Table 2.

Newcastle-Ottawa Scale.

Study	Study design	Selection	Comparability	Outcome/exposure	NOS score
Adane et al. [2], Ethiopia	Prospective	***	**	***	8
Chang et al. [23], Taiwan	Prospective	***		**	5
Eksombatchai et al. [1], South Korea	Retrospective	**	*	***	6
Viswanathan et al. [24], India	Retrospective	***	*	**	6
Satung et al. [25], Thailand	Retrospective	****	**	**	8
Alisjahbana et al. [26], Indonesia	Prospective	***	*	**	6
Ghanta et al. [27], India	Prospective	***	*	**	6
Jiménez-Corona et al. [28], Mexico	Prospective	****	**	**	8
Yoon et al. [29], South Korea	Prospective	****	**	*	7
Prakash [30], India	Retrospective	****	*	*	6
Kang et al. [31], South Korea	Retrospective	****	*	**	7
Siddiqui et al. [32], India	Prospective	***	**	*	6
Barss et al. [33], Canada	Retrospective	****	**	*	7
Delgado-Sánchez et al. [34], Mexico	Retrospective	****	**	*	7
Ayeni et al. [35], Nigeria	Retrospective	****	*	*	6
Kornfeld et al. [36], India	Prospective	***	**	**	7
Gil-Santana et al. [37], Brazil	Retrospective	****	**	*	7
Magee et al. [38], Georgia	Retrospective	****	**	*	7
Mukhtar and Butt [39], Pakistan	Prospective	****	**	**	8
Chiang et al. [40], Taiwan	Retrospective	****	**	***	9
Magee et al. [41], Georgia	Prospective	****	**	***	9
Muñoz-Torrico et al. [42], Mexico	Retrospective	****	*	***	8
Perez-Navarro et al. [43], Mexico	Prospective	****	**	***	9
Sembiah et al. [44], India	Prospective	****	*	***	8
Arriaga et al. [45], Brazil	Prospective	****	**	***	9
Sulaiman et al. [46], Malaysia	Retrospective	****	*	*	6
Rout et al. [47], India	Case control	***	*	*	5
Leung et al. [17], China	Prospective	****	**	***	9
Sahakyan et al. [48], Armenia	Retrospective	****	**	*	7
Lee et al. [49], South Korea	Retrospective	****	*	*	6
Haile Workneh et al. [50], Ethiopia	Prospective	****	**	**	8
You et al. [51], China	Retrospective	****	*	*	6
Hongguang et al. [52], China	Prospective	****	*	*	6
Wang et al. [7], Taiwan	Retrospective	****	**	*	7
Mahato et al. [53], Nepal	Prospective	****	**	**	8
Lin et al. [54], China	Prospective	***	**	*	6
Wu et al. [55], China	Retrospective	****	**	*	7
Mi et al. [56], China	Retrospective	****	**	**	8
Nandakumar et al. [57], India	Retrospective	****	**	***	9
Mave et al. [58], India	Prospective	****	**	**	8
Choi et al. [59], Nigeria	Retrospective	****	**	***	9
Xhardo et al. [60], Albania	Cross-sectional	****	**	*	7
Baltas et al. [61], London	Retrospective	****	**	***	9
Tok et al. [62], Malaysia	Retrospective	****	**	***	9

Each asterisk (*) represents a point that contributes to the overall quality score of the study. One * means one point.