| Name of study |
Ansung‐Ansan cohort study, part of the Korean Genome and Epidemiology Study (KoGES), to investigate the trends in diabetes and associated risk factors |
| Inclusion criteria |
Urban (Ansan) and rural (Ansung) communities (within 60 km of Seoul) |
| Exclusion criteria |
Unknown glucose status, individuals with known diabetes, participants who were newly diagnosed with type 2 diabetes at baseline examination; persons with a history of malignant diseases,
liver failure, end‐stage renal disease, rheumatological diseases and acute or chronic infectious diseases, individuals who had taken steroids in the previous 3 months; individuals who did not undergo any follow‐up examination after the baseline examination |
| Notes |
Baseline data for i‐IFG, i‐IGT and IFG/IGT |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Study participation: description of source population or population of interest |
Low risk |
Ansung‐Ansan Cohort Study, part of the Korean Genome and Epidemiology Study (KoGES) |
| Study participation: description of glycaemic status at baseline |
Low risk |
Yes |
| Study participation: adequate description of sampling frame & recruitment |
Low risk |
Yes |
| Study participation: adequate description of period & recruitment place |
Low risk |
Yes |
| Study participation: adequate description of inclusion & exclusion criteria |
Low risk |
Inclusion and exclusion criteria described |
| Study attrition: description of attempts to collect information on participants who dropped out |
Low risk |
Yes |
| Study attrition: reasons for loss to follow‐up provided |
Low risk |
Yes (follow‐up rate at 12 years 60.6%) |
| Study attrition: adequate description of participants lost to follow‐up |
Low risk |
Yes |
| Study attrition: no important differences between participants who completed the study and those who did not |
Unclear risk |
Not reported |
| Glycaemic status measurement: provision of clear definition or description of glycaemic status |
Low risk |
Yes |
| Glycaemic status measurement: valid and reliable method of glycaemic status measurement |
Low risk |
Yes |
| Glycaemic status measurement: continuous variables reported or appropriate cut points used |
Low risk |
IFG: FPG 5.6–6.9 and no diagnosis of diabetes; IGT: 2‐h PG 7.8 to < 11.1; i‐IFG5.6: IFG without IGT; i‐IGT: IGT without IFG; IGT/IGT: IFG+IGT; 'prediabetes': IFG or IGT |
| Glycaemic status measurement: same method and setting of measurement of the glycaemic status for all study participants |
Low risk |
Yes |
| Outcome measurement: clear definition of the outcome provided |
Low risk |
FPG ≥ 7.0; 2‐h PG ≥ 11.1; HbA1c ≥ 6.5; current antihyperglycaemic treatment |
| Outcome measurement: method of outcome measurement used valid & reliable |
Low risk |
Yes |
| Outcome measurement: same method & setting of outcome measurement for all study participants |
Low risk |
Yes |
| Study confounding: important confounders measured |
Low risk |
Yes |
| Study confounding: clear definitions of important confounders provided |
Low risk |
Yes |
| Study confounding: measurement of confounders valid & reliable |
Low risk |
Yes |
| Study confounding: same method & setting for measurements of confounders for all study participants |
Low risk |
Yes |
| Study confounding: appropriate methods used if missing confounder data imputed |
Unclear risk |
Not reported |
| Study confounding: important potential confounders accounted for in study design |
Low risk |
Yes |
| Study confounding: important potential confounders accounted for in the analysis |
Low risk |
Yes |
| Statistical analysis & reporting: sufficient presentation of data to assess adequacy of the analytic strategy |
Low risk |
Cumulative incidence, incidence rate, hazard ratio |
| Statistical analysis & reporting: the statistical model is adequate for the design of the study |
Low risk |
Multivariate Cox proportional hazard model |
