Dullaart 1992

Methods	RCT, parallel, 2 arms (n6 LA vs mixed fats), 2 years Summary risk of bias: moderate to high
Participants	People with type I diabetes with elevated urinary albumin CVD risk: moderate Intervention: randomised 18, analysed 16 Control: randomised 20, analysed 20 % male: 81% intervention, 75% control Age: mean (SD) intervention 44 (12), control 41 (14) Age range: unclear (21‐65 inclusion) Smokers: intervention 50%, control 55% Hypertension: intervention 6%, control 10% Medications taken by ≥ 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 < 20% of the control group: anti‐hypertensives Location: Netherlands Ethnicty: not reported
Interventions	Type: dietary advice Comparison: LA (n6) 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 SFA from meat and milk products Control: to continue their usual diet. All participants were urged not to alter total fat and protein content. Dose: aim unclear Baseline PUFA: 6.6% E PUFA Compliance: TC fell more in intervention (‐0.45 mmol/L) than control (0.10 mmol/L) from baseline to 2 years. 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%: intervention13.7 (SD 1.8), control 16.5 (SD 1.4) Dietary assessment using 1 week dietary recall, reported at 2 years. Energy intake, MJ/d: intervention 7.42 (SD 2.02), control 8.48 (SD 2.48) Total fat intake, % E: intervention 37 (SD 4), control 40 (SD 7) SFA intake, % E: intervention 13 (SD 2), control 16 (SD 3) PUFA intake, % E: (calculated from P/S and SFA intake) intervention 12.5 (SD not reported), control 9.0 (SD not reported), increase 3.5%E PUFA n‐3 intake: not reported PUFA n‐6 intake, % E: not reported, but intervention 11%E LA (SD 2), control 7%E LA (SD 3) PUFA/SFA ratio: intervention 0.96 (SD 0.16), control 0.56 (SD 0.25) MUFA intake: not reported CHO intake, % E: intervention 43 (SD 4), control 41 (SD 7) Protein intake, % E: intervention 18 (SD 4), control 17 (SD 3) Trans fat intake: not reported Cholesterol intake, mg/d: intervention 174 (SD 49), control 245 (SD 120) Compliance, other methods: not reported Inclusion basis: aimed to increase LA rather than total PUFA intake. Intake data suggests 3.5% E PUFA dose, > 10% increase from control 9% E intake Supported by plasma cholesteryl ester LA and TC PUFA dose: 3.5% E PUFA Duration of intervention: 2 years
Outcomes	Main trial outcomes: albuminuria and lipids Dropouts: intervention 2 of 20, control 4 of 20 Available outcomes: weight, HDL , TGs, HbA1c (TC, glucose, insulin reported but too different at baseline to use, LDL not reported in control group, renal outcomes such as glomerular filtration rate, albuminuria, mean arterial pressure not used) Response to contact: yes, trial author confirmed no MI or other CVD events occurred during trial
Notes	Most outcomes are estimated from figures. Trial funding: Dutch Diabetes Research Fund
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	Likely that diet‐advice group had more time and attention
Compliance	Low risk	TC fell more in intervention (‐0.45 mmol/L) than control (0.10 mmol/L) from baseline to 2 years. Significant difference between plasma cholesteryl ester LA in intervention and control at 2 years
Other bias	Low risk	None noted