Table 3 Bias risk assessment with reference to the Newcastle Ottawa Scale (NOS)
Studies | Stars allotted | Total no of stars (n) | Comment on the quality of study |
|---|---|---|---|
Paramo 2002 [11] | ******* | 7/9 | Good |
Huong 2006 [12] | ******** | 8/9 | Good |
Muñoz Rodriguez 2000 [13] | ****** | 6/9 | Satisfactory |
Tarr 2007 [14] | ******* | 7/9 | Good |
Cervera 2013 [15] | ******* | 7/9 | Good |
Cavallasca 2008[16] | ******* | 7/9 | Good |
Ideguchi 2013 [17] | ******* | 7/9 | Good |
Luo 2015 [18] | ******** | 8/9 | Good |
Mecacci 2009[19] | ****** | 6/9 | Satisfactory |
Ko 2011 [20] | ******* | 7/9 | Good |