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

Revisiting the Immunometabolic Basis for the Metabolic Syndrome from an Immunonutritional View

Metabolic syndrome (MetS) implies different conditions where insulin resistance constitutes a major hallmark of the disease. The disease incurs a high risk for the development of cardiovascular complications, and takes its toll in regard to the gut-liver axis (pancreas, primary liver and colorectal)-associated immunity. The modulation of immunometabolic responses by immunonutritional factors (IFs) has emerged as a key determinant of the gut-liver axis' metabolic and immune health. IFs from plant seeds have shown in vitro and pre-clinical effectiveness primarily in dealing with various immunometabolic and inflammatory diseases. Only recently have immunonutritional studies established the engagement of innate intestinal immunity to effectively control immune alterations in inflamed livers preceding the major features of the MetS. However, integrative analyses and the demonstration of causality between IFs and specific gut-liver axis-associated immunometabolic imbalances for the MetS remain ill-defined in the field. Herein, a better understanding of the IFs with a significant role in the MetS, as well as within the dynamic interplay in the functional differentiation of innate immune key effectors (i.e., monocytes/macrophages), worsening or improving the disease, could be of crucial relevance. The development of an adequate intermediary phenotype of these cells can significantly contribute to maintaining the function of Tregs and innate lymphoid cells for the prevention and treatment of MetS and associated comorbidities.

Association of adipokines with insulin resistance and metabolic syndrome including obesity and diabetes

Adipose tissue (AT) acts as a highly active endocrine organ, which secretes a wide range of adipokine hormones. In the past few years, several adipokines (leptin, adiponectin, resistin etc.) have been discovered showing metabolic consequences in relation to insulin resistance (IR), obesity and diabetes. These adipokines are considered to be an important component playing an important role in the regulation of energy metabolism. They have been shown to be involved in the pathogenesis of metabolic syndrome (MetS) and cardiac diseases. The current article provides a holistic summary of recent knowledge on adipokines and emphasizes their importance in association with IR, obesity, diabetes and MetS. Adipokines such as leptin, adiponectin, resistin and tumor necrosis factor-alpha (TNF-α) have been involved in the regulation of an array of metabolic functions and disease associated with it, e.g. appetite and energy balance of the body, suppression of atherosclerosis and liver fibrosis, obesity with type 2 diabetes (T2D) and IR. An important adipokine, Interleukin-6 (IL-6), also correlates positively with human obesity and IR and also the elevated level of IL-6 predicts development of T2D. All of these hormones have important correlation with energy homeostasis, glucose and lipid metabolism, cardiovascular function and immunity. All the possible connections have extended the biological emphasis of AT secreted adipokines as an investigator in the development of MetS, and are now no longer considered as only an energy storage site.

Neuroprotection in metabolic syndrome by environmental enrichment. A lifespan perspective

Metabolic syndrome (MetS) is defined by the concurrence of different metabolic conditions: obesity, hypertension, dyslipidemia, and hyperglycemia. Its incidence has been increasingly rising over the past decades and has become a global health problem. MetS has deleterious consequences on the central nervous system (CNS) and neurological development. MetS can last several years or be lifelong, affecting the CNS in different ways and treatments can help manage condition, though there is no known cure. The early childhood years are extremely important in neurodevelopment, which extends beyond, encompassing a lifetime. Neuroplastic changes take place all life through - childhood, adolescence, adulthood, and old age - are highly sensitive to environmental input. Environmental factors have an important role in the etiopathogenesis and treatment of MetS, so environmental enrichment (EE) stands as a promising non-invasive therapeutic approach. While the EE paradigm has been designed for animal housing, its principles can be and actually are applied in cognitive, sensory, social, and physical stimulation programs for humans. Here, we briefly review the central milestones in neurodevelopment at each life stage, along with the research studies carried out on how MetS affects neurodevelopment at each life stage and the contributions that EE models can provide to improve health over the lifespan.

Association of coffee consumption pattern and metabolic syndrome among middle-aged and older adults: A cross-sectional study

Objectives

The association between coffee consumption and the risk of metabolic syndrome (MetS) remains inconsistent. The aim of this study was to evaluate the association between coffee intake and components of MetS.

