Association study of the single nucleotide polymorphisms in adiponectin-associated genes with type 2 diabetes in Han Chinese

Adiponectin gene polymorphisms and risk of type 2 diabetes: an updated evidence for meta-analysis

BACKGROUND

Growing body of evidence suggest the association between SNP - 11377 C > G and SNP + 276 G > T polymorphisms of adiponectin gene with type 2 diabetes (T2D). However, these findings have not been conclusive and consistent. The present study quantitatively evaluates the data on the association between DIPOQ - 11377C/G, and + 276G/T polymorphisms and risk of T2D through a meta-analysis.

METHODS

A systematic search was performed in the PubMed, Web of science, Scopus and Cochrane library databases to extract published studies according to the inclusion criteria. Among the 741 studies, 391 of them were screened as full text and 31 studies were finally included in the meta-analysis. Analysis of data was performed using random-effects model. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to analyze the strength of association. Subgroup and meta-regression analyses were performed to identify the potential source of heterogeneity.

RESULTS

The pooled analysis showed that there was no statistically significant association between genotypes of CC (OR = 0.76, 95% CI: 0.53-1.09, P = 0.14), CG (OR = 0.93, 95% CI: 0.72-1.20, P = 0.58) and GG (OR = 1, 95% CI: 0.80-1.26, P = 0.94) ADIPO - 11377 polymorphism with increased risk of T2D. In addition, the results revealed a trend toward an increased risk of T2D for the SNP + 276 TT genotype (OR = 0.87, 95% CI: 0.77-0.98, P = 0.026) as compared with the GT and GG genotypes. Subgroup analysis by ethnicity indicated significant association between the TT genotype of the SNP + 276 and increased risk of T2D among Europeans. Met-regression demonstrated significant association between the GT genotype of + 276 polymorphism with risk of T2D in male individuals (slope: 0.0006; 95% CI: 0.0002-0.0009; P < 0.001).

CONCLUSIONS

Collectively, our findings demonstrated a positive association between ADIPOQ + 276 G > T polymorphism with increased risk of T2D in male individuals with European ethnicity.

Meta-analysis of the association between adiponectin SNP 45, SNP 276, and type 2 diabetes mellitus

Objective

The present study aimed to determine whether the polymorphisms at rs2241766 and rs1501299 on the ADIPOQ gene were related to the susceptibility of type 2 diabetes mellitus (T2DM).

Methods

Eight databases, PubMed, GWAS, Embase, Lochrane, Ebsco, CNKI (Chinese National Knowledge Infrastructure), VIP (Viper Database) and ChinaInfo were searched, and a meta-analysis of susceptibility was conducted between SNP45, SNP276 polymorphisms and T2DM. Furthermore, HWE test was conducted to assess the genetic balance of the study, evaluate the quality of Newcastle–Ottawa quality assessment scale (NOS), and establishing allelic, dominant, recessive, heterozygous, and homozygous gene models.

Results

This meta-analysis included 53 articles, encompassing 9285 cases with rs2241766 and 14156 controls and 7747 cases with rs1501299 and 10607 controls. For the rs2241766 locus, a significant correlation was found in the three models by the subgroup analysis. Western Asians: dominant gene model (TT + TG vs. GG, P = 0.01); heterozygous gene model (TG vs. GG, P = 0.02); homozygous gene model (TT vs. GG, P = 0.01). South Asians: dominant gene model (TT + TG vs. GG, P = 0.004); heterozygous gene model (TG vs. GG, P = 0.009); homozygous gene model (TT vs. GG, P = 0.005). However, no statistically significant correlation was established among the five genetic models for rs1501299 locus.

Conclusion

The findings of the present study indicated that the T allele of rs2241766 polymorphism is the susceptibility locus of T2DM in the West Asian population, but has a protective effect in the South Asian population, albeit further studies are needed in other populations. Also, no association was found between the ADIPOQ rs1501299 polymorphism and T2DM.

[Association of adiponectin gene alleles with type 2 diabetes mellitus in residents of Bashkortostan]

Type 2 diabetes mellitus (T2DM) is one of the most acute problems of the modern world. The disease is characterized by high ratio of micro- and macrovascular complications. T2DM is a multifactorial and polygenic disease, structure of hereditary predisposition to which may be population-specific. Aim - the analysis of allelic associations of adiponectin gene (ADIPOQ, rs17366743) with T2DM, its clinical and metabolic characteristics and complications in T2DM patients resident in the Republic of Bashkortostan.

MATERIAL AND METHODS

3 PCR-based method of genotyping with polymorphic marker rs17366743 of ADIPOQ gene in 433 T2DM patients and 428 healthy controls, residents of Bashkortostan.

RESULTS

The ratio of genotype CT and allele С was higher in T2DM patients compared with controls (15.7% vs. 6.8%; p=0.0002 and 7.8% vs. 3.4%; p<0.0001, respectively). Genotype ТТ and allele Т were less frequent in T2DM than in healthy subjects (84.3 and 93,2%; p=0.0002; 92.2 and 96.6%, p<0.0001, respectively). The association with the development of diabetic retinopathy and cataract was shown (p=0,044, p=0,008, respectively).

