The analysis will be on an intention-to-treat basis. The unpaired Student's t-test and the Mann-Whitney U-test will be used to analyse univariate parametric and non-parametric data respectively. Serial measurements will be analysed by using repeated measures analysis of variance; any significant overall differences between groups will be investigated with t-tests at individual time intervals. The Chi-squared test will be used to compare categorical data. A p value < 0.05 is considered significant. The number and reason for participants not completing the study will be reported.