Variables | Study year | p-value | |||
2015 (n = 2863) | 2017 (n = 2863) | 2020 (n = 2863) | |||
N (%) | N (%) | N (%) | |||
Exposure variable | Insomnia symptoms | 446 (15.6) | 418 (14.6) | 336 (11.7) | < 0.001 |
Sociodemographic factors | Age (70 plus) | 1040 (36.3) | 1149 (40.5) | 1441 (50.3) | < 0.001 |
Sex (male) | 1270 (44.4) | ||||
Education (> elementary) | 449 (15.7) | ||||
Residence (urban) | 1392 (48.6) | ||||
Marital status (widowed) | 802 (28.4) | 786 (27.7) | 937 (32.8) | 0.002 | |
Subjective economic status (low) | 762 (26.6) | 1022 (35.7) | 978 (34.2) | < 0.001 | |
Religion (Buddhist) | 2619 (91.5) | ||||
Mental ill-health | Self-reported poor mental health | 798 (27.9) | 824 (28.8) | 685 (23.9) | < 0.001 |
Emotional/psychiatric disease | 12 (0.4) | 9 (0.3) | 22 (0.8) | 0.029 | |
Poor quality of life/happiness | 769 (26.9) | 1050 (36.7) | 1074 (34.2) | < 0.001 | |
Probable depression | 334 (11.7) | 279 (9.7) | 160 (5.6) | < 0.001 | |
Brain disease/dementia | 17 (0.6) | 26 (0.9) | 37 (1.3) | 0.013 | |
Physical ill-health | Poor self-rated physical health status | 746 (26.1) | 900 (31.4) | 734 (25.6) | < 0.001 |
Hypertension | 984 (34.4) | 1129 (39.4) | 1303 (45.5) | < 0.001 | |
Cardiovascular disease | 137 (4.8) | 154 (5.4) | 195 (6.8) | < 0.001 | |
Diabetes | 414 (14.5) | 419 (14.6) | 543 (19.0) | < 0.001 | |
Osteoporosis | 108 (3.8) | 103 (3.6) | 175 (6.1) | < 0.001 | |
Chronic lung disease | 21 (0.7) | 42 (1.5) | 42 (1.5) | 0.003 | |
Kidney disease | 47 (1.6) | 80 (2.8) | 123 (4.3) | < 0.001 | |
Physical injury | 342 (11.9) | 463 (16.2) | --- | < 0.001 | |
ADL disability | 72 (2.5) | 107 (3.7) | 218 (7.6) | < 0.001 | |
Cancer | 11 (0.4) | 24 (0.8) | 44 (1.5) | < 0.001 | |
Lifestyle factors | Current tobacco smoking | 339 (11.8) | 380 (13.3) | 316 (11.0) | <0.001 |
Hazardous alcohol use | 99 (3.5) | 186 (6.5) | 57 (2.0) | < 0.001 | |
Physical inactivity | 1606 (56.1) | 1256 (43.9) | 1444 (50.4) | < 0.001 | |
BMI-obesity class II | 189 (6.6) | 225 (7.9) | 220 (7.1) | 0.333 | |
Meal skipping | 156 (5.4) | 460 (16.1) | 379 (13.2) | < 0.001 |
Outcome variables | Model 1: unadjusted odds ratio (95% CI) | p-value | Model 2: adjusted odds ratio (95% CI)a | p-value |
Mental ill-health | ||||
Self-reported poor mental health | 1.68 (1.51 to 1.87) | < 0.001 | 0.99 (0.85 to 1.14) | 0.837 |
Poor quality of life/happiness | 3.21 (2.88 to 3.58) | < 0.001 | 1.25 (1.09 to 1.42) | 0.002 |
Depressive symptoms | 4.81 (4.13 to 5.60) | < 0.001 | 3.96 (3.30 to 4.76) | < 0.001 |