CONCLUSIONS

Allele C and genotype CT are risk markers of T2DM (OR=2.43 and 2.56 respectively).

Adiponectin gene rs1501299 polymorphism is associated with increased risk of anterior cruciate ligament rupture

Anterior cruciate ligament (ACL) rupture is one the most common musculoskeletal soft tissue injuries of the knee. Although the exact mechanisms of this injury remain uncertain, genetic variants have been considered to be an intrinsic risk factor associated with ACL rupture. Therefore, the aim of the present study was to determine whether the adiponectin +276G/T polymorphism is associated with susceptibility to ACL rupture in a Thai population. Genotyping for rs1501299 was conducted in 98 participants with ACL rupture and 95 healthy controls by polymerase chain reaction-restriction fragment length polymorphism analysis. The results demonstrated that the GG genotype and G allele were significantly associated with an increased risk of ACL rupture [odds ratio (OR)=1.91, P=0.026; OR=1.89, P=0.004], whereas the TT genotype was significantly associated with a reduced risk of ACL rupture (OR=0.32, P=0.019). Furthermore, ACL injury patients with non-contact sports carrying the GG genotype and G allele exhibited a significantly higher risk of ACL rupture (OR=2.13, P=0.031; OR=1.84, P=0.029). In addition, overweight patients carrying the GG genotype and G allele had a significantly increased (8-fold) risk of ACL rupture (OR=8.00, P<0.001; OR=5.15, P<0.001), whereas overweight patients with the adiponectin +276G/T GT genotype had a significantly lower risk of ACL rupture (OR=0.13, P<0.001). Therefore, the adiponectin +276G/T polymorphism GG genotype and G allele were significantly associated with the risk of ACL rupture, particularly in overweight patients. These findings indicate that the adiponectin +276G/T polymorphism may play a role in the development of ACL rupture in the Thai population.

The polymorphism of rs266729 in adiponectin gene and type 2 diabetes mellitus: A Meta-Analysis

Genome-wide association studies and meta-analyses indicate that the polymorphism of rs266729 in adiponectin gene increases the risk of type 2 diabetes mellitus (T2DM); however, these study methods have not been able to identify the underlying genetic effect on the development of T2DM. A genetic model-free approach was conducted to determine the underlying genetic model of inheritance of T2DM because of rs266729 in adiponectin gene.We searched available studies on the association between the rs266729 in adiponectin gene and T2DM in accordance with the inclusion and exclusion criteria. Based on the information extracted from the studies, generalized odds ratio value (GOR) was used to evaluate whether the rs266729 polymorphism was a risk factor for T2DM. The parameter λ was calculated to estimate the genetic model, which was defined as the quotient of natural logarithm odds ratio of GC to CC divided by the natural logarithm odds ratio of GG to CC. Finally, binary logistic regression analysis was used to calculate the genetic effect of rs266729 on T2DM.Data from 7 studies were included in this meta-analysis. The total number of subjects was 12,323, comprising 5,948 cases and 6,395 controls. Mean (standard deviation) age of cases was 59.50 (11.53), and that of the controls was 53.80 (11.65), whereas the proportion of male was 40.9 and 50.0%, respectively. GOR was 1.13 (1.02, 1.25) and λ was 0.47 (0.29, 0.64). The result of logistic regression indicated that the G allele influenced the development of T2DM in the additive model, whereas the genetic effect was 1.13 (1.06, 1.19). Sources of control populations were the cause of between-study heterogeneity; nonetheless, there was no publication bias among studies.The G allele of rs266729 in adiponectin gene increases the risk of T2DM through an additive genetic model with an effect of 1.13 (1.06, 1.19).

Association of KALRN, ADIPOQ, and FTO gene polymorphism in type 2 diabetic patients with coronary artery disease: possible predisposing markers

OBJECTIVES

Recently, several genes have been introduced as potential genetic markers for diabetes mellitus and coronary artery diseases (CAD).

METHODS

In this case-control study, the associations of rs2241766 T/G of ADIPOQ, rs9289231 T/G of KALRN, and rs9939609 A/T of FTO polymorphisms with genetic susceptibility to CAD in type 2 diabetic (T2D) patients were investigated. A total of 224 T2D patients undergoing coronary angiography were randomly recruited into the study. Of the total diabetic patients, 152 were also diagnosed with CAD, whereas the rest were control participants. Genotyping of single-nucleotide polymorphisms was performed by high-resolution melting analysis.

RESULTS

Genotype analysis showed that the minor allele (G) frequency of rs2241766 ADIPOQ was statistically significant in the CAD group compared with the control group [odds ratio (OR), 2.779; 95% confidence interval (CI), 1.403-5.504; P=0.003]. Also, it was found that the minor allele (G) frequency of rs9289231 KALRN was significantly associated with the risk of CAD (OR, 2.098; 95% CI, 1.096-4.017; P=0.025). In addition, no significant association was observed between the minor allele (A) of the FTO rs9939609 polymorphism and CAD (OR, 1.088; 95% CI, 0.578-2.015; P=0.788). It is speculated that the GG genotype and the G allele of the rs9289231 polymorphism of KALRN and the rs224766 polymorphism of ADIPOQ genes may be considered genetic risk factors for CAD in T2D patients and genetic variations of these genes may play a major role in the process of these disorders.

