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

Association of adiponectin gene single nucleotide polymorphisms with environmental risk factors in type 2 diabetes mellitus: An updated evidence of haplotype-based analysis study

BACKGROUND AND AIM

Adiponectin (ADIPOQ) gene is considered to be one of the promising players in deciphering the genetic bases of type 2 diabetes. This study investigated the associations between haplotype combinations of three single nucleotide polymorphisms (SNPs) of the ADIPOQ gene and two SNPs of the adiponectin receptor 1 (AdipoR1) and 2 (AdipoR2) genes with environmental risk factors for the prediction of T2DM disorder susceptibility in the Iranian population.

METHODS

This case-control and cross-sectional study was conducted on 182 patients with T2DM and 155 healthy controls. Genotyping was performed using amplification refractory mutation system-PCR (ARMS-PCR) for rs17300539G/A, rs2241766T/G, and rs1501299G/T of the ADIPOQ gene, rs1342387C/T of the AdipoR1 gene, and rs10773989T/C of the AdipoR2 gene.

RESULTS

All polymorphisms met the Hardy-Weinberg equilibrium (p> 0.05). The studied SNPs; rs17300539, rs2241766 of the ADIPOQ gene and rs10773989 of the AdipoR2 gene, were significantly associated with an increased risk of T2DM. Two-way ANOVA analysis indicated that GG carriers of rs2241766T/G had a significantly lower waist-to-hip ratio (P= 0.049) and body mass index (P= 0.011) and higher HbA1c (P= 0.048) compared to TT carriers, while TT genotype carriers of rs2241766T/G showed the higher plasma adiponectin concentration compared to TG and GG carriers (P= 0.009 and P= 0.013, respectively). CC carriers of rs10773989T/C displayed a significantly higher LDL level compared to the TT genotype carries (P= 0.036). Also plasma adiponectin concentrations were significantly lower in AA genotype carriers of rs17300539G/A compared to GG and GA genotypes carriers in the control group only (P= 0.005 and P= 0.016, respectively). According to Combined Haplotype ([rs17300539, rs2241766, rs1501299]/[rs17300539, rs2241766, rs1501299]) analysis, GTT-homozygote carriers displayed the highest plasma adiponectin concentration and in contrast, GGG/GTG, ATG/GTG, and GGG/GGG showed the lowest plasma adiponectin concentration in the controls (p> 0.05).

CONCLUSION

The adiponectin gene haplotype combinations were associated with plasma adiponectin concentration in healthy individuals. In T2DM, adiponectin genetic variants displayed less effect on adiponectin plasma concentration.

Association of ADIPOQ Single-Nucleotide Polymorphisms with the Two Clinical Phenotypes Type 2 Diabetes Mellitus and Metabolic Syndrome in a Kinh Vietnamese Population

PURPOSE

Genetic factors play an important role in the development of type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS). However, few genetic association studies related to these disorders have been performed with Vietnamese subjects. In this study, the potential associations of ADIPOQ single nucleotide polymorphisms (SNPs) with T2DM and MetS in a Kinh Vietnamese population were investigated.

PATIENTS AND METHODS

A study with 768 subjects was conducted to examine the associations of four ADIPOQ SNPs (rs266729, rs1501299, rs3774261, and rs822393) primarily with T2DM and secondarily with MetS. The TaqMan SNP genotyping assay was used to determine genotypes from subjects' DNA samples.

RESULTS

After statistical adjustment for age, sex, and body mass index, the ADIPOQ SNP rs266729 was found to be associated with increased risk of T2DM under multiple inheritance models: codominant (OR = 2.30, 95% CI = 1.16-4.58), recessive (OR = 2.17, 95% CI = 1.11-4.26), and log-additive (OR = 1.32, 95% CI = 1.02-1.70). However, rs1501299, rs3774261, and rs822393 were not associated with risk for T2DM. Additionally, rs266729, rs3774261, and rs822393 were statistically associated with MetS, while rs1501299 was not. Haplotype analysis showed a strong linkage disequilibrium between the SNP pairs rs266729/rs822393 and rs1501299/rs3774261, and the haplotype rs266729(G)/rs822393(T) was not statistically associated with MetS.

