Table 1. Baseline characteristics by changes in sleep duration a.
| Changes in sleep duration | ||||||
| decreased by ≥2 h (n = 1496) | decreased by 1 h (n = 726) | stable (n = 1055) | increased by 1 h (n = 701) | increased by ≥2 h (n = 1441) | P value | |
| Age (years) b | 80.6 (80.1, 81.1) | 78.0 (77.4, 78.7) | 78.3 (77.7, 78.9) | 78.4 (77.7, 79.1) | 81.6 (81.1, 82.1) | <0.0001 |
| Sex (males, %) | 47.9 | 51.2 | 51.0 | 50.6 | 48.4 | 0.21 |
| BMI (kg/m2) | 21.1 (20.9, 21.3) | 21.3 (21.0, 21.5) | 21.4 (21.1, 21.6) | 21.1 (20.9, 21.4) | 20.7 (20.5, 20.9) | <0.0001 |
| Residence (rural, %) | 73.2 | 64.7 | 65.6 | 68.6 | 70.7 | <0.01 |
| Education (illiterate, %) | 55.9 | 47.5 | 45.0 | 49.0 | 54.8 | <0.0001 |
| Marital status (married, %) | 48.2 | 56.6 | 58.1 | 54.4 | 46.8 | <0.0001 |
| Household income (≥10000 Yuan, %) | 54.0 | 56.8 | 60.4 | 61.2 | 52.9 | <0.01 |
| Regular physical Activity (%) | 32.0 | 40.8 | 39.6 | 42.5 | 36.2 | 0.19 |
| Smoking status (%) | ||||||
| Smoker | 22.0 | 25.3 | 24.5 | 22.3 | 21.6 | 0.04 |
| Ex-smoker | 16.1 | 15.2 | 15.8 | 14.7 | 15.3 | 0.70 |
| Non-smoker | 61.9 | 59.5 | 59.7 | 63.0 | 63.1 | 0.04 |
| Drinker status (%) | ||||||
| Drinker | 20.4 | 22.0 | 22.2 | 20.4 | 21.4 | 0.56 |
| Ex-drinker | 14.9 | 11.7 | 12.6 | 13.0 | 13.1 | 0.64 |
| Non-drinker | 64.7 | 66.3 | 65.2 | 66.6 | 65.5 | 0.86 |
| History of diseases (%) | ||||||
| Hypertension | 18.8 | 20.6 | 19.8 | 20.4 | 19.3 | 0.71 |
| Diabetes | 2.37 | 3.06 | 3.72 | 2.89 | 3.35 | 0.71 |
| CVD | 4.41 | 4.58 | 4.38 | 4.48 | 4.85 | 0.61 |
| Sleep duration in 2008 (hours/per day) | 9.11 (9.03, 9.20) | 7.86 (7.73, 7.99) | 7.76 (7.65, 7.86) | 7.03 (6.90, 7.15) | 6.43 (6.34, 6.52) | <0.0001 |
| Sleep duration in 2011 (hours/per day) | 5.85 (5.76, 5.94) | 6.86 (6.73, 6.99) | 7.75 (7.65, 7.86) | 8.03 (7.89, 8.16) | 9.74 (9.64, 9.83) | <0.0001 |
| Sleep quality (%) | ||||||
| Very good | 16.9 | 16.4 | 14.0 | 16.0 | 12.2 | 0.11 |
| Good | 60.8 | 55.1 | 55.7 | 49.6 | 40.9 | <0.0001 |
| Fair | 17.4 | 20.1 | 22.5 | 22.4 | 30.9 | <0.0001 |
| Bad | 4.55 | 7.99 | 7.38 | 11.1 | 14.4 | <0.0001 |
| Very bad | 0.35 | 0.41 | 0.42 | 0.90 | 1.60 | <0.01 |
| ADL disability (%) | 3.54 | 3.99 | 2.56 | 2.43 | 4.86 | 0.02 |
| Negative well-being | 9.39 (9.31, 9.46) | 9.45 (9.35, 9.56) | 9.41 (9.33, 9.50) | 9.44 (9.33, 9.55) | 9.33 (9.26, 9.41) | 0.29 |
| MMSE scores in 2008 | 26.9 (26.8, 27.1) | 27.5 (27.3, 27.7) | 27.5 (27.3, 27.7) | 27.5 (27.3, 27.7) | 27.0 (26.8, 27.1) | <0.0001 |
| MMSE scores in 2011 | 25.3 (25.0, 25.6) | 26.2 (25.8, 26.7) | 26.3 (25.9, 26.6) | 26.0 (25.6, 26.5) | 24.6 (24.3, 24.9) | <0.0001 |
Abbreviations: BMI, body mass index; ADL, Activities of daily living; CVD, cardiovascular disease; MMSE, Mini-Mental State Examination.
a Analysis of variance or logistic regression analysis.
b Mean (95% confidence interval) (all such values).