Hyejin Lee

Optimal hemoglobin A1C Cutoff Value for Diagnosing type 2 diabetes mellitus in Korean adults

Commonly used tests for the diagnosis of diabetes include measurements of fasting plasma glucose levels and the oral glucose tolerance test (OGTT). Recently, a hemoglobin A1C (A1C) level of 6.5% has been included as a criterion for diabetes diagnosis by the American Diabetes Association. We aimed to determine appropriate A1C cutoff values for identifying patients with diabetes or prediabetes, including impaired glucose tolerance and impaired fasting glucose among Korean adults and to determine whether these cutoffs vary according to age. We recruited 4616 adults without a history of diabetes from 10 university hospitals. A 75-g OGTT and A1C sampling were performed in all examinees. Pointwise area under the receiver operating characteristic curve was used to evaluate the diagnostic accuracy of the A1C cutoff. An A1C threshold of 6.1% proved to be the optimal limit for diagnosing diabetes, with 63.8% sensitivity and 88.1% specificity. The cutoff value increased with age (5.9% in 18-39 years, 6.2% in 40-64 years, and 6.4% in older than 65 years) and were similar for men and women. An A1C cutoff of 5.7% had reasonable sensitivity (48.6%) and specificity (65.7%) for the identification of prediabetes. Further prospective studies should be carried out to determine whether the application of age-specific diagnostic criteria is appropriate.

Serum C-Reactive Protein Levels in Normal-Weight Polycystic Ovary Syndrome

Background/Aims Serum levels of highly sensitive C-reactive protein (hsCRP), a vascular inflammatory marker, may predict the development of cardiovascular disease (CVD) and type 2 diabetes. Women with polycystic ovary syndrome (PCOS) are at greater risk for type 2 diabetes and CVD. The aim of this study was to compare hsCRP levels between normal weight women with PCOS and controls with a normal menstrual cycle and to determine the factors associated with serum hsCRP levels. Methods Thirty-nine lean PCOS patients and 24 healthy, regular cycling women were enrolled in this study. We performed anthropometric measurements, fat computed tomography (CT), and blood sampling to determine blood chemistry and levels of hsCRP, gonadotropins, testosterone, and sex-hormone binding globulin. We also conducted 75-g oral glucose-tolerance test and euglycemic hyperinsulinemic clamp to assess insulin sensitivity. Results Serum hsCRP concentrations were higher in women with PCOS than in women with regular mensturation. However, this difference was no longer significant after adjusting for body mass index (BMI). hsCRP levels were correlated with waist circumference (r=0.46, p<0.01), BMI (r=0.46, p<0.01), visceral fat area (r=0.45, p<0.01), and systolic (r=0.42, p<0.05) and diastolic blood pressure (r=0.39, p<0.05). hsCRP also tended to be negatively associated with insulin-mediated glucose uptake (IMGU) (r=-0.31, p=0.07). A multiple regression analysis revealed that BMI (β=0.29, p<0.05), systolic blood pressure (β=0.39, p<0.01), and IMGU (β=-0.31, p<0.05) predicted serum hsCRP levels in women with PCOS. Conclusions PCOS by itself does not seem to be associated with increased hsCRP levels, whereas known CVD risk factors affect serum hsCRP levels in PCOS.

Hyperandrogenemia is implicated in both the metabolic and reproductive morbidities of polycystic ovary syndrome

OBJECTIVE To determine the features of polycystic ovary syndrome (PCOS) that are implicated in the associated reproductive and metabolic morbidities. DESIGN Cross-sectional case-control study. SETTING Academic medical setting. PATIENT(S) A total of 1,062 women with PCOS and 1,887 women without PCOS. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Physical examination including hirsutism scoring, biochemical and hormone measurements, ovarian ultrasound, and a 75-g oral glucose tolerance test to measure glucose and insulin levels. RESULT(S) A factor analysis identified four dominant factors in women with PCOS. These factors were interpreted as follows: [1] metabolic and hyperandrogenemia factor, [2] oligomenorrhea and hyperandrogenemia factor, [3] blood pressure factor, and [4] ovarian morphology factor. In women with PCOS, hyperandrogenemia was a significant predictor of metabolic syndrome after adjusting for age, body mass index, and insulin resistance in the regression analysis. CONCLUSION(S) A factor analysis identified multiple factors that are responsible for the abnormalities associated with PCOS. Hyperandrogenemia was a common underlying feature of the metabolic and reproductive abnormalities in women with PCOS but not in women without PCOS.

Genome-wide association study identified new susceptibility loci for polycystic ovary syndrome

STUDY QUESTION Are there any novel genetic markers of susceptibility to polycystic ovary syndrome (PCOS)? SUMMARY ANSWER We identified a novel susceptibility locus on chromosome 8q24.2 and several moderately associated loci for PCOS in Korean women. WHAT IS KNOWN ALREADY PCOS is a highly complex disorder with significant contributions from both genetic and environmental factors. Previous genome-wide association studies (GWAS) in the Han Chinese population identified several risk loci for PCOS. However, GWAS studies on PCOS remain very few. The aim of this study was to identify novel markers of susceptibility to PCOS through GWAS. STUDY DESIGN, SIZE, DURATION A two-stage GWAS was conducted. The initial discovery set for GWAS consisted of 976 PCOS cases and 946 controls. The second stage (replication study) included 249 PCOS cases and 778 controls. PARTICIPANTS/MATERIALS, SETTING, METHODS Patients were diagnosed according to the Rotterdam criteria. Genomic DNAs were genotyped using the HumanOmni1-Quad v1 array. In the replication stage, the 21 most promising signals selected from the discovery stage were tested for their association with PCOS. MAIN RESULTS AND THE ROLE OF CHANCE One novel locus with genome-wide significance and seven moderately associated loci for PCOS were identified. The strongest association was on chromosome 8q24.2 (rs10505648, OR = 0.52, P = 5.46 × 10(-8)), and other association signals were located at 4q35.2, 16p13.3, 4p12, 3q26.33, 9q21.32, 11p13 and 1p22 (P = 5.72 × 10(-6)-6.43 × 10(-5)). The strongest signal was located upstream of KHDRBS3, which is associated with telomerase activity, and could drive PCOS and related phenotypes. LIMITATIONS, REASONS FOR CAUTION The limitation of our study is the modest sample size used in the replication cohort. The limited sample size may contribute to a lack of statistical power to detect an association or show a trend in severity. WIDER IMPLICATIONS OF THE FINDINGS Our findings provide new insight into the genetics and biological pathways of PCOS and could contribute to the early diagnosis and prevention of metabolic and reproductive morbidities. STUDY FUNDING/COMPETING INTERESTS This work was supported in part by the grant from the Korea Centers for Disease Control and Prevention (2009-E00591-00). The work was also supported by the Ewha Global Top5 Grant 2013 of Ewha Womans University. None of the authors has any conflict of interest to declare.

Sleep Disorder and Cardiovascular Risk Factors among Patients with Type 2 Diabetes Mellitus

Background/Aims Sleep disorder (SD) is associated with an increased risk of cardiovascular disease and is more prevalent among individuals with type 2 diabetes mellitus. These health problems not only frequently coexist but also exacerbate each other. We conducted a cross-sectional study to estimate the prevalence of SD among diabetic patients and to investigate the relationship between SD and cardiovascular risk among these patients. Methods We recruited 784 patients with type 2 diabetes and conducted a self-administered questionnaire. We assessed sleep quality using the Pittsburgh Sleep Quality Index and the risk of obstructive sleep apnea (OSA) using the Berlin Questionnaire. Additional information included blood pressure and metabolic profiles. Results Of the 784 diabetic patients, 301 (38.4%) patients had poor sleep quality, and 124 (15.8%) were at high risk for OSA. Patients at increased risk for OSA were more obese; they also had higher blood pressure, fasting plasma insulin levels, insulin resistance assessed by homeostasis model assessment (HOMA-IR), and serum triglycerides levels (p < 0.05). The frequency of risk for OSA was higher among obese patients compared with non-obese patients (34.8% vs. 9.4%, p < 0.05). Logistic regression analysis revealed that male sex and bone mass index were independent predictors of risk for OSA. Conclusions SD was prevalent among type 2 diabetic patients, and OSA could aggravate their risk for cardiovascular disease. Clinical treatment of these patients should include evaluation and intervention for SD.

