Veterans Admin 1969.

Methods	Veterans Administration Trial RCT, 2 arms, parallel (n6 LA vs SFA), up to 8 years Summary risk of bias: moderate to high
Participants	Men living at the Veterans Administration Centre CVD risk: low Control: randomised 422, analysed 422 Intervention: randomised 424, analysed 424 Mean years in trial: control 3.7, intervention 3.7 % male: 100 Age: mean control 65.6, intervention 65.4 Age range: all 54‐88 years Smokers: intervention 283, control 279 (unknown intervention 41, control 58) Hypertension: unclear Medications taken by ≥ 50% of those in the control group: not reported Medications taken by 20%‐49% of those in the control group: not reported Medications taken by some, but < 20% of the control group: digitalis, diuretics, oestrogens, corticoids, androgens, coumarins, nicotinic acid Location: USA Ethnicity: white 90%, black 7%, Asian 1%, Hispanic 1%, other 1%
Interventions	Type: diet provided (residential institution) Comparison: ↑ corn, soybean, safflower and cottonseed oils (n‐6) vs usual institutional diet Control aims: provided, total fat 40% E (whole diet provided) Intervention aims: total fat 40% E, 2/3 of SFA replaced by unsaturated fats (from corn, soybean, safflower and cottonseed oils), dietary cholesterol reduced (whole diet provided) Dose aim: 2/3 of baseline SFA is increase of ˜12%E PUFA Baseline n‐6: 4% E LA, control arm 4.8% E PUFA Compliance by biomarkers: subcutaneous 18:2 + 18:3 11.7% fat at baseline, rising to 12.8% fat in control and 34.8% fat in intervention (after "prolonged" adherence to diet). Serum TC reduced, but not statistically significantly in intervention compared to control (‐0.37 mmol/L, 95% CI ‐0.77 to 0.03). Compliance by dietary intake: unclear,checked using coloured tickets to assess dining room attendance ‐ described as 49% in intervention and 56% in controls. Laboratory analysis of the mean of over 400 weekly collections of diet provided: Energy intake, kcal/d: intervention 2496, control 2496 Total fat intake, % E: intervention 38.9 (SD 1.9), control 40.1 (SD 2.2) SFA intake, % E: intervention 8.3, control 18.5 (decrease 10.2% E SFA) PUFA intake: not reported but shown in graph as 18:2 + 18:3 ˜12% of dietary fat (4.8% E) in control and 43% in intervention (17.2% E), increase 12.4% E PUFA n‐3 intake, % E: not reported PUFA n‐6 intake, % E: intervention 16.1, control 4.4 (increase 11.7% E LA) Trans fat intake: not reported MUFA intake, % E: intervention 14.6, control 17.1 (decrease 2.5% E MUFAs) CHO intake: not reported Sugars intake: not reported Protein intake, % E: intervention 15.6 (SD not reported), control 15.4 (SD not reported) Alcohol intake: not reported Compliance by other methods: no others reported Inclusion basis: aim was to increase unsaturated fats, not total PUFA. Total PUFA not reported but LA dose 11.7% E (best estimate), > 10% increase from baseline of ˜5% E PUFA dose: 11.7% E from total PUFA (best estimate from food composition data) Duration of intervention: up to 8‐9 years
Outcomes	Main trial outcomes: mortality, heart disease Dropouts: intervention 117, control 58 withdrawals over whole trial, a few participants were involved for up to 8‐9 years Available outcomes: mortality, CV mortality (sudden death, definite MI, definite stroke, angina, PAD events), cancer deaths, cancer diagnoses, stroke, non‐fatal MI, total MI, CHD deaths (fatal MI and sudden death due to CHD), CHD events (any MI or sudden death due to CHD), some data on TC, but no variance info Response to contact: attempted but no author contact established (trial published in 1969)
Notes	Trial dates: recruitment 1959‐1967 Trial funding: mainly US Public Health Service, Los Angeles County Heart Assoc, Arthur Dodd Fuller Assoc, but Corn Products Co (provided Corn oil and margarine), National Soybean Processors Assoc (provided soybean oil), Pitman‐Moore Co (provided margarine), Frozen Desserts Co (imitation ice cream). All trial authors worked for academic or health institutions
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "table of random numbers used"
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Institution provided diet in a masked fashion
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Physician knowledge of allocation was assessed and found not much better than random
Incomplete outcome data (attrition bias) All outcomes	Low risk	All followed up via Veterans Admin system
Selective reporting (reporting bias)	Unclear risk	No protocol or trials registry entry located
Attention bias	Low risk	Appeared equivalent, diet provided to both arms
Compliance	Low risk	Subcutaneous 18:2 + 18:3 11.7% fat at baseline, rising to 12.8% fat in control and 34.8% fat in intervention (after "prolonged" adherence to diet). TC reduced, but not statistically significantly in intervention compared to control (‐0.37 mmol/L, 95% CI ‐0.77 to 0.03).
Other bias	Low risk	None found