Meta-analysis of associations between TCF7L2 polymorphisms and risk of type 2 diabetes mellitus in the Chinese population

Metabolic and genetic risk factors associated with pre-diabetes and type 2 diabetes in Thai healthcare employees: A long-term study from the Siriraj Health (SIH) cohort study

BACKGROUND

The study of non-communicable diseases (NCDs) in a developing country like Thailand has rarely been conducted in long-term cohorts, especially among the working-age population. We aim to assess the prevalence and incidence of risk factors and their associations underlying NCDs, especially type-2 diabetes mellitus (T2DM) among healthcare workers enrolled in the Siriraj Health (SIH) study cohort.

METHODS

The SIH study was designed as a longitudinal cohort and conducted at Siriraj hospital, Thailand. A total of 5,011 participants (77% women) were recruited and follow-up. Physical examinations, blood biochemical analyses, family history assessments, behavior evaluations, and genetics factors were assessed.

RESULTS

The average age was 35.44±8.24 years and 51% of participants were overweight and obese. We observed that men were more likely to have a prevalence of T2DM and dyslipidemia (DLP) compared to women. Aging was significantly associated with pre-diabetes and T2DM (P<0.001). Additionally, aging, metabolic syndrome, and elevated triglycerides were associated with the development of pre-diabetes and T2DM. The minor T allele of the rs7903146(C/T) and rs4506565 (A/T) were associated with a high risk of developing pre-diabetes with odds ratios of 2.74 (95% confidence interval [CI]: 0.32-23.3) and 2.71 (95% CI: 0.32-23.07), respectively; however, these associations were statistically insignificant (P>0.05).

CONCLUSION

The findings of the SIH study provide a comprehensive understanding of the health status, risk factors, and genetic factors related to T2DM in a specific working population and highlight areas for further research and intervention to address the growing burden of T2DM and NCDs.

Interaction between Dietary Fat Intake and Metabolic Genetic Risk Score on 25-Hydroxyvitamin D Concentrations in a Turkish Adult Population

Previous studies have pointed out a link between vitamin D status and metabolic traits, however, consistent evidence has not been provided yet. This cross-sectional study has used a nutrigenetic approach to investigate the interaction between metabolic-genetic risk score (GRS) and dietary intake on serum 25-hydroxyvitamin D [25(OH)D] concentrations in 396 unrelated Turkish adults, aged 24-50 years. Serum 25(OH)D concentration was significantly lower in those with a metabolic-GRS ≥ 1 risk allele than those with a metabolic-GRS < 1 risk allele (p = 0.020). A significant interaction between metabolic-GRS and dietary fat intake (energy%) on serum 25(OH)D levels was identified (Pinteraction = 0.040). Participants carrying a metabolic-GRS ≥ 1 risk allele and consuming a high fat diet (≥38% of energy = 122.3 ± 52.51 g/day) had significantly lower serum 25(OH)D concentration (p = 0.006) in comparison to those consuming a low-fat diet (<38% of energy = 82.5 ± 37.36 g/d). In conclusion, our study suggests a novel interaction between metabolic-GRS and dietary fat intake on serum 25(OH)D level, which emphasises that following the current dietary fat intake recommendation (<35% total fat) could be important in reducing the prevalence of vitamin D deficiency in this Turkish population. Nevertheless, further larger studies are needed to verify this interaction, before implementing personalized dietary recommendations for the maintenance of optimal vitamin D status.

Association of Combined TCF7L2 and KCNQ1 Gene Polymorphisms with Diabetic Micro- and Macrovascular Complications in Type 2 Diabetes Mellitus

BACKGROUND

Vascular complications are the major morbid consequences of type 2 diabetes mellitus (T2DM). The transcription factor 7-like 2 (TCF7L2), potassium voltage-gated channel subfamily Q member 1 (KCNQ1), and inwardly-rectifying potassium channel, subfamily J, member 11 gene (KCNJ11) are common T2DM susceptibility genes in various populations. However, the associations between polymorphisms in these genes and diabetic complications are controversial. This study aimed to investigate the effects of combined gene-polymorphisms within TCF7L2, KCNQ1, and KCNJ11 on vascular complications in Thai subjects with T2DM.