Brain disease/dementia | 2.03 (1.38 to 3.01) | < 0.001 | 0.95 (0.57 to 1.59) | 0.843 |
Physical ill-health | ||||
Poor self-rated physical health status | 2.13 (1.92 to 2.36) | < 0.001 | 1.60 (1.41 to 1.83) | < 0.001 |
Hypertension | 1.51 (1.36 to 1.68) | < 0.001 | 1.25 (1.09 to 1.43) | < 0.001 |
Cardiovascular disease | 1.74 (1.44 to 2.10) | < 0.001 | 1.42 (1.11 to 1.82) | 0.006 |
Diabetes | 1.50 (1.31 to 1.71) | < 0.001 | 1.39 (1.18 to 1.63) | < 0.001 |
Osteoporosis | 2.28 (1.86 to 2.81) | < 0.001 | 1.66 (1.27 to 2.17) | < 0001 |
Chronic lung disease | 2.01 (1.43 to 2.95) | < 0.001 | 2.16 (1.46 to 3.20) | < 0.001 |
Kidney disease | 1.55 (1.19 to 2.03) | < 0.001 | 1.18 (0.84 to 1.65) | 0.345 |
Physical injury | 1.49 (1.28 to 1.74) | < 0.001 | 1.38 (1.10 to 1.64) | < 0.001 |
ADL disability | 1.23 (0.99 to 1.52) | 0.058 | --- | |
Cancer | 1.30 (0.79 to 2.14) | 0.305 | --- | |
Lifestyle factors | ||||
Current tobacco smoking | 0.83 (0.71 to 0.98) | 0.028 | 0.99 (0.80 to 1.22) | 0.907 |
Hazardous alcohol use | 0.83 (0.63 to 1.09) | 0.170 | --- | |
Physical inactivity | 1.17 (1.05 to 1.29) | 0.004 | 1.14 (1.01 to 1.30) | 0.033 |
Body mass index (BMI)-obesity | 1.07 (0.88 to 1.31) | 0.500 | --- | |
Meal skipping | 1.56 (1.35 to 1.81) | < 0.001 | 1.68 (1.44 to 1.96) | < 0.001 |
Outcome variables | Insomnia symptoms | Model 1: unadjusted odds ratio (95% CI) | p-value | Model 2: adjusted odds ratio (95% CI)a | p-value |
Mental ill-health | |||||
Incident self-reported poor mental health | 0 waves 1 wave 2-3 waves |
1 (Reference) 1.41 (1.14 to 1.73) 2.10 (1.44 to 2.06) |
< 0.001 < 0.001 |
1 (Reference) 1.39 (1.12 to 1.72) 1.97 (1.33 to 2.92) |
0.003 < 0.001 |
Incident poor quality of life/happiness | 0 waves 1 wave 2-3 waves |
1 (Reference) 1.17 (0.94 to 1.45) 1.67 (1.15 to 2.44) |
0.169 0.008 |
1 (Reference) 1.15 (0.92 to 1.44) 1.77 (1.18 to 2.64) |
0.227 0.005 |
Incident depressive symptomsb | 0 waves 1 wave 2-3 waves |
1 (Reference) 2.53 (1.83 to 3.51) 5.26 (3.43 to 8.06) |
< 0.001 < 0.001 |
1 (Reference) 2.45 (1.74 to 3.44) 5.27 (3.36 to 8.27) |
< 0.001 < 0.001 |
Incident brain disease/dementia | 0 waves 1 wave 2-3 waves |
1 (Reference) 1.32 (0.72 to 2.44) 2.12 (0.92 to 4.90) |
0.373 0.078 |
--- | |
Physical ill-health | |||||
Incident poor self-rated physical health status | 0 waves 1 wave 2-3 waves |
1 (Reference) 1.50 (1.22 to 1.84) 2.96 (2.00 to 4.38) |
< 0.001 < 0.001 |
1 (Reference) 1.41 (1.14 to 1.75) 2.66 (1.75 to 4.05) |
0.002 < 0.001 |
