Descriptive statistics and correlations
Out of the 500,000 participants in the UKBB database, a total of 8,014 participants had an SMI diagnosis and provided data on the variables of interest. Only data from participants who responded to all questions were included. On average, the participants were 55.61 years old (SD = 7.71 years), 70% were female and the majority were white (96.72%; Table 1). Table 1 gives an overview of all averages and standard deviations of the variables used in this model.
Table 1
Means and standard deviations for all variables included in the model, grouped by SMI diagnosis.
| Depression (N = 8007; 99.99%) | Bipolar Disorder (N = 200; 2.5%) | Schizophrenia or Psychosis Disorder (N = 155; 1.9%) |
Age | | | |
- Mean (SD) | 55.6 (7.7) | 55.0 (8.1) | 54.6 (8.2) |
Sex | | | |
- Male | 2404 (30%) | 85 (42.5%) | 57 (36.8%) |
- Female | 5603 (70%) | 115 (57.5%) | 98 (63.2%) |
Ethnicity - White - Asian or Asian British - Black or Black British - Mixed - Other | 7744 (96.7%) 71 (0.9%) 57 (0.7%) 55 (0.7%) 80 (1.0%) | 185 (92.5%) 4 (2.0%) 2 (1.0%) 3 (1.5%) 6 (3.0%) | 142 (91.6%) 1 (0.7%) 2 (1.3%) 3 (1.9%) 7 (4.5%) |
Townsend Deprivation Index - Mean (SD) | -1.35 (2.8) | -0.5 (3.2) | -0.17 (3.5) |
Amount of days/week doing moderate physical activity (> 10minutes) | | | |
- Mean (SD) | 3.7 (2.3) | 3.6 (2.4) | 3.4 (2.5) |
Amount of days/week doing vigorous physical activity (> 10minutes) | | | |
- Mean (SD) | 1.8 (1.8) | 1.9 (2.0) | 1.6 (2.0) |
Amount of days/week going for a walk (> 10minutes) | | | |
- Mean (SD) | 5.6 (1.7) | 5.9 (1.6) | 5.8 (1.7) |
Time spent walking for pleasure | | | |
- Less than 15 minutes - Between 15 and 30 minutes - Between 30 minutes and 1 hour - Between 1 and 1.5 hours - Between 1.5 and 2 hours - Between 2 and 3 hours - Over 3 hours | 136 (2.0%) 1525 (19.0%) 2970 (37.1%) 1483 (18.4%) 791 (9.9%) 545 (6.7%) 557 (6.9%) | 2 (1.0%) 52 (26.0%) 75 (37.5%) 29 (14.5%) 23 (11.5%) 7 (3.5%) 12 (6.0%) | 7 (4.5%) 41 (26.5%) 53 (34.2%) 18 (11.6%) 19 (12.3%) 11 (7.1%) 6 (3.9) |
Sleep duration | | | |
- Mean (SD) | 7.2 (1.1) | 7.6 (1.5) | 7.5 (1.4) |
Sleeplessness/Insomnia | | | |
- Never/Rarely | 1471 (18.4%) | 40 (20%) | 41 (26.4%) |
- Sometimes | 3765 (47%) | 98 (49%) | 65 (42%) |
- Usually | 2771 (34.6%) | 62 (31%) | 49 (31.6%) |
Current Tobacco Smoking | | | |
- No | 7773 (97.1%) | 186(93%) | 149(96.1%) |
- Only occasionally | 234 (2.9%) | 14 (7%) | 6 (3.9%) |
- Yes, on most or all days | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) |
Smokers in Household | | | |
- No Household Member Smokes | 7229 (90.3%) | 178 (89%) | 135 (87.1%) |
− 1 Household Member Smokes | 673 (8.4%) | 18 (9%) | 16 (10.3%) |
- More than 1 Household Member Smokes | 105 (1.3%) | 4 (2%) | 4 (2.6%) |
Frequency of drinking alcohol | | | |
- Never | 513 (6.4%) | 24 (12%) | 22 (14.2%) |
- Special Occasions Only | 907 (11.3%) | 31 (15.5%) | 29 (18.7%) |
− 1 to 3 Times a Month | 1045 (13.1%) | 24 (12%) | 22 (14.2%) |
- Once or Twice a Week | 1923 (24.0%) | 31 (15.5%) | 26 (16.8%) |
− 3 or 4 Times a Week - Daily or Almost Daily | 1915 (23.9%) 1704 (21.3%) | 46 (23%) 44 (22%) | 22 (14.2%) 34 (21.9%) |
Greenspace Percentage (1000m) | | | |
- Mean (SD) | 42.6 (22.2) | 37.9 (21.4) | 36.8 (19.5) |
Water Percentage (1000m) | | | |
- Mean (SD) | 1.3 (2.6) | 1.3 (2.9) | 1.3 (2.9) |
Euclidean Distance to Coast | | | |
- Mean (SD) | 45.7(26.3) | 46.6 (25.0) | 46.2 (24.5) |
Domestic Garden Percentage (1000m) | | | |
- Mean (SD) | 26.5 (11.7) | 28.3 (11.3) | 28.3 (10.8) |
Family-relationship Satisfaction | | | |
- Prefer not to say | 1196 (14.9%) | 19 (9.5%) | 12 (7.7%) |
- Extremely Unhappy | 68 (0.9%) | 6 (3.0%) | 7 (4.5%) |
- Very Unhappy | 73 (0.9%) | 4 (2.0%) | 5 (3.2%) |
- Moderately Unhappy | 158 (2.0%) | 6 (3.0%) | 6 (3.8%) |