Method

A cross-sectional survey including 1,719 adults was conducted in Guangdong, China. Data on age, gender, education level, marriage status, body mass index (BMI), current smoking and drinking status and breakfast habit, coffee consumption type, and daily servings were derived based on 2-day, 24-h recall. MetS were assessed according to the International Diabetes Federation definition. Multivariable logistic regression was conducted to examine the association between the coffee consumption type, daily servings, and the components of MetS.

Results

Regardless of the coffee type, compared with non-coffee consumers, coffee consumers had higher odds ratios (ORs) of the elevated fasting blood glucose (FBG) in both men [OR: 3.590; 95% confidence intervals (CI): 2.891-4.457] and women (OR: 3.590; 95% CI: 2.891-4.457). In women, the risk of elevated blood pressure (BP) was 0.553 times (OR: 0.553; 95% CI: 0.372-0.821, P = 0.004) for people who drank total coffee > 1 serving/day than for non-coffee drinkers.

Conclusion

In conclusion, regardless of type, coffee intake is associated with an increased prevalence of FBG in both men and women, but has a protective effect on hypertension only in women.

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 of AdipoQ gene variation (rs1501299) and oxidative stress with cardiovascular disease in North West Indian population of Punjabi women

BACKGROUND

Till to date whether adiponectin AdipoQ gene variation (rs 1501299) is associated with cardiovascular disease, still remains controversial. Therefore, we aimed to relate the SNP (rs1501299) of adiponectin gene and oxidative stress in context to CVD in Punjabi women of North West India.

METHODS

In the present case-control study menopausal women with CVD as cases (n=265) and menopausal women without CVD as controls (n=258) were recruited. Genotyping of rs1501299 single nucleotide polymorphism of adiponectin gene was carried out by RFLP-PCR analysis. Biochemical parameters were analyzed according to the standard procedures.

RESULTS

Distribution of homozygous TT genotype of normolipidemic (p=0.001) and hyperlipidemic (p=0.001) women with CVD was significantly more frequent as compared to women without CVD. rs1501299 T allele carriers with CVD also showed significant (p=0.001) higher frequency distribution as compared to women without CVD. Under recessive model of inheritance TT mutant type homozygotes conferred ~9 fold higher risk [p=0.001; OR= 9.60 (2.92-31.58)] towards CVD susceptibility for MDA>1.50; ~11 fold higher risk [p=0.007; OR= 11.11 (1.49-82.83)] towards CVD for LDL carbonyl protein>15.04 and ~9 fold higher risk [p=0.001; OR= 9.75 (2.30-41.22)] towards CVD susceptibility for SOD≤5.55. Under logistic regression analysis oxidative stress and TT genotype were significantly correlated with CVD.

CONCLUSIONS

Our study revealed significant association of AdipoQ (rs1501299) gene polymorphism and oxidative stress with cardiovascular disease in Punjabi women of North West India. However, additional studies are required to support these findings.

Association of Candidate Gene Polymorphism with Metabolic Syndrome among Mongolian Subjects: A Case-Control Study

Metabolic syndrome (MetS) is complex and determined by the interaction between genetic and environmental factors and their influence on obesity, insulin resistance, and related traits associated with diabetes and cardiovascular disease risk. Some dynamic markers, including adiponectin (ADIPOQ), brain-derived neurotrophic factor (BDNF), and lipoprotein lipase (LPL), are implicated in MetS; however, the influence of their genetic variants on MetS susceptibility varies in racial and ethnic groups. We investigated the association of single nucleotide polymorphism (SNP)-SNP interactions among nine SNPs in six genes with MetS's genetic predisposition in Mongolian subjects. A total of 160 patients with MetS for the case group and 144 healthy individuals for the control group were selected to participate in this study. Regression analysis of individual SNPs showed that the ADIPOQ + 45GG (odds ratio (OR) = 2.09, p = 0.011) and P⁺P⁺ of LPL PvuII (OR = 2.10, p = 0.038) carriers had an increased risk of MetS. Conversely, G allele of LPL S447X (OR = 0.45, p = 0.036) and PGC-1α 482Ser (OR = 0.26, p = 0.001) allele were estimated as protective factors, respectively. Moreover, a haplotype containing the G-P⁺-G combination was related to MetS. Significant loci were also related to body mass index (BMI), systolic blood pressure (SBP), serum high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), and fasting blood glucose (FBG), adipokines, and insulin as well as insulin resistance (p < 0.05). Our results confirm that ADIPOQ + 45T > G, LPL PvII, and PGC-1α Gly482Ser loci are associated with MetS in Mongolian subjects.

