (n = 180)			5th to 8th (n = 163)			9th to 12th (n = 207)
	Coef	s.e.	P	Coef	s.e.	P	Coef	s.e.	P	Coef	s.e.	P
Percent body fat
Average daily sleep	−1.91	0.68	0.005	−0.67	0.76	0.38	−0.44	0.71	0.54	0.21	0.68	0.75
Weekday sleep duration	−2.97	0.81	<0.001	−0.83	0.51	0.10	−0.25	0.63	0.70	0.92	0.55	0.09
Weekend sleep duration	−1.22	0.47	0.01	−0.08	0.52	0.88	−0.36	0.50	0.48	−0.63	0.43	0.14
Sleep problems/night eating	−0.05	1.07	0.96	−0.77	0.72	0.29	1.03	0.74	0.17	1.05	0.66	0.11
Bedtime difference	0.45	0.75	0.55	0.40	0.65	0.54	0.03	0.55	0.95	0.56	0.59	0.34
Wake-time difference	0.25	0.56	0.65	0.32	0.47	0.50	−0.19	0.37	0.61	−0.80	0.40	0.05
Total sleep difference	−0.00	0.38	0.99	−0.17	0.40	0.67	0.22	0.47	0.64	0.90	0.38	0.02
BMI z-score
Average daily sleep	−0.32	0.06	<0.001	−0.09	0.09	0.27	−0.18	0.08	0.02	−0.03	0.07	0.49
Weekday sleep duration	−0.29	0.08	<0.001	−0.09	0.06	0.14	−0.13	0.07	0.05	0.03	0.06	0.59
Weekend sleep duration	−0.13	0.05	0.01	0.00	0.06	0.95	−0.11	0.05	0.02	−0.07	0.05	0.16
Sleep problems/night eating	0.05	0.14	0.74	−0.06	0.08	0.47	0.10	0.10	0.32	−0.03	0.08	0.74
Bedtime difference	0.14	0.08	0.08	0.04	0.08	0.59	0.06	0.07	0.34	0.04	0.06	0.54
Wake-time difference	0.08	0.06	0.17	0.06	0.05	0.21	−0.01	0.04	0.83	−0.07	0.05	0.16
Total sleep difference	−0.00	0.05	0.95	−0.04	0.05	0.42	0.04	0.05	0.31	0.07	0.04	0.11
Weight status (overweight)
Average daily sleep	−0.52	0.20	0.01	−0.15	0.20	0.47	−0.29	0.28	0.30	0.18	0.24	0.44
Weekday sleep duration	−0.58	0.20	<0.01	−0.19	0.21	0.36	−0.28	0.27	0.30	0.45	0.22	0.04
Weekend sleep duration	−0.10	0.11	0.36	0.14	0.15	0.38	−0.08	0.17	0.63	−0.15	0.12	0.21
Sleep problems/night eating	−0.04	0.29	0.89	−0.54	0.31	0.08	0.11	0.33	0.73	0.12	0.24	0.61
Bedtime difference	0.21	0.14	0.14	−0.16	0.22	0.46	−0.05	0.23	0.83	0.11	0.20	0.59
Wake-time difference	0.27	0.12	0.03	0.14	0.13	0.26	0.02	0.14	0.89	−0.28	0.14	0.05
Total sleep difference	−0.14	0.11	0.19	−0.24	0.17	0.16	−0.05	0.16	0.77	0.26	0.12	0.03

P < 0.05 is highlighted in boldface.

Coef, coefficient.

^aAdjusted for demographic variables and depression, energy intake (average daily calories), and energy expenditure (average counts per min).