- Moderately Happy | 621 (7.8%) | 14 (7.0%) | 13 (8.5%) |
- Very Happy | 2718 (33.9%) | 87 (43.5%) | 57 (36.8%) |
- Extremely Happy | 3173 (39.6%) | 64 (32.0%) | 55 (35.5%) |
Financial Situation Satisfaction | | | |
- Prefer not to say | 575 (7.2%) | 13 (6.5%) | 8 (5.1%) |
- Extremely Unhappy | 23 (0.3%) | 2 (1%) | 4 (2.6%) |
- Very Unhappy | 161 (2.0%) | 12 (6%) | 11 (7.1%) |
- Moderately Unhappy | 266 (3.3%) | 7 (3.5%) | 6 (3.9%) |
- Moderately Happy | 793 (9.9%) | 18 (9.0%) | 20 (12.9%) |
- Very Happy | 6357 (45.7%) | 94 (47.0%) | 71 (45.8%) |
- Extremely Happy | 2532 (31.6%) | 54 (27.0%) | 35 (22.6%) |
Friendships Satisfaction | | | |
- Prefer not to say | 915 (11.4%) | 18 (9.0%) | 10 (6.5%) |
- Extremely Unhappy | 81 (1.0%) | 6 (3.0%) | 11 (7.1%) |
- Very Unhappy | 21 (0.3%) | 2 (1.0%) | 3 (1.8%) |
- Moderately Unhappy | 51 (0.6%) | 4 (2.0%) | 2 (1.3%) |
- Moderately Happy | 415 (5.2%) | 18 (9.0%) | 10 (6.5%) |
- Very Happy | 2805 (35.0%) | 79 (39.5%) | 59 (38.1%) |
- Extremely Happy | 3719 (46.5%) | 73 (36.5%) | 60 (38.7%) |
Ability to Confide in Others | | | |
- Never or Almost Never | 945 (11.8%) | 29 (14.5%) | 27 (17.4%) |
- Once Every Few Months | 491 (6.1%) | 15 (7.5%) | 10 (6.5%) |
- About Once a Month | 584 (7.3%) | 14 (7.0%) | 12 (7.7%) |
- About Once a Week | 1080 (13.4%) | 32 (16.0%) | 23 (14.8%) |
− 2–4 Times a Week | 1049 (13.1%) | 25 (12.5%) | 21 (13.6%) |
- Almost Daily | 3858 (48.2%) | 85 (42.5%) | 62 (40%) |
Loneliness/Isolation | | | |
- No | 5743(71.7%) | 125 (62.5%) | 95 (61.3%) |
- Yes | 2264 (28.3%) | 75 (37.5%) | 60 (38.7%) |
Leisure Activity - Sports | | | |
- No | 5465(68.3%) | 143 (71.5%) | 124 (80.0%) |
- Yes | 2542 (31.7%) | 57 (28.5%) | 31 (20.0%) |
Leisure Activity - Pub | | | |
- No | 6350 (79.3%) | 158 (79.0%) | 126 (81.3%) |
- Yes | 1657 (20.7%) | 42 (21%) | 29 (18.7%) |
Leisure Activity - Education | | | |
- No | 7090 (88.5%) | 171 (85.5%) | 127 (81.9%) |
- Yes | 917 (11.5%) | 29 (14.5%) | 28 (18.1%) |
Leisure Activity - Religion | | | |
- No | 6655 (83.1%) | 154 (77.0%) | 117 (75.5%) |
- Yes | 1352 (16.9%) | 46 (23.0%) | 38 (24.5%) |
Leisure Activity - Group Activity | | | |
- No | 4832 (60.3%) | 110 (55.0%) | 80 (51.6%) |
- Yes | 3175 (39.7%) | 90 (45.0%) | 75 (48.4%) |
General Happiness with own health | | | |
- Do Not Know/Prefer Not to Answer | 33 (0.1%) | 11 (0.3%) | 22 (0.3%) |
- Extremely Unhappy | 91 (0.4%) | 30 (0.8%) | 130 (1.7%) |
- Very Unhappy | 282 (1.1%) | 86 (2.3%) | 285 (3.8%) |
- Moderately Unhappy | 1555 (6.0%) | 377 (10.1%) | 989 (13.3%) |
- Moderately Happy | 10286 (39.6%) | 1723 (46.2%) | 3333 (44.7%) |
- Very Happy | 11057 (42.5%) | 1246 (33.4%) | 2232 (30.0%) |
- Extremely Happy | 2692 (10.4%) | 260 (7.0%) | 458 (6.1%) |
Health Satisfaction | | | |
- Do Not Know/Prefer Not to Answer | 42 (0.2%) | 10 (0.3%) | 18 (0.2%) |
- Extremely Unhappy | 42 (0.2%) | 13 (0.3%) | 66 (0.9%) |
- Very Unhappy | 172 (0.7%) | 67 (1.8%) | 209 (2.8%) |
- Moderately Unhappy | 1421 (5.5%) | 313 (8.4%) | 852 (11.4%) |
- Moderately Happy | 11657 (44.8%) | 1860 (49.8%) | 3759 (50.5%) |
- Very Happy | 10897 (41.9%) | 1308 (35.0%) | 2247 (30.2%) |
- Extremely Happy | 1765 (6.8%) | 162 (4.3%) | 298 (4.0%) |
Health Score - Mean (SD) | -0.21 (0.8) | − .015 (0.8) | -0.09 (0.8) |
Syndemic Model