METHODS

We conducted a case-control study comprising 960 T2DM patients and 740 non-diabetes controls. Single nucleotide polymorphisms in TCF7L2, KCNQ1, and KCNJ11 were genotyped and evaluated for their association with diabetic vascular complications.

RESULTS

The gene variants TCF7L2 rs290487-T, KCNQ1 rs2237892-C, and KCNQ1 rs2237897-C were associated with increased risk of T2DM. TCF7L2 rs7903146-C, TCF7L2 rs290487-C, KCNQ1 rs2237892-T, and KCNQ1 rs2237897-T revealed an association with hypertension. The specific combination of risk-alleles that have effects on T2DM and hypertension, TCF7L2 rs7903146-C, KCNQ1 rs2237892-C, and KCNQ1 rs2237897-T, as genetic risk score (GRS), pronounced significant association with coronary artery disease (CAD), cumulative nephropathy and CAD, and cumulative microvascular and macrovascular complications (respective odds ratios [ORs] with 95% confidence interval [95% CI], comparing between GRS 2-3 and GRS 5-6, were 7.31 [2.03 to 26.35], 3.92 [1.75 to 8.76], and 2.33 [1.13 to 4.79]).

CONCLUSION

This study demonstrated, for the first time, the effect conferred by specific combined genetic variants in TCF7L2 and KCNQ1 on diabetic vascular complications, predominantly with nephropathy and CAD. Such a specific pattern of gene variant combination may implicate in the progression of T2DM and life-threatening vascular complications.

Association of TCF7L2 gene polymorphisms, methylation, and gene-environment interaction with type 2 diabetes mellitus risk: A nested case-control study in the Rural Chinese Cohort Study

BACKGROUND

To assess the associations of single-nucleotide polymorphisms (SNPs) and methylation of transcription factor 7-like 2 (TCF7L2) gene with type 2 diabetes mellitus (T2DM) risk and further explore the interactions among SNPs, methylation, and environmental factors involved in T2DM risk.

METHODS

We conducted a nested case-control study with 290 pairs of T2DM cases and matched controls. We genotyped 3 SNPs of TCF7L2 in all included participants and tested 14 CpG loci of TCF7L2 in 76 pairs of cases and controls. Conditional logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) for T2DM risk according to SNPs and methylation of TCF7L2. Multifactor dimensionality reduction (MDR) analysis was used to explore the potential TCF7L2 gene-environment interactions in T2DM risk.

RESULTS

We found no statistically significant association between the TCF7L2 polymorphisms and T2DM risk. We observed significant positive associations of methylation at CpG5 and CpG7_8 with T2DM risk. For each 1% increase in DNA methylation at CpG5 and CpG7_8, T2DM risk increased 12% (OR 1.12, 95% CI 1.01-1.25) and 32% (OR 1.32, 95% CI 1.07-1.63), respectively. Additionally, MDR analyses identified significant SNP-environment interactions among rs290487, alcohol drinking, and hypertension and methylation-environment interactions among CpG5, CpG7_8 and hypertension (P <0.05).

CONCLUSIONS

TCF7L2 polymorphisms were not independently associated with T2DM risk. However, TCF7L2 methylation were positively associated with T2DM risk in rural Chinese adults. Interactions among TCF7L2 polymorphisms, TCF7L2 methylation and environmental factors also suggest a possible etiologic pattern for T2DM.

