Table 1.

Quality assessment checklist.

Criteria used to assess study

Clearly defined study objective Appropriate design for study question Inclusion and exclusion criteria clear and appropriate Representative sample (and comparison) Sample size calculation presented Appropriate selection of outcome Appropriate measurement of outcome Standardised collection of data Adequate length of follow up for research question Baseline participation >70% (all groups) Losses and drop outs <20% Adequate description of losses and completers Appropriate analysis of outcomes measured Numerical description of important outcomes given Adjusted and unadjusted calculations provided (with CI if appropriate)

CI = confidence interval