Table 2 The comparisons of baseline socio-demographic factors, lifestyle behaviors, disease history and frailty status according to sleep duration and cognitive function in older adults (n = 912)
| Â | Sleep duration (h/day) N (%) | MMSE score N (%) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Variables |  < 7 (N = 234) | 7 (N = 225) | 8–9 (N = 359) |  > 9 (N = 94) | p value | 30 (N = 253) | 29 (N = 215) | 27–28 (N = 220) |  < 27 (N = 224) | p value |
Socio-demographic factors | ||||||||||
 Men | 94 (40.17) | 115 (51.11) | 205 (57.10) | 63 (67.02) |  < 0.001 | 150 (59.29) | 127 (59.07) | 121 (55.00) | 79 (35.27) |  < 0.001 |
 Age (years) | 73.53 ± 5.55 | 73.08 ± 6.33 | 74.12 ± 6.66 | 77.20 ± 7.34 |  < 0.001 | 72.09 ± 5.62 | 72.91 ± 6.12 | 74.23 ± 6.22 | 77.09 ± 6.86 |  < 0.001 |
  65–74 | 139 (59.4) | 147 (65.33) | 210 (58.5) | 37 (39.36) |  | 181 (71.54) | 142 (66.05) | 122 (55.45) | 88 (39.29) |  |
  75–84 | 87 (37.18) | 67 (29.78) | 117 (32.59) | 39 (41.49) |  | 64 (25.3) | 64 (29.77) | 84 (38.18) | 98 (43.75) |  |
   > 85 | 8 (3.42) | 11 (4.89) | 32 (8.91) | 18 (19.15) |  | 8 (3.16) | 9 (4.19) | 14 (6.36) | 38 (16.96) |  |
 Education |  |  |  |  | 0.02 |  |  |  |  |  < 0.001 |
  No education | 40 (17.09) | 25 (11.11) | 27 (7.52) | 12 (12.77) |  | 1 (0.40) | 4 (1.86) | 14 (6.36) | 85 (37.95) |  |
  Primary education | 66 (28.21) | 63 (28) | 108 (30.08) | 21 (22.34) |  | 54 (21.34) | 54 (25.12) | 73 (33.18) | 77 (34.38) |  |
  Secondary or tertiary education | 128 (54.7) | 137 (60.89) | 224 (62.4) | 61 (64.89) |  | 198 (78.26) | 157 (73.02) | 133 (60.45) | 62 (27.68) |  |
 Married | 163 (69.66) | 160 (71.11) | 264 (73.54) | 65 (69.15) | 0.71 | 204 (80.63) | 174 (80.93) | 157 (71.36) | 117 (52.23) |  < 0.001 |
 Body mass index (kg/m2) | 24.05 ± 3.81 | 24.65 ± 3.27 | 24.47 ± 3.46 | 24.13 ± 3.37 | 0.52 | 24.37 ± 3.15 | 24.36 ± 3.34 | 24.46 ± 3.61 | 24.29 ± 3.91 | 0.90 |
  < 18.5 | 12 (5.13) | 6 (2.67) | 12 (3.34) | 7 (7.45) |  | 8 (3.16) | 7 (3.26) | 7 (3.18) | 15 (6.7) |  |
  18.5–25 | 142 (60.68) | 125 (55.56) | 205 (57.1) | 49 (52.13) |  | 142 (56.13) | 129 (60) | 129 (58.64) | 121 (54.02) |  |
  25–30 | 67 (28.63) | 84 (37.33) | 120 (33.43) | 34 (36.17) |  | 93 (36.76) | 68 (31.63) | 71 (32.27) | 73 (32.59) |  |
   ≥ 30 | 13 (5.56) | 10 (4.44) | 22 (6.13) | 4 (4.26) |  | 10 (3.95) | 11 (5.12) | 13 (5.91) | 15 (6.7) |  |
Lifestyle behaviors | ||||||||||
 Smoking | 18 (7.69) | 20 (8.89) | 38 (10.58) | 8 (8.51) | 0.67 | 22 (8.7) | 25 (11.63) | 18 (8.18) | 19 (8.48) | 0.57 |
 Alcohol drinking | 24 (10.26) | 36 (16) | 47 (13.09) | 11 (11.7) | 0.32 | 39 (15.42) | 30 (13.95) | 28 (12.73) | 21 (9.38) | 0.25 |
 Physical activity | 173 (73.93) | 178 (79.11) | 251 (69.92) | 58 (61.7) | 0.008 | 198 (78.26) | 161 (74.88) | 162 (73.64) | 139 (62.05) |  < 0.001 |
Disease history | ||||||||||
 Hypertension | 108 (46.15) | 107 (47.56) | 200 (55.71) | 53 (56.38) | 0.06 | 126 (49.8) | 106 (49.3) | 107 (48.64) | 129 (57.59) | 0.19 |
