Skrivarhaug 2006.

Study characteristics
Methods	Study design: prospective cohort longitudinal Location: Norway Time period: examined for DR at baseline between 1989 and 1990 and at follow‐up from 2002 to 2003 Outcome: PDR Outcome measurement: incidence and RR (95% CI)
Participants	Number of participants: 368 Diabetes type: T1D Inclusion criteria: all new‐onset cases of T1D in Norway in children below 15 years of age, between 1973 and 1982, examined for DR at baseline between 1989 and 1990 and at follow‐up from 2002 to 2003 Exclusion criteria: not reported
Notes	Link to data extraction table, risk of bias assessment, and results: osf.io/hyqwt/?view_only=fc20c8d029cc4953838052dd1b77a1fa
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