Incident hypertension | 0 waves 1 wave 2-3 waves |
1 (Reference) 1.23 (0.98 to 1.56) 1.82 (1.20 to 2.76) |
0.081 0.005 |
1 (Reference) 1.20 (0.94 to 1.54) 1.65 (1.06 to 2.57) |
0.114 0.025 |
Incident cardiovascular disease | 0 waves 1 wave 2-3 waves |
1 (Reference) 0.99 (0.70 to 1.41) 0.95 (0.52 to 1.76) |
0.951 0.881 |
--- | |
Incident diabetes | 0 waves 1 wave 2-3 waves |
1 (Reference) 1.22 (0.90 to 1.66) 1.65 (1.03 to 2.64) |
0.205 0.039 |
1 (Reference) 1.20 (0.87 to 1.65) 1.60 (0.97 to 2.63) |
0.270 0.064 |
Incident osteoporosis | 0 waves 1 wave 2-3 waves |
1 (Reference) 1.81 (1.33 to 2.48) 3.79 (2.51 to 5.71) |
< 0.001 < 0.001 |
1 (Reference) 1.63 (1.18 to 2.25) 2.99 (1.93 to 4.63) |
0.003 < 0.001 |
Incident chronic lung disease | 0 waves 1 wave 2-3 waves |
1 (Reference) 2.09 (1.15 to 3.01) 3.46 (1.59 to 7.56) |
0.016 0.002 |
1 (Reference) 2.19 (1.16 to 4.12) 4.12 (1.79 to 9.46) |
0.006 < 0.001 |
Incident kidney disease | 0 waves 1 wave 2-3 waves |
1 (Reference) 1.86 (1.28 to 2.71) 2.32 (1.33 to 4.03) |
< 0.001 0.003 |
1 (Reference) 1.86 (1.26 to 2.74) 2.06 (1.14 to 3.69) |
0.002 0.016 |
Incident physical injury | 0 waves 1 wave 2-3 waves |
1 (Reference) 1.39 (1.09 to 1.77) 1.93 (1.33 to 2.81) |
0.008 < 0.001 |
1 (Reference) 1.43 (1.10 to 1.84) 1.81 (1.22 to 2.69) |
0.007 0.003 |
Incident ADL disability | 0 waves 1 wave 2-3 waves |
1 (Reference) 1.32 (1.01 to 1.73) 1.53 (1.00 to 2.33) |
0.041 0.048 |
1 (Reference) 1.48 (0.86 to 1.62) 1.21 (0.74 to 1.96) |
0.309 0.451 |
Incident cancer | 0 waves 1 wave 2-3 waves |
1 (Reference) 1.07 (0.55 to 2.06) 0.60 (0.14 to 2.52) |
0.846 0.482 |
--- | |
Lifestyle factors | |||||
Incident current tobacco smoking | 0 waves 1 wave 2-3 waves |
1 (Reference) 1.16 (0.83 to 1.63) 0.95 (0.52 to 1.71) |
0.377 0.854 |
--- | |
Incident hazardous alcohol use | 0 waves 1 wave 2-3 waves |
1 (Reference) 0.85 (0.60 to 1.19) 0.76 (0.42 to 1.40) |
0.344 0.379 |
--- | |
Incident physical inactivity | 0 waves 1 wave 2-3 waves |
1 (Reference) 1.15 (0.87 to 1.51) 0.80 (0.51 to 1.26) |
0.337 0.339 |
--- | |
Incident body mass index (BMI)-obesity | 0 waves 1 wave 2-3 waves |
1 (Reference) 1.45 (1.00 to 2.09) 0.42 (0.15 to 1.16) |
0.049 0.095 |
1 (Reference) 1.34 (0.90 to 1.99) 0.44 (0.17 to 1.33) |
0.154 0.158 |
Incident meal skipping | 0 waves 1 wave 2-3 waves |
1 (Reference) 1.37 (1.12 to 1.68) 2.00 (1.46 to 2.74) |
0.002 < 0.001 |
1 (Reference) 1.34 (1.07 to 1.68) 2.15 (1.51 to 3.06) |
0.010 <0.001 |
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