Table 1.
Clinical characteristics of the study population (n = 6,048).
| Sleep duration | P | ||||
|---|---|---|---|---|---|
| Very short | Short | Recommended | Long | ||
| Boys | n = 349 | n = 1,937 | n = 914 | n = 18 | |
| Age (years) | 15.84 ± 1.83 | 14.34 ± 2.13 | 14.64 ± 1.93 | 14.56 ± 1.50 | <0.001 |
| Height SDS | 0.65 ± 1.05 | 0.81 ± 1.05 | 0.64 ± 1.03 | 0.95 ± 1.09 | 0.102 |
| Weight SDS | 0.48 ± 1.02 | 0.46 ± 1.03 | 0.23 ± 1.07 | 0.44 ± 0.89 | <0.001 |
| BMI SDS | 0.21 ± 1.10 | 0.12 ± 1.06 | −0.07 ± 1.09 | 0.01 ± 0.89 | <0.001 |
| WC SDS | −0.03 ± 1.17 | −0.15 ± 1.11 | −0.33 ± 1.16 | −0.41 ± 0.95 | <0.001 |
| SBP (mmHg) | 110.61 ± 9.70 | 109.37 ± 10.79 | 109.32 ± 10.54 | 111.39 ± 11.03 | 0.193 |
| DBP (mmHg) | 69.93 ± 8.16 | 67.15 ± 9.54 | 67.74 ± 9.41 | 67.33 ± 8.30 | 0.033 |
| Glucose (mg/dL) | 88.43 ± 6.93 | 90.21 ± 6.45 | 90.36 ± 6.68 | 89.06 ± 3.61 | <0.001 |
| T-C (mg/dL) | 152.40 ± 27.47 | 151.88 ± 26.55 | 151.84 ± 26.45 | 152.33 ± 28.53 | 0.801 |
| HDL-C (mg/dL) | 47.07 ± 9.52 | 48.69 ± 9.23 | 48.68 ± 9.22 | 49.61 ± 9.15 | 0.033 |
| TG (mg/dL) | 89.30 ± 53.40 | 83.71 ± 48.59 | 84.28 ± 47.26 | 80.83 ± 35.57 | 0.244 |
| LDL-C (mg/dL) | 87.45 ± 23.99 | 86.45 ± 23.31 | 86.30 ± 22.15 | 86.56 ± 24.56 | 0.519 |
| Alcohol consumption (%) | 34 (9.7%) | 102 (5.3%) | 85 (9.3%) | 3 (16.7%) | <0.001 |
| Smoking (%) | 79 (22.6%) | 363 (18.7%) | 214 (23.4%) | 9 (50.0%) | <0.001 |
| Physical activity (%) | 43 (12.3%) | 245 (12.7%) | 110 (12.0%) | 2 (11.1%) | 0.969 |
| Household income ≤ 1st quartile (%) | 35 (10.0%) | 213 (11.0%) | 124 (13.6%) | 2 (11.1%) | 0.174 |
| Rural residence (%) | 51 (14.6%) | 322 (16.6%) | 191 (20.9%) | 4 (22.2%) | 0.015 |
| Hypertension (%) | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | >0.999 |
| Diabetes mellitus (%) | 0 (0%) | 2 (0.10%) | 0 (0%) | 0 (0%) | 0.724 |
| Dyslipidemia (%) | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | >0.999 |
| Sleep duration (hr) | 4.98 ± 0.62 | 6.99 ± 0.71 | 8.73 ± 0.78 | 11.22 ± 0.43 | <0.001 |
| Girls | n = 428 | n = 1,674 | n = 709 | n = 19 | |
| Age (years) | 15.52 ± 1.86 | 14.38 ± 2.13 | 14.77 ± 1.99 | 13.74 ± 1.41 | <0.001 |
| Height SDS | 0.37 ± 1.02 | 0.46 ± 1.02 | 0.37 ± 1.06 | 0.13 ± 0.89 | 0.507 |
| Weight SDS | 0.37 ± 1.13 | 0.26 ± 1.00 | 0.12 ± 1.13 | −0.06 ± 1.15 | <0.001 |
| BMI SDS | 0.27 ± 1.16 | 0.10 ± 1.00 | −0.02 ± 1.12 | −0.12 ± 1.23 | <0.001 |
| WC SDS | −0.04 ± 1.17 | −0.11 ± 1.05 | −0.17 ± 1.12 | 0.00 ± 1.05 | 0.060 |
| SBP (mmHg) | 104.60 ± 9.35 | 103.86 ± 9.07 | 103.29 ± 9.32 | 100.11 ± 10.03 | 0.007 |
| DBP (mmHg) | 67.62 ± 7.98 | 65.89 ± 7.91 | 66.01 ± 8.26 | 64.47 ± 7.41 | 0.004 |
| Glucose (mg/dL) | 87.85 ± 6.89 | 88.76 ± 6.97 | 88.74 ± 6.44 | 89.74 ± 7.30 | 0.051 |
| T-C (mg/dL) | 161.80 ± 28.26 | 161.05 ± 25.54 | 161.68 ± 24.48 | 164.53 ± 25.20 | 0.857 |
| HDL-C (mg/dL) | 52.58 ± 9.92 | 51.69 ± 9.71 | 51.73 ± 9.62 | 47.84 ± 6.48 | 0.109 |
| TG (mg/dL) | 81.10 ± 41.19 | 84.03 ± 42.27 | 86.84 ± 41.97 | 125.84 ± 73.30 | 0.001 |
| LDL-C (mg/dL) | 92.95 ± 24.03 | 92.54 ± 22.03 | 92.60 ± 21.63 | 91.42 ± 22.32 | 0.793 |
| Alcohol consumption (%) | 17 (3.97%) | 64 (3.82%) | 52 (7.33%) | 1 (5.26%) | 0.003 |
| Smoking (%) | 53 (12.38%) | 116 (6.93%) | 86 (12.13%) | 1 (5.26%) | <0.001 |
| Physical activity (%) | 61 (14.25%) | 180 (10.75%) | 54 (7.62%) | 1 (5.26%) | 0.004 |
| Household income (%) | 44 (10.28%) | 172 (10.27%) | 101 (14.25%) | 2 (10.53%) | 0.039 |
| Residence (rural) | 54 (12.62%) | 277 (16.55%) | 141 (19.89%) | 4 (21.05%) | 0.015 |
| Hypertension (%) | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | >0.999 |
| Diabetes mellitus (%) | 0 (0%) | 0 (0%) | 1(0.1%) | 0 (0%) | 0.393 |
| Dyslipidemia (%) | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | >0.999 |
| Sleep duration (hr) | 4.93 ± 0.71 | 6.94 ± 0.75 | 8.76 ± 0.81 | 11.42 ± 0.51 | <0.001 |
Data are expressed as the means ± standard deviations (SD).
SDS, standard deviation score; WC, waist circumference; BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; T-C, total cholesterol; TG, triglyceride; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol.