Analysis
Statistical analysis was carried out using IBM Statistical Package for Social Sciences (SPSS) for Windows, version 10. Baseline data in the two groups were summarised using descriptive statistics. Normality testing was undertaken using the Shapiro-Wilks test. If data was normally distributed the two groups were compared using an analysis of covariance (ANCOVA) adjusting for baseline scores. If the assumptions underpinning ANCOVA modelling were not met, a Mann Whitney test was carried out. Participants were analysed according to the group they were allocated. Only complete cases were analysed, and no imputation was undertaken. This reflects the fact that drop outs obtained were accounted for in the initial sample size calculation and there was no difference in the characteristics of those who dropped out at baseline.