Increased Epicardial Adipose Tissue Thickness in Type 2 Diabetes Mellitus and Obesity

Background Epicardial adipose tissue (EAT) is suggested to play an important role in the progression of metabolic syndrome. We aimed to establish a simple method to measure EAT and examine the differences in EAT thickness according to the presence of type 2 diabetes mellitus or obesity. Methods A total of 94 patients (42.6% type 2 diabetes mellitus, 53.2% obese, mean age 61±13) who underwent multidetector computed tomography were enrolled. Thickness of EAT was measured on the parasternal short and horizontal long axis view. Epicardial fat area (EFA) was measured at the level of left main coronary artery (LMCA). Results All EAT thicknesses were correlated with EFA at the LMCA level (r=0.235 to 0.613, all Ps<0.05), and EAT thickness in the left atrioventricular groove (LAVG) had the highest correlation coefficient (r=0.613). EFA, and EAT thicknesses in the LAVG and the left ventricular apex were higher in the group with type 2 diabetes mellitus than in the group without type 2 diabetes mellitus when adjusted only for body mass index. When adjusted only for type 2 diabetes mellitus, EFA, and EAT thicknesses in the LAVG and the right atrioventricular groove were higher in obese group than in nonobese group. Conclusion In conclusion, EAT thickness can be easily measured and represent EFA. EAT thickness, especially in LAVG, was higher in groups with type 2 diabetes mellitus and obesity independently. These findings implicate that EAT thickness may be a useful indicator for type 2 diabetes mellitus and obesity.

FTO Gene Variants Are Associated with PCOS Susceptibility and Hyperandrogenemia in Young Korean Women

Background The fat mass and obesity-associated (FTO) gene is associated with obesity and type 2 diabetes mellitus. Obesity and insulin resistance are also common features of polycystic ovary syndrome (PCOS). Therefore, the FTO gene might be a candidate gene for PCOS susceptibility. The aim of the present study was to evaluate the effects of FTO gene variants on PCOS susceptibility and metabolic and reproductive hormonal parameters. Methods We recruited 432 women with PCOS (24±5 years) and 927 healthy women with regular menstrual cycles (27±5 years) and performed a case-control association study. We genotyped the single nucleotide polymorphisms rs1421085, rs17817449, and rs8050136 in the FTO gene and collected metabolic and hormonal measurements. Results Logistic regression revealed that the G/G genotype (rs1421085, 1.6%), the C/C genotype (rs17817449, 1.6%), and the A/A genotype (rs8050136, 1.6%) were strongly associated with an increased risk of PCOS (odds ratio, 2.551 to 2.559; all P<0.05). The strengths of these associations were attenuated after adjusting for age and BMI. The women with these genotypes were more obese and exhibited higher free androgen indices (P<0.05) and higher free testosterone levels (P=0.053 to 0.063) compared to the other genotypes. However the significant differences disappeared after adjusting for body mass index (BMI). When we analyzed the women with PCOS and the control groups separately, there were no significant differences in the metabolic and reproductive hormonal parameters according to the FTO gene variants. Conclusion The rs1421085, rs17817449, and rs8050136 variants of the FTO gene were associated with PCOS susceptibility and hyperandrogenemia in young Korean women. These associations may be mediated through an effect of BMI.

