Introduction
Methods
Measures
Exposure variable
Outcome variables
Mental ill-health outcomes
Physical ill-health outcomes
Life style factor outcomes
Mortality outcome
Covariates
Data analysis
Results
Variables | Study year | P-value | ||
---|---|---|---|---|
2015 (n = 5616) | 2017 (n = 3600) | 2020 (n = 2863) | ||
N (%) | N (%) | N (%) | ||
Sociodemographic factors | ||||
Age (70 plus) | 2282 (40.6) | 1628 (45.2) | 1441 (50.3) | < 0.001 |
Sex (male) | 2686 (47.8) | 1653 (45.9) | 1224 (42.8) | < 0.001 |
Education (> elementary) | 1024 (18.3) | 686 (19.2) | 470 (16.6) | 0.144 |
Residence (rural) | 3008 (53.6) | 1804 (50.1) | 1375 (48.0) | < 0.001 |
Marital status (widowed) | 1673 (30.4) | 1032 (28.7) | 937 (32.8) | 0.002 |
Subjective economic status (low) | 1588 (29.3) | 1351 (39.4) | 978 (35.7) | < 0.001 |
Religion (Buddhist) | 5208 (92.9) | 3273 (91.5) | 2585 (91.1) | 0.007 |
Mental ill-health | ||||
Self-reported poor mental health | 1647 (30.0) | 1146 (31.0) | 741 (23.5) | < 0.001 |
Poor quality of life/happiness | 1689 (31.6) | 1466 (41.3) | 1074 (34.2) | < 0.001 |
Probable depression | 581 (11.3) | 296 (8.3) | 127 (4.4) | < 0.001 |
Insomnia symptoms | 911 (16.4) | 545 (15.2) | 336 (11.7) | < 0.001 |
Brain disease/dementia | 47 (0.8) | 53 (1.5) | 37 (1.3) | 0.013 |
Loneliness | 1195 (21.6) | 852 (23.8) | 610 (21.3) | 0.024 |
Physical ill-health | ||||
Poor self-rated physical health status | 1527 (27.8) | 1255 (34.9) | 734 (25.6) | < 0.001 |
Hypertension | 1951 (34.7) | 1463 (40.6) | 1303 (45.5) | < 0.001 |
Cardiovascular disease | 277 (4.9) | 213 (5.9) | 195 (6.8) | < 0.001 |
Kidney disease | 105 (1.9) | 123 (3.4) | 123 (4.3) | < 0.001 |
Diabetes | 849 (15.1) | 571 (15.9) | 543 (19.0) | < 0.001 |
Osteoporosis | 187 (3.3) | 132 (3.7) | 175 (6.1) | < 0.001 |
Chronic lung disease | 49 (0.9) | 58 (1.6) | 42 (1.5) | 0.003 |
ADL disability | 207 (3.8) | 208 (5.6) | 222 (7.0) | < 0.001 |
Cancer | 29 (0.5) | 35 (1.0) | 44 (1.5) | < 0.001 |
Lifestyle factors | ||||
Current tobacco smoking | 706 (12.6) | 490 (13.2) | 341 (10.8) | < 0.001 |
Hazardous alcohol use | 201 (3.6) | 236 (6.4) | 59 (1.9) | < 0.001 |
Physical inactivity | 3288 (59.5) | 1689 (45.8) | 1590 (50.4) | < 0.001 |
Body mass index (BMI)-underweighta | 563 (10.0) | 363 (10.1) | 327 (11.4) | 0.108 |
BMI-obesity class IIa | 361 (6.4) | 270 (7.5) | 220 (7.0) | 0.135 |
Longitudinal analyses with health outcomes and loneliness as exposure variable
Outcome variables | Lone-liness | Model 1: unadjusted odds ratio (95% CI) | p-value | Model 2: adjusted odds ratio (95% CI)a | p-value |