Meta-Analysis of Adiponectin as a Biomarker for the Detection of Metabolic Syndrome

Previous studies revealed the potential significance of circulating adiponectin levels with respect to the diagnosis and prediction of metabolic syndrome, but uncertainty has been noted across different cohorts. Systematic evaluation was performed for diagnostic accuracy and predictivity of adiponectin variation for metabolic syndrome in enrolled studies including 1,248 and 6,020 subjects, respectively. Adiponectin can identify metabolic syndrome with moderate accuracy (area under the curve = 0.81, 95% CI: 0.77–0.84). Heterogeneity analysis revealed that an increasing index of insulin resistance was independently associated with improving the performance of adiponectin upon metabolic syndrome diagnosis (ratio of diagnostic odds ratio = 3.89, 95% CI: 1.13–13.9). In addition, reductions in adiponectin were associated with increasing metabolic syndrome incidence in a linear dose-response manner. The risk of hypoadiponectinemia with metabolic syndrome was especially increased in men (P < 0.05). Further Mendelian randomization analysis identified that the amplified risk could be attributed to increased susceptibility (up to 7%) to insulin resistance compared with women. In conclusion, adiponectin measurement might have potential benefits in the detection of metabolic syndrome. Factors that affect insulin resistance should be considered for adjustment in future assessments.

Adiponectin Single Nucleotide Polymorphisms and Serum Levels Are Relevant to Prognosis of Patients With Aneurysmal Subarachnoid Hemorrhages

To investigate the association of adiponectin gene polymorphisms and its levels with aneurysmal subarachnoid hemorrhages (aSAHs) prognosis. This case-control study enrolled 138 patients with aSAH and 102 healthy controls as case group and control group, respectively. Prognosis of case group was evaluated using Glasgow Outcome Scale. Polymerase chain reaction-restriction fragment length polymorphism was used to examine the genotypes of 45T>G and -11377C>G. Enzyme-linked immunosorbent assay was used to detect adiponectin levels. Logistic regression analysis was applied to assess the association of adiponectin gene polymorphism with aSAH prognosis. Case group had increased GG genotype and G allele genotype frequencies of 45T>G and -11377C>G compared with control group (all P < 0.01). In case group, TT genotype had the highest adiponectin level compared with both TG and GC genotypes (both P < 0.05). As for -11377C>G, GG genotype had the lowest adiponectin levels, followed by CG genotype and CC genotype in both groups (P < 0.05). In general, case group had decreased adiponectin levels compared with control group (P < 0.05). Univariate analysis showed that hypertension, Hunt-Hess grade, aneurysm size, aneurysms multiplicity and -11377C>G were associated with aSAH prognosis, while multivariate logistic regression analysis confirmed that hypertension, Hunt-Hess grade, residual flow in aneurysms and aneurysm size were independent risk factors for aSAH prognosis. Decreased adiponectin levels may be a pathological index for aSAH, which may be explain by the G allele of -11377C>G in adiponectin. Moreover, hypertension, Hunt-Hess grade, residual flow in aneurysms and aneurysm size may be independent risk factors for aSAH prognosis.

Fruit and vegetable consumption and risk of the metabolic syndrome: a meta-analysis

OBJECTIVE

Several epidemiological studies have been performed to evaluate the association of fruit and vegetable consumption with risk of the metabolic syndrome (MetS), but the results remain controversial. Thus, we conducted a systematic meta-analysis to assess the associations of fruit or/and vegetable consumption with risk of MetS, separately.