CONCLUSION

Our case-control study in the Iranian population suggested a possible association between the mentioned single-nucleotide polymorphisms and CAD in T2D patients. However, further replication studies and comprehensive meta-analyses are required.

Association between ADIPOQ +45T>G polymorphism and type 2 diabetes: a systematic review and meta-analysis

Recently, a number of studies have reported the association between the single nucleotide polymorphisms (SNPs) +45T>G polymorphism in the adiponectin (ADIPOQ) gene and type 2 diabetes mellitus (T2DM) risk, though the results are inconsistent. In order to obtain a more precise estimation of the relationship, a meta-analysis was performed. In this current study, the Medline, Embase, Pubmed, ISI Web of Knowledge, Ovid, Science Citation Index Expanded Database, Wanfang Database, and China National Knowledge Infrastructure were searched for eligible studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to estimate the strength of association. Forty-five publications were included in the final meta-analysis with 9986 T2DM patients and 16,222 controls for ADIPOQ +45T>G polymorphism according to our inclusion and exclusion criteria. The +45T>G polymorphism was associated with an overall significantly increased risk of T2DM (G vs. T: OR = 1.18, 95% CI = 1.06–1.32; The dominant model: OR = 1.18, 95% CI = 1.03–1.33; The recessive model: OR = 1.47, 95% CI = 1.20–1.78; The homozygous model: OR = 1.62, 95% CI = 1.25–2.09; Except the heterozygous model: OR = 1.11, 95% CI = 0.98–1.24). Subgroup analysis revealed a significant association between the +45T>G polymorphism and T2D in an Asian population. Thus, this meta-analysis indicates that the G allele of the ADIPOQ +45T>G polymorphisms associated with a significantly increased risk of T2DM in the Asian population.

Correlation of serum adiponectin and adiponectin gene polymorphism with metabolic syndrome in Chinese adolescents

BACKGROUND/OBJECTIVES

To investigate the association of adiponectin and its gene polymorphisms with metabolic syndrome (MetS) and cardiovascular disease (CVD) risk factors in Chinese adolescents.

SUBJECTS/METHODS

This cross-sectional study enrolled 919 healthy middle school students (aged 11-16 years; 46.7% females). All participants underwent anthropometric and biochemical examinations, and MetS was diagnosed using 2007 International Diabetes Federation criteria. The presence of adiponectin and its genotypes of single nucleotide polymorphisms (SNPs) rs266729 (-11377C/G), rs2241766 (+45T/G) and rs1501299 (+276G/T) was detected.

RESULTS

(1) Serum adiponectin levels were negatively correlated with numerous CVD risk factors (all P<0.05), and following adjustments for confounding factors, a lower adiponectin level was an independent risk factor for MetS (odds ratio=5.59; 95% confidence interval: 1.90, 16.41). Central obesity and low levels of high-density lipoprotein cholesterol were positively associated with MetS and reduced serum adiponectin levels. (2) The genotype and frequencies of SNP-11377 and SNP+276 in a MetS group and non-MetS group were not significantly different. Subjects with genotype SNP+45 GG were at higher risk for MetS compared with subjects with genotypes SNP+45 TT (P=0.033) or TT+TG (P=0.021). Subjects with genotype SNP+276 TT or TT+TG had higher levels of serum adiponectin compared with subjects with SNP+276 GG (P=0.012 and 0.014, respectively).

CONCLUSIONS

Adiponectin may be used as a predictive biomarker of MetS, and shows a significant association with CVD risk factors in Chinese adolescents. Adiponectin gene polymorphisms are associated with serum adiponectin concentrations and the presence of MetS.

Sequence variants of ADIPOQ and association with type 2 diabetes mellitus in Taiwan Chinese Han population

Diabetes is a serious global health problem. Large-scale genome-wide association studies identified loci for type 2 diabetes mellitus (T2DM), including adiponectin (ADIPOQ) gene and transcription factor 7-like 2 (TCF7L2), but few studies clarified the effect of genetic polymorphisms of ADIPOQ and TCF7L2 on risk of T2DM. We attempted to elucidate association between T2DM and polymorphic variations of both in Taiwan's Chinese Han population, with our retrospective case-control study genotyping single nucleotide polymorphisms (SNPs) in ADIPOQ and TCF7L2 genes both in 149 T2DM patients and in 139 healthy controls from Taiwan. Statistical analysis gauged association of these polymorphisms with risk of T2DM to show ADIPOQ rs1501299 polymorphism variations strongly correlated with T2DM risk (P = 0.042), with rs2241766 polymorphism being not associated with T2DM (P = 0.967). However, both polymorphisms rs7903146 and rs12255372 of TCF7L2 were rarely detected in Taiwanese people. This study avers that ADIPOQ rs1501299 polymorphism contributes to risk of T2DM in the Taiwanese population.