---|---|---|---|---|---|
Mental ill-health | |||||
Poor self-rated mental health status | No Yes | 1 Reference 2.23 (2.03 to 2.44) | < 0.001 | 1 Reference 1.70 (1.52 to 1.90) | < 0.001 |
Study wave | Wave 1 Wave 2 Wave 3 | 1 (Reference) 0.89 (0.80 to 1.00) 0.64 (0.50 to 0.73 | 0.042 < 0.001 | ||
Poor quality of life/happiness | No Yes | 1 Reference 2.20 (2.00 to 2.40) | < 0.001 | 1 Reference 1.57 (1.39 to 1.78) | < 0.001 |
Study wave | Wave 1 Wave 2 Wave 3 | 1 (Reference) 1.50 (1.36 to 1.67) 1.21 (1.07 to 1.36) | < 0.001 0.002 | ||
Depressive symptoms | No Yes | 1 Reference 6.52 (5.79 to 7.35) | < 0.001 | 1 Reference 15.24 (12.90 to18.25) | < 0.001 |
Study wave | Wave 1 Wave 2 Wave 3 | 1 (Reference) 0.54 (0.45 to 0.65) 0.29 (0.23 to 0.37) | < 0.001 < 0.001 | ||
Insomnia symptoms | No Yes | 1 Reference 2.40 (2.22 to 2.53) | < 0.001 | 1 Reference 2.30 (2.12 to 2.49) | < 0.001 |
Study wave | Wave 1 Wave 2 Wave 3 | 1 (Reference) 0.79 (0.70 to 0.90) 0.60 (0.52 to 0.70) | < 0.001 < 0.001 | ||
Brain disease/dementia | No Yes | 1 Reference 1.71 (1.40 to 2.08) | < 0.001 | 1 Reference 1.28 (0.87 to 1.89) | 0.213 |
Study wave | Wave 1 Wave 2 Wave 3 | 1 (Reference) 1.27 (0.83 to 1.94) 1.46 (0.92 to 2.32) | 0.279 0.107 | ||
Physical ill-health | |||||
Poor self-rated physical health status | No Yes | 1 Reference 2.11 (1.93 to 2.31) | < 0.001 | 1 Reference 1.39 (1.23 to 1.57) | < 0.001 |
Study wave | Wave 1 Wave 2 Wave 3 | 1 (Reference) 1.28 (1.14 to 1.43) 0.83 (0.73 to 0.94) | < 0.001 0.005 | ||
Hypertension | No Yes | 1 Reference 1.35 (1.23 to 1.48) | < 0.001 | 1 Reference 1.14 (1.02 to 1.27) | 0.019 |
Study wave | Wave 1 Wave 2 Wave 3 | 1 (Reference) 1.21 (1.11 to 1.30) 1.40 (1.28 to 1.53) | < 0.001 < 0.001 | ||
Cardiovascular disease | No Yes | 1 Reference 1.33 (1.18 to 1.51) | < 0.001 | 1 Reference 1.13 (0.93 to 1.37) | 0.217 |
Study wave | Wave 1 Wave 2 Wave 3 | 1 (Reference) 1.12 (0.95 to 1.33) 1.38 (1.14 to 1.66) | 0.176 < 0.001 | ||
Kidney disease | No Yes | 1 Reference 1.46 (1.26 to 1.70) | < 0.001 | 1 Reference 1.51 (1.14 to 1.99) | 0.005 |
Study wave | Wave 1 Wave 2 Wave 3 | 1 (Reference) 1.58 (1.23 to 2.03) 2.16 (1.65 to 2.83) | < 0.001 < 0.001 | ||
Diabetes | No Yes | 1 Reference 1.17 (1.08 o 1.27) | < 0.001 | 1 Reference 1.09 (0.95 to 1.24) | 0.212 |
Study wave | Wave 1 Wave 2 Wave 3 | 1 (Reference) 0.89 (0.81 to 0.98) 1.09 (0.97 to 1.21) | 0.017 0.152 | ||
Osteoporosis | No Yes | 1 Reference 1.72 (1.41 to 2.09) | < 0.001 | 1 Reference 1.34 (1.08 to 1.16) | 0.009 |