Association between ABCC8 Ala1369Ser Polymorphism (rs757110 T/G) and Type 2 Diabetes Risk in an Iranian Population: A Case-Control Study

OBJECTIVE

Glucose metabolism increases ATP/ADP ratio within the β-cells and causes ATP-sensitive K+ (KATP) channel closure and consequently insulin secretion. The enhanced activity of the channel may be a mechanism contributing to the reduced first-phase of insulin secretion observed in T2DM. There is no study to date in the Kurdish ethnic group regarding the relationship between SNP Ala1369Ser (rs757110 T/G) of SUR1 gene and T2DM, and additionally, the results of this association in other populations are inconsistent. Therefore, our aim in this study was to explore the possible association between SNP Ala1369Ser and type 2 diabetes in an Iranian Kurdish ethnic group.

METHODS

In this study, we checked out the frequency of alleles and genotypes of SNP Ala1369Ser in T2DM individuals (207 patients; men/women: 106/101) and non-T2DM subjects (201 controls; men/women: 97/104), and their effects on anthropometric, clinical, and biochemical parameters. Genomic DNA was extracted from the leukocytes of blood specimens using a standard method. We amplified the ABCC8 rs757110 polymorphic site (T/G) using a polymerase chain reaction (PCR) method and a designed primer pair. To perform the PCR-RFLP method, the amplicons were subjected to restriction enzymes and the resulting fragments separated by gel electrophoresis.

RESULTS

The frequency of the G-allele of Ala1369Ser polymorphism was significantly (0.01) higher in the case group than the control group (19% vs. 9%, respectively). In the dominant model (TT vs. TG+GG), there was a significant relationship between this SNP and an increased risk of T2DM (P = 0.00). T2DM patients with TG+GG genotypes had significantly higher fasting plasma insulin and HOMA-IR than those who had the TT genotype (P = 0.02 and 0.01, respectively).

CONCLUSION

Our study is the first study to investigate the association between Ala1369Ser ABCC8 genetic variation and T2DM in the Kurdish population of western Iran. The obtained results clearly show that Ala1369Ser polymorphism of ABCC8 is associated with an increased risk of T2DM in this population.

The Importance of Precision Medicine in Type 2 Diabetes Mellitus (T2DM): From Pharmacogenetic and Pharmacoepigenetic Aspects

BACKGROUND

Type 2 Diabetes Mellitus (T2DM) is a worldwide disorder as the most important challenges of health-care systems. Controlling the normal glycaemia greatly profit long-term prognosis and gives explanation for early, effective, constant, and safe intervention.

MATERIAL AND METHODS

Finding the main genetic and epigenetic profile of T2DM and the exact molecular targets of T2DM medications can shed light on its personalized management. The comprehensive information of T2DM was earned through the genome-wide association study (GWAS) studies. In the current review, we represent the most important candidate genes of T2DM like CAPN10, TCF7L2, PPAR-γ, IRSs, KCNJ11, WFS1, and HNF homeoboxes. Different genetic variations of a candidate gene can predict the efficacy of T2DM personalized strategy medication.

RESULTS

SLCs and AMPK variations are considered for metformin, CYP2C9, KATP channel, CDKAL1, CDKN2A/2B and KCNQ1 for sulphonylureas, OATP1B, and KCNQ1 for repaglinide and the last but not the least ADIPOQ, PPAR-γ, SLC, CYP2C8, and SLCO1B1 for thiazolidinediones response prediction.

CONCLUSION

Taken everything into consideration, there is an extreme need to determine the genetic status of T2DM patients in some known genetic region before planning the medication strategies.

The Association of Transcription Factor 7 like 2 Gene Polymorphism with Diabetic Nephropathy in Patients with Type 2 Diabetes Mellitus

BACKGROUND

The exact relationship between the different TCF7L2 gene polymorphisms and the development of diabetic nephropathy (DN) remains unclear.

OBJECTIVE

To investigate the association of TCF7L2 rs12255372 (G/T) gene polymorphism and diabetic nephropathy (DN) in patients with type 2 diabetes (T2D).

METHODS

100 patients with T2D (50 patients without DN and 50 patients with DN) and 50 age and sex-matched healthy controls (HC) were enrolled in the study. Genotyping for the rs12255372 (G>T) polymorphism in the TCF7L2 gene was performed by real-time PCR.