Adiponectin gene polymorphisms in Egyptian type 2 diabetes mellitus patients with and without diabetic nephropathy

Recently, several reports addressed the associations of adiponectin (ADIPOQ) gene polymorphisms with abnormal adiponectin serum levels, type 2 diabetes mellitus (T2DM), and diabetic nephropathy (DN); however, results are inconsistent. This study aimed to investigate the possible association of ADIPOQ gene polymorphisms with T2DM and/or DN and whether they affect serum adiponectin levels in Egyptian population. Two hundred and ninety-six T2DM patients (100 normoalbuminuric patients, 103 microalbuminuric patients, and 93 macroalbuminuric patients) and 209 controls were enrolled in the present study. Polymorphisms of +45, -11391, and +276 of the ADIPOQ gene were detected using polymerase chain reaction restriction fragment length polymorphism. Serum adiponectin was measured using ELISA. Our results revealed that ADIPOQ +45 TG and GG genotypes and G allele were significantly associated with T2DM, micro/macroalbuminuria, and decreased serum adiponectin level. ADIPOQ -11391 AA genotype frequency was significantly increased in T2DM group. Moreover, GA and AA genotypes and A allele of ADIPOQ -11391 were significantly associated with susceptibility to macroalbuminuria despite increased serum adiponectin concentrations. While, ADIPOQ +276 TT genotype and T allele were protective factors regarding the susceptibility to T2DM and micro/macroalbuminuria, and they were significantly associated with increased adiponectin levels. We observed also that the decrease of the serum Adiponectin level was accompanied by an insulin resistance, albuminuria, as well as an increase of serum creatinine. We concluded that ADIPOQ +45; ADIPOQ -11391 gene polymorphisms are associated with T2DM and/or DN in Egyptian population. While, ADIPOQ +276 gene polymorphism is a protective factor regarding T2DM and/or DN susceptibility.

Mendelian randomization studies do not support a causal role for reduced circulating adiponectin levels in insulin resistance and type 2 diabetes

Adiponectin is strongly inversely associated with insulin resistance and type 2 diabetes, but its causal role remains controversial. We used a Mendelian randomization approach to test the hypothesis that adiponectin causally influences insulin resistance and type 2 diabetes. We used genetic variants at the ADIPOQ gene as instruments to calculate a regression slope between adiponectin levels and metabolic traits (up to 31,000 individuals) and a combination of instrumental variables and summary statistics-based genetic risk scores to test the associations with gold-standard measures of insulin sensitivity (2,969 individuals) and type 2 diabetes (15,960 case subjects and 64,731 control subjects). In conventional regression analyses, a 1-SD decrease in adiponectin levels was correlated with a 0.31-SD (95% CI 0.26-0.35) increase in fasting insulin, a 0.34-SD (0.30-0.38) decrease in insulin sensitivity, and a type 2 diabetes odds ratio (OR) of 1.75 (1.47-2.13). The instrumental variable analysis revealed no evidence of a causal association between genetically lower circulating adiponectin and higher fasting insulin (0.02 SD; 95% CI -0.07 to 0.11; N = 29,771), nominal evidence of a causal relationship with lower insulin sensitivity (-0.20 SD; 95% CI -0.38 to -0.02; N = 1,860), and no evidence of a relationship with type 2 diabetes (OR 0.94; 95% CI 0.75-1.19; N = 2,777 case subjects and 13,011 control subjects). Using the ADIPOQ summary statistics genetic risk scores, we found no evidence of an association between adiponectin-lowering alleles and insulin sensitivity (effect per weighted adiponectin-lowering allele: -0.03 SD; 95% CI -0.07 to 0.01; N = 2,969) or type 2 diabetes (OR per weighted adiponectin-lowering allele: 0.99; 95% CI 0.95-1.04; 15,960 case subjects vs. 64,731 control subjects). These results do not provide any consistent evidence that interventions aimed at increasing adiponectin levels will improve insulin sensitivity or risk of type 2 diabetes.

The rs266729 single-nucleotide polymorphism in the adiponectin gene shows association with gestational diabetes

AIM

Gestational diabetes mellitus (GDM) is a condition of impaired glucose tolerance during pregnancy in women without previous diagnosis of diabetes. It is associated with serious complications for both mother and child in the pre- and postnatal period. Moreover, women with GDM are at an increased risk of developing type 2 diabetes. Adiponectin is an important factor involved in the regulation of both carbohydrate and lipid metabolism. Polymorphisms in its gene (ADIPOQ) are known to affect the individual's predisposition to metabolic syndrome and type 2 diabetes. The aim of the current study was to investigate the possible association between three common single-nucleotide polymorphisms in ADIPOQ and gestational diabetes.

METHODS

A total of 394 individuals were recruited to the study-130 pregnant women with GDM, 130 pregnant women without glucose intolerance and 134 female population controls. All subjects were genotyped for rs266729, rs2241766 and rs1501299 in the ADIPOQ gene.

RESULTS

A significant association with the disease was observed for rs266729 (p = 0.0037). The rare G allele was found to be over-represented among controls (pregnant, population and pooled). While no association was found for rs2241766 and rs1501299, a GTG haplotype formed by the three polymorphisms was found to be more common among controls (0.004).

CONCLUSION

The adiponectin promoter polymorphism rs266729 is associated with gestational diabetes. The minor G allele appears to confer protection against pregnancy-related diabetes mellitus. This effect is probably due to the influence of the variant on the adiponectin transcription regulation during gestation.