DESIGN

We searched PubMed, EMBASE and Web of Science databases up to July 2017 for relevant available articles. Pooled OR with 95 % CI were calculated with the fixed- or random-effects model.

RESULTS

A total of nine studies for fruit consumption, nine studies for vegetable consumption and seven studies for fruit and vegetable consumption were identified as eligible for the present meta-analysis. The pooled OR (95 % CI) of MetS for the highest v. lowest category were 0·87 (0·82, 0·92; I 2=46·7 %) for fruit consumption, 0·85 (0·80, 0·91; I 2=0·0 %) for vegetable consumption and 0·76 (0·62, 0·93; I 2=83·5 %) for fruit and vegetable consumption. In subgroup analyses stratified by continent where the study was conducted, the inverse association of fruit consumption (0·86 (0·77, 0·96)) and vegetable consumption (0·86 (0·80, 0·92)) with risk of MetS remained significant in Asia. There was no evidence of small-study effect.

CONCLUSIONS

Our meta-analysis indicates that fruit or/and vegetable consumption may be inversely associated with risk of MetS. It suggests that people should consume more fruits and vegetables to decrease the risk of MetS.

High Molecular Weight Adiponectin Levels are Neither Influenced by Adiponectin Polymorphisms Nor Associated with Insulin Resistance in Mixed-ancestry Hyperglycemic Subjects from South Africa

Background

High molecular weight (HMW) adiponectin has antiatherogenic, antiinflammatory and antidiabetic properties and these effects have been linked to its effect on high density lipoprotein cholesterol (HDL-c). Single nucleotide polymorphisms (SNPs) in the adiponectin gene influence adiponectin levels. We examined the relationship between HMW-adiponectin levels and cardiometabolic traits in normo- and hyperglycemic mixed ancestry South Africans and correlated these levels to two common polymorphisms.

Methods

HMW-adiponectin was determined in 101 subjects from the Cape Town Bellville South community-based study on a mixed ancestry population. Comparisons were made between individuals with normo- and hyperglycemia. Two common SNPs, ADIPOQ SNPs rs17300539 and rs266729, known to affect adiponectin levels were also tested for. Levels of HMW-adiponectin were then correlated with cardiometabolic traits in all groups.

Results

Levels of HMW-adiponectin were not significantly different in the normo- and hyperglycemic groups (median 11.6 vs. 10.5 μg/mL, p=0.3060) and in men and women (8.44 vs. 11.34 μg/mL, p=0.67). ADIPOQ SNPs rs17300539 and rs266729 did not influence levels of HMW-adiponectin. Robust correlation analyses revealed a significant positive correlation between HMW-adiponectin and HDL-c (r=0.45; 95%CI: 0.27–0.59), similarly in normo- and hyperglycemic participants (p > 0.99). This association was substantially attenuated in robust linear regressions adjusted for age, gender and adiposity.

Conclusions

Adiponectin levels in this population were not determined by the commonest SNPs of the adiponectin gene, were unaffected by glycemic status; but were significantly correlated with HDL-c levels. Previous studies have attributed some of the beneficial effects of adiponectin to its effect on HDL-c.

Gene Polymorphisms of FABP2, ADIPOQ and ANP and Risk of Hypertriglyceridemia and Metabolic Syndrome in Afro-Caribbeans

OBJECTIVES

The metabolic syndrome (MetS) is a cluster of metabolic abnormalities and cardiovascular risk factors that are highly heritable and polygenic. We investigated the association of allelic variants of three candidate genes, rs1799883-FABP2, rs1501299-ADIPOQ and rs5065-ANP with MetS and its components, individually and in combination, using a genetic risk score.

METHODS

A cross-sectional study was conducted in 462 Afro-Caribbeans subjects without cardiovascular complications or lipid-lowering medications. Cardiovascular risk factors and MetS components (NCEP-ATPIII criteria) were recorded. The 3 SNPs were genotyped. The genetic risk score was calculated by summing the number of risk alleles at each locus. Logistic regressions were used.

