Associations of body mass index with glycated albumin and glycated albumin/glycated hemoglobin A1c ratio in Chinese diabetic and non-diabetic populations

L-shaped association between the GA/HbA1c ratio and all-cause mortality in U.S. adults with NAFLD: a cross-sectional study from the NHANES 1999-2004

OBJECTIVE

It is currently unclear whether there is a relationship between the ratio of glycated albumin to hemoglobin A1c (GA/HbA1c) and mortality in individuals diagnosed with nonalcoholic fatty liver disease (NAFLD). The primary objective of the study was to investigate the relationship between the GA/HbA1c ratio and all-cause mortality in adults with NAFLD in the U.S.

METHODS

The investigation included a total of 5,295 individuals aged ≥ 18 years who were diagnosed with NAFLD, these individuals were selected from the National Health and Nutrition Examination Survey conducted between 1999 and 2004. To evaluate the outcomes of death, the researchers relied on National Death Index (NDI) records up to December 31, 2019. To better understand the nonlinear relationship between the GA/HbA1c ratio and mortality among individuals with NAFLD, this study employed both subgroup and sensitivity analyses. Furthermore, Cox proportional hazards models and two-part Cox proportional hazards model were utilized.

RESULTS

The study included a total of 5,295 adult patients with NAFLD in the U.S. During a median follow-up period of 16.9 years, there were 1,471 recorded deaths, including 419 cardiovascular deaths. After accounting for various factors, a higher GA/HbA1c ratio exhibited a positive and nonlinear association with an increased risk of all-cause mortality in patients with NAFLD. Furthermore, the study revealed an L-shaped relationship between the GA/HbA1c ratio and all-cause mortality, with the inflection point occurring at a GA/HbA1c ratio of 2.21. When the GA/HbA1c ratio exceeded 2.21, each 1-unit increase in the ratio was associated with a 33% increase in the adjusted hazard ratio (HR 1.33; 95% CI 1.14, 1.60) for all-cause mortality.

CONCLUSIONS

A nonlinear correlation between the ratio of GA to HbA1c and all-cause mortality was observed in U.S. adults with NAFLD. In addition, an elevated GA/HbA1c ratio was linked to an increased risk of all-cause mortality in these patients.

Glycated serum proteins and albumin but not glycated albumin show negative correlation with BMI in an overweight/obese, diabetic population from the United States

BACKGROUND AND AIMS

Multiple previously published studies have shown a weak to medium, negative correlation between BMI and glycated albumin (GA). However, many of these studies were in populations with a narrow range of BMI. It is unknown whether this trend exists if a wider BMI range is used. This is an important question for proper interpretation of GA levels in obese populations.

MATERIALS AND METHODS

A retrospective analysis of clinical trial data (NCT02519309) was performed. After appropriate exclusions, 334 subjects remained. These included 73.7% with type 2 diabetes (T2D) diagnosis and 26.3% with prediabetes. BMI ranged from 24.8-86.9 kg/m2. Laboratory data were measured in a CLIA-certified laboratory using commercially available, automated methods.

RESULTS

No significant, negative correlation was seen between GA and BMI. However, individual components (glycated serum proteins and albumin) as well as the GA/HbA1c ratio show a weak, negative correlation with BMI for all subjects and those with T2D. The strongest negative correlation was with albumin. Examination by traditional BMI subgroups also showed statistically significant differences for those with T2D, but not for the prediabetic cohort. Correlations between BMI and C-reactive protein were similar in those with diabetes and prediabetes; however, correlation between BMI and insulin was stronger in those with diabetes.

CONCLUSION

Negative correlations between BMI and albumin or BMI and glycated serum proteins persist in diabetic populations that are obese and overweight, even when a statistically significant negative correlation is not observed between BMI and GA. Inflammation or insulin-mediated changes in protein synthesis could be contributors to these negative correlations, but BMI-related changes to the glomerulus could also affect clearance of albumin or glycated proteins and should be examined.

Inverse Associations between Measures of Adiposity and Glycated Albumin in US Adults, NHANES 1999-2004

BACKGROUND

Glycated albumin (GA) is a short-term measure of glycemic control. Several studies have demonstrated an inverse association between body mass index (BMI) and GA, which may affect its performance as a biomarker of hyperglycemia. We investigated cross-sectional associations between GA and multiple measures of adiposity, and compared its performance as a glycemic biomarker by obesity status, in a nationally representative sample of US adults.

METHODS

We measured GA in adults from the 1999-2004 National Health and Nutrition Examination Survey. Separately in adults with and without diabetes, we assessed associations of GA with adiposity measures (BMI, waist circumference, trunk fat, total body fat, and fat mass index) in sex-stratified multivariable regression models. We compared sensitivity and specificity of GA to identify elevated hemoglobin A1c (HbA1c), by obesity status.

