Table 4.

The Relationship between Self-Reported Sleep Duration and Gender- and Age-Specific Z-Score of Adiposity Variables among Chinese Adolescents Aged 10–20 Years, Stratified by Gender

Sleep* Duration (hr)	Male*				Female*
	N	Mean ± SD	β (se#)	P	N	Mean ± SD	β (se)	P
Z-score of BMI
<8	92	0.05 ± 0.94	0.02(0.14)	0.8863	80	0.16 ± 1.10	0.30(0.16)	0.0664
8~8.9	82	−0.15 ± 0.97	Ref	—	79	−0.16 ± 0.92	Ref	—
≥9	99	0.08 ± 1.04	0.34(0.15)	0.0276	68	−0.01 ± 0.93	0.21(0.16)	0.1891
Z-score of Total Body Fat
<8	92	−0.04 ± 0.88	−0.04(0.14)	0.7526	80	0.24 ± 1.08	0.43(0.16)	0.0077
8~8.9	82	−0.08 ± 0.93	Ref	—	79	−0.20 ± 0.91	Ref	—
≥9	99	0.11 ± 1.12	0.24(0.16)	0.1441	67	−0.05 ± 0.93	0.24(0.17)	0.1558
Z-score of % Lean Body Mass
<8	92	0.02 ± 1.02	−0.01(0.15)	0.9450	80	−0.19 ± 1.01	−0.33(0.15)	0.0297
8~8.9	82	0.03 ± 0.91	Ref	—	79	0.16 ± 0.93	Ref	—
≥9	99	−0.05 ± 1.03	−0.06(0.16)	0.6850	67	0.03 ± 1.01	−0.26(0.17)	0.1200
Z-score of Truncal Fat
<8	92	−0.04 ± 0.90	−0.06(0.13)	0.6686	80	0.23 ± 1.09	0.39(0.16)	0.0127
8~8.9	82	−0.09 ± 0.88	Ref	—	79	−0.19 ± 0.91	Ref	—
≥9	99	0.12 ± 1.14	0.27(0.16)	0.1021	67	−0.05 ± 0.92	0.24(0.17)	0.1549
Z-score of Waist Circumference
<8	92	0.00 ± 0.83	−0.04(0.12)	0.7292	80	0.23 ± 1.08	0.43(0.16)	0.0075
8~8.9	82	−0.15 ± 0.94	Ref	—	79	−0.20 ± 0.92	Ref	—
≥9	99	0.12 ± 1.15	0.38(0.16)	0.0194	68	−0.04 ± 0.92	0.26(0.15)	0.0770
Z-score of Hip Circumference
<8	92	0.10 ± 0.93	0.08(0.13)	0.5154	80	0.25 ± 1.00	0.36(0.16)	0.0224
8~8.9	82	−0.20 ± 0.95	Ref	—	79	−0.14 ± 0.97	Ref	—
≥9	99	0.08 ± 1.05	0.41(0.15)	0.0056	68	−0.13 ± 0.95	0.10(0.18)	0.5847

^*Regression model adjusted for physical activity and Tanner stage. General estimation equation (GEE) was used to account for intra-twin pair correlations.

^*Mean ± SD among <8-hr, 8~8.9-hr, and ≥9-hr groups were 6.67 ± 0.64 hr, 8.06 ± 0.16 hr and 9.50 ± 0.75 hr for males; 6.76 ± 0.57 hr, 8.04 ± 0.13 hr, and 9.49 ± 0.78 hr for females, respectively.

^#se, standard error of β.