RESULTS

Fifty-eight participants (12.6%) were diabetics and 116 (25.1%) had a MetS. In a dominant model, rs1799883 was associated with hypertriglyceridemia (OR 2.22; P = 0.014) and hypertriglyceridemic waist (HTGW), (P = 0.014) but not significantly with overweight (P = 0.049), abdominal obesity (P = 0.033) and MetS (P = 0.068). In a dominant model, the OR of MetS and HTGW for rs1501299 were 1.80 (P = 0.028) and 2.19 (P = 0.040) respectively. In a recessive model, the OR of hypertriglyceridemia for rs5065 was 1.94 (P = 0.075). The genetic risk score was significantly associated with MetS. Subjects carrying 4-5 risk alleles (18.8%) had a nearly 2.5-fold-increased risk of MetS compared to those carrying 0-1 risk allele (24.3%): OR 2.31; P = 0.025.

CONCLUSIONS

This study supports the association of FABP2, ANP and ADIPOQ gene variants with MetS or its components in Afro-Caribbeans and suggests a cumulative genetic influence of theses variants on this syndrome and a potential effect on lipid metabolism.

Association of Adiponectin Polymorphism with Metabolic Syndrome Risk and Adiponectin Level with Stroke Risk: A Meta-Analysis

Many previous studies have provided evidence that the ADIPOQ +45T>G polymorphism (rs2241766) might cause metabolic syndrome (MS). As a cardiovascular manifestation of MS, the incidence of stroke is associated with adiponectin; however, the results remain controversial and inconsistent. Systematic searches of relevant studies published up to Dec 2014 and Jan 2016 on the ADIPOQ +45T>G polymorphism and the risk of MS and adiponectin levels and the risk of stroke, respectively, were conducted in MEDLINE and EMBASE. The odds ratio (OR) or risk ratio (RR) and their 95% confidence interval (95% CI) were extracted. Sixteen studies containing 4,113 MS cases and 3,637 healthy controls indicated a weak positive association between ADIPOQ +45 T>G and MS in the dominant genetic model (OR = 1.30, 95% CI = 1.03-1.65), which was also validated by stratified subgroup analyses. Twelve studies including 26,213 participants and 4,246 stroke cases indicated that 5 μg/ml increments in adiponectin level were not relevant to stroke risk (RR = 1.05, 95% CI = 1.00-1.10, P = 0.069). This study suggested a weak positive association of ADIPOQ +45T>G with MS and a strong association with metabolic-related disease. Additionally, adiponectin level was not a causal factor of increasing stroke risk.

The Role of Adiponectin in Cardiometabolic Diseases: Effects of Nutritional Interventions

Adiponectin is an adipocyte-derived hormone abundantly present in plasma that exerts its effects through the activation of 3 receptors. Its concentrations are negatively regulated by the accumulation of visceral fat, and clinical studies implicate hypoadiponectinemia in the pathogenesis of diabetes mellitus type 2, coronary artery disease, hypertension, and left ventricular hypertrophy. In contrast, high concentrations of adiponectin are associated with a decreased risk of coronary artery disease, with an improvement in the differentiation of preadipocytes into adipocytes, and with increased endothelial nitric oxide production. Therefore, adiponectin appears to be an important molecule involved in limiting the pathogenesis of obesity-linked disorders, and it may have potential benefits in the treatment and prevention of cardiovascular disease. Caloric restriction, moderate alcohol consumption, and consuming a Mediterranean diet increase adiponectin concentrations, and current evidence suggests a positive, dose-dependent relation between ω-3 (n-3) fatty acid intake and circulating concentrations of adiponectin. Recently, it was reported that the administration of aged garlic extract and a single food intervention with pistachios can increase adiponectin concentrations in individuals with metabolic syndrome. Moreover, the Mediterranean diet is associated with higher adiponectin concentrations. Additional studies are needed to evaluate the potential benefits of increasing adiponectin by nutritional interventions in the treatment and prevention of cardiometabolic diseases.

Prevalence and Determinants of Metabolic Syndrome-identified by Three Criteria among Men in Rural China: A Population-based Cross-sectional Study Conducted during 2007-2008

OBJECTIVE

The aim of this study was to estimate MS prevalence according to three criteria and its risk factors among men in rural China.