Antidiabetic and Hypolipidemic Activities of Curculigo latifolia Fruit:Root Extract in High Fat Fed Diet and Low Dose STZ Induced Diabetic Rats

Curculigo latifolia fruit is used as alternative sweetener while root is used as alternative treatment for diuretic and urinary problems. The antidiabetic and hypolipidemic activities of C. latifolia fruit:root aqueous extract in high fat diet (HFD) and 40 mg streptozotocin (STZ) induced diabetic rats through expression of genes involved in glucose and lipid metabolisms were investigated. Diabetic rats were treated with C. latifolia fruit:root extract for 4 weeks. Plasma glucose, insulin, adiponectin, lipid profiles, alanine aminotransferase (ALT), gamma glutamyltransferase (GGT), urea, and creatinine levels were measured before and after treatments. Regulations of selected genes involved in glucose and lipid metabolisms were determined. Results showed the significant (P < 0.05) increase in body weight, high density lipoprotein (HDL), insulin, and adiponectin levels and decreased glucose, total cholesterol (TC), triglycerides (TG), low density lipoprotein (LDL), urea, creatinine, ALT, and GGT levels in diabetic rats after 4 weeks treatment. Furthermore, C. latifolia fruit:root extract significantly increased the expression of IRS-1, IGF-1, GLUT4, PPAR α , PPAR γ , AdipoR1, AdipoR2, leptin, LPL, and lipase genes in adipose and muscle tissues in diabetic rats. These results suggest that C. latifolia fruit:root extract exerts antidiabetic and hypolipidemic effects through altering regulation genes in glucose and lipid metabolisms in diabetic rats.

Adiponectin-11377CG gene polymorphism and type 2 diabetes mellitus in the Chinese population: a meta-analysis of 6425 subjects

Background

Although adiponectin −11377CG gene polymorphism is implied to be associated with increased type 2 diabetes mellitus (T2DM) risk, results of individual studies are inconsistent.

Objective and Methods

A meta-analysis consisting of 12 individual studies, including a total of 6425 participants, was carried out in order to investigate the association of adiponectin −11377CG gene polymorphism with T2DM. The pooled odds ratio (OR) and its corresponding confidence interval (CI) at 95% were assessed through the random- or fixed- effect model.

Results

A significant relationship was observed between adiponectin −11377CG gene polymorphism and T2DM under allelic (OR: 1.150, 95% CI: 1.060 to 1.250, P = 0.001), recessive (OR: 1.450, 95% CI: 1.180–1.770, P = 0.0004), dominant (OR: 1.071, 95% CI: 1.013–1.131, P = 0.015), additive (OR: 1.280, 95% CI: 1.090–1.510, P = 0.002), and homozygous genetic models (OR: 1.620, 95% CI: 1.310–1.990, P<0.00001). No significant association was found between them under the heterozygous genetic model (OR: 1.640, 95% CI: 0.850–3.170, P = 0.140).

Conclusions

Adiponectin −11377CG gene polymorphism was significantly associated with T2DM risk susceptibility. G allele carriers are predisposed to T2DM risk.

Common variants in genes encoding adiponectin (ADIPOQ) and its receptors (ADIPOR1/2), adiponectin concentrations, and diabetes incidence in the Diabetes Prevention Program

AIMS

Baseline adiponectin concentrations predict incident Type 2 diabetes mellitus in the Diabetes Prevention Program. We tested the hypothesis that common variants in the genes encoding adiponectin (ADIPOQ) and its receptors (ADIPOR1, ADIPOR2) would associate with circulating adiponectin concentrations and/or with diabetes incidence in the Diabetes Prevention Program population.

METHODS

Seventy-seven tagging single-nucleotide polymorphisms (SNPs) in ADIPOQ (24), ADIPOR1 (22) and ADIPOR2 (31) were genotyped. Associations of SNPs with baseline adiponectin concentrations were evaluated using linear modelling. Associations of SNPs with diabetes incidence were evaluated using Cox proportional hazards modelling.

RESULTS

Thirteen of 24 ADIPOQ SNPs were significantly associated with baseline adiponectin concentrations. Multivariable analysis including these 13 SNPs revealed strong independent contributions of rs17366568, rs1648707, rs17373414 and rs1403696 with adiponectin concentrations. However, no ADIPOQ SNPs were directly associated with diabetes incidence. Two ADIPOR1 SNPs (rs1342387 and rs12733285) were associated with ∼18% increased diabetes incidence for carriers of the minor allele without differences across treatment groups, and without any relationship with adiponectin concentrations.

CONCLUSIONS

  ADIPOQ SNPs are significantly associated with adiponectin concentrations in the Diabetes Prevention Program cohort. This observation extends prior observations from unselected populations of European descent into a broader multi-ethnic population, and confirms the relevance of these variants in an obese/dysglycaemic population. Despite the robust relationship between adiponectin concentrations and diabetes risk in this cohort, variants in ADIPOQ that relate to adiponectin concentrations do not relate to diabetes risk in this population. ADIPOR1 variants exerted significant effects on diabetes risk distinct from any effect of adiponectin concentrations.