CONCLUSION

The results show that rs266729 is a lead candidate SNP associated with increased risk of developing T2DM and MetS in a Kinh Vietnamese population, while rs3774261 is associated with MetS only. Further functional characterization is needed to uncover the mechanism underlying the potential genotype-phenotype associations.

Association between adiponectin rs17300539 and rs266729 gene polymorphisms with serum adiponectin level in an Iranian diabetic/pre-diabetic population

OBJECTIVE

Adiponectin is an adipokine that is mostly secreted from adipose tissues and has a significant role in the improvement of insulin resistant and type 2 diabetes mellitus (T2DM). This study is conducted to examine the association of rs17300539 and rs266729 with T2DM and serum adiponectin level in Iranian population.

METHOD

A case-control study was conducted on 80 individuals with fasting plasma glucose (FPG) >100 (mg/dl) as diabetic-pre-diabetic group, and 80 individuals with fasting plasma glucose 70-100 (mg/dl) as control group. DNA extraction was done on samples and genotyping method was performed by PCR-RFLP.

RESULT

The frequency of GA genotype in rs17300539 (diabetic/pre-diabetic 35.5%, control 11.3%, (OR [95%CI]=4.18[1.8-9.6]; p=0.001) and allele A (diabetic/pre-diabetic 31%, control 9%, (OR [95% CI]=4.67[2-10.7]) was significantly more in diabetic/pre-diabetic group compared to control group. The difference in the genotype frequency for rs266729 in diabetic group compared to that in control was not significant. The levels of adiponectin in diabetic cases had no difference compared to the control group in both polymorphisms. The rs266729 was not associated with any metabolic parameter except waist circumference (p=0.03), however, rs17300539 shows association only with fasting plasma glucose, triglyceride, and total cholesterol (p=0.007, 0.039, 0.0032, respectively).

CONCLUSION

Our findings showed that there is an association between rs17300539 with the increase of T2DM but rs266729 showed no association with the risk of T2DM. Allele A of rs17300539 increased the risk of diabetes. There is no association between adiponectin level and both polymorphisms.

Adiponectin Expression and Genotypes in Italian People with Severe Obesity Undergone a Hypocaloric Diet and Physical Exercise Program

Adiponectin exerts positive effects on metabolic and inflammatory processes. Adiponectin levels and some single-nucleotide polymorphisms (SNPs) seem to be associated with obesity. Here, we investigated the effects of a 4-week Hypocaloric diet and Physical exercise Program (HPP) on 268 young people with severe obesity. We evaluated the relationship between adiponectin levels and anthropometric and biochemical parameters, at baseline and after a 4-week HPP. Finally, we investigated some adiponectin gene variants and their correlation to biochemical parameters. Adiponectin levels were statistically lower in people with severe obesity than in controls. At the end of the HPP, all the people with severe obesity showed a Body Mass Index (BMI) reduction with a statistically significant increase in adiponectin levels. Genotyping, the adiponectin gene demonstrated a significant difference in 3 polymorphisms within the people with severe obesity. Besides, c.11377C>G and c.11391G>A homozygous subjects experienced more advantages by HPP. Furthermore, c.268G>A heterozygous subjects showed an enhancement in lipid profile as well in adiponectin levels. The best predictor of the changes in adiponectin levels was represented by the c.268G>A WT allele. Our study confirmed that a 4-weeks HPP in people with severe obesity results in metabolic amelioration associated with a significant increase of adiponectin levels. Importantly, we found that a specific genetic background in the ADIPOQ gene can predispose toward a more significant weight loss.

NUTRIOGENETIC TEST IN CLINICAL PRACTICE: GOALS AND OPPORTUNITIES

Nutgenogenetics is the science of the influence of genetically determined differences on the assimilation of nutrients and their metabolism. The goal of nutrigenetics is to create an individual diet that will allow to optimize health status and prevent deseases. This test assesses the genetic contribution to the individual effectiveness of low-fat, low-carb diets and various types of sport exercises in order to reduce body weight. In the presence of some genetically determined conditions (Gilbert’s syndrome, hemochromatosis) - there is a need to follow a certain diet for the prevention of complications. A relative risk of insulin resistance and dyslipidemia, features of eating behavior can also be determined.

