Gene Polymorphisms and Susceptibility to Functional Dyspepsia: A Systematic Review and Meta-Analysis

Table 1

Characteristics of studies included in the meta-analyses of GNB3 825C>T, SCL6A4 5HTTLPR, and CCK-1R 779T>C polymorphisms and FD susceptibility.

Author (year)	Country	Diagnostic criteria	Genotyping method	Age (year) (SD)		Gender () (M/F)		Genotype, CC/CT/TT, or LL/SL/SS ()		HWE	NOS
				Case	Control	Case	Control	Case	Control
GNB3 825C>T polymorphism
Holtmann (2004)	Germany	Rome II	PCR	46.4 (1.9)	44.4 (1.3)	20/36	40/72	34/18/4	46/62/4	0.002	8
Camilleri (2006)	America	Rome II	PCR	55.8 (13.0)	59.5 (12.7)	27/23	17/22	32/10/8	17/21/1	0.07	7
Tahara (2008)	Japan	Rome II	PCR	60.1 (13.1)	61.1 (13.1)	33/56	55/39	20/38/31	23/48/23	0.84	7
Van Lelyveld (2008)	Netherlands	Rome II	PCR	42.3 (10.6)	41.9 (18.3)	32/80	94/242	48/54/10	180/126/30	0.25	9
De Vries (2009)	Netherlands	Rome II	PCR	49.7 (12.3)	40.1 (12.3)	62/66	120/253	60/56/12	199/138/36	0.10	7
Oshima (2010)	Japan	Rome III	PCR	44.5 (13.3)	48.0 (18.6)	25/43	325/436	17/29/22	191/368/202	0.37	8
Shimpuku (2011)	Japan	Rome III	PCR	59.2 (14.2)	37.2 (9.1)	36/38	57/7	14/44/16	17/28/19	0.32	9
Kim (2012)	Korea	Rome III	PCR	49.0 (15.0)	47.0 (15.0)	62/105	167/267	52/76/39	112/215/107	0.85	8
Chung (2014)	Korea	Rome III	PCR	46.8 (15.7)	50.5 (11.1)	21/29	41/40	5/27/18	15/51/15	0.02	8
Hwang (2014)	Korea	Rome III	PCR	50.3 (18.2)	53.3 (19.3)	35/77	112/157	20/62/29	64/132/73	0.77	7
Yamawaki (2015)	Japan	Rome III	PCR	N/A	N/A	39/35	34/30	14/46/14	16/29/19	0.46	9
Singh (2016)	India	Rome III	PCR-RFLP	38.4 (12.0)	37.3 (11.5)	173/64	152/43	125/86/26	143/95/12	0.45	9
Triantafyllou (2016)	Greece	Rome III	PCR-RFLP	50.2 (15.0)	53.7 (12.0)	61/113	68/113	99/60/15	137/38/6	0.11	7
SCL6A4 5HTTLPR polymorphism
Camilleri (2006)	America	Rome II	PCR	55.8 (13.0)	59.5 (12.7)	27/23	17/22	14/24/12	14/19/6	0.91	7
Van Lelyveld (2008)	Netherlands	Rome II	PCR	42.3 (10.6)	41.9 (18.3)	32/80	94/242	37/50/25	108/170/58	0.52	9
Toyoshima (2011)	Japan	Rome III	PCR	51.8 (17.6)	46.8 (17.1)	26/27	326/320	3/20/30	24/174/448	0.17	7
Hwang (2014)	Korea	Rome III	PCR	50.3 (18.2)	53.3 (19.3)	35/77	112/157	3/42/66	8/71/185	0.71	7
CCK-1R 779T>C polymorphism
Camilleri (2006)	America	Rome II	PCR	55.8 (13.0)	59.5 (12.7)	27/23	17/22	0/11/39	0/9/30	0.42	7
Tahara (2009)	Japan	Rome III	PCR-RFLP	58.0 (14.0)	59.6 (13.1)	57/67	71/48	12/57/55	11/55/53	0.54	7
Hwang (2014)	Korea	Rome III	PCR	50.3 (18.2)	53.3 (19.3)	35/77	112/157	4/50/56	13/107/149	0.26	7
Singh (2016)	India	Rome III	PCR-RFLP	38.4 (12.0)	37.3 (11.5)	173/64	152/43	19/124/94	46/122/82	0.96	9

M: male; F: female; HWE: Hardy-Weinberg equilibrium; NOS: Newcastle-Ottawa Scale; PCR: polymerase chain reaction; RFLP: restriction fragment length polymorphism; N/A: not available.