Table 2 Descriptive characteristics of included studies and outcomes
Author | Type of outcome | Sub-type of outcome | Study type(s) | Total included studies | Total participants |
|---|---|---|---|---|---|
Zhu et al. [28] | Mortality | All-cause mortality | Cohort | 18 | 19,813 |
Xu et al. [5] | CVD mortality in all DR | Cohort | 10 | 11,239 | |
CVD mortality in mild DR | 4 | 7,361 | |||
CVD mortality in severe DR | 6 | 9,691 | |||
Zhu et al. [8] | Disease | Obstructive sleep apnoea | Case–control | 6 | 1,092 |
Kjærsgaard et al. [35] | Primary open angle glaucoma | Cohort | 2 | 241,037 | |
Cross-sectional | 4 | 15,389 | |||
Shiferaw et al. [30] | Chronic kidney disease | Cohort | 2 | 781 | |
Song et al. [31] | Non-alcoholic fatty liver disease all DR | Cross-sectional | 8 | 7,170 | |
Non-alcoholic fatty liver disease non-proliferative DR | 3 | 3,977 | |||
Non-alcoholic fatty liver disease proliferative DR | 3 | 3,977 | |||
Wu and You [7] | Mental health | Depression (Type I) | Case–control | 3 | 971 |
Zou et al. [29] | Depression (Type II) | Cross-sectional | 9 | 31,766 | |
Trott et al. [32] | Eating disorders | Cross-sectional and case–control | 7 | 1,091 | |
Chai et al. [33] | Dementia | Cohort | 3 | 46,185 | |
Alzheimer’s | Cohort | 2 | 7,754 | ||
Wu et al. [34] | Cognitive impairment | Cross-sectional | 5 | 2,451 | |
Cohort | 5 | 1,397 |