Adiponectin and leptin gene polymorphisms in women with gestational diabetes mellitus

PURPOSE

Gestational diabetes mellitus (GDM) is the glucose intolerance occurring during pregnancy. The prevalence of GDM is increased in obese women. Leptin and adiponectin are adipokines that play an important role in the regulation of insulin secretion and glucose and lipid metabolism. The aim of this study was to examine the association between adiponectin and leptin gene polymorphisms and the development of GDM.

METHODS

This case-control study included 204 pregnant women with GDM and 207 pregnant women with normal glucose tolerance (NGT). The diagnosis of GDM was based on a 75-g oral glucose tolerance test (OGTT) at 24-28 weeks' gestation. To discriminate the ADIPOQ rs266729, rs1501299 and LEP rs2167270 alleles, TaqMan® Pre-Designed SNP Genotyping Assays were used.

RESULTS

There was a statistically significant association between the ADIPOQ rs266729 gene polymorphism and GDM. Among women with GDM, a higher prevalence of the G allele was observed (GG and CG genotypes). Multivariate logistic regression analysis, taking into account age, BMI before pregnancy, past pregnancies and the ADIPOQ rs266729 gene polymorphism, revealed that the presence of a G allele is an independent risk factor for GDM. Moreover, there was the association between the LEP rs2167270 polymorphism and the requirement for daily insulin, which was significantly higher in women with the A allele (AA and GA genotypes).

CONCLUSIONS

The results of our study suggest an association between adiponectin gene rs266729 as well as leptin gene rs2167270 polymorphisms and GDM.

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.

The role of adiponectin gene variants in glycemic control in patients with Type 2 diabetes

The aim of this study was to investigate the association between glycemic control in Type 2 diabetes mellitus patients and common genetic variants of ADIPQO gene. A total of 427 Type 2 diabetes patients were recruited in the study and divided into two groups: 172 patients with good glycemic control and 249 with poor glycemic control. Genotyping of C11377G, G276T and T45G ADIPQO SNPs were carried out using restriction fragment length polymorphisms-polymerase chain reaction. The results showed that C11377G ADIPQO SNP is strongly associated with glycemic control in Type 2 diabetes patients. Patients with the GG genotype at adiponectin C11377G had better glycemic control than those with CC or CG genotypes. However, other examined SNPs were not correlated with glycemic control in Type 2 diabetes patients. Other parameters that impacted glycemic control include duration of the disease (p < 0.01), use of insulin therapy (p < 0.01) and presence of neuropathy complications (p < 0.01). However, no contribution was observed for gender, statin use, lipid profile and other oral medications to glycemic control (p > 0.05). Glycemic control among Type 2 diabetes patients might be affected by variants in ADIPQO gene.

Relationship between HLA-G polymorphism and susceptibility to recurrent miscarriage: a meta-analysis of non-family-based studies

PURPOSE

The HLA-G 14-bp insertion/deletion polymorphism had been inconsistently associated with recurrent miscarriage (RM) risk. We examined the association by performing a meta-analysis.

METHODS

Eligible articles were searched in PubMed, EMBASE and CNKI without language limitation. We included all the articles about two or more miscarriages associated with HLA-G 14-bp polymorphism. The odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations. Statistical analyses were performed by the STATA10.0 software.

RESULTS

17 studies were included, representing 1786 cases and 1574 controls. The current meta-analysis showed that 14-bp polymorphism was not associated with RM risk in all genetic models and allele contrast(+14 bp vs. -14 bp: OR = 1.13; 95% CI, 0.96,1.32; +14 bp/+14 bp vs. -14 bp/-14 bp: OR = 1.16, 95% CI, 0.85, 1.59; +14 bp/-14 bp vs. -14 bp/-14 bp: OR = 1.21, 95% CI, 0.92,1.58; dominant model: OR = 1.33; 95% CI, 0.99,1.78; recessive model: OR = 1.06; 95% CI, 0.79,1.43). Moreover, a significant heterogeneity was evident across studies. On the other hand, the subgroup analysis demonstrated that there was a significant association between HLA-G 14-bp polymorphism and patients with three or more miscarriages(+14 bp vs. -14 bp: OR = 1.27; 95% CI, 1.04, 1.55; dominant model: OR = 1.52; 95% CI, 1.16, 1.99; and model +14 bp/-14 bp versus -14 bp/-14 bp: OR = 1.51; 95% CI, 1.15, 1.97;).

