Table 2.

Methodological quality system employed to assess quality of studies included in the review

Rating	Definition	Study description	Design and methods
*	Weak	Many details missing (three or more of the following: setting, intervention design, duration, intensity, population, or statistical analysis), irrelevant design or methods.	Methodologic flaws (in statistical methods used, design of intervention, etc.).
**	Moderate	Some details missing (one or two).	Small sample size (<50) or short duration (<1 month).
***	Strong	Some details missing (one or two).	Larger sample size (≥50) and longer duration (>1 month).
****	Very strong	Very clear, all details provided.	Larger sample size (≥50), longer duration (>1 month), and all of the following criteria: population randomly allocated or matched for intervention or control, generalizable results, or validated assessment.

Note: Instrument reproduced from Seymour et al. (2004)