Study wave | Wave 1 Wave 2 Wave 3 | 1 (Reference) 0.95 (0.75 to 1.20) 1.86 (1.49 to 2.32) | 0.660 < 0.001 | ||
Chronic lung disease | No Yes | 1 Reference 1.22 (0.94 to 1.58) | 0.140 | ||
ADL disability | No Yes | 1 Reference 2.03 (1.84 to 2.23) | < 0.001 | 1 Reference 2.16 (1.78 to 2.62) | < 0.001 |
Study wave | Wave 1 Wave 2 Wave 3 | 1 (Reference) 1.60 (1.27 to 2.00) 2.41 (1.93 to 3.01) | < 0.001 < 0.001 | ||
Cancer | No Yes | 1 Reference 1.17 (0.73 to 1.89) | 0.512 | ||
Lifestyle factors | |||||
Current tobacco smoking | No Yes | 1 Reference 0.88 (0.79 to 0.99) | 0.032 | 1 Reference 0.95 (0.80 to 1.13) | 0.547 |
Study wave | Wave 1 Wave 2 Wave 3 | 1 (Reference) 1.12 (0.99 to 1.26) 1.03 (0.89 to 1.18) | 0.061 0.726 | ||
Hazardous alcohol use | No Yes | 1 Reference 0.95 (0.80 to 1.13) | 0.579 | ||
Physical inactivity | No Yes | 1 Reference 1.15 (1.08 to 1.23) | < 0.001 | 1 Reference 1.18 (1.06 o 1.31) | 0.002 |
Study wave | Wave 1 Wave 2 Wave 3 | 1 (Reference) 0.55 (0.51 to 0.60) 0.69 (0.63 to 0.76) | < 0.001 < 0.001 | ||
Body mass index (BMI)-obesity class II | No Yes | 1 Reference 1.15 (0.97 to 1.36) | 0.117 | ||
BMI-underweight | No Yes | 1 Reference 1.42 (1.24 to 1.63) | < 0.001 | 1 Reference 1.27 (1.10 to 1.48) | < 0.001 |
Study wave | Wave 1 Wave 2 Wave 3 | 1 (Reference) 0.92 (0.81 to 1.05) 1.10 (0.96 to 1.27) | 0.201 0.180 | ||
Model 1: unadjusted Hazard Ratio (95% CI) | Model 2: adjusted Hazard Ratio (95% CI) | ||||
Mortality | 1 Reference 1.58 (1.27 to 1.98) | < 0.001 | 1 Reference 1.66 (1.24 to 2.22) | < 0.001 |
Longitudinal associations between loneliness and incident health indicators
Outcome variables | Loneliness | Model 1: unadjusted odds ratio (95% CI) | p-value | Model 2: adjusted odds ratio (95% CI)a | p-value |
---|---|---|---|---|---|
Mental ill-health | |||||
Incident poor self-rated mental health status | 0 wave 1 wave 2–3 waves | 1 Reference 1.61 (1.32 to 1.97) 2.88 (2.16 to 3.85) | < 0.001 < 0.001 | 1 Reference 1.53 (1.24 to 1.88) 2.65 (1.96 to 3.58) | < 0.001 < 0.001 |
Incident poor quality of life/happiness | 0 wave 1 wave 2–3 waves | 1 Reference 1.67 (1.36 to 2.04) 2.38 (1.73 to 3.26) | < 0.001 < 0.001 | 1 Reference 1.62 (1.31 to 2.00) 2.33 (1.67 to 3.23) | < 0.001 < 0.001 |
Incident depressive symptoms | 0 wave 1 wave 2–3 waves | 1 Reference 8.36 (5.44 to12.85) 23.66 (14.92 to 37.53) | < 0.001 < 0.001 | 1 Reference 9.32 (5.92 to 14.69) 26.15 (15.98 to 42.80) | < 0.001 < 0.001 |
Incident insomnia symptoms | 0 wave 1 wave 2–3 waves | 1 Reference 1.85 (1.48 to 2.30) 3.11 (2.34 to 4.14) | < 0.001 < 0.001 | 1 Reference 1.87 (1.49 to 2.35) 2.98 (2.21 to 4.03) | < 0.001 < 0.001 |
