Swedish Breast CA 1990.
| Methods | RCT | |
| Participants | Women who had had surgery for breast cancer (Sweden)
CVD risk: low
Control: randomised 121, analysed 63
Intervention: randomised 119, analysed 106
Mean years in trial: control 1.9, randomised 1.5
% male: 0%
Age: mean 58 (not described by randomisation group) Baseline BMI: intervention 6 BMI < 20, 81 BMI 20 to 24.9, 34 BMI ≥ 25; control 9 BMI < 20, 74 BMI 20 to 24.9, 36 BMI ≥ 25 |
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| Interventions | Reduced fat vs usual diet Control aims: usual diet Intervention aims: 20%E to 25%E from fat, increase energy from CHO to replace lost energy Control methods: no advice provided, only seen at baseline and 2 years Intervention methods: 4 to 6 sessions during the first 2 months, group meetings every 6 to 8 weeks, evening classes in low fat cooking, 3 monthly counselling during the first year, then at 18 months Weight goals: "The total energy and/or protein intake was to be held constant" Total fat intake (at 2 years): intervention ‐12.9 (SD unclear) (24 overall), control ‐3.1 (SD unclear) (34.1 overall) %E Saturated fat intake (change to 2 years): intervention ‐6.8 (SD unclear), control ‐1.9 (SD unclear) %E Style: diet advice Setting: community |
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| Outcomes | Stated trial outcomes: dietary intake Available outcomes: weight, BMI |
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| Notes | No exact variance or P values reported for weight and BMI outcomes, so have estimated variance from P value < 0.05 for the difference between the 2 arms for weight. As P value > 0.05 for BMI no variance could be estimated | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | "randomly assigned" |
| Allocation concealment (selection bias) | Unclear risk | No details provided |
| Blinding (performance bias and detection bias) All outcomes | High risk | No for participants, unclear for those assessing outcomes |
| Incomplete outcome data (attrition bias) All outcomes | High risk | Outcome data ignored for those who dropped out (48% of the intervention group), > 5%/year |
| Selective reporting (reporting bias) | Unclear risk | No protocol found |
| Other bias | Low risk | |
| Free of systematic difference in care? | High risk | Different levels of time and follow‐up in the 2 groups |
| Free of dietary differences other than fat? | Low risk | Focus on fat |