CONCLUSIONS

Our comprehensive meta-analysis indicated that there was insufficient evidence to demonstrate a conclusive association between the HLA-G 14-bp insertion/deletion polymorphism and the risk of RM. But HLA-G 14-bp insertion/deletion polymorphic variation was associated with RM risk in patients with three or more miscarriages. Larger and well-designed studies may eventually provide a better, comprehensive understanding of the association between the HLA-G 14-bp insertion/deletion polymorphism and RM in the future.

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.

Genetic association of ADIPOQ gene variants with type 2 diabetes, obesity and serum adiponectin levels in south Indian population

OBJECTIVE

To investigate the genetic association of eight variants of the adiponectin gene with type 2 diabetes mellitus (T2DM), obesity and serum adiponectin level in the south Indian population.

METHODS

The study comprised of 1100 normal glucose tolerant (NGT) and 1100 type 2 diabetic, unrelated subjects randomly selected from the Chennai Urban Rural Epidemiology Study (CURES), in southern India. Fasting serum adiponectin levels were measured by radioimmunoassay. The variants were screened by polymerase chain reaction-restriction fragment length polymorphism. Linkage disequilibrium was estimated from the estimates of haplotype frequencies.

RESULTS

Of the 8 variants, four SNPs namely, +276 G/T (rs1501299), -4522 C/T (rs822393), -11365 C/G (rs266729), and +712 G/A (rs3774261) were significantly associated with T2DM in our study population. The -3971 A/G (rs822396) and -11391 G/A (rs17300539) SNPs' association with T2DM diabetes was mediated through obesity (where the association with type 2 diabetes was lost after adjusting for BMI). There was an independent association of +276 G/T (rs1501299) and -3971 A/G (rs822396) SNPs with generalized obesity and +349 A/G (rs2241767) with central obesity. Four SNPs, -3971 A/G (rs822396), +276 G/T (rs1501299), -4522 C/T (rs822393) and Y111H T/C (rs17366743) were significantly associated with hypoadiponectinemia. The haplotypes GCCATGAAT and AGCGTGGGT conferred lower risk of T2DM in this south Indian population.

CONCLUSION

The adiponectin gene variants and haplotype contribute to the genetic risk towards the development of type 2 diabetes, obesity and hypoadiponectinemia in the south Indian population.

Interactions between vascular wall and perivascular adipose tissue reveal novel roles for adiponectin in the regulation of endothelial nitric oxide synthase function in human vessels

BACKGROUND

Adiponectin is an adipokine with potentially important roles in human cardiovascular disease states. We studied the role of adiponectin in the cross-talk between adipose tissue and vascular redox state in patients with atherosclerosis.

METHODS AND RESULTS

The study included 677 patients undergoing coronary artery bypass graft surgery. Endothelial function was evaluated by flow-mediated dilation of the brachial artery in vivo and by vasomotor studies in saphenous vein segments ex vivo. Vascular superoxide (O2(-)) and endothelial nitric oxide synthase (eNOS) uncoupling were quantified in saphenous vein and internal mammary artery segments. Local adiponectin gene expression and ex vivo release were quantified in perivascular (saphenous vein and internal mammary artery) subcutaneous and mesothoracic adipose tissue from 248 patients. Circulating adiponectin was independently associated with nitric oxide bioavailability and O2(-) production/eNOS uncoupling in both arteries and veins. These findings were supported by a similar association between functional polymorphisms in the adiponectin gene and vascular redox state. In contrast, local adiponectin gene expression/release in perivascular adipose tissue was positively correlated with O2(-) and eNOS uncoupling in the underlying vessels. In ex vivo experiments with human saphenous veins and internal mammary arteries, adiponectin induced Akt-mediated eNOS phosphorylation and increased tetrahydrobiopterin bioavailability, improving eNOS coupling. In ex vivo experiments with human saphenous veins/internal mammary arteries and adipose tissue, we demonstrated that peroxidation products produced in the vascular wall (ie, 4-hydroxynonenal) upregulate adiponectin gene expression in perivascular adipose tissue via a peroxisome proliferator-activated receptor-γ-dependent mechanism.

