| Name of study |
European Prospective Investigation of Cancer (EPIC)‐Norfolk cohort |
| Inclusion criteria |
Participants aged 40–74 years from the Norfolk region, UK; individuals with HbA1c measurements at baseline and the second health assessment |
| Exclusion criteria |
Diabetes at baseline, missing data |
| Notes |
Baseline data for HbA1c 6.0–6.4 cohort (N = 370) |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Study participation: description of source population or population of interest |
Low risk |
Population‐based study monitoring individuals recruited from general practice in the Norfolk region, UK |
| 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 |
| Study attrition: adequate description of participants lost to follow‐up |
Unclear risk |
Scarce data |
| Study attrition: no important differences between participants who completed the study and those who did not |
Unclear risk |
Scarce data |
| Glycaemic status measurement: provision of clear definition or description of glycaemic status |
Low risk |
HbA1c (50% of all participants had information on this measure at baseline); analyses were limited to these individuals |
| 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 |
HbA1c 6.0–6.4 |
| 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 |
HbA1c ≥ 6.5; reported physician‐diagnosed diabetes or diabetes medications; antihyperglycaemic medication; diagnosis through medical records, registers or death certificates; results for clinically and/or biochemically diagnosed diabetes were used |
| 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, odds ratio |
| Statistical analysis & reporting: the statistical model is adequate for the design of the study |
Low risk |
Logistic regression (for every 0.5% increase in HbA1c as well as for different categories of HbA1c) |
