Adiponectin gene polymorphisms and risk of gestational diabetes mellitus: A meta-analysis

Table 1 Quality assessment of included case control studies using the Newcastle-Ottawa scale

Author	Yr	Selection				Comparability		Exposure			Score
		Case definition	Case representativeness	Control selection	Control definition	Important confounders	Every confounders	Ascertainment	Consistency	Non-response rate
Low et al[7]	2011	1	1	0	1	1	0	1	1	1	7
Takhshid et al[2]	2015	1	1	1	1	0	0	1	1	1	7
Daher et al[8]	2011	1	1	1	1	1	0	1	1	1	8
Han et al[4]	2012	1	1	0	1	1	0	1	1	1	7
Gao et al[10]	2016	1	1	1	1	1	0	1	1	1	8
Luan et al[13]	2015	1	1	1	1	1	0	1	1	1	8
Li et al[12]	2017	1	1	1	1	1	0	1	1	1	8
Li et al[11]	2013	1	1	1	1	0	0	1	1	1	7
Zhang et al[14]	2014	1	1	1	1	1	0	1	1	1	8
Beltcheva et al[1]	2014	1	1	0	1	1	0	1	1	1	7
Pawlik et al[3]	2017	1	1	1	1	0	0	1	1	1	7
Chen et al[15]	2011	1	1	1	1	0	0	1	1	1	7
Wang et al[16]	2016	1	1	1	1	0	0	1	1	1	7

The quality evaluation content mainly includes three aspects: case selection, baseline comparability, and exposure factors with nine evaluation items. If the evaluation item is met, 1 point is obtained, otherwise 0, and the score ranges from 0 to 9.