RESULTS

The rs12255372 polymorphism showed a statistically significant difference between HC and patients with and without DN in both the genotype and allele frequency. However, the rs12255372 polymorphism genotype or allele frequency was not statistically different between patients with DN and those patients without DN. The G allele was found to be higher in patients and the T allele was higher in HC suggesting that the G allele was the risk allele for developing T2D & DN and that the T allele was protective.

CONCLUSION

rs12255372 TCF7L2 gene polymorphism was strongly associated with type 2 diabetes mellitus and DN. The association between rs12255372 polymorphism and DN was a mere reflection of a complicated diabetes mellitus rather than a direct independent association.

Meta-analysis of association between TCF7L2 polymorphism rs7903146 and type 2 diabetes mellitus

BACKGROUND

Large scale association studies have found a significant association between type 2 diabetes mellitus (T2DM) and transcription factor 7-like 2 (TCF7L2) polymorphism rs7903146. However, the quality of data varies greatly, as the studies report inconsistent results in different populations. Hence, we perform this meta-analysis to give a more convincing result.

METHODS

The articles, published from January 1st, 2000 to April 1st, 2017, were identified by searching in PubMed and Google Scholar. A total of 56628 participants (34232 cases and 22396 controls) were included in the meta-analysis. A total of 28 studies were divided into 4 subgroups: Caucasian (10 studies), East Asian (5 studies), South Asian (5 studies) and Others (8 studies). All the data analyses were analyzed by the R package meta.

RESULTS

The significant association was observed by using the dominant model (OR = 1.41, CI = 1.36 - 1.47, p < 0.0001), recessive model (OR = 1.58, CI = 1.48 - 1.69, p < 0.0001), additive model(CT vs CC) (OR = 1.34, CI = 1.28-1.39, p < 0.0001), additive model(TT vs CC) (OR = 1.81, CI = 1.69-1.94, p < 0.0001)and allele model (OR = 1.35, CI = 1.31-1.39, p < 0.0001).

CONCLUSION

The meta-analysis suggested that rs7903146 was significantly associated with T2DM in Caucasian, East Asian, South Asian and other ethnicities.

Cardiovascular disease and cancer: Evidence for shared disease pathways and pharmacologic prevention

Cardiovascular disease (CVD) and cancer are leading causes of mortality and morbidity worldwide. Strategies to improve their treatment and prevention are global priorities and major focus of World Health Organization's joint prevention programs. Emerging evidence suggests that modifiable risk factors including diet, sedentary lifestyle, obesity and tobacco use are central to the pathogenesis of both diseases and are reflected in common genetic, cellular, and signaling mechanisms. Understanding this important biological overlap is critical and may help identify novel therapeutic and preventative strategies for both disorders. In this review, we will discuss the shared genetic and molecular factors central to CVD and cancer and how the strategies commonly used for the prevention of atherosclerotic vascular disease can be applied to cancer prevention.

A comparison of gene expression profiles in patients with coronary artery disease, type 2 diabetes, and their coexisting conditions

Background

To support a hypothesis that there is an intrinsic interplay between coronary artery disease (CAD) and type 2 diabetes (T2D), we used RNA-seq to identify unique gene expression signatures of CAD, T2D, and coexisting conditions.

Methods

After transcriptome sequencing, differential expression analysis was performed between each disordered state and normal control group. By comparing gene expression profiles of CAD, T2D, and coexisting conditions, common and specific patterns of each disordered state were displayed. To verify the specific gene expression patterns of CAD or T2D, the gene expression data of GSE23561 was extracted.

