Melatonin Receptor 1B Genetic Variants on Susceptibility to Gestational Diabetes Mellitus: A Hospital-Based Case–Control Study in Wuhan, Central China

Figures & data

Table 1 Demographic and Clinical Characteristics of Subjects

	GDM (n=818)	Non-GDM (n=861)	t/χ^2	P
Age (year)	30.98±4.54	28.81±4.16	10.223	<0.001
Pre-pregnancy BMI (kg/m^2)	22.15±3.69	20.87±6.54	4.631	<0.001
FPG (mmol/L)	5.04±0.86	4.34±0.31	20.908	<0.001
1h-PG (mmol/L)	10.42±1.70	7.37±1.33	33.878	<0.001
2h-PG (mmol/L)	9.13±1.73	6.50±0.97	34.926	<0.001
Gravidity
1	285 (35.76)	340 (40.19)	5.303	0.071
2	235 (29.49)	254 (30.02)
≥3	277 (34.75)	252 (29.79)
Parity
Nulliparous	481 (58.87)	526 (61.16)	0.915	0.339
Multiparous	336 (41.13)	334 (38.84)
Family history of diabetes
No	569 (69.90)	748 (88.10)	83.560	<0.001
Yes	245 (30.10)	101 (11.90)

Notes: Data were given as the mean ± SD or as n (%), with the significance of differences between groups evaluated using t-test or χ² test. Bold represents significant P values.

Abbreviations: GDM, gestational diabetes mellitus; BMI, body mass index; FPG, fasting plasma glucose; PG, plasma glucose; SD, standard deviation.

Table 2 Associations Between MTNR1B Gene SNPs and the Risk of GDM

	GDM	Non-GDM	Crude OR (95% CI)	Crude P	Adjusted* OR (95% CI)	Adjusted P
	(n=818)	(n=861)
rs10830962
Allele
C	781	949	Ref		Ref
G	811	745	1.727 (1.311–2.275)	<0.001	2.155 (1.494–3.108)	<0.001
Genotypes
CC	189	272	Ref		Ref
CG	403	405	1.432 (1.136–1.805)	0.002	1.423 (1.059–1.912)	0.019
GG	204	170	1.727 (1.311–2.275)	<0.001	2.056 (1.444–2.927)	<0.001
rs10830963
Allele
C	769	965	Ref		Ref
G	813	721	1.656 (1.258–2.179)	<0.001	1.727 (1.225–2.434)	0.002
Genotypes
CC	185	287	Ref		Ref
CG	399	391	1.583 (1.256–1.996)	<0.001	1.626 (1.210–2.187)	0.001
GG	207	165	1.946 (1.477–2.564)	<0.001	2.328 (1.637–3.310)	<0.001
rs1387153
Allele
C	808	950	Ref		Ref
T	768	736	1.447 (1.103–1.899)	0.008	1.884 (1.318–2.691)	0.001
Genotypes
CC	208	285	Ref		Ref
CT	392	380	1.413 (1.126–1.775)	0.003	1.401 (1.045–1.878)	0.024
TT	188	178	1.447 (1.103–1.899)	0.008	1.812 (1.280–2.565)	0.001
rs7936247
Allele
G	809	952	Ref		Ref
T	779	738	1.487 (1.135–1.948)	0.004	1.928 (1.349–2.754)	<0.001
Genotypes
GG	211	285	Ref		Ref
GT	387	382	1.368 (1.090–1.718)	0.007	1.357 (1.013–1.817)	0.041
TT	196	178	1.487 (1.135–1.948)	0.004	1.844 (1.305–2.607)	0.001
rs4753426
Allele
C	1184	1191	Ref		Ref
T	394	467	0.665 (0.452–0.979)	0.039	0.445 (0.266–0.745)	0.002
Genotypes
CC	444	434	Ref		Ref
CT	296	323	0.896 (0.729–1.101)	0.295	0.795 (0.611–1.034)	0.086
TT	49	72	0.665 (0.452–0.979)	0.039	0.466 (0.283–0.769)	0.003

Notes: *Adjusted by age, pre-pregnancy BMI, family history of diabetes.

Abbreviations: MTNR1B, melatonin receptor 1B; SNPs, single-nucleotide polymorphisms; GDM, gestational diabetes mellitus; OR, odds ratio; CI, confidence interval; Ref, reference genotype.

Table 3 Relationships Between MTNR1B Gene Polymorphisms and Glycemic Traits

	Variables	Genotype			F	P
		AA	AB	BB
rs10830962	FPG	4.71±0.78*	4.76±0.71*	4.88±0.92	3.773	0.023
	1h-PG	8.95±2.23*^♦	9.29±2.07	9.52±2.24	5.532	0.004
	2h-PG	8.05±2.04	8.12±1.83	8.24±2.17	0.774	0.461
rs10830963	FPG	4.71±0.78*	4.77±0.71	4.87±0.92	3.473	0.031
	1h-PG	8.88±2.25*^♦	9.33±2.06	9.54±2.22	7.856	<0.001
	2h-PG	8.00±2.05	8.14±1.82	8.26±2.16	1.323	0.267
rs1387153	FPG	4.72±0.77	4.81±0.85	4.76±0.65	1.566	0.209
	1h-PG	9.06±2.24	9.32±2.18	9.33±2.04	1.859	0.156
	2h-PG	8.07±1.96	8.19±2.03	8.06±1.86	0.665	0.515
rs4753426	FPG	4.80±0.80	4.78±0.76	4.69±0.09	0.853	0.427
	1h-PG	9.32±2.09	9.24±2.21	9.11±2.42	0.494	0.610
	2h-PG	8.17±1.93	8.14±1.98	8.04±2.31	0.157	0.855
rs7936247	FPG	4.72±0.77	4.82±0.85	4.76±0.66	1.909	0.149
	1h-PG	9.03±2.23	9.34±2.17	9.35±2.03	2.530	0.080
	2h-PG	8.06±1.95	8.19±2.03	8.09±1.84	0.542	0.582

Notes: AA: homozygote of major allele, AB: heterozygote, BB: homozygote of minor allele; *Compared with BB Genotype by post hoc LSD test, P<0.05; ^♦Compared with AB Genotype by post hoc LSD test, P<0.05. Bold represents significant P values.

Abbreviations: MTNR1B, melatonin receptor 1B; FPG, fasting plasma glucose; PG, plasma glucose.

Table 4 Analysis of Gene–Gene Interactions

Model	Training Accuracy	Test Accuracy	Cross-Validation Consistency
X2	0.5536	0.5536	10/10
X2, X3	0.5623	0.5439	9/10
X2, X3, X4	0.5708	0.5528	10/10