McIllmurray 1987.
| Methods | RCT, parallel, 2 arms (GLA vs "inert placebo"), 40 months Summary risk of bias: moderate to high |
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| Participants | People within one month following operation to remove Dukes's C colorectal cancer N: intervention 25 (plus some dropouts), control: 24 (plus some dropouts (analysed intervention 25, control 24). 5 dropped out, but arms unclear Level of risk for CVD: low Male: not reported Mean age (SD) in years: intervention 62.1 (not reported), control 64.8 (not reported) Age range: intervention 48‐81, control 45‐77 Smokers: not reported Hypertension: not reported Medications taken by at least 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 less than 20% of the control group: not reported Location: UK Ethnicity: not reported |
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| Interventions | Type: supplement (EPO) Comparison: GLA vs "inert placebo" (unclear what) Intervention: 6 capsules/d containing 500 mg GLA plus 10 mg natural vitamin E (Efamol). GLA 0.5 g/d, 60 mg/d vitamin E plus vitamin supplements including vitamin C, zinc sulphate and pyridoxine. Control: 6 capsules/d containing an inert placebo, identical in appearance (not specified what). Plus vitamin supplements including vitamin C, zinc sulphate and pyridoxine Dose aim: (assuming placebo contains no PUFA) increase 0.5 g/d GLA, 5 kcal or 0.2% E GLA, assume 70% LA*, 4.2 g/d or 37.8 kcal/d or 1.9% E LA, 2.1% E n‐6 Baseline n‐6: unclear Compliance by biomarkers: unclear, no serum total cholesterol or tissue fatty acid levels reported Compliance by dietary intake: unclear, states that one participant stopped taking the supplements at 12 months
Duration of intervention: 40 months |
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| Outcomes | Main study outcome: unclear, "survival", probably mortality Dropouts: 5 (unclear from which groups) Available outcomes: mortality, cancer mortality (face flushing reported as a side effect, but no numbers provided and assumed due to concomitant pyridoxine) |
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| Notes | Study funding: not stated, Efamol Ltd provided the EPO capsules and inert capsules. *EPO described as being ˜70% LA in some publications, this and a 1 g capsule size have been assumed where no other details are provided Response to contact: Prof McIllmurray replied "I don't have the records ... so I have nothing more than what appears in the publication. I do not recall there being any cardiovascular events." |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote: "assigned at random" |
| Allocation concealment (selection bias) | Unclear risk | No details |
| Blinding of participants and personnel (performance bias) All outcomes | Unclear risk | No details apart from the placebo was identical in appearance to the EPO capsules |
| Blinding of outcome assessment (detection bias) All outcomes | Unclear risk | Not stated |
| Incomplete outcome data (attrition bias) All outcomes | Unclear risk | 5 dropouts, unclear from which arms |
| Selective reporting (reporting bias) | Unclear risk | No protocol or trials register entry found |
| Attention Bias | Low risk | Probably as intervention was capsules in both groups |
| Compliance | Unclear risk | Not stated |
| Other bias | Unclear risk | None noted, but contents of placebo capsules unclear |