Table 2.

Association of the 5-HTTLPR polymorphism with IBS susceptibility.

Analysis model	n	ORr (95% CI)	ORf (95% CI)	Ph
L vs. S
Total analysis	6	0.90 (0.40–2.02)	0.84 (0.71–0.99)	0.000
North China	2	1.12 (0.86–1.46)	1.12 (0.86–1.46)	0.523
South China	4	0.83 (0.22–3.06)	0.70 (0.57–0.87)	0.000
In HWE	4	1.41 (1.11–1.79)	1.41 (1.11–1.79)	0.398
IBS-C	5	1.84 (1.48–2.30)	1.84 (1.48–2.30)	0.740
IBS-D	4	0.87 (0.67–1.1.4)	0.87 (0.67–1.1.4)	0.678
IBS-M	4	1.05 (0.67–1.65)	1.07 (0.78–1.48)	0.142
LL vs. SS
Total analysis	6	1.15 (0.36–3.71)	0.87 (0.66–1.16)	0.000
North China	2	1.17 (0.74–1.84)	1.17 (0.74–1.84)	0.5360
South China	4	1.23 (0.16–9.12)	0.72 (0.50–1.03)	0.000
In HWE	4	2.17 (1.16–4.08)	2.20 (1.36–3.55)	0.016
IBS-C	5	2.88 (1.90–4.39)	2.90 (1.93–4.35)	0.391
IBS-D	4	0.83 (0.51–1.35)	0.83 (0.51–1.35)	0.896
IBS-M	4	1.12 (0.44–2.84)	1.15 (0.63–2.12)	0.152
LL vs. LS+SS
Total analysis	6	1.19 (0.34–4.14)	0.80 (0.63–1.03)	0.000
North China	2	1.23 (0.83–1.83)	1.23 (0.83–1.83)	0.745
South China	4	1.22 (0.13–10.98)	0.60 (0.43–0.83)	0.000
In HWE	4	2.29 (1.25–4.20)	2.24 (1.44–3.47)	0.008
IBS-C	5	3.00 (2.07–4.35)	3.04 (2.10–4.39)	0.639
IBS-D	4	0.91 (0.58–1.41)	0.91 (0.58–1.41)	0.935
IBS-M	4	0.98 (0.38–2.49)	0.97 (0.56–1.67)	0.095
LL+LS vs. SS
Total analysis	6	0.83 (0.45–1.52)	0.85 (0.67–1.07)	0.000
North China	2	1.04 (0.70–1.55)	1.04 (0.70–1.54)	0.498
South China	4	0.77 (0.30–1.57)	0.76 (0.57–1.01)	0.000
In HWE	4	1.17 (0.85–1.62)	1.17 (0.85–1.61)	0.825
IBS-C	5	1.43 (1.04–1.96)	1.44 (1.06–1.96)	0.391
IBS-D	4	0.82 (0.57–1.19)	0.82 (0.57–1.19)	0.610
IBS-M	4	1.18 (0.75–1.85)	1.18 (0.75–1.85)	0.716

5-HTTLPR, serotonin transporter gene-linked polymorphic region; IBS, irritable bowel syndrome; ORr, Odds ratio for random effects model; ORf, Odds ratio for fixed effects model; CI, confidence interval; P_h, P value for heterogeneity test; South China including Fujian, Guangzhou, Jiangxi, Yunnan; HWE, Hardy–Weinberg equilibrium.