Black 1994.

Methods	RCT
Participants	People with non‐melanoma skin cancer (USA) CVD risk: low Control: randomised 67, analysed 58 Intervention: randomised 66, analysed 57 Mean years in trial: 1.9 % male: control 67%, intervention 54% Age: mean control 52.3 (sd 13.2), intervention 50.6 (sd 9.7)
Interventions	Reduced fat vs. usual diet Control aims: no dietary advice Intervention aims: total fat 20%E, protein 15%E, CHO 65%E Control methods: no dietary change, 4 monthly clinic visits Intervention methods: 8 weekly classes, with behavioural techniques, plus 4 monthly clinic visits Total fat intake ("during study" months 4‐24): low fat 20.7 (sd 5.5), cont 37.8 (sd 4.1)%E Saturated fat intake ("during study, months 4‐24): low fat 6.6 (sd 1.8), cont 12.8 (sd 2.0)%E Style: diet advice Setting: community
Outcomes	Stated trial outcomes: incidence of actinic keratosis and non‐melanoma skin cancer Data available on total mortality? yes Cardiovascular mortality? yes Events available for combined cardiovascular events: cardiovascular deaths Secondary outcomes: cancer deaths (none) Tertiary outcomes: none (weight data provided, but no variance info)
Notes	At 2 years control ‐1.5kg n=50?, intervention ‐1kg n=51?
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"list of randomly generated numbers"
Allocation concealment (selection bias)	Unclear risk	Randomisation method not clearly described
Blinding (performance bias and detection bias) All outcomes	High risk	Physician blinding: adequate Participant blinding: inadequate
Incomplete outcome data (attrition bias) All outcomes	Low risk	For mortality. Unclear for other outcomes
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	Minor, all have 4 monthly clinic visits, the intervention group had 8 behavioural technique classes that the control group did not have
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