Dullart 1992.

Methods	RCT, parallel, 2 arms (n‐6 LA vs SFA), 2 years Summary risk of bias: moderate to high
Participants	Type I diabetics with elevated urinary albumin CVD risk: moderate Control: randomised 20, analysed 20 Intervention: randomised 18, analysed 16 % male: 81% intervention, 75% control Mean (SD) age in years: control 41 (14), intervention 44 (12) Age range: unclear (21‐65 inclusion) Smokers: control 55%, intervention 50% Hypertension: control 10%, intervention 6% Medications taken by at least 50% of those in the control group: insulin Medications taken by 20%‐49% of those in the control group: not reported Medications taken by some, but less than 20% of the control group: anti‐hypertensive drugs Location: Netherlands Ethnicty: not reported
Interventions	Type: dietary advice Comparison: LA (n‐6) vs usual diet Intervention: diet advice given at every visit throughout the 2‐year period to increase linoleic acid achieving a polyunsaturated: saturated fatty acid ratio close to 1.0. Advice to replace butter or saturated margarines by polyunsaturated margarines and to restrict the intake of saturated fat from meat and milk products Control: to continue their usual diet. All participants were urged not to alter total fat and protein content. Dose: (intake data) intervention group 13% E SFA, P/S 0.985, PUFA 9.4% E. Control group 15% E SFA, P/S 0.45, PUFA 6.6% E (CHO and protein were consistent between groups across the trial). Increase 2.8% E PUFA, most of which n‐6 Baseline n‐6: unclear, 6.6% E PUFA, most of which was n‐6 Compliance: poor, no significant difference between plasma cholesteryl ester LA in intervention and control at 2 years Plasma cholesteryl esters at 2 years LA mol %: intervention 62.2% (SD 4.2), control 57.4% (SD 4.9) Oleic acid mol %: intervention 13.7% (SD 1.8), control 16.5% (SD 1.4) Dietary assessment using 1 week dietary recall, reported at 2 years Energy intake: intervention 7.42 MJ/d (SD 2.02), control 8.48 MJ/d (SD 2.48) Total fat intake: intervention 37% E (SD 4), control 40% E (SD 7) Saturated fat intake: intervention 13% E (SD 2), control 16% E (SD 3) PUFA intake: not reported PUFA n‐3 intake: not reported PUFA n‐6 intake: not reported n‐6 LA: intervention 11% E (SD 2), control 7% E (SD 3) PUFA/SFA ratio: intervention 0.96% E (SD 0.16), control 0.56% E (SD 0.25) MUFA intake: not reported CHO intake: intervention 43% E (SD 4), control 41% E (SD 7) Protein intake: intervention 18% E (SD 4), control 17% E (SD 3) Trans fat intake: not reported Cholesterol intake, mg/d: intervention 174 (SD 49), control 245 (SD 120) Duration of intervention: 2 years
Outcomes	Main study outcomes: albuminurea and lipids Dropouts: intervention 2 of 20, control 4 of 20 Available outcomes: weight, HDL cholesterol, TGs, HbA1c (total cholesterol, LDL, glucose, insulin reported but too different at baseline to use, renal outcomes such as GFR, albuminurea, mean arterial pressure not used)
Notes	Most outcomes are estimated from figures Study funding: Dutch Diabetes Research Fund Response to contact: yes, Prof Dullart confirmed that no CVD events or deaths occurred
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "patients were stratified according to sex and randomised in blocks of ten men and six women"
Allocation concealment (selection bias)	Low risk	Assigned using opaque sealed envelopes by independent statistical investigator with no contact with participants
Blinding of participants and personnel (performance bias) All outcomes	High risk	No information on blinding. Participants could not be blinded as they received dietary advice
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No details
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No details on dropouts apart from the exclusion of 2 intervention participants from the trial due to pregnancy and decision not to participate
Selective reporting (reporting bias)	Unclear risk	No protocol or trial registration located
Attention Bias	High risk	Intervention groups received diet advice at every visit. As the control group were advised to stick to their usual diet it is likely that they received less attention and time.
Compliance	High risk	Compliance poor assessed by biomarkers
Other bias	Low risk	None noted