Association of Methylenetetrahydrofolate Reductase C677T Gene Polymorphisms with Mild Cognitive Impairment Susceptibility: A Systematic Review and Meta-Analysis

Table 1

Study characteristics.

Author	Year	Country	Study type	Ethnicity	Age (y),		Gender		Sample size		NOS
					MCI	Control	MCI	Control	MCI	Control
							Female (%)	Female (%)
Roussotte [36]	2017	Turkey	Cohort study	Caucasian			128 (35.65)	94 (45.63)	359	206	7
Luo [37]	2015	China	Case-control study	Caucasian			55 (42.64)	55 (42.31)	129	131	7
Kaur [38]	2018	India	Cohort study	Asian			192 (69.57)	81 (27.18)	263	276	5
El-Batch [39]	2010	Turkey	Case-control study	Caucasian			13 (46.43)	15 (75.00)	28	20	7
Zou [40]	2016	China	Case-control study	Caucasian			55 (44.35)	54 (43.55)	124	124	6
Xing [41]	2019	China	Case-control study	Asian			23 (46.00)	24 (40.00)	50	60	6
Wang [42]	2019	China	Case-control study	Asian			73 (44.24)	58 (51.79)	165	112	6
Li [43]	2017	China	Case-control study	Asian			36 (55.38)	33 (52.38)	65	63	6

MCI: mild cognitive impairment; NOS: Newcastle-Ottawa scale.