Table 2.

Quality of the included studies.

No.	References	Selection				Compatibility	Exposure
		Is the case definition adequate?	Representativeness of the cases	Selection of controls	Definition of controls		Ascertainment of exposure	Same method of ascertainment for cases and controls	Non-response rate
1	Chaparro et al.15	*	*	*	*	**	*	*	*
2	Chaparro‑Narváez et al.16	*	*	*	*	**	*	*	*
3	Dayanand et al.17	*	*	*	*	**	*	*	*
4	Devineni et al.18	*	*			**	*	*	*
5	Genton et al.19	*	*	*	*	**	*	*	*
6	Hermansyah et al.20	*	*			**	*	*	*
7	Kochar et al.21	*	*	*	*	**	*	*	*
8	Kochar et al.22	*	*	*	*	**	*	*	*
9	Laman et al.23	*	*	*	*	**	*	*	*
10	Langford et al.24	*	*	*	*	**	*	*	*
11	Limaye et al.25	*	*	*	*	**	*	*	*
12	Medina-Morales et al.26	*	*	*	*	**	*	*	*
13	Mittal et al.27	*	*	*	*	**	*	*	*
14	Mohapatra et al.28	*	*	*	*	**	*	*	*
15	Nayak et al.29	*	*	*	*	**	*	*	*
16	Punnath et al.30	*	*	*	*	**	*	*	*