Study Random selection
in the population
Definition of inclusion
and exclusion criteria
Report of losses
to follow-up
Validated
measurements
Statistical
analysis
Risk of
bias
Altiparmak et al. [18] No Yes No Yes Yes High
González-García et al. [21] No Yes No Yes No High
Garcez-Filho et al. [22] No Yes Yes Yes Yes Moderate
Santagata et al. [23] No Yes No Yes No High
Albanese et al. [24] No Yes No Yes Yes High

Each study was categorized as low, moderate or high risk of bias.