Table 1.
Baseline Characteristics of Participants Stratified by Sleep Duration
| Variable | Level | Normal Sleep | Less Sleep | More Sleep | P-value |
|---|---|---|---|---|---|
| Age (mean (SD)) | 57.32 (8.31) | 59.06 (8.41) | 59.27 (9.74) | <0.001 | |
| Gender, n (%) | Female | 1532 (52.2) | 1768 (54.5) | 142 (51.1) | 0.149 |
| Male | 1405 (47.8) | 1479 (45.5) | 136 (48.9) | ||
| Education, n (%) | Less than lower secondary education | 2608 (88.8) | 2918 (89.9) | 263 (94.6) | 0.008 |
| Secondary or above | 329 (11.2) | 329 (10.1) | 15 (5.4) | ||
| Marital status, n (%) | Married | 2685 (91.4) | 2863 (88.2) | 232 (83.5) | <0.001 |
| Non-married | 252 (8.6) | 384 (11.8) | 46 (16.5) | ||
| Residence, n (%) | Rural | 1945 (66.2) | 2056 (63.3) | 200 (71.9) | 0.003 |
| Urban | 992 (33.8) | 1191 (36.7) | 78 (28.1) | ||
| Smoking, n (%) | No | 1785 (60.8) | 1998 (61.5) | 164 (59.0) | 0.636 |
| Yes | 1152 (39.2) | 1249 (38.5) | 114 (41.0) | ||
| Drinking, n (%) | No | 1813 (61.8) | 1970 (60.7) | 163 (58.6) | 0.491 |
| Yes | 1123 (38.2) | 1274 (39.3) | 115 (41.4) | ||
| BMI (median [IQR]) | 23.42 [21.19, 26.05] | 23.14 [20.87, 25.78] | 22.65 [20.71, 25.48] | 0.001 | |
| WC (median [IQR]) | 85.00 [78.40, 93.00] | 84.20 [78.00, 91.45] | 84.20 [78.30, 91.75] | 0.010 | |
| SBP (mean (SD)) | 128.84 (20.72) | 128.68 (20.51) | 130.23 (23.15) | 0.526 | |
| DBP (mean (SD)) | 75.82 (12.14) | 74.91 (12.01) | 76.26 (14.13) | 0.010 | |
| TG (median [IQR]) | 107.08 [74.34, 157.53] | 106.20 [76.11, 154.88] | 107.53 [75.22, 157.53] | 0.962 | |
| LDL (median [IQR]) | 113.66 [93.94, 136.66] | 114.05 [91.62, 136.86] | 116.75 [91.24, 138.79] | 0.754 | |
| MET (mean (SD)) | 7731.60 (7711.35) | 7097.81 (7241.78) | 7893.20 (6808.54) | 0.074 | |
| ADL (mean (SD)) | 0.18 (0.66) | 0.34 (0.88) | 0.32 (0.86) | <0.001 | |
| Glucose (mean (SD)) | 110.39 (34.62) | 109.77 (35.65) | 109.05 (33.16) | 0.781 | |
| CESD (median [IQR]) | 3.00 [0.00, 6.00] | 4.00 [2.00, 9.00] | 4.00 [1.00, 6.00] | <0.001 |
Notes: Data are presented as mean (standard deviation, SD) for normally distributed continuous variables, median [interquartile range, IQR] for non-normally distributed continuous variables, and n (%) for categorical variables. Comparisons were made using one-way analysis of variance (ANOVA) for normally distributed data, the Kruskal–Wallis test for non-normally distributed data, and the Chi-square test for categorical data. Statistical significance was defined as a two-tailed P < 0.05. Sleep duration categories were defined as: Normal sleep (7–9 hours/night), Less sleep (<7 hours/night), and More sleep (>9 hours/night).
Abbreviations: ADL, Activities of Daily Living; BMI, Body Mass Index; CESD, Center for Epidemiologic Studies Depression Scale; DBP, Diastolic Blood Pressure; IQR, Interquartile Range; LDL, Low-Density Lipoprotein; MET, Metabolic Equivalent of Task; SD, Standard Deviation; SBP, Systolic Blood Pressure; TG, Triglycerides; WC, Waist Circumference.