DESIGN

Cross-sectional study.

SETTING

The Nantong Metabolic Syndrome Study (NMSS) was conducted during 2007-2008 in Nantong, China.

PARTICIPANTS

6997 male participants aged 18-74 years.

MEASUREMENTS

In person interviews, blood glucose and lipid measurements were accomplished.

RESULTS

The prevalence of MS was 12.86%, 8.55% and 15.28% according to IDF, ATPIII and ATPIII-modified criteria, respectively. The IDF and ATP III-modified criteria agreed only moderately with ATP III criteria (κ= 0.56 and 0.68), whereas ATP III-modified and the IDF criteria agreed perfectly (κ= 0.90). Vigorous occupational physical activity was associated with a low prevalence of MS with Odds ratio (OR) of 0.58 (95% confidence interval (CI): 0.45-0.74). Beer drinkers (alcohol ≤ 6.2 g/day) and rice wine drinkers (alcohol ≤ 9.0 g/day) had about 34% and 33% low risks of developing MS respectively, compared with non-drinkers. OR of MS was 1.95 (95% CI: 1.39-2.73) in men who had familial history of at least two diseases, including hypertension and diabetes, compared with men without familial history of those diseases.

CONCLUSIONS

Our data suggested that MS is highly prevalent among men in rural China. Family history of diabetes and hypertension is a risk factor in MS development. Physical activity, rice wine and beer consumption are associated with a significantly lower risk.

ADIPOQ single nucleotide polymorphism: Association with adiponectin and lipoproteins levels restricted to men

Adiponectin is an adipokine inversely correlated with obesity, which has beneficial effect on insulin resistance and lipid metabolism. Considering its potential as a therapeutic target in the metabolic disorder contexts, and in order to add knowledge in the area, our study evaluated the ADIPOQ 276G > T polymorphism effect on adiponectin levels, and on lipoproteins of clinical interest in a population sample composed of 211 healthy individuals. Significant effects were observed only among men: the carriers of heterozygous genotype (GT) showed high levels of adiponectin (p = 0.018), while the rare homozygous genotype (TT) gave its carriers a negative phenotype, represented by higher levels of low density lipoprotein cholesterol (LDL-C) (p = 0.004 and p = 0.005) and total cholesterol (TC) (p = 0.010 and p = 0.005) compared to carriers of other genotypes (GG and GT respectively), the independent effect of SNP on LDL-C and TC levels was confirmed by multiple regression analysis (p = 0.008 and p = 0.044). We found no evidence of correlation between circulating adiponectin levels and biochemical markers, which suggests, therefore, an SNP 276G > T independent effect on adiponectin levels and on lipoprotein metabolism in men enrolled in this study.

Adiponectin gene (ADIPOQ) polymorphisms correlate with the progression of nephropathy in Taiwanese male patients with type 2 diabetes

AIMS

Polymorphisms of the ADIPOQ gene were associated with diabetic nephropathy (DN) in case-control studies predominantly among European populations. Gender may modify the ADIPOQ associated risk for DN. We investigated the association of 18 ADIPOQ polymorphisms with DN in a prospective Taiwanese cohort of type 2 diabetes (T2D) and explored whether gender plays a role in this genetic association.

METHODS

Selected single nucleotide polymorphisms (SNPs) of ADIPOQ were genotyped in 566 T2D patients with normoalbuminuria at baseline. DN was defined based on urinary albumin-to-creatinine ratio (ACR). The Cox proportional hazard model was used to explore the association of individual SNP to DN events under different genetic models over a 6-year follow-up period. Analyses were further stratified by gender.

RESULTS

In male patients, the adjusted hazard ratios under the recessive models were 1.81 for rs2241766 TT (vs. GT+GG, 95% CI=1.10-2.96, p=0.019) and 1.89 for rs1063537 CC (vs. CT+TT, 95% CI=1.15-3.11, p=0.013). In the Kaplan-Meier survival curve, males carrying rs2241766 TT (vs. GT+GG, p=0.050) and rs1063537 CC (vs. CT+TT, p=0.037) recessive homozygotes also had a reduced nephropathy-free survival rate. SNPs rs2241767 and rs2082940, both in strong correlation with tag SNP rs1063537 (r(2)≥ 0.96), were also associated with DN progression in males. In females, ADIPOQ polymorphisms were not associated with the progression of DN.

