Study | Reason for exclusion |
---|---|
Benton 1978 | No control group |
Bezan 1988 | Survey, no control group |
Danis 2000 | Non‐randomised cohort study |
Eime 2004 | Interview survey, no control group |
Forst 2006 | Cohort study, no control group, observational |
Mancini 2005 | No distinct control group |
Murthy 1994 | Uncontrolled before and after study |