CONCLUSIONS

We demonstrate for the first time that adiponectin improves the redox state in human vessels by restoring eNOS coupling, and we identify a novel role of vascular oxidative stress in the regulation of adiponectin expression in human perivascular adipose tissue.

Common variants in adiponectin gene are associated with coronary artery disease and angiographical severity of coronary atherosclerosis in type 2 diabetes

BACKGROUND

Adiponectin, an adipokine facilitating insulin action, has antiatherogenic effects. This study investigated whether common single nucleotide polymorphisms (SNPs) in the adiponectin gene influenced plasma adiponectin level and whether they were associated with the risk of coronary artery disease (CAD) and its angiographical severity in type 2 diabetes in Chinese population.

METHODS

11 tagging SNPs were genotyped in 1110 subjects with or without CAD in type 2 diabetes. Variants of adiponectin gene were determined by Taqman polymerase chain reaction method. The plasma adiponectin concentrations were measured by sandwich enzyme-linked immunosorbent assay. The severity and extent of coronary atherosclerosis were assessed using the angiographic Gensini score and Sullivan Extent score.

RESULTS

Among the 11 SNPs, the minor G allele of SNP rs266729 was significantly associated with higher odds of CAD (odds ratio (95% CI) = 1.49 (1.10 - 2.16), P = 0.022) after adjusting for covariates. In stepwise multivariate logistic regression, SNP rs266729 was a significant independent factor of CAD. Multivariate linear regression analysis revealed that rs266729 (β = -0.101, P < 0.0001), rs182052 (β = -0.044, P = 0.0035), and rs1501299 (β = 0.073, P < 0.0001) were significantly associated with adiponectin level, and also indicated that the minor G allele of SNP rs266729 had higher Gensini score (β = 0.139, P < 0.001) and Sullivan Extent score (β = 0.107, P < 0.001). Haplotypes analysis revealed different haplotype distributions in case and control subjects (P = 0.0003), with two common haplotypes GGG and GAG of the rs266729, rs182052, and rs1501299 being associated in heterozygotes with a greater than threefold increase in cardiovascular risk (odds ratio (95% CI)=3.39 (1.83 - 6.30), P = 0.0001).

CONCLUSIONS

In our population, genetic variants in the adiponectin gene influence plasma adiponectin levels, and one of them is a strong determinant of CAD susceptibility and its angiographical severity in type 2 diabetes. This study has provided further evidence for a role of adiponectin in the development of CAD.

Association of genetic variants in the adiponectin gene with metabolic syndrome: a case-control study and a systematic meta-analysis in the Chinese population

Background

The prevalence of metabolic syndrome has been rising worldwide, including in China, but knowledge on specific genetic determinants of metabolic syndrome is very limited. A number of studies have reported that polymorphisms in the ADIPOQ gene are associated with metabolic syndrome in Chinese Han populations. However, data is still conflicting. The objective of this study was to examine the associations of the adiponectin genetic variants with metabolic syndrome by a case-control study and meta-analyses in Chinese.

Methods

We first investigated the association of ADIPOQ rs2241766 (+45T>G in exon 2), rs266729 (−11377C>G in promoter) and rs1501299 (+276G>T in intron 2) polymorphisms with metabolic syndrome in a Hubei Han Chinese population with 322 metabolic syndrome patients and 161 normal controls recruited from the Yichang, Hubei. Then we comprehensively reviewed the association between ADIPOQ rs2241766/rs266729/rs1501299 and metabolic syndrome in the Chinese populations via a meta-analysis. The strength of association was assessed by odds ratios (ORs) with 95% confidence intervals (CI).