CONCLUSIONS

ADIPOQ genetic polymorphisms rs2241766 (+45T>G), rs1063537, rs2241767 and rs2082940 were correlated with the progression of DN in Taiwanese male patients with T2D. The role of gender in this ADIPOQ genetic association needs to be further investigated in other populations.

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.

Association of adiponectin gene (ADIPOQ) rs2241766 polymorphism with obesity in adults: a meta-analysis

Background

Adiponectin plays an important role in regulating glucose levels and fatty acid oxidation. Multiple studies have assessed the association between rs2241766 polymorphism in the adiponectin (ADIPOQ) gene and obesity susceptibility. However, the results are inconsistent and inconclusive. The aim of this meta-analysis was to investigate this association in adults.

Method

Several electronic databases were searched for relevant literature published up to November 2013. Statistical analyses were performed using software Review Manager (Version 5.02) and STATA (Version 10.0). The pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated with a random-effects model or a fixed-effect model depending on heterogeneity among studies. Q tests and Egger’s tests were performed to assess heterogeneity and publication bias. Sensitivity analysis was conducted to confirm the reliability and stability of the meta-analysis.

Results

A total of 2,819 obese and 3,024 controls in 18 case-control studies were included in the meta-analysis. The results indicated that compared with TT genotype, the ADIPOQ-rs2241766 GG genotype was associated with an increased risk for obesity (OR = 1.39, 95% CI: 1.11–1.73, P for heterogeneity = 0.520, I² = 0%) in overall studies. Whereas, GT genotype was associated with a borderland increased risk for obesity (OR = 1.13, 95% CI: 0.94–1.36, P for heterogeneity = 0.006, I² = 51%). The susceptibility of obesity was increased based on genotypes of TT<GT<GG (P for trend = 0.011). Subgroup analysis of different regions revealed that the ADIPOQ-rs2241766 GG genotype increased obesity risk in the Chinese studies (OR = 1.54, 95% CI: 1.19–2.00) but not in the non-Chinese studies (OR = 1.02, 95% CI: 0.66–1.58). Similar results were observed in allelic, recessive, and dominant genetic models. There was no significant evidence of publication bias in the overall, Chinese, and non-Chinese studies (P = 0.426, P = 0.935, and P = 0.390, respectively).

Conclusion

The results of this meta-analysis suggest that the ADIPOQ-rs2241766 G/T polymorphism might be associated with obesity in Chinese studies but not in non-Chinese studies in adults. Better-designed studies that consider confounding factors and assess larger sample sizes with a focus on ADIPOQ-rs2241766G/T polymorphisms and obesity are required in the future.

Association of the ADIPOQ T45G polymorphism with insulin resistance and blood glucose: a meta-analysis

Results of published studies on the association of the ADIPOQ T45G polymorphism with insulin resistance (IR) and blood glucose are conflicting. In this study, we performed a meta-analysis to further investigate such an association. Articles that evaluate the effect of the T45G polymorphism on IR and blood glucose were identified from the PubMed and Embase databases. Five indices, including fasting blood glucose (FBG), fasting insulin (F-insulin), 2-h blood glucose (2-h BG), 2-h insulin, and homeostasis model assessment insulin resistance index (HOMA-IR), were used to assess the effects of the T45G polymorphism on IR and blood glucose under a dominant model. 24 articles involving 7630 subjects were included. Twenty-two studies on FBG, 17 on F-insulin, 20 on HOMA-IR, and 3 on 2-h BG were included. No study on 2-h insulin was found. This meta-analysis revealed no significant association between the ADIPOQ T45G polymorphism and IR and blood glucose in the overall population and subgroup subjects under a dominant model, regardless of whether FBG, F-insulin, 2-h BG, or HOMA-IR was used. The present meta-analysis indicated that the mutation allele may have no function in IR development. The ADIPOQ T45G polymorphism is not associated with IR and blood glucose.