Results

A strong overlap of 191 genes across CAD, T2D and coexisting conditions, were mainly involved in a viral infectious cycle, anti-apoptosis, endocrine pancreas development, innate immune response, and blood coagulation. In T2D-specific PPI networks involving 64 genes, TCF7L2 (Degree = 169) was identified as a key gene in T2D development, while in CAD-specific PPI networks involving 64 genes, HIF1A (Degree = 124), SMAD1 (Degree = 112) and SKIL (Degree = 94) were identified as key genes in the CAD development. Interestingly, with the provided expression data from GSE23561, the three genes were all up-regulated in CAD, and SMAD1 and SKIL were specifically differentially expressed in CAD, while HIF1A was differentially expressed in both CAD and T2D, but with opposite trends.

Conclusions

This study provides some evidences in transcript level to uncover the association of T2D, CAD and coexisting conditions, and may provide novel drug targets and biomarkers for these diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s13000-017-0630-7) contains supplementary material, which is available to authorized users.

Current Understanding on Role of the Wnt Signaling Pathway Effector TCF7L2 in Glucose Homeostasis

The role of the Wnt signaling pathway in metabolic homeostasis has drawn our intensive attention, especially after the genome-wide association study discovery that certain polymorphisms of its key effector TCF7L2 are strongly associated with the susceptibility to type 2 diabetes. For a decade, great efforts have been made in determining the function of TCF7L2 in various metabolic organs, which have generated both considerable achievements and disputes. In this review, I will briefly introduce the canonical Wnt signaling pathway, focusing on its effector β-catenin/TCF, including emphasizing the bidirectional feature of TCFs and β-catenin post-translational modifications. I will then summarize the observations on the association between TCF7L2 polymorphisms and type 2 diabetes risk. The main content, however, is on the intensive functional exploration of the metabolic role of TCF7L2, including the disputes generated on determining its role in the pancreas and liver with various transgenic mouse lines. Finally, I will discuss those achievements and disputes and present my future perspectives.

The TCF7L2 rs7903146 (C/T) polymorphism is associated with risk to type 2 diabetes mellitus in Southern-Brazil

OBJECTIVE

The aim of this study was to investigate the association between the rs7903146 (C/T) polymorphism in the TCF7L2 gene and type 2 diabetes mellitus, in a Southern-Brazilian population.

MATERIALS AND METHODS

The TCF7L2 rs7903146 polymorphism was genotyped in 953 type 2 diabetic patients and 535 non-diabetic subjects. All subjects were white. The polymorphism was genotyped by Real-Time PCR using TaqMan MGB probes (Life Technologies). Odds ratios (OR) and 95% confidence intervals (CI) were calculated for additive, recessive and dominant inheritance models.

RESULTS

Genotype and allele frequencies of the rs7903146 polymorphism differed significantly between type 2 diabetic patients and non-diabetic subjects (P = 0.001 and P = 0.0001, respectively). The frequency of the minor allele was 38% in type 2 diabetes group and 31% in non-diabetic subjects, and this allele was significantly associated with type 2 diabetes risk (OR = 1.42, 95% CI 1.15 - 1.76 for the dominant model of inheritance). Moreover, the T/T genotype was associated with a higher risk for type 2 diabetes (OR = 1.83, 95% CI 1.3-2.5) than the presence of only one copy of the T allele (OR = 1.31, 95% CI 1.1-1.6). Both results were adjusted for age and gender.

CONCLUSIONS

Our results confirm the association between the TCF7L2 rs7903146 polymorphism and increase risk for type 2 diabetes in Southern-Brazil.

Design of an allele-specific PCR assay to genotype the rs12255372 SNP in a pilot study of association between common TCF7L2 polymorphisms and type 2 diabetes in Venezuelans

OBJECTIVE

The global burden of diabetes mellitus will impact strongly American countries in the coming decades. Type 2 diabetes mellitus (T2DM) is a multifactorial disease and the basis for its genetic susceptibility remains not fully understood. Different population studies have demonstrated that variants of the TCF7L2 gene are strongly associated with an increased risk of T2DM. Moreover, institutions or countries with limited budget to conduct genetic research need cost effective methods for detecting DNA variants.

