Nordwall 2015.

Study characteristics
Methods	Study design: retrospective cohort longitudinal Location: Sweden Time period: diagnosed 1983 to 1987 and followed until 2005 to 2008 Outcome: PDR Outcome measurement: incidence and mean difference
Participants	Number of participants: 451 Diabetes type: T1D Inclusion criteria: T1D diagnosed 1983 to 1987 in Southeast Sweden, < 35 years of age and on insulin < 6 months from diagnosis Exclusion criteria: not reported
Notes	Link to data extraction table, risk of bias assessment, and results: osf.io/d4k5n/?view_only=414f9ee474174fc8a81333ffb9967a5f
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