RESULTS

In covariate-adjusted regression models, all adiposity measures were inversely associated with GA in adults without diabetes (β=-0.48 to -0.22%-point GA per 1 SD adiposity measure; n = 9750) and with diabetes (β=-1.73 to -0.92%-point GA per SD). Comparing adults with vs without obesity, GA exhibited lower sensitivity (43% vs 54%) with equivalent specificity (99%) to detect undiagnosed diabetes (HbA1c ≥ 6.5%). Among adults with diagnosed diabetes (n = 1085), GA performed well to identify above-target glycemia (HbA1c ≥ 7.0%), with high specificity (>80%) overall but lower sensitivity in those with vs without obesity (81% vs 93%).

CONCLUSIONS

Inverse associations between GA and adiposity were present in people with and without diabetes. GA is highly specific but may not be sufficiently sensitive for diabetes screening in adults with obesity.

Fetal glycated albumin levels in offspring of obese women

OBJECTIVE

To determine the association between maternal obesity and fetal glycated albumin (GA) levels among pregnant women.

METHODS

A comparative, cross-sectional study of 59 consenting, normoglycemic, pregnant women, who met the criteria for maternal obesity, attending the antenatal clinic of the University College Hospital, Nigeria, from June 2019 to December 2019. They were recruited at 36 weeks of gestation, followed up until delivery, and compared with 58 nonobese, normoglycemic pregnant controls. At delivery, blood samples were taken from the mothers and from the umbilical cords of their newborns for serum GA assay. Maternal and newborn variables were recorded, and comparisons were made using χ² tests, independent t tests, odds ratios, analysis of variance, and Pearson correlates. Statistical significance was set at P < 0.05.

RESULTS

The odds of elevated newborn GA were 3.21 times higher in obese women compared with nonobese women (P = 0.005) and 5-min APGAR scores were higher in the newborns of nonobese women (P = 0.039). There was a significant correlation between maternal and neonatal GA for all participants (r = 0.346, P = 0.000).

CONCLUSION

These findings suggest that maternal obesity is associated with elevated fetal GA and low APGAR scores at 5 min in normoglycemic women.

GA/HbA1c ratio is a simple and practical indicator to evaluate the risk of metabolic dysfunction-associated fatty liver disease in type 2 diabetes: an observational study

BACKGROUND

It is still debatable whether glycated albumin/glycated hemoglobin A1C (GA/HbA1C) ratio is associated with metabolic dysfunction-associated fatty liver disease (MAFLD), and few studies have been conducted in type 2 diabetes mellitus (T2DM). Therefore, we aimed to investigate the association between GA/HbA1C ratio and MAFLD and to evaluate whether GA/HbA1C ratio can be used an indicator of MAFLD in Chinese patients with T2DM.

METHODS

This cross-sectional study consisted of 7117 T2DM patients including 3296 men and 3821 women from real-world settings. Abdominal ultrasonography was performed to diagnose MAFLD. In addition to comparing the clinical characteristics among the GA/HbA1C ratio quartile groups, we also investigated the associations of GA/HbA1C ratio and quartiles with MAFLD in T2DM subjects.

RESULTS

There was a significantly decreased trend in the MAFLD prevalence across the GA/HbA1C ratio quartiles (56.3%, 47.4%, 37.8%, and 35.6% for the first, second, third, and fourth quartile, respectively, P < 0.001 for trend) after adjusting for gender, age, and diabetes duration. Fully adjusted Binary logistic regression indicated that both GA/HbA1C ratio (OR: 0.575, 95% CI: 0.471 to 0.702, P < 0.001) and quartiles (P < 0.001 for trend) were inversely associated with the presence of MAFLD among T2DM patients. Additionally, HOMA2-IR values were clearly increased in the T2DM subjects with MAFLD compared with those without MAFLD (P < 0.001), and markedly increased from the highest to the lowest GA/HbA1C ratio quartile (P < 0.001 for trend).

CONCLUSIONS

GA/HbA1C ratio is closely and negatively associated with MAFLD in T2DM subjects, which may attribute to that GA/HbA1C ratio reflects the degree of insulin resistance. GA/HbA1C ratio may act as a simple and practical indicator to evaluate the risk of MAFLD in T2DM.

Association of glycated albumin to hemoglobin A1c ratio with all-cause and cardiovascular mortality among US adults: A population-based cohort study

AIMS

To investigate the association of glycated albumin to hemoglobin A1c (GA/HbA1c) ratio, an indicator of blood glucose fluctuations, with all-cause and cardiovascular mortality among US adults.

