Methods	RCT
Participants	Newly diagnosed non-insulin dependant diabetics (UK) CVD risk: moderate Control: randomised unclear (249 split between the 2 groups, 125?), analysed for mortality unclear (all but 2 overall at 16 years) Intervention: randomised unclear (249 split between the 2 groups, 125?), analysed as above Mean years in trial: overall 9.3? % male: overall 49 Age: mean overall 47.1 (all <65)
Interventions	Reduced and modified dietary fat vs average diet Control aims: total fat 40%E, PUFA 12%E, protein 20%E, CHO 40%E (reducing simple sugars), 1500kcal/day Intervention aims: total fat 26%E, PUFA 16%E, protein 20%E, CHO 54%E (reducing simple sugars), 1500kcal/day Control methods: dietary advice from diabetes dietitian Intervention methods: dietary advice from diabetes dietitian Total fat intake (at 7-9 years): low & mod fat 32 (sd unclear), cont 41 (sd unclear)%E Saturated fat intake (at 7-9 years): low & mod fat 10.7 (sd unclear), cont 20.4 (sd unclear) %E Style: diet advice Setting: community (outpatients clinic)
Outcomes	Stated trial outcomes: retinopathy Data available on total mortality? yes, but unable to ascertain from which intervention groups (34 deaths at 10 years) Cardiovascular mortality? no Events available for combined cardiovascular events: none Secondary outcomes: none Tertiary outcomes: BMI, total cholesterol
Notes
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	“random number sequence, provided and allotted by a separate agency” (Prof Richard Peto)
Allocation concealment (selection bias)	Low risk
Blinding (performance bias and detection bias) All outcomes	High risk	Participants not blinded, physicians unclear
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Unclear, deaths, cancer and CV events are drop-outs - unclear if any data missing
Selective reporting (reporting bias)	Low risk	Not relevant for primary and secondary outcomes as all trialists asked for data
Other bias	Low risk
Free of systematic difference in care?	Low risk	Dietetic advice for both groups. See Control and Intervention Methods in Interventions section of the Table of Characteristics of Included Studies
Free of dietary differences other than fat?	Low risk	See Control and Intervention Aims in Interventions section of the Table of Characteristics of Included Studies