Methods
Participants	Institutionalised women living in a mental hospital (USA) CVD risk: low Control: randomised 2320, analysed unclear Intervention: randomised 2344, analysed unclear Mean years in trial: control 1.0, intervention 1.1 % male: 0 Age: unclear, ranges from <30 to >70
Interventions	Modified fat diet vs. usual diet Control aims: usual institutional diet provided Intervention aims: institutional diet modified to total fat 45%E, PUFA 18-20%E, P/S 2.5, less than 150mg/day dietary chol Control methods: whole diet provided Intervention methods: whole diet provided Total fat intake (over 4 years): mod fat 37.8 (sd unclear)%E, cont 39.1 (sd unclear)%E Saturated fat intake (over 4 years): mod fat 9.2 (sd unclear)%E, cont 18.3 (sd unclear) %E Style: diet provided Setting: residential institution
Outcomes	Stated trial outcomes: MI, mortality, sudden deaths Data available on total mortality? yes Cardiovascular mortality? yes Events available for combined cardiovascular events: total MI plus sudden death plus stroke Secondary outcomes: stroke, cancer deaths, total MI Tertiary outcomes: none (data provided on total cholesterol and TGs but no variance info)
Notes	This was a 4.5 year institutional study, but as turnover of participants was very high average time in trial per participant was actually around one year. Participants were replaced as they left, and often left the institution and later returned
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	“stratified randomisation”
Allocation concealment (selection bias)	Unclear risk	Randomisation method not clearly described
Blinding (performance bias and detection bias) All outcomes	Low risk	Physician blinding: adequate Participant blinding: adequate
Incomplete outcome data (attrition bias) All outcomes	High risk	No, participants appear to have been lost on leaving the institution
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?	Low risk	Whole diet provided for both groups. See Control and Intervention Methods in Interventions section of the Table of Characteristics of Included Studies
Free of dietary differences other than fat?	Low risk	See Control and Intervention Aims in Interventions section of the Table of Characteristics of Included Studies