(Answer items 1–5 ‘yes’ or ‘no’.)

Screening: was there a clear aim?

1. Was the selection of participants appropriate? (Consider source population, inclusion or exclusion criteria, methods of selection.)
2. Was the measurement of variables appropriate? (Consider validity and reliability of instruments/measures used.)
3. Was there appropriate control of bias? (Consider sources of bias, were appropriate methods outlined to deal with any issues such as recall bias, interviewer bias, non-responders, note response rate.)
4. Was the use of statistics appropriate? (Consider primary outcome stated a priori, note sample size.)
5. Was the study free of conflict of interest? (Consider declarations of conflict of interest or identification of funding sources.)
6. List any other limitations of the study.