Spearman correlation coefficients indicated a high correlation between the two Syndemic contributors, ethnicity and TDI. As TDI is a continuous variable based on externally verified census methods, and ethnicity is a categorical self-input variable, we elected to eliminate ethnicity from the model to improve model stability. Primary analyses indicated high correlations between several variables (days engaging in vigorous physical activity and practising a sport during leisure activities; engaging in religious activities in leisure time and engaging in group activities in leisure time; and alcohol intake frequency and pub visits in leisure time), which were allowed to be estimated in the model. The measurement model analysis confirmed that the selected variables show appropriate fits (Leisure time – pub and Leisure time – education for the Personal Resilience construct, and smoke frequency for the Addictive Behaviours construct). Sensitivity analyses on the effect of removing these contributors from the model resulted in comparable model indices, so to provide a broader insight into the model, we elected to keep the contributors in the final SEM.
The results of the SEM indicated a reasonably good fit of the tested model. Although χ² was significant (χ²= 6035.766, p < 0.001, df = 281), the TLI and CFI indicators demonstrate a reasonably good model fit (TLI = 0.786, CFI = 0.815). The RMSEA indicated a very good fit of the model (RMSEA = 0.051). This implies that the model provides a reasonably good fit to the data, however, the model could probably be improved. A closer investigation of the individual relationships within the model for future iterations is therefore necessary.
Table 2
Variables | Unstandardized Coefficient | Standardized Coefficient (β)* | R²** | p Value | |
Physical Activity | | | | | |
| Time spent walking for Fun | 1.000 | 0.1 | 0.012 | |
| Amount of days/week going for a walk | 4.659 | 0.39 | 0.151 | < .001 |
| Amount of days/week doing moderate physical activity | 12.340 | 0.78 | 0.607 | < .001 |
| Amount of days/week doing vigorous physical activity | 7.563 | 0.61 | 0.374 | < .001 |
Addictive Behaviours | | | | | |
| Alcohol intake frequency Frequency of Smoking | 1.000 1.170 | 0.07 0.77 | 0.021 < 0.001 | 0.590 |
| Amount of Smokers in household | 0.422 | 0.13 | 0.002 | 0.004 |
Personal Resilience | | | | | |
| Leisure – Sports Leisure – Education Leisure – Group Activities Leisure – Pub Leisure – Religion | 1.00 0.124 1.150 0.150 0.159 | 0.09 0.02 0.1 0.3 0.02 | 0.109 < 0.001 0.009 0.052 0.309 | 0.212 < .001 0.208 0.093 |
| Friendship Satisfaction | 13.664 | 0.64 | 0.401 | < .001 |
| Ability to Confide in Others | 18.769 | 0.46 | 0.204 | < .001 |
| Financial Situation Satisfaction Loneliness/Isolation Family Relationships Satisfaction | 9.451 -4.777 15.466 | 0.4 -0.46 0.63 | 0.166 0.210 0.399 | < .001 < .001 < .001 |
Exposure to Nature | | | | | |
| Euclidean Distance to the Coast | 1.000 | 0.09 | 0.187 | |
| Water Percentage | -0.157 | -0.13 | 0.015 | < .001 |
| Greenspace Percentage | -5.001 | -0.51 | 0.544 | < .001 |
| Domestic Garden Percentage | 8.287 | 1.59 | 0.566 | < .001 |
Sleep Behaviour | | | | | |
| Number of Hours spent Sleeping | 1.000 | 0.35 | 0.123 | |
| Sleeplessness/Insomnia Behaviour | -1.375 | -0.76 | 0.581 | < .001 |
Health Experience | | | | | |
| General Happiness about own Health | 1.000 | 0.65 | 0.370 | |
| Personal Health Satisfaction | 1.126 | 0.76 | 0.629 | < .001 |
The regression results depicting direct effects for all latent factors are outlined in Table 2. Within the latent factors of personal resilience, exposure to nature, physical activity level, and sleep behaviour the selected contributors were found to be significantly related to each other with few exceptions. In the latent factor of personal resilience, education pursued in leisure time (p = 0.212), engaging in religious activities in leisure time (p = 0.093), and going to the pub in leisure time (p = 0.205) were not found to be significantly related to the other representatives. Similarly, for the latent factor addictive behaviour, the frequency of smoking was not significantly related to alcohol intake (p = 0.590), whereas the amount of smokers in the household was (p = 0.004).
