Table 1.
Baseline characteristics of participants by estimated total sleep duration per day
| ≤6 h (n = 11 108) | 6–8 h (n = 50 041) (Reference group) | 8–9 h (n = 31 003) | 9–10 h (n = 16 316) | >10 h (n = 8164) | |
|---|---|---|---|---|---|
| Age (years), mean (SD) | 50.2 (9.5) | 50.0 (9.5) | 50.6 (9.9) | 51.1 (10.2) | 51.6 (10.5) |
| ≥50 years (%) | 5579 (50.2) | 25 040 (50.0) | 16 372 (52.8) | 8853 (54.3) | 4521 (55.4) |
| Male (%) | 5051 (45.5) | 21 743 (43.5) | 12 412 (40.0) | 6329 (38.8) | 3238 (39.7) |
| Urban resident (%) | 6977 (62.8) | 29 848 (59.7) | 16 017 (51.7) | 7351 (45.1) | 3516 (43.1) |
| Body mass index (kg/m2), mean (SD) | 27.2 (5.5) | 26.3 (5.0) | 25.7 (4.9) | 25.7 (5.0) | 25.9 (5.6) |
| Waist to hip ratio, mean (SD) | 0.885 (0.086) | 0.877 (0.084) | 0.870 (0.080) | 0.869 (0.079) | 0.873 (0.084) |
| Education (Trade, college, or university, %) | 2325 (21.0) | 12 314 (24.6) | 5935 (19.2) | 2242 (13.8) | 858 (10.5) |
| Physical activity, MET × min/week | |||||
| Low (<600) | 2562/10 379 (24.7) | 8328/47 645 (17.5) | 4429/29 540 (15.0) | 2464/15 317 (16.1) | 1499/7299 (20.5) |
| Moderate (600–3000) | 3548/10 379 (34.2) | 17 276/47 645 (36.3) | 11 573/29 540 (39.2) | 6133/15 317 (40.0) | 2864/7299 (39.2) |
| High (>3000) | 4269/10 379 (41.1) | 22 041/47 645 (46.3) | 13 538/29 540 (45.8) | 6720/15 317 (43.9) | 2936/7299 (40.2) |
| AHEI score, mean (SD) | 34.8 (8.5) | 34.7 (8.4) | 35.2 (8.3) | 35.1 (8.3) | 34.7 (8.4) |
| Smoker (current and former, %) | 3441 (31.1) | 16 178 (32.5) | 9730 (31.6) | 5273 (32.6) | 2902 (35.8) |
| Drinker (current and former, %) | 2215 (20.3) | 16 379 (33.2) | 10 041 (32.7) | 5152 (31.9) | 2952 (36.6) |
| Hypertension (%) | 4272 (38.5) | 19 100 (38.2) | 12 411 (40.1) | 6756 (41.4) | 3581 (43.9) |
| Diabetes (%) | 1188 (10.7) | 3316 (6.6) | 1739 (5.6) | 984 (6.0) | 568 (7.0) |
| Depression (%) | 1056 (9.5) | 3741 (7.5) | 1975 (6.4) | 1259 (7.8) | 917 (11.3) |
| Chronic obstructive pulmonary disease (%) | 81 (0.7) | 318 (0.6) | 188 (0.6) | 121 (0.7) | 77 (0.9) |
| Health conditiona (%) | 8196 (73.8) | 35 739 (71.4) | 21 688 (70.0) | 11 860 (72.7) | 6441 (78.9) |
| No. of participants taking nap (%) | 2279 (20.5) | 13 723 (27.4) | 13 647 (44.0) | 9790 (60.0) | 5842 (71.6) |
| Duration of daytime naps (min), median (q1–q3) | 30 (30–60) | 45 (30–60) | 60 (30–60) | 60 (40–90) | 60 (60–120) |
| Total estimated sleep duration (h), median (q1–q3) | 5.5 (5.0–6.0) | 7.5 (7.0–8.0) | 9.0 (8.5–9.0) | 9.5 (9.5–10.0) | 11.0 (10.5–11.5) |
AHEI, alternate healthy eating index; SD, standard deviation.
aHealth condition is defined as having any disabilities, symptoms, or history diseases.
Disabilities: having trouble grasping/handling with fingers, walking about (or require a walking stick cane/walker), bending down and picking up objects, reading, seeing the individual grains of rice/corn on the plate or a person from across the room (with glass worn), speaking, or hearing in a normal conversation. Symptoms: having experienced any of the following in the last 6 months: chest pain or breathlessness with usual activity, cough (≥2 weeks), sputum while coughing, blood in sputum, wheezing or whistling in the chest, early morning cough with chest tightness, diarrhoea (≥3 days), vomiting, loss of appetite, painful or bleeding teeth/gums, jaundice, burning while passing urine, swelling of feet or face, blood in urine, involuntary weight loss of >3 kg. History diseases: having been diagnosed with diabetes, hypertension (or high blood pressure), hepatitis (or jaundice), chronic obstructive pulmonary disease, asthma, tuberculosis, malaria, or Chagas.