SUBJECTS AND METHODS

We standardized a rapid and simple allele-specific PCR method for genotyping the rs12255372 single nucleotide polymorphism (SNP) in a pilot study exploring the association of three TCF7L2 polymorphisms (rs7903146, rs12255372 and DG10S478) with T2DM in 70 patients and 73 controls from Venezuela.

RESULTS

The performance of the designed allele-specific PCR reaction for rs12255372 genotyping was reliable and accurate. Patients carrying the TCF7L2 rs7903146 T allele (CT + TT genotypes) and heterozygous CT genotype had a significantly higher risk for T2DM (OR = 2.9 and 2.3, respectively). Although rs12255372 and DG10S478 risk alleles predominated in T2DM group no statistical significance was found.

CONCLUSIONS

We developed a novel allele-specific PCR method for easier and rapid detection of rs12255372 polymorphism without the use of expensive instrumentation and reagents. Our study in a relatively small sample of the Venezuelan population replicated the association of the rs7903146 SNP with T2DM. Further studies with larger sample size and more biochemical data should be conducted to explore the genetic basis of T2DM susceptibility in Venezuela.

Association of the Genetic Polymorphisms in Transcription Factor 7-Like 2 and Peroxisome Proliferator-Activated Receptors- γ 2 with Type 2 Diabetes Mellitus and is Interaction with Obesity Status in Emirati Population

BACKGROUND

Transcription factor 7-like 2 gene (TCF7L2) and peroxisome proliferator-activated receptors-γ2 (PPAR-γ2) have a profound effect on the incidence of type 2 diabetes mellitus (T2DM) and had previously been found to be associated with T2DM risk in various ppopulations. However, studies in the Arab population are inconsistent. We conducted a case control study to confirm the association of variants rs10885409 of TCF7L2 and Pro12Ala (rs1801282) of PPAR-γ2 with risk of T2DM and related complications in Emirati population of Arab origin. We also investigated the interaction of these associations with obesity status.

METHODS

DNA was extracted from the saliva samples of 272 T2DM patients and 216 nondiabetic Emiratis. Genotyping for rs10885409 (TCF7L2) and rs1801282 (PPAR-γ2 P12A) variants was accomplished with a TaqMan assay. The subgroups were constituted according to obesity status.

RESULTS

In the nonobese group, the rs10885409 C allele in the recessive model was significantly associated with the incidence of T2DM (OR 1.975 [95% CI 1.127-3.461], P = 0.017), but this association was not observed in the obese group or when BMI was not considered. PPAR-γ2 risk allele Pro12 frequency (0.96) was similar in the groups tested and more than 90% population was homozygous for this allele.

CONCLUSIONS

Our case-control study is the first of its kind in Emiratis which establishes TCF7L2 rs10885409 C allele as a T2DM risk factor in Emiratis and this association is modulated by obesity status. We also confirmed that Pro12Ala mutation in PPAR-γ2 is not associated with T2DM risk in this population.

Association between PGC-1alpha gene polymorphisms and type 2 diabetes risk: a case-control study of an Iranian population

OBJECTIVE

The peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) gene could play a role in the onset of type 2 diabetes mellitus. The aim of this study was to explore the possible associations among polymorphisms Gly482Ser, Thr394Thr and Thr528Thr of the PGC-1alpha gene and the risk of type 2 diabetes in Kurdish-Iranians.

METHODS

DNA specimens from all 173 type 2 diabetes subjects and 173 normoglycemic subjects were genotyped by the polymerase chain reaction-restriction fragment length polymorphism method. Genotypic and allelic frequencies were analyzed in each group. Serum lipids, fasting glucose, fasting serum insulin, homeostasis model assessment of insulin resistance and glycated hemoglobin levels were determined using the conventional methods. The data were analyzed using SPSS software.

