Table 1.
Baseline characteristics of the population according to sleep duration in the Singapore Chinese Health Study (n = 63,147, 1,143 cases)
| Characteristics | Daily sleep duration |
P-value | ||||
|---|---|---|---|---|---|---|
| ≤ 5 hours | 6 hours | 7 hours | 8 hours | ≥ 9 hours | ||
| Number of participants, n | 6,133 | 14,712 | 20,599 | 17,317 | 4,386 | |
| ESRD cases, n | 152 | 234 | 325 | 328 | 104 | |
| Age at recruitment, year | 58.8 ± 8.1 | 56.7 ± 7.9 | 55.8 ± 7.7 | 55.9 ± 8.1 | 58.3 ± 8.4 | < 0.001 |
| Body mass index, kg/m2 | 23.1 ± 3.3 | 23.2 ± 3.3 | 23.1 ± 3.2 | 23.1 ± 3.3 | 23.1 ± 3.5 | 0.06 |
| Men (%) | 2,378 (38.8) | 6,484 (44.1) | 9,066 (44.0) | 8,004 (46.2) | 1,964 (44.8) | < 0.001 |
| Cantonese dialect (%) (%) | 3,066 (50.0) | 6,727 (45.7) | 9,462 (45.9) | 7,906 (45.7) | 2,071 (47.2) | < 0.001 |
| Level of education | < 0.001 | |||||
| No formal education | 2,111 (34.4) | 4,155 (28.2) | 5,391 (26.2) | 4,350 (25.1) | 1,295 (29.5) | |
| Primary school | 2,738 (44.6) | 6,400 (43.5) | 9,023 (43.8) | 7,761 (44.8) | 2,073 (47.3) | |
| Secondary school or higher | 1,284 (20.9) | 4,157 (28.3) | 6,185 (30.0) | 5,206 (30.1) | 1,018 (23.2) | |
| Ever smoked (%) | 1,907 (31.1) | 4,449 (30.2) | 5,921 (28.7) | 5,413 (31.3) | 1,611 (36.7) | < 0.001 |
| Weekly physical activitya (%) | 1,785 (29.1) | 4,871 (33.1) | 6,904 (33.5) | 5,870 (33.9) | 1,334 (30.4) | < 0.001 |
| Alcohol intake (%) | < 0.001 | |||||
| Non/occasionally drinkers | 5,448 (88.8) | 12,971 (88.2) | 18,290 (88.8) | 15,254 (88.1) | 3,874 (88.3) | |
| Weekly drinkers | 410 (6.7) | 1,233 (8.4) | 1,709 (8.3) | 1,433 (8.3) | 320 (7.3) | |
| Daily drinkers | 275 (4.5) | 508 (3.5) | 600 (2.9) | 630 (3.6) | 192 (4.4) | |
| Coffee consumption (%) | < 0.001 | |||||
| None to < 1 cup/day | 2,026 (33.0) | 4,464 (30.3) | 6,019 (29.2) | 4,924 (28.4) | 1,345 (30.7) | |
| 1 cup/day | 2,111 (34.4) | 5,069 (34.5) | 7,397 (35.9) | 6,586 (38.0) | 1,594 (36.3) | |
| ≥ 2 cups/day | 1,996 (32.6) | 5,179 (35.2) | 7,183 (34.9) | 5,807 (33.5) | 1,447 (33.0) | |
| Total protein intake g/day | 58.8 ± 10.1 | 59.0 ± 9.7 | 59.2 ± 10.0 | 59.2 ± 10.1 | 59.3 ± 10.2 | 0.0107 |
| Red meat intake g/day | 30.3 ± 19.2 | 30.3 ± 18.6 | 30.4 ± 18.5 | 30.5 ± 18.7 | 31.6 ± 19.2 | 0.0015 |
| Weekly ginseng intake (%) | 183 (3.0) | 399 (2.7) | 510 (2.5) | 460 (2.7) | 106 (2.4) | 0.19 |
| Weekly medicinal soup intake (%) | 667 (10.9) | 1,549 (10.5) | 1,982 (9.6) | 1,674 (9.7) | 474 (10.8) | 0.001 |
| Current daily incense users (%) | 4,637 (75.6) | 11,329 (77.0) | 15,747 (76.5) | 13,420 (77.5) | 3,412 (77.8) | 0.008 |
| Comorbidities (%) | ||||||
| Hypertension | 1,731 (28.2) | 3,437 (23.4) | 4,591 (22.3) | 4,002 (23.1) | 1,211 (27.6) | < 0.001 |
| Coronary artery disease | 370 (6.0) | 580 (3.9) | 719 (3.5) | 656 (3.8) | 262 (6.0) | < 0.001 |
| Stroke | 135 (2.2) | 170 (1.2) | 223 (1.1) | 269 (1.6) | 149 (3.4) | < 0.001 |
| Diabetes | 671 (11.0) | 1,268 (8.6) | 1,586 (7.7) | 1,565 (9.0) | 581 (13.3) | < 0.001 |
Data are shown as n (%) for categorical variables and mean ± SD for continuous variables.
a
Physical activity defined as at least 30 minutes of moderate activity, vigorous activity or strenuous sports.