Table 1.

Baseline characteristics and methodological quality of the included studies focused on IL-17A/F genetic polymorphisms

Ref.	Year	Country	Ethnicity	Number		Gender (M/F)		Age (yr)		Genotyping method	Genetype	NOS score
				Case	Control	Case	Control	Case	Control
Yu et al[42]	2012	China	Asian	270	268	130/140	136/132	47.4 ± 14.1	47.1 ± 12.9	PCR-LDR	IL-17A/F	8
Hayashi et al[10]	2012	Japan	Asian	202	475	114/88	241/234	41.1 ± 14.3	59.4 ± 12.7	PCR-SSCP	IL-17A	8
Kim et al[41]	2011	South Korea	Asian	268	258	-	-	-	-	Direct sequencing	IL-17A	6
Chen[40]	2009	China	Asian	148	373	83/65	233/140	38.4 ± 12.9	37.9 ± 16.1	PCR-RFLP	IL-17F	8
Seiderer et al[26]	2008	Germany	Caucasian	216	967	110/106	609/358	42.6 ± 14.8	47.4 ± 11.3	PCR-RFLP	IL-17F	8
Arisawa et al[39]	2008	Japan	Asian	111	248	56/55	133/115	39.0 ± 14.3	46.6 ± 18.4	PCR-SSCP	IL-17A/F	7

F: Female; LDR: Ligase detection reaction; M: Male; NOS: Newcastle-Ottawa Scale; PCR: Polymerase chain reaction; RFLP: Restriction fragment length polymorphism; SSCP: Single-strand conformation polymorphism.