A comprehensive profile of DNA copy number variations in a Korean population: identification of copy number invariant regions among Koreans

To examine copy number variations among the Korean population, we compared individual genomes with the Korean reference genome assembly using the publicly available Korean HapMap SNP 50 k chip data from 90 individuals. Korean individuals exhibited 123 copy number variation regions (CNVRs) covering 27.2 mb, equivalent to 1.0% of the genome in the copy number variation (CNV) analysis using the combined criteria of P value (P < 0.01) and standard deviation of copy numbers (SD ≥ 0.25) among study subjects. In contrast, when compared to the Affymetrix reference genome assembly from multiple ethnic groups, considerably more CNVRs (n = 643) were detected in larger proportions (5.0%) of the genome covering 135.1 mb even by more stringent criteria (P < 0.001 and SD ≥ 0.25), reflecting ethnic diversity of structural variations between Korean and other populations. Some CNVRs were validated by the quantitative multiplex PCR of short fluorescent fragment (QMPSF) method, and then copy number invariant regions were detected among the study subjects. These copy number invariant regions would be used as good internal controls for further CNV studies. Lastly, we demonstrated that the CNV information could stratify even a single ethnic population with a proper reference genome assembly from multiple heterogeneous populations.

Pathway Analysis Based on a Genome-Wide Association Study of Polycystic Ovary Syndrome.

Background Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in women of reproductive age, and it is affected by both environmental and genetic factors. Although the genetic component of PCOS is evident, studies aiming to identify susceptibility genes have shown controversial results. This study conducted a pathway-based analysis using a dataset obtained through a genome-wide association study (GWAS) to elucidate the biological pathways that contribute to PCOS susceptibility and the associated genes. Methods We used GWAS data on 636,797 autosomal single nucleotide polymorphisms (SNPs) from 1,221 individuals (432 PCOS patients and 789 controls) for analysis. A pathway analysis was conducted using meta-analysis gene-set enrichment of variant associations (MAGENTA). Top-ranking pathways or gene sets associated with PCOS were identified, and significant genes within the pathways were analyzed. Results The pathway analysis of the GWAS dataset identified significant pathways related to oocyte meiosis and the regulation of insulin secretion by acetylcholine and free fatty acids (all nominal gene-set enrichment analysis (GSEA) P-values < 0.05). In addition, INS, GNAQ, STXBP1, PLCB3, PLCB2, SMC3 and PLCZ1 were significant genes observed within the biological pathways (all gene P-values < 0.05). Conclusions By applying MAGENTA pathway analysis to PCOS GWAS data, we identified significant pathways and candidate genes involved in PCOS. Our findings may provide new leads for understanding the mechanisms underlying the development of PCOS.

Adipokines, insulin-like growth factor binding protein-3 levels, and insulin sensitivity in women with polycystic ovary syndrome

Background/Aims Many women with polycystic ovary syndrome (PCOS) exhibit insulin resistance. Adipose tissue plays an important role in insulin resistance, and adipokines including tumor necrosis factor (TNF)-α and adiponectin are altered in PCOS. Insulin-like growth factor binding protein-3 (IGFBP-3), alone or in conjunction with other adipokines, is also associated with insulin resistance. We evaluated the effects of TNF-α, adiponectin, and IGFBP-3 on insulin sensitivity and the relationships among these proteins in women with PCOS. Methods We recruited 40 women with PCOS and 40 age- and body mass index (BMI)-matched regular cycling women (controls). The women were divided into obese (BMI ≥ 25 kg/m2) and nonobese (BMI < 25 kg/m2) groups. Anthropometric measurements were performed, and serum levels of TNF-α, adiponectin, and IGFBP-3 were determined. Insulin sensitivity was estimated using the metabolic clearance rate (MCR) of glucose calculated from the oral glucose tolerance test. Results Serum levels of TNF-α and IGFBP-3 did not differ between the PCOS and control groups, but adiponectin levels in the PCOS group were lower than those in control women in the nonobese group (p < 0.05). TNF-α, adiponectin, and IGFBP-3 levels were not correlated with each other in women with PCOS, but a significant positive correlation was observed between adiponectin levels and MCR (p < 0.05). Multiple regression analysis revealed that adiponectin levels were significantly associated with insulin sensitivity (p < 0.05) in women with PCOS. Conclusions IGFBP-3 and TNF-α levels were not associated with insulin sensitivity, but adiponectin levels were related to insulin sensitivity in women with PCOS.