Randomisation and stratification
weight loss
Randomisation was undertaken using a minimisation programme located on a computer in each of the recruiting centres by a trial administrator not involved in delivery of the programmes. Randomisation was stratified by four factors:BMI < or ≥ projected median of 30 kg/mAge < or ≥ projected median of 45 years in the FHRPC since weight loss success is often greater amongst older participantsModerate or high risk of BC as calculated by the local FHRPC (i.e. lifetime Tyrer- Cuzick risk ≥17–29.99% or >30%)Recruiting centreThe study involved unequal randomisation to the three groups to allow the most efficient design to consider the larger predicted clinically important weight difference between the minimal intervention written group and each of the two programmes, as well as the smaller expected difference between the two different programmes. With 30 in the minimal intervention group and 74 subjects in each of the two ‘active’ treatment groups, the trial had 90% power to detect differences in percentage weight loss of 4% or more between the control group and an active treatment group, and a difference of 3% or more between the two active treatment groups. The study was powered for these two analyses as reported previously [