Amerindians show association to obesity with adiponectin gene SNP45 and SNP276: population genetics of a food intake control and "thrifty" gene

Adiponectin gene polymorphisms SNP45 and SNP276 have been related to metabolic syndrome (MS) and related pathologies, including obesity. However results of associations are contradictory depending on which population is studied. In the present study, these adiponectin SNPs are for the first time studied in Amerindians. Allele frequencies are obtained and comparison with obesity and other MS related parameters are performed. Amerindians were also defined by characteristic HLA genes. Our main results are: (1) SNP276 T is associated to low diastolic blood pressure in Amerindians, (2) SNP45 G allele is correlated with obesity in female but not in male Amerindians, (3) SNP45/SNP276 T/G haplotype in total obese/non-obese subjects tends to show a linkage with non-obese Amerindians, (4) SNP45/SNP276 T/T haplotype is linked to obese Amerindian males. Also, a world population study is carried out finding that SNP45 T and SNP276 T alleles are the most frequent in African Blacks and are found significantly in lower frequencies in Europeans and Asians. This together with the fact that there is a linkage of this haplotype to obese Amerindian males suggest that evolutionary forces related to famine (or population density in relation with available food) may have shaped world population adiponectin polymorphism frequencies.

The association studies of ADIPOQ with type 2 diabetes mellitus in Chinese populations

Adiponectin, which is secreted by the white adipose tissue, plays an important role in type 2 diabetes mellitus (T2DM) and its complications. Since 2002, many investigators explored the association between ADIPOQ single nucleotide polymorphisms and T2DM in different ethnic populations from different regions. In China, the results of numerous studies of the association between ADIPOQ and T2DM were not consistent, which may be caused by population-specific effects or environmental effects. This review describes the association between ADIPOQ and T2DM, the metabolic characteristics and the complications of T2DM in Chinese populations.

Association of adiponectin gene polymorphism (+T45G) with acute coronary syndrome and circulating adiponectin levels

We investigated the association of adiponectin gene polymorphisms (+T45G and +G276T) and adiponectin levels with acute coronary syndrome (ACS) among Arabs in Qatar. A case-control study was performed in 142 Arab patients with ACS and 122 controls. Genotypes were determined using TaqMan real-time polymerase chain reaction assay. The TT, TG, and GG genotype frequencies of the T45G variant were significantly different among cases and controls (P = .023) but not significant for G276T genotypic frequencies. It was found that only the +45G allele was significantly associated with 3-fold increased risk of ACS (odds ratio = 2.77; 1.03-6.96; P = .043) among patients, using the genetic recessive model. Carriers of GG alleles had significantly lower adiponectin levels compared to TT/TG carriers of T45G in patients with ACS. The present study suggests that only T45G single-nucleotide polymorphism in the adiponectin gene is associated with higher odds for ACS events and has an effect on serum adiponectin levels among Arab populations.

Single-nucleotide polymorphisms and haplotypes in the adiponectin gene contribute to the genetic risk for type 2 diabetes in Tunisian Arabs

Adiponectin is an adipocyte-produced protein involved in regulating glucose, lipid, and energy metabolism, and is encoded by ADIPOQ (APM1) gene. ADIPOQ polymorphisms were previously associated with type 2 diabetes (T2DM) in Caucasian and non-Caucasian populations. We investigated the contribution of 13 polymorphisms in the promoter, coding regions, and 3'untranslated region of ADIPOQ gene to T2DM in 917 patients and 748 normoglycemic control subjects. ADIPOQ genotyping was done by allelic discrimination method. Of the 13 ADIPOQ variants analyzed, higher minor allele frequency of rs16861194 (P<0.001), rs17300539 (P<0.001), rs266729 (P<0.001), rs822396 (P=0.02), rs2241767 (P=0.03), and rs1063538 (P=0.02) were seen in T2DM cases. Varied association of ADIPOQ genotypes with T2DM was seen according to the genetic model used: rs17300539 and rs266729 were significantly associated with T2DM under the three models, while rs16861194 was association with T2DM under additive and dominant models, and rs822396, rs2241766, and rs1063538 were associated with T2DM under the dominant models only. Haploview analysis revealed low linkage disequilibrium between the ADIPOQ variants, resulting in high haplotype diversity, and two blocks were identified, each differentially associated with T2DM. These results support a significant association of ADIPOQ gene polymorphism with T2DM in Tunisian Arabs.

The role of inflammatory pathway genetic variation on maternal metabolic phenotypes during pregnancy

Background

Since mediators of inflammation are associated with insulin resistance, and the risk of developing diabetes mellitus and gestational diabetes, we hypothesized that genetic variation in members of the inflammatory gene pathway impact glucose levels and related phenotypes in pregnancy. We evaluated this hypothesis by testing for association between genetic variants in 31 inflammatory pathway genes in the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) cohort, a large multiethnic multicenter study designed to address the impact of glycemia less than overt diabetes on pregnancy outcome.