 Diabetes mellitus | 38 (16.24) | 26 (11.56) | 62 (17.27) | 25 (26.6) | 0.01 | 42 (16.6) | 32 (14.88) | 35 (15.91) | 42 (18.75) | 0.73 |
 Heart disease | 73 (31.2) | 66 (29.33) | 105 (29.25) | 31 (32.98) | 0.88 | 80 (31.62) | 66 (30.7) | 49 (22.27) | 80 (35.71) | 0.02 |
 Hyperlipidemia | 68 (29.06) | 60 (26.67) | 83 (23.12) | 18 (19.15) | 0.19 | 71 (28.06) | 55 (25.58) | 51 (23.18) | 52 (23.21) | 0.56 |
 Gout | 21 (8.97) | 33 (14.67) | 38 (10.58) | 10 (10.64) | 0.26 | 38 (15.02) | 17 (7.91) | 24 (10.91) | 23 (10.27) | 0.10 |
 Hyperuricemia | 21 (8.97) | 24 (10.67) | 38 (10.58) | 12 (12.77) | 0.78 | 28 (11.07) | 16 (7.44) | 21 (9.55) | 30 (13.39) | 0.22 |
 Arthritis | 53 (22.65) | 42 (18.67) | 71 (19.78) | 13 (13.83) | 0.32 | 47 (18.58) | 39 (18.14) | 45 (20.45) | 48 (21.43) | 0.79 |
 Osteoporosis | 49 (20.94) | 48 (21.33) | 56 (15.6) | 9 (9.57) | 0.03 | 41 (16.21) | 32 (14.88) | 37 (16.82) | 52 (23.21) | 0.10 |
 Stroke | 9 (3.85) | 10 (4.44) | 21 (5.85) | 16 (17.02) |  < 0.001 | 10 (3.95) | 11 (5.12) | 14 (6.36) | 21 (9.38) | 0.09 |
 Cataract | 125 (53.42) | 86 (38.22) | 160 (44.57) | 48 (51.06) | 0.008 | 96 (37.94) | 96 (44.65) | 95 (43.18) | 132 (58.93) |  < 0.001 |
 Cancer | 7 (2.99) | 17 (7.56) | 20 (5.57) | 8 (8.51) | 0.11 | 15 (5.93) | 14 (6.51) | 12 (5.45) | 11 (4.91) | 0.90 |
 Fall history | 64 (27.35) | 42 (18.67) | 79 (22.01) | 26 (27.66) | 0.10 | 38 (15.02) | 41 (19.07) | 45 (20.45) | 87 (38.84) |  < 0.001 |
 Sleep impairment | 142 (60.68) | 93 (41.33) | 140 (39) | 34 (36.17) |  < 0.001 | 103 (40.71) | 99 (46.05) | 86 (39.09) | 121 (54.02) | 0.006 |
 Taking sleeping pills | 69 (29.49) | 57 (25.33) | 72 (20.06) | 15 (15.96) | 0.02 | 43 (17.00) | 48 (22.33) | 52 (23.64) | 70 (31.25) | 0.003 |
Frailty status |  |  |  |  |  < 0.001 |  |  |  |  |  < 0.001 |
 Robust (0 components) | 87 (37.18) | 106 (47.11) | 148 (41.23) | 28 (29.79) |  | 134 (52.96) | 98 (45.58) | 85 (38.64) | 52 (23.21) |  |
 Pre-frailty (1 ~ 2 components) | 131 (55.98) | 110 (48.89) | 165 (45.96) | 37 (39.36) |  | 106 (41.9) | 105 (48.84) | 113 (51.36) | 119 (53.13) |  |
 Frailty (≥ 3 component) | 16 (6.84) | 9 (4.00) | 46 (12.81) | 29 (30.85) |  | 13 (5.14) | 12 (5.58) | 22 (10) | 53 (23.66) |  |
Frailty components | ||||||||||
 Shrinking | 37 (15.81) | 27 (12.00) | 41 (11.42) | 14 (14.89) | 0.41 | 22 (8.7) | 31 (14.42) | 30 (13.64) | 36 (16.07) | 0.09 |
 Poor endurance and energy | 10 (4.27) | 1 (0.44) | 14 (3.9) | 12 (12.77) |  < 0.001 | 12 (4.74) | 6 (2.79) | 6 (2.73) | 13 (5.8) | 0.27 |
 Low physical activity | 35 (14.96) | 26 (11.56) | 79 (22.01) | 25 (26.6) | 0.001 | 39 (15.42) | 34 (15.81) | 35 (15.91) | 57 (25.45) | 0.01 |
 Slowness | 88 (37.61) | 60 (26.67) | 129 (35.93) | 52 (55.32) |  < 0.001 | 51 (20.16) | 54 (25.12) | 82 (37.27) | 142 (63.39) |  < 0.001 |
 Weakness | 60 (25.64) | 55 (24.44) | 108 (30.08) | 50 (53.19) |  < 0.001 | 47 (18.58) | 56 (26.05) | 65 (29.55) | 105 (46.88) |  < 0.001 |