Incident brain disease/dementia | 0 wave 1 wave 2–3 waves | 1 Reference 1.30 (0.70 to 2.39) 1.79 (0.87 to 3.71) | 0.408 0.116 | ||
Physical ill-health | |||||
Incident poor self-rated physical health status | 0 wave 1 wave 2–3 waves | 1 Reference 1.58 (1.29 to 1.92) 2.41 (1.81 to 3.20) | < 0.001 < 0.001 | 1 Reference 1.44 (1.17 to 1.77) 2.12 (1.57 to 2.86) | < 0.001 < 0.001 |
Incident hypertension | 0 wave 1 wave 2–3 waves | 1 Reference 1.15 (0.92 to 1.44) 1.17 (0.84 to 1.62) | 0.213 0.350 | ||
Incident cardiovascular disease | 0 wave 1 wave 2–3 waves | 1 Reference 1.28 (0.91 to 1.79) 1.57 (1.03 to 2.41) | 0.162 0.038 | 1 Reference 1.27 (0.89 to 1.81) 1.55 (0.98 to 2.44) | 0.181 0.089 |
Incident kidney disease | 0 wave 1 wave 2–3 waves | 1 Reference 1.72 (1.17 to 2.54) 2.10 (1.31 to 3.37) | 0.006 0.002 | 1 Reference 1.59 (1.07 to 2.38) 1.82 (1.11 to 3.01) | 0.023 0.018 |
Incident diabetes | 0 wave 1 wave 2–3 waves | 1 Reference 1.33 (0.98 to 1.80) 1.66 (1.13 to 2.44) | 0.068 0.009 | 1 Reference 1.34 (0.98 to 1.82) 1.64 (1.10 to 2.45) | 0.072 0.015 |
Incident osteoporosis | 0 wave 1 wave 2–3 waves | 1 Reference 1.41 (1.04 to 1.92) 1.28 (0.86 to 1.95) | 0.026 0.243 | 1 Reference 1.27 (0.93 to 1.74) 1.05 (0.68 to 1.62) | 0.139 0.831 |
Incident chronic lung disease | 0 wave 1 wave 2–3 waves | 1 Reference 0.98 (0.53 to 1.80) 1.09 (0.49 to 2.42) | 0.942 0.835 | ||
Incident ADL disability | 0 wave 1 wave 2–3 waves | 1 Reference 1.85 (1.37 to 2.49) 3.01 (2.12 to 4.25) | < 0.001 < 0.001 | 1 Reference 1.22 (1.04 to 1.98) 2.32 (1.59 to 3.37) | 0.026 < 0.001 |
Incident cancer | 0 wave 1 wave 2–3 waves | 1 Reference 1.62 (0.85 to 3.11) 1.41 (0.58 to 3.39) | 0.145 0.447 | ||
Lifestyle factors | |||||
Incident current tobacco smoking | 0 wave 1 wave 2–3 waves | 1 Reference 0.94 (0.68 to 1.31) 0.80 (0.50 to 1.29) | 0.725 0.361 | ||
Incident hazardous alcohol use | 0 wave 1 wave 2–3 waves | 1 Reference 0.82 (0.58 to 1.14) 0.61 (0.37 to 1.02) | 0.228 0.059 | ||
Incident physical inactivity | 0 wave 1 wave 2–3 waves | 1 Reference 0.89 (0.69 to 1.15) 1.18 (0.83 to 1.18) | 0.373 0.371 | ||
Incident body mass index (BMI)-obesity class II | 0 wave 1 wave 2–3 waves | 1 Reference 1.35 (0.91 to 2.01) 1.70 (1.04 to 2.76) | 0.141 0.034 | 1 Reference 1.41 (0.94 to 2.13) 1.66 (0.99 to 2.79) | 0.101 0.056 |
Incident BMI-underweight | 0 wave 1 wave 2–3 waves | 1 Reference 1.20 (0.90 to 1.59) 2.19 (1.57 to 3.05) | 0.224 < 0.001 | 1 Reference 1.08 (0.80 to 1.48) 1.87 (1.31 to 2.66) | 0.628 < 0.001 |