Results

Fasting, 1-hour, and 2-hour glucose, fasting and 1-hour C-peptide, and HbA1c levels were measured in blood samples obtained from HAPO participants during an oral glucose tolerance test at 24-32 weeks gestation. We tested for association between 458 SNPs mapping to 31 genes in the inflammatory pathway and metabolic phenotypes in 3836 European ancestry and 1713 Thai pregnant women. The strongest evidence for association was observed with TNF alpha and HbA1c (rs1052248; 0.04% increase per allele C; p-value = 4.4×10⁻⁵), RETN and fasting plasma glucose (rs1423096; 0.7 mg/dl decrease per allele A; p-value = 1.1×10⁻⁴), IL8 and 1 hr plasma glucose (rs2886920; 2.6 mg/dl decrease per allele T; p-value = 1.3×10⁻⁴), ADIPOR2 and fasting C-peptide (rs2041139; 0.55 ug/L decrease per allele A; p-value = 1.4×10⁻⁴), LEPR and 1-hour C-peptide (rs1171278; 0.62 ug/L decrease per allele T; p-value = 2.4×10⁻⁴), and IL6 and 1-hour plasma glucose (rs6954897; −2.29 mg/dl decrease per allele G, p-value = 4.3×10⁻⁴).

Conclusions

Based on the genes surveyed in this study the inflammatory pathway is unlikely to have a strong impact on maternal metabolic phenotypes in pregnancy although variation in individual members of the pathway (e.g. RETN, IL8, ADIPOR2, LEPR, IL6, and TNF alpha,) may contribute to metabolic phenotypes in pregnant women.

Genetic variants in ADIPOQ gene and the risk of type 2 diabetes: a case-control study of Chinese Han population

This study was to evaluate the association between ADIPOQ gene variants and type 2 diabetes mellitus (T2DM). TaqMan(®) assay was performed to test the genotypes in T2DM patients (n = 1,105) and normal control subjects (n = 1,107). Serum adiponectin concentration was measured by ELISA kit. The variant genotypes rs7649121AT and rs7649121AT/TT, compared with the AA genotype, were associated with a significantly decreased risk of T2DM [Adjusted OR (95% CI) = 0.79(0.66-0.95), 0.80(0.67-0.96), respectively]. In stratified analysis, rs2241767AG genotype increased the risk of T2DM in obesity group [Adjusted OR (95% CI) = 1.32(1.03-1.69)]. Patients with genotype AG/GG of rs2241767 had lower levels of serum adiponectin than those with the genotype AA (P = 0.044). Haplotype analyses were not significant. Crossover analysis of rs7649121 and environmental risk factor (obesity) indicated that the protect effect of rs7649121AT/TT maybe offset by the environmental risk. Those who exposed to environmental risk factor (obesity) had a chance to attack T2DM compared with those who did not expose to the two factors [Adjusted OR (95% CI) = 1.64(1.30-2.06)]. This study suggested that the ADIPOQ gene polymorphisms were associated with the risk of T2DM in a Chinese Han population.

Associations between single-nucleotide polymorphisms (+45T>G, +276G>T, -11377C>G, -11391G>A) of adiponectin gene and type 2 diabetes mellitus: a systematic review and meta-analysis

AIMS/HYPOTHESIS

The associations between adiponectin polymorphisms and type 2 diabetes have been studied widely; however, results are inconsistent.

METHODS

We searched electronic literature databases and reference lists of relevant articles. A fixed or random effects model was used on the basis of heterogeneity. Sub-group and meta-regression analyses were conducted to explore the sources of heterogeneity.

RESULTS

There were no statistically significant associations between +45T>G (rs2241766), +276G>T (rs1501299), -11391G>A (rs17300539) and type 2 diabetes risk. However, for -11377C>G (rs266729), the pooled OR (95% CI) for G vs C allele was 1.07 (1.03-1.11, p = 0.001). Subgroup analysis by study design revealed that -11377C>G (rs266729) dominant model (CG+GG vs CC, p = 0.0008) and G vs C allele (p = 0.0004) might be associated with type 2 diabetes risk in population-based case-control studies. After stratification by ethnicity, we found that -11377C>G (rs266729) dominant model (CG+GG vs CC, p = 0.004) and G vs C allele (p = 0.001) might be associated with type 2 diabetes risk in white individuals. In individuals with a family history of diabetes, the presence of -11391G>A (rs17300539) dominant model (GA+AA vs GG) and A vs G allele might be associated with increased risk of type 2 diabetes.

CONCLUSIONS/INTERPRETATION

The presence of +45T>G (rs2241766), +276G>T (rs1501299) and -11391G>A (rs17300539) do not appear to influence the development of type 2 diabetes. However, G vs C allele of -11377C>G (rs266729) might be a risk factor for type 2 diabetes.

Effects of genetic variations in the adiponectin pathway genes on the risk of colorectal cancer in the Chinese population

Background

Decreased expression of adiponectin (ADIPOQ) is associated with an increased risk for developing colorectal cancer (CRC) in humans. This study was designed to determine whether polymorphisms present in the ADIPOQ and its type 1 receptor (ADIPOR1) could affect the risk of CRC.

Methods

We measured five polymorphisms in the ADIPOQ and two polymorphisms in ADIPOR1, and analyzed their associations with CRC risk in 420 CRC patients and 555 age- and gender-matched healthy individuals.