Table 3
| Variables | Unstandardized Coefficient | Standardized Coefficient (β)* | p Value | 95% CI | |
| Health Experience | | | | | |
Physical Activity | 0.784 | 0.18 | < 0.001 | -0.901, 1.112 | |
Addictive Behaviours | 0.068 | 0.01 | 0.742 | 2.074, 6.656 | |
Personal Resilience | 6.069 | 0.41 | < 0.001 | -14.543, -0.117 | |
Exposure to Nature | -0.004 | -0.02 | 0.023 | -0.006, 0.032 | |
Sleep behaviour | 0.282 | 0.18 | < 0.001 | 0.241, 1.288 | |
Townsend Deprivation Index | -0.013 | -0.06 | < 0.001 | -0.014, -0.002 | |
Personal Resilience – Religion ~~ Personal Resilience – Group Activities | 0.425 | 0.55 | < 0.001 | 0.407, 0.442 | |
Personal Resilience – Sports ~~ Physical Activity – Amount of days/week doing vigorous physical activity | 0.076 | 0.3 | < 0.001 | 0.070, 0.081 | |
Personal Resilience – Pub ~~ Addictive Behaviours – Alcohol Intake frequency | 0.061 | 0.23 | < 0.001 | 0.056, 0.66 | |
Table 3 gives an overview of all main effects. All latent variables predicted health experience, apart from addictive behaviours (p = 0.742). This implies that the latent variables for physical activity, exposure to nature, personal resilience, and sleep behaviour, as well as the measure for TDI equally predict health experience. The higher the level of physical activity, personal resilience, and good sleep behaviours, the higher the health experience. Equally, the lower TDI, the higher health experience. Contrary to theoretical evidence, the lower the exposure to nature, the higher health experience seems to be. Addictive behaviours seem to not be directly related to health experience in the context of this data and model.
Figure 2 shows relationships between the variables of the model with effects and standardised path coefficients. The standardised path coefficients between the latent variables have been excluded to improve readability.
Table 4 shows the correlations between the latent factors of health behaviours. The latent factors of exposure to nature, physical activity, and sleep behaviour were significantly related to personal resilience (p ≤ 0.001). This implies that individual levels of personal resilience affect individual levels of exposure to nature, physical activity, and sleep behaviour. Beyond these significant relationships, no other latent factors showed significant interrelatedness.
Table 4
Correlation between the Latent Factors.
| Covariances | Unstandardized Coefficient | Standardized Coefficient (β)* | p Value | 95% CI |
Personal Resilience ~~ | | | | |
Exposure to Nature | 0.003 | -0.029 | 0.001 | -0.060, 0.001 |
Physical Activity | 0.001 | 0.110 | < 0.001 | 0.076, 0.143 |
Sleep Behaviour | 0.004 | 0.223 | < 0.001 | 0.174, 0.271 |
Addictive Behaviours | 0.000 | 0.723 | 0.576 | 0.581, 0.864 |
Exposure to Nature ~~ Physical Activity Sleep Behaviour Addictive Behaviour | -0.003 -0.008 -0.007 | -0.014 0.021 -0.157 | 0.142 0.162 0.598 | -0.045, 0.017 -0.013, 0.055 -0.319, 0.006 |
Physical Activity ~~ Sleep Behaviour Addictive Behaviour | 0.001 -0.000 | 0.014 0.184 | 0.484 0.964 | -0.024, 0.052 0.013, 0.354 |
Sleep Behaviour ~~ Addictive Behaviours | 0.001 | -0.032 | 0.538 | -0.221, 0.156 |