Bates 1977.
| Methods | RCT, parallel, 4 arms (n‐6 GLA + LA vs MUFA using either margarines or supplements), 2 years Summary risk of bias: moderate to high |
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| Participants | People with chronic progressive multiple sclerosis CVD risk: low Intervention A, C: 38 per arm Control B, D: 38 per arm Mean years in trial: 2 % male: unclear (quote: "no statistically significant difference between groups") Age: unclear (quote: "no statistically significant difference between groups") Age range: unclear Smokers: unclear Hypertension: unclear 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 Comparison: GLA + linoleic (n‐6) vs oleic (MUFA) Intervention aims A: increase polyunsaturated fats with addition of 8 × 0.6 mL/d of evening primrose oil (Naudicelle) in capsules (360 mg/d GLA plus 3.42 g/d linoleic acid plus < 1% ALA) Control aims B: increase monounsaturated fats with addition of 8 × 0.6mL/d of oleic acid in capsules (4.8 g oleic acid/d) A vs B dose aim: increase 0.34 g/d GLA, 3.78 g/d or 34 kcal or 1.7% E n‐6 Intervention aims C: increase linoleic acid with addition of 11.5 g/d in a spread Control aims D: increase oleic acid with addition of 4 g/d in a spread C vs D dose aim: increase 11.5 g/d or 104 kcal or 5% E n‐6 Baseline n‐6: unclear Compliance by biomarkers: unclear, no serum total cholesterol reported, no tissue fatty acids reported Compliance by dietary intake assessment: unclear, not reported
Duration of intervention: 2 years |
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| Outcomes | Main study outcome: progression or regression of multiple sclerosis (MS) Dropouts: A, 4; B, 7; C, 3; D, 4. (reported as died/withdrawn and not separated) Available outcomes: MS progression (deaths clearly occurred, but reported with dropouts (not separated) and the author did not have access to the data any longer) |
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| Notes | Study funding: Multiple Sclerosis Society, Van den Berghs provided intervention and control spreads free. Response to contact: yes, Prof Bates states that data on mortality are no longer available. Similar reply from Prof Robert Dworkin (who used Professor Bates' data later for a joint publication) |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote: "randomly allocated" |
| Allocation concealment (selection bias) | Unclear risk | Not reported |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | Paper states "double blind", capsules of "identical appearance" and "similar spread" |
| Blinding of outcome assessment (detection bias) All outcomes | Unclear risk | Paper states "double blind" with no further details |
| Incomplete outcome data (attrition bias) All outcomes | Unclear risk | Deaths and dropouts combined; no reasons for dropping out provided |
| Selective reporting (reporting bias) | Unclear risk | No protocol or trials registry entry located |
| Attention Bias | Low risk | Capsules and spreads provided to all participants; no suggestion of attention bias |
| Compliance | Unclear risk | Not reported |
| Other bias | Low risk | None found |