Methods	RCT
Participants	Women diagnosed with stage I or II breast cancer over the past 2 years (USA) CVD risk: low Control: randomised unclear (at least 56), analysed 56 Intervention: randomised unclear (at least 50), analysed 50 Mean years in trial: unclear (1 year max follow up) % male: 0 Age: mean control unclear (71% postmenopausal), intervention unclear (56% post-menopausal) (all 20-65)
Interventions	Reduced fat vs usual diet Control aims: no formal intervention Intervention diet aims: total fat 20%E, high fibre, plant based micronutrients Intervention stress: separate parallel arm, stress reduction programme (data not used here) Control methods: no formal intervention Intervention methods: nutrition intervention programme, 15 sessions (42 hours) over 15 weeks, group-based, dietitian led, 2 individual sessions using social cognitive theory and patient centred counselling to increase self efficacy and confidence Total fat intake (at 12 months): low fat 29.9 (sd unclear), cont 33.6 (sd unclear)%E Saturated fat intake: unclear Style: diet advice Setting: community
Outcomes	Stated trial outcomes: diet and BMI Data available on total mortality? yes Cardiovascular mortality? yes (no events) Events available for combined cardiovascular events: cardiovascular deaths, non fatal MI, stroke (no events) Secondary outcomes: total and non-fatal MI, stroke, cancer deaths (events only for cancer deaths) Tertiary outcomes: weight
Notes
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	“randomised”, stratified by medical centre, cancer stage and age, randomised number/envelope method by project coordinator
Allocation concealment (selection bias)	Low risk	The project coordinator had contact with those from the University of Massachussets, but not those from the other 3 centres, and allocation could not be altered later
Blinding (performance bias and detection bias) All outcomes	High risk	Participants not blinded, unclear about researchers
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Unclear, deaths, cancer and CV events are drop-outs, trialists asked for data - unclear if any data missing
Selective reporting (reporting bias)	Low risk	Not relevant for primary and secondary outcomes as all trialists asked for data
Other bias	Low risk
Free of systematic difference in care?	High risk	High intensity programme for intervention group, nothing for control group. See Control and Intervention Methods in Interventions section of the Table of Characteristics of Included Studies
Free of dietary differences other than fat?	High risk	Intervention also focused on fibre and plant based micronutrients. See Control and Intervention Aims in Interventions section of the Table of Characteristics of Included Studies