RESULTS

The GA genotype of Gly482Ser was associated with a significant susceptibility for type 2 diabetes (odds ratio 5.23, p<0.000). Furthermore, the GA genotype of Thr528Thr had a higher risk for type 2 diabetes (odds ratio 2.37, p<0.002). Normoglycemic persons carrying the GA+AA genotypes of Gly482Ser variation had significantly lower high-density lipoprotein cholesterol in comparison with persons having GG genotype. In comparison with GG genotype carriers, normoglycemic subjects carrying the GA+AA genotypes of Thr394Thr variation had significantly higher fasting blood sugar, fasting serum insulin and homeostasis model assessment of insulin resistance. Normoglycemic subjects with the GA+AA genotypes of Thr528Thr variation had significantly higher levels of low-density lipoprotein cholesterol compared with subjects having the GG genotype. Type 2 diabetes subjects carrying the GA+AA genotypes of this polymorphism had significantly higher waist-hip ratio in comparison with the GG genotype carriers. We also found that haplotype 394-GG/482-GA/528-GG of PGC-1alpha was significantly associated with higher risk of type 2 diabetes.

CONCLUSIONS

Our findings revealed significant associations between PGC-1alpha Gly482Ser and Thr528Thr polymorphisms and type 2 diabetes in Kurdish-Iranians.

Insulin resistance and its correlation with risk factors for developing diabetes mellitus in 100 omani medical students

OBJECTIVES

The aim of this study was to assess the prevalence of insulin resistance (IR) in healthy young Omanis and relate this with their body mass index (BMI) and family history (FH) of diabetes mellitus (DM).

METHODS

This study was conducted between May 2009 and February 2010 at Sultan Qaboos University, Muscat, Oman. A detailed questionnaire was completed by 50 male and 50 female medical students between 20-25 years old. Fasting blood samples were obtained for serum glucose and insulin measurements. IR was calculated using the homeostasis model assessment-estimated insulin resistance (HOMA-IR) formula (fasting insulin x fasting glucose/22.5) and a value above 2.5 was considered elevated. The results were analysed using the Statistical Package for the Social Sciences (SPSS).

RESULTS

PARTICIPANTS WERE CLASSIFIED INTO THE FOLLOWING BMI CATEGORIES: 59% were normal (18.5-24.9 kg/m(2)), 26% were overweight or obese (>24.9 kg/m(2)) and 15% were underweight (<18.5 kg/m(2)). A FH of DM was present in 74%. The HOMA-IR index was elevated in 16% and was directly correlated to the BMI (P = 0.003). There was no correlation between IR and a positive FH of DM.

CONCLUSION

There is a high prevalence of IR (16%) and obesity (26%) in healthy young Omani medical students. Counselling is recommended for all overweight and obese individuals in an attempt to prevent or delay the onset of DM in the future.

Association of the rs11196218 polymorphism in TCF7L2 with type 2 diabetes mellitus in Asian population

OBJECTIVE

To clarify the association of rs11196218 polymorphism in transcription factor 7-like 2 (TCF7L2) and type 2 diabetes mellitus (T2DM) in Asian population by a case-control study and meta-analysis.

METHODS

In the case-control study, 1842 patients with T2DM and 7777 normal glucose-tolerant controls in the Henan province of China were genotyped for rs11196218 in TCF7L2 by PCR-ligase detection reaction. We used allele, co-dominant, dominant and recessive models to evaluate the risk association and performed a meta-analysis of the results of different genetic models in previous studies and the current study.

RESULTS

The AG genotype of rs11196218 was associated with risk of T2DM in the Henan population (odds ratio 1.37, 95% confidence interval 1.06-1.78), and dominant model showed marginal significant association (1.28, 0.99-1.67). Meta-analysis of 10 studies revealed the dominant model associated with T2DM in the overall population (1.20, 1.05-1.36). When stratified by region (southern and northern China and Japan), both the AG genotype and the dominant model were associated with risk of T2DM in southern Chinese (1.31, 1.03-1.66; 1.27, 1.01-1.60, respectively).

CONCLUSION

The rs11196218 polymorphism in TCF7L2 is associated with risk of T2DM in Asian population.