Bojestig 1998.

Study characteristics
Methods	Study design: prospective cohort longitudinal Location: Sweden Time period: DM diagnosed between 1961 and 1980 and followed up between 1990 and 1992 Outcome: PDR Outcome measurement: cumulative incidence
Participants	Number of participants: 213 Diabetes type: T1D Inclusion criteria: T1D; onset before the age of 15 years; lived within catchment area of the paediatric clinic, University Hospital, Linkoping, Sweden Exclusion criteria: not reported
Notes	Link to data extraction table, risk of bias assessment, and results: osf.io/prd4t/?view_only=97fe8cf9a841490dbdb22ff26c542ebc
Item	Authors' judgement	Support for judgement
Study participation	Unclear	See ‘Notes’ above for link to risk of bias assessment
Study attrition	Unclear	See ‘Notes’ above for link to risk of bias assessment
Prognostic factor measurement	Unclear	See ‘Notes’ above for link to risk of bias assessment
Outcome measurement	Unclear	See ‘Notes’ above for link to risk of bias assessment
Adjustment for other prognostic factors	Unclear	See ‘Notes’ above for link to risk of bias assessment
Statistical analysis and reporting	Unclear	See ‘Notes’ above for link to risk of bias assessment