Results

The G allele frequency of rs2241766 in metabolic syndrome patients was significantly higher than those of controls group (29.8% vs 23.3%, OR = 1.40, P = 0.033). The logistic regression analysis adjusted by gender and age showed a nominally significant association for rs2241766 GG+GT genotype (P = 0.065, OR = 1.55) and rs1501299 GG genotype in recessive model (OR = 1.54, P = 0.066). However, no association was observed for rs266729 in our sample. We identified thirteen studies for rs2241766 (2,684 metabolic syndrome patients and 2,864 controls), three studies for rs266729, and eleven studies for rs1501299 (2,889 metabolic syndrome patients and 3,304 controls) in Chinese. Meta-analysis indicated significant associations for the rs2241766 G allele (OR = 1.14, 95%CI = 1.05–1.24, P = 0.003), rs266729 GG+GT genotypes (OR = 0.80, 95%CI = 0.68–0.92, P = 0.003) and rs1501299 GG+TG genotypes (OR = 1.42, 95%CI 1.16–1.75, P = 0.001).

Conclusions

Our results demonstrated ADIPOQ as a pleiotropic locus for metabolic syndrome and its components in the Han Chinese population.

A comprehensive investigation of variants in genes encoding adiponectin (ADIPOQ) and its receptors (ADIPOR1/R2), and their association with serum adiponectin, type 2 diabetes, insulin resistance and the metabolic syndrome

Background

Low levels of serum adiponectin have been linked to central obesity, insulin resistance, metabolic syndrome, and type 2 diabetes. Variants in ADIPOQ, the gene encoding adiponectin, have been shown to influence serum adiponectin concentration, and along with variants in the adiponectin receptors (ADIPOR1 and ADIPOR2) have been implicated in metabolic syndrome and type 2 diabetes. This study aimed to comprehensively investigate the association of common variants in ADIPOQ, ADIPOR1 and ADIPOR2 with serum adiponectin and insulin resistance syndromes in a large cohort of European-Australian individuals.

Methods

Sixty-four tagging single nucleotide polymorphisms in ADIPOQ, ADIPOR1 and ADIPOR2 were genotyped in two general population cohorts consisting of 2,355 subjects, and one cohort of 967 subjects with type 2 diabetes. The association of tagSNPs with outcomes were evaluated using linear or logistic modelling. Meta-analysis of the three cohorts was performed by random-effects modelling.

Results

Meta-analysis revealed nine genotyped tagSNPs in ADIPOQ significantly associated with serum adiponectin across all cohorts after adjustment for age, gender and BMI, including rs10937273, rs12637534, rs1648707, rs16861209, rs822395, rs17366568, rs3774261, rs6444175 and rs17373414. The results of haplotype-based analyses were also consistent. Overall, the variants in the ADIPOQ gene explained <5% of the variance in serum adiponectin concentration. None of the ADIPOR1/R2 tagSNPs were associated with serum adiponectin. There was no association between any of the genetic variants and insulin resistance or metabolic syndrome. A multi-SNP genotypic risk score for ADIPOQ alleles revealed an association with 3 independent SNPs, rs12637534, rs16861209, rs17366568 and type 2 diabetes after adjusting for adiponectin levels (OR=0.86, 95% CI=(0.75, 0.99), P=0.0134).

Conclusions

Genetic variation in ADIPOQ, but not its receptors, was associated with altered serum adiponectin. However, genetic variation in ADIPOQ and its receptors does not appear to contribute to the risk of insulin resistance or metabolic syndrome but did for type 2 diabetes in a European-Australian population.

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.

Genetic association of adiponectin with type 2 diabetes in Jordanian Arab population

Adiponectin, a protein exclusively secreted by adipose tissue and present at low levels in obese individuals, is now widely recognized as a key determinant of insulin sensitivity and protection against obesity-associated metabolic syndrome. In Jordan, prevalence of diabetes (17.1%) is twice that of the United States (7.8%). In this study, we examined the contribution of the promoter variant rs266729 (-11377C>G) of the ADIPOQ gene as a risk factor for diabetic patients in Jordan. DNA was extracted from blood samples for patients and controls .Polymerase chain reaction and restriction fragment length polymorphism were used to genotype this variant. A total of 420 type 2 diabetic patients and 230 controls were successfully genotyped. The results showed a significant genotypic (p=0.00001) and allelic (p=0.01) association with variant in the diabetic patients as compared to controls. This suggests that the ADIPOQ gene plays a major role in increasing the risk of diabetes, at least in the Jordanian Arab population.

