Table 2. Baseline characteristics of study participants by sleep duration among women.
| Characteristics | Overall | Sleep duration (hours) | P for quadratic trend | ||||
|---|---|---|---|---|---|---|---|
| ≤ 5 | 6 | 7 | 8 | ≥ 9 | |||
| Number | 105,974 | 15,378 | 30,413 | 35,442 | 19,602 | 5,139 | |
| Age (years)a | 40.2 (9.7) | 41.8 (11.0) | 40.5 (9.6) | 39.9 (9.2) | 39.5 (9.5) | 39.1 (10.8) | <0.001 |
| Seoul center (%) | 64.6 | 69.4 | 68.8 | 63.8 | 58.4 | 54.1 | <0.001 |
| Obesity (%) | 13.5 | 17.3 | 14.0 | 12.0 | 12.2 | 13.4 | <0.001 |
| Current smoker (%) | 2.5 | 3.7 | 2.6 | 2.0 | 2.2 | 2.3 | 0.022 |
| Alcohol intake (%)b | 5.9 | 8.6 | 6.0 | 5.0 | 5.2 | 6.0 | 0.041 |
| HEPA (%) | 15.0 | 16.2 | 15.3 | 15.0 | 14.2 | 12.5 | <0.001 |
| High education (%)d | 74.3 | 68.4 | 74.6 | 76.6 | 75.0 | 71.4 | 0.006 |
| Married (%) | 82.4 | 76.6 | 79.4 | 84.2 | 87.5 | 87.0 | <0.001 |
| Depression (%) | 16.3 | 27.5 | 17.4 | 12.9 | 12.6 | 14.9 | <0.001 |
| Hypertension | 7.0 | 10.0 | 7.1 | 6.0 | 6.4 | 7.0 | 0.038 |
| Diabetes | 2.7 | 3.7 | 2.7 | 2.3 | 2.7 | 3.4 | 0.524 |
| History of CVD | 0.9 | 1.4 | 0.9 | 0.8 | 0.8 | 1.1 | 0.021 |
| BMI (kg/m2) | 21.8 (3.0) | 22.2 (3.3) | 21.9 (3.1) | 21.6 (2.9) | 21.6 (3.0) | 21.6 (3.1) | <0.001 |
| Systolic BP (mmHg)a | 102.5 (12.2) | 103.5 (12.8) | 102.5 (12.3) | 102.2 (12.1) | 102.2 (12.0) | 102.3 (12.0) | 0.003 |
| Diastolic BP (mmHg)a | 65.5 (8.7) | 66.1 (9.1) | 65.5 (8.8) | 65.3 (8.6) | 65.2 (8.6) | 65.2 (8.4) | <0.001 |
| Glucose (mg/dl)a | 92.3 (12.3) | 92.5 (13.1) | 92.2 (12.0) | 92.0 (11.5) | 92.4 (12.7) | 92.5 (14.3) | 0.013 |
| Total cholesterol (mg/dl)a | 189.0 (33.3) | 191.7 (34.1) | 189.6 (33.1) | 188.5 (32.8) | 187.6 (33.4) | 186.9 (33.8) | <0.001 |
| LDL-C (mg/dl)a | 111.4 (30.4) | 113.4 (31.7) | 111.5 (30.4) | 110.8 (29.8) | 110.9 (30.3) | 110.5 (30.5) | 0.001 |
| HDL-C (mg/dl)a | 64.8 (14.8) | 64.9 (15.3) | 65.3 (14.6) | 65.1 (14.6) | 63.9 (14.4) | 63.2 (14.4) | <0.001 |
| Triglycerides (mg/dl)c | 72 (55–99) | 74 (56–103) | 71 (55–98) | 71 (55–96) | 72 (56–99) | 73 (56–102) | <0.001 |
| ALT (U/l)c | 13 (11–18) | 14 (11–19) | 13 (11–18) | 13 (10–17) | 13 (10–18) | 13 (10–17) | <0.001 |
| HOMA-IRc | 1.06 (0.71–1.55) | 1.04 (0.69–1.57) | 1.04 (0.70–1.54) | 1.06 (0.72–1.53) | 1.08 (0.73–1.57) | 1.10 (0.74–1.61) | <0.001 |
| hsCRP (mg/l)c | 0.3 (0.2–0.7) | 0.3 (0.2–0.7) | 0.3 (0.2–0.7) | 0.3 (0.2–0.6) | 0.3 (0.2–0.7) | 0.3 (0.2–0.7) | <0.001 |
| Total energy intakec,e | 1437.5 (1092.2–1810.2) | 1411.9 (1052.9–1808.1) | 1417.7 (1074.4–1793.4) | 1443.3 (1104.3–1806.0) | 1465.1 (1124.0–1824.4) | 1476.4 (1107.6–1861.2) | <0.001 |
| Poor sleep quality | 22.8 | 53.8 | 25.5 | 14.8 | 11.4 | 13.9 | <0.001 |
Data are expressed as
a mean (standard deviation)
c median (interquartile range), or percentage.
b ≥ 20 g of ethanol per day
d ≥ college graduate
e among 165,861 participants with plausible estimated energy intake levels (within three standard deviations from the log-transformed mean energy intake).
CVD, cardiovascular disease; ALT, alanine aminotransferase; BMI, body mass index; BP, blood pressure; HDL-C, high-density lipoprotein cholesterol; HEPA, health-enhancing physical activity; hsCRP, high sensitivity C-reactive protein; HOMA-IR, homeostasis model assessment of insulin resistance.