Hardin 1956.

Study characteristics
Methods	Study design: prospective cohort Location: USA Time period: period ending September 1954 Outcome: PDR Outcome measurement: incidence
Participants	Number of participants: 132 Diabetes type: T2D Inclusion criteria: juvenile diabetes (developed disease aged 6 months to 19 years); second decade of diabetes Exclusion criteria: not reported
Notes	Link to data extraction table, risk of bias assessment, and results: osf.io/vwcn2/?view_only=98b37d2b3c364592b1f421bd4ffd5e61
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	No	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