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.

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.

Association between polymorphisms in the adiponectin gene and cardiovascular disease: a meta-analysis

Background

Previous studies have examined the associations between polymorphisms of adiponectin gene (ADIPOQ) and cardiovascular disease (CVD), but those studies have been inconclusive. The aim of this study was to access the relationship between three single nucleotide polymorphisms (SNPs), +45 T > G (rs2241766), +276 G > T (rs1501299) and -11377 C > G (rs266729) in ADIPOQ and CVD.

Methods

A comprehensive search was conducted to identify all studies on the association of ADIPOQ gene polymorphisms with CVD risk. The fixed and random effect pooled measures (i.e. odds ratio (OR) and 95% confidence interval (CI)) were calculated in the meta-analysis. Heterogeneity among studies was evaluated using Q test and the I². Publication bias was estimated using modified Egger’s linear regression test.

Results

Thirty-seven studies concerning the associations between the three polymorphisms of ADIPOQ gene and CVD risk were enrolled in this meta-analysis, including 6,398 cases and 10,829 controls for rs2241766, 8,392 cases and 18,730 controls for rs1501299 and 7,835 cases and 14,023 controls for rs266729. The three SNPs were significantly associated with CVD, yielding pooled ORs of 1.22 (95%CI: 1.07, 1.39; P = 0.004), 0.90 (95%CI: 0.83, 0.97; P = 0.007) and 1.09(95%CI: 1.01, 1.17; P = 0.032) for rs2241766, rs1501299 and rs266729, respectively. Rs2241766 and rs1501299 were significantly associated with coronary heart disease (CHD), yielding pooled ORs of 1.29 (95%CI: 1.09, 1.52; P = 0.004) and 0.89 (95%CI: 0.81, 0.99; P = 0.025), respectively. The pooled OR for rs266729 and CHD was 1.09 (95%CI: 0.99, 1.19; P = 0.090). Significant between-study heterogeneity was found in our meta-analysis. Evidence of publication bias was observed in the meta-analysis.

Conclusions

The present meta-analysis showed that the associations between rs2241766, rs1501299 and rs266729 in the ADIPOQ and CVD were significant but weak. High quality studies are still needed to confirm the associations, especially for rs2241766.

Polymorphisms in the vitamin D receptor gene and type 1 diabetes mellitus risk: an update by meta-analysis

Four well known polymorphisms (BsmI, FokI, ApaI, TaqI) in the VDR gene have been implicated in susceptibility to type 1 diabetes mellitus (T1DM), but the results to date have been inconclusive. The aim of this study was to investigate the association between polymorphisms in the VDR gene and T1DM risk by meta-analysis. A total of 57 case-control studies in 26 published studies were included. The results indicated that the BsmI polymorphism is associated with increased risk of T1DM (BB+Bb vs. bb: OR=1.30, 95% CI=1.03-1.63), while the FokI, ApaI and TaqI polymorphisms were not. In the subgroup analysis by ethnicity, the increased risk of T1DM remained in the Asian subgroup for the BsmI polymorphism; whereas no significant association was found in other populations for other polymorphisms. Results from the current study suggest that the BsmI polymorphism is associated with increased risk of T1DM, especially in Asians. Further studies are needed to confirm our results.

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.

Association of the adiponectin rs266729 C>G variant and coronary heart disease in the low risk 'Golden Years' type 1 diabetes cohort

The C-allele of rs266729 is associated with CHD, while the G-allele of rs17300539 is associated with metabolic traits. We examined these in type 1 diabetes. For rs266729, the C-allele was associated with 8-fold increase in CHD. For rs17300539, the G-allele was associated with increases in triglycerides and waist circumference.