Association between ADAM12 Single-Nucleotide Polymorphisms and Knee Osteoarthritis: A Meta-Analysis

Table 2

Quality assessment of included studies.

Item/study	Kerna et al., 2009	Lou et al., 2014	Poonpet et al., 2016	Rodriguez-Lopez et al., 2009	Shin et al., 2012	Valdes et al., 2006	Wang et al., 2015
Adequate definition of cases
Representativeness of cases	—		—	—	—	—	—
Selection of control subjects	—	—	—	—	—	—	—
Definition of control subjects
Control for important factor or additional factor	—		—	—	—
Exposure assessment
Same method of ascertainment for all subjects
Nonresponse rate

A study could be awarded a maximum of one for each item except for the item “control for important factor or additional factor.” The definition/explanation of each column of the Newcastle-Ottawa Scale is available from http://www.ohri.ca/programs/clinical_epidemiology/oxford.asp.