Association of gene variants with susceptibility to type 2 diabetes among Omanis

Table 1 Anthropometric and biochemical characteristics of Omani type 2 diabetes mellitus patients and controls

	T2D patients			Controls
	Mean ± SD or median (range)1			Mean ± SD or median (range)1
	Males	Females	Total	Males	Females	Total
Total number (n)	473	519	992	121	173	294
Age (yr)	56 ± 11	56 ± 10	56 ± 11	41 (35-80)1	44 (32-79)1	43 (32-80)1
Weight (kg)	78.8 ± 15.4NS	75.1 ± 17.0	76.8 ± 16.4	76.8 ± 14.2	70.3 ± 13	73.7 ± 14.7
Height (cm)	165 ± 9a	152 ± 9	157 (106-182)1NS	167 ± 8	154 ± 6	159 ± 9
BMI (kg/m2)	29.1 ± 4.8b	32.8 ± 10.3	30 (15-58)1	27.6 ± 4.3	29.5 ± 5.2	29.3 ± 5.8
Waist circumference (cm)	100 ± 12	100 ± 13	100 ± 13	95 ± 13	91 ± 11	92 ± 12
Fasting blood glucose (mmol/L)	8.7 (3-24)1	9.0 (3-25)1	8.8 (3-25)1	5.1 ± 0.31	4.9 ± 0.36	5.1 ± 0.41
HbA1C (%)	8.3 ± 1.8	8.3 (4.9-15.5)1	8.2 (4.1-18.6)1	5.7 ± 0.46	5.7 (4.0-7.9)1	5.7 ± 0.44
Obesity status (%)
Underweight	-	0.5	0.3	2.1	1	1.4
Normal weight	16.8	12.5	14.5	22.2	18.2	19.1
Overweight	45	30.2	36.1	43.8	34.5	38.9
Obese	38.2	56.8	49.1	29.9	45.8	39.6
Missing	-	-	-	2.1	0.5	1

¹Median (range = minimum-maximum) displayed in the table when the variable does not follow a normal distribution pattern. In all parameters, P < 0.001 between diabetics and controls, except: NS;

^aP < 0.05 between diabetics and controls;

^bP < 0.01 between diabetics and controls. NS: No significant difference between diabetics and controls; T2D: Type 2 diabetes mellitus; BMI: Body mass index.

Table 2 Risk allele frequencies for the tested gene variants among Omani type 2 diabetes mellitus patients and control participants

Gene	Gene variant	Risk/non-	Risk allele frequency (f)		1P value	OR	95%CI
	(SNPs)	risk allele	T2D patients (n = 992)	Controls (n = 294)			for OR
KCNJ11	rs5219	T/C	0.320	0.222	25.8 × 10-6	1.74	1.37-2.22
TCF7L2	rs7903146	T/C	0.445	0.354	20.001	1.46	1.16-1.83
CDKAL1	rs10946398	C/A	0.364	0.311	20.002	1.44	1.15-1.80
CDKN2A/B	rs10811661	T/C	0.836	0.799	0.020	1.40	1.06-1.84
FTO	rs9939609	A/T	0.480	0.435	0.358	1.11	0.899-1.37
FTO	rs8050136	A/C	0.458	0.425	0.770	1.03	0.829-1.29
IGF2BP2	rs4402960	T/G	0.400	0.357	0.286	1.13	0.904-1.41
SLC30A8	rs13266634	C/T	0.857	0.855	0.329	1.16	0.859-1.57
CAPN10	rs3792267 (-43)	G/A	0.802	0.790	0.445	1.11	0.850-1.45
HHEX	rs1111875	T/C	0.301	0.280	0.636	1.06	0.839-1.33

¹P value: Level of significance;

²P value remained significant after correction for multiple testing (< 0.005). The P value, OR and 95%CI were calculated for the association between each gene variant with T2D risk. f: Frequency; T2D: Type 2 diabetes mellitus; SNPs: Single nucleotide polymorphisms.

Table 3 Fixation index, heterozygosity, Fst and % variation among Omani type 2 diabetes mellitus patients and control participants

Gene	Gene variants	T2D patients		Controls		Fst	% variation among T2D and controls	1P value
		F	He	F	He
KCNJ11	rs5219	0.190	0.352	0.091	0.314	0.012	2.07	0.000
TCF7L2	rs7903146	0.017	0.486	0.000	0.476	0.009	1.62	0.000
CDKAL1	rs10946398	0.084	0.424	0.056	0.405	0.003	0.48	0.020
CDKN2A/B	rs10811661	0.000	0.275	0.003	0.320	0.002	0.37	0.042
FTO	rs9939609	0.000	0.502	0.000	0.497	0.002	0.31	0.050
FTO	rs8050136	0.006	0.493	0.000	0.503	0.001	0.12	0.147
IGF2BP2	rs4402960	0.066	0.448	0.000	0.476	0.002	0.23	0.089
SLC30A8	rs13266634	0.061	0.230	0.188	0.201	0.000	0.00	1.000
CAPN10	rs3792267	0.057	0.300	0.000	0.335	0.000	0.00	0.517
HHEX	rs1111875	0.055	0.398	0.052	0.382	0.001	0.00	0.341

This provides a measure of genetic differentiation among population; ¹P value: Level of significance; F: Fixation index; He: Heterozygosity; Fst: The inbreeding coefficient within subpopulation, relative to total; T2D: Type 2 diabetes mellitus.