Appendix Table A2.
Risk of Bias Summary from Included Observational Studies
| AUTHOR(S) (YEAR) | SELECTION OF PARTICIPANTS | GROUP ALLOCATION | RESIDUAL CONFOUNDING | DEVIATION FROM INTENDED INTERVENTION | MEASUREMENT OF OUTCOMES | INCOMPLETE OUTCOME DATA | SELECTIVE REPORTING | OTHER BIASES | OVERALL RISK OF BIAS RATING |
|---|---|---|---|---|---|---|---|---|---|
| Adams and Nielson (2012) | + | + | + | − | + | + | + | + | High |
| Chan et al. (2009) | + | + | + | − | − | + | ? | + | Moderate-to-high |
| Hardin et al (2017) | + | + | + | − | − | + | ? | + | Moderate |
| Mercer et al. (2015) | + | + | + | − | − | + | ? | + | Moderate-to-high |
| Murphy and Neven (2014) | + | + | + | − | − | + | ? | + | Moderate |
| Stokes-Buzzelli et al. (2010) | − | − | + | − | − | + | ? | + | Moderate |
| Stowe (2011) | − | + | + | − | + | + | + | + | High |
Domain-based evaluation adapted from the Cochrane Collaboration risk of bias table.
− = low risk of bias; + = high risk of bias; ? = unclear.