Results

Multivariate logistic regression analyses revealed that the CRC risks (adjusted odds ratio and 95% confidence interval) associated with the ADIPOR1 genotypes were 0.53 (95% CI, 0.35-0.81) for rs12733285C/T, 0.59 (95% CI, 0.45-0.78) for rs1342387A/G, and 0.59 (95% CI, 0.39-0.89) for rs1342387A/A, respectively. Furthermore, the risks were more significant in carriers of the allele A of rs1342387A/G (adjusted OR, 0.59; 95% CI, 0.46-0.77) than noncarriers (G/G). In a further subgroup analysis, we observed that rs266729G/C was associated with an increased risk for colon cancer (adjusted OR, 1.50; 95% CI, 1.05-2.14) but not for rectal cancer (adjusted OR, 0.88; 95% CI, 0.63-1.22), and that carriers of the G allele had an increased risk for developing colon cancer (adjusted OR, 1.45; 95% CI, 1.03-2.05).

Conclusions

We conclude that the rs12733285C/T genotype and the carriage of the A allele of rs1342387 (A/G or A/A) in ADIPOR1 are the protective factors for CRC, while that rs266729G/C and G allele of ADIPOQ are the risk factors for colon cancer after excluding rectal cancer cases.

Association of adiponectin SNP+45 and SNP+276 with type 2 diabetes in Han Chinese populations: a meta-analysis of 26 case-control studies

Recently, many studies have reported that the SNP+45(T>G) and SNP+276(G>T) polymorphisms in the adiponectin gene are associated with type 2 diabetes (T2DM) in the Chinese Han population. However, the previous studies yielded many conflicting results. Thus, a meta-analysis of the association of the adiponectin gene with T2DM in the Chinese Han population is required. In the current study, we first determined the distribution of the adiponectin SNP+276 polymorphism in T2DM and nondiabetes (NDM) control groups. Our results suggested that the genotype and allele frequencies for SNP+276 did not differ significantly between the T2DM and NDM groups. Then, a meta-analysis of 23 case-control studies of SNP+45, with a total of 4161 T2DM patients and 3709 controls, and 11 case-control studies of SNP+276, with 2533 T2DM patients and 2212 controls, was performed. All subjects were Han Chinese. The fixed-effects model and random-effects model were applied for dichotomous outcomes to combine the results of the included studies. The results revealed a trend towards an increased risk of T2DM for the SNP+45G allele as compared with the SNP+45T allele (OR = 1.34; 95% CI, 1.11–1.62; P<0.01) in the Chinese Han population. However, there was no association between SNP+276 and T2DM (OR = 0.90; 95% CI, 0.73–1.10; P = 0.31). The results of our association study showed there was no association between the adiponectin SNP+276 polymorphism and T2DM in the Yunnan Han population. The meta-analysis results suggested that the SNP+45G allele might be a susceptibility allele for T2DM in the Chinese Han population. However, we did not observe an association between SNP+276 and T2DM.

Interactions among related genes of renin-angiotensin system associated with type 2 diabetes

OBJECTIVE

To explore the association between epistasis among related genes of the renin-angiotensin system (RAS) and type 2 diabetes.

RESEARCH DESIGN AND METHODS

Gene polymorphisms were genotyped in 394 type 2 diabetic patients and 418 healthy control subjects in this case-control study. We used the multifactor dimensionality reduction method to identify gene-gene interactions.

RESULTS

No single locus was associated with type 2 diabetes, except for the insert/deletion (I/D) polymorphism of the ACE gene in female subjects. In multi-locus analyses, in male subjects the model of rs2106809 (ACE2), rs220721 (Mas), rs699 (AGT), and I/D (ACE) was significant (P = 0.043). This combination was associated with a 4.00 times (95% CI 2.51-6.38; P < 0.0001) greater prevalence of type 2 diabetes. In female subjects, the model of rs2106809 (ACE2), I/D (ACE), and rs1403543 (AGTR2) was significant (P = 0.012). This three-locus combination was associated with a 2.76 times (1.91-3.97; P < 0.0001) greater prevalence of type 2 diabetes.

CONCLUSIONS

Interactions among RAS-related genes were associated with type 2 diabetes in a Chinese population.

Association of the ADIPOQ rs17360539 and rs266729 polymorphisms with type 2 diabetes: a meta-analysis

Published data on the association between ADIPOQ polymorphisms and type 2 diabetes are inconsistent. The present meta-analysis was performed to clarify the role of polymorphisms in proximal promoter region of ADIPOQ (rs17360539 and rs266729) in type 2 diabetes. The MEDLINE, EMBASE and Science Citation Index Expanded database were searched for eligible studies. Odd ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of association. The pooled ORs were performed for per-allele model (A/a) and others genetic models. A total of 10267 T2DM patients and 12837 controls was included in the meta-analysis. Overall the -11377G allele had an 8% elevated risk of T2DM compared to -11377C allele in all subjects (P=0.034, OR=1.08, 95% CI 1.01-1.15). The -11391A allele showed no significant effect on T2DM risk in all subjects (P=0.240, OR=1.10, 95% CI 0.94-1.29) compared to -11391G allele. In the subgroup analyses by ethnicity, -11391A allele increased T2DM risk in European population (P=0.046, OR=1.09, 95% CI 1.00-1.09). In conclusion, the accumulated evidence suggested that the ADIPOQ -11377G allele is a low-penetrant risk factor for developing type 2 diabetes, but -11391A is a risk factor only in European Caucasians.