METHODS

This cohort study used data from the National Health and Nutrition Examination Survey 1999-2004. Participants were linked to National Death Index mortality data through December 31, 2015. Cox proportional hazards model was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs), and restricted cubic spline (RCS) regression was conducted.

RESULTS

A total of 11,508 US adults (weighted mean age, 43.9 years; 5748 males [weighted, 48.9 %]) were included. During a median follow‑up of 13.6 years, 1963 total deaths occurred, including 383 cardiovascular deaths. After multivariable adjustments, a higher GA/HbA1c ratio was associated with a higher risk of all-cause (tertiles: P for trend < 0.001; continuous: HR 1.49 [95 % CI 1.32-1.69]) and cardiovascular (tertiles: P for trend = 0.048; continuous: HR 1.65 [95 % CI 1.27-2.14]) mortality. RCS revealed a linear relationship of GA/HbA1c ratio to mortality.

CONCLUSIONS

In the nationally representative cohort of US adults, GA/HbA1c ratio was significantly associated with the risk of all-cause and cardiovascular mortality. These findings suggest that GA/HbA1c ratio may serve as an effective indicator for identifying high-risk individuals.

Analytical Challenges in Diabetes Management: Towards Glycated Albumin Point-of-Care Detection

Diabetes mellitus is a worldwide-spread chronic metabolic disease that occurs when the pancreas fails to produce enough insulin levels or when the body fails to effectively use the secreted pancreatic insulin, eventually resulting in hyperglycemia. Systematic glycemic control is the only procedure at our disposal to prevent diabetes long-term complications such as cardiovascular disorders, kidney diseases, nephropathy, neuropathy, and retinopathy. Glycated albumin (GA) has recently gained more and more attention as a control biomarker thanks to its shorter lifespan and wider reliability compared to glycated hemoglobin (HbA1c), currently the “gold standard” for diabetes screening and monitoring in clinics. Various techniques such as ion exchange, liquid or affinity-based chromatography and immunoassay can be employed to accurately measure GA levels in serum samples; nevertheless, due to the cost of the lab equipment and complexity of the procedures, these methods are not commonly available at clinical sites and are not suitable to home monitoring. The present review describes the most up-to-date advances in the field of glycemic control biomarkers, exploring in particular the GA with a special focus on the recent experimental analysis techniques, using enzymatic and affinity methods. Finally, analysis steps and fundamental reading technologies are integrated into a processing pipeline, paving the way for future point-of-care testing (POCT). In this view, we highlight how this setup might be employed outside a laboratory environment to reduce the time from measurement to clinical decision, and to provide diabetic patients with a brand-new set of tools for glycemic self-monitoring.

Combining HbA1c and glycated albumin improves detection of dysglycaemia in mixed-ancestry South Africans

BACKGROUND

Combining HbA_1c with glycated albumin (GA) may improve detection of dysglycaemia. As BMI correlates positively with HbA_1c and negatively with GA, HbA_1c may be more effective in obese and GA in nonobese individuals.

METHODS

To relate these findings to Africans, we assessed in 1274 South Africans living in CapeTown (male 26%; age 48±16y; BMI 28.7 kg/m² (range 15.6-73.8); obesity 39.9% and no prior diabetes history) the: (1) correlation of BMI with HbA_1c and GA, (2) ability of HbA_1c and GA separately and jointly, to detect OGTT-diagnosed dysglycaemia (diabetes plus prediabetes). Data collection took place between 2014 and 2016 in the City of Cape Town. Dysglycaemia was diagnosed by glucose criteria for the OGTT. Youden index was used to optimize diagnostic thresholds for HbA_1c and GA.

FINDINGS

Normal glucose tolerance, prediabetes and diabetes occurred in 76%, 17% and 7%, respectively. BMI positively correlated with HbA_1c [r = 0·34 [95%CI: 0·29,0·39)] and negatively with GA [-0·08 (0·13,0·03)]. For HbA_1c the optimal threshold by Youden-index for dysglycaemia diagnosis was: 6·0% (95%CI: 5·8,6·2) and for GA: 13·44% (12·72,14·71). In the nonobese, obese and total cohort, HbA_1c-alone detected: 51% (42-60), 72% (65,78), 63% (57,68), respectively; GA-alone detected 55% (52% (46,63), 52% (44, 59) and 53% (47,53), respectively; whereas: HbA_1c+GA detected: 69% (60,76), 82% (75,87) and 76% (71, 81). Therefore, for the total cohort detection of dysglycaemia HbA_1c-alone vs HbA_1c+GA detected 63% (57,68) vs 76% (71,81).

INTERPRETATION

The opposite correlations of HbA_1c and GA with BMI have now been demonstrated in an African-based population. Improving detection of dysglycaemia by combining HbA_1c and GA has important implications for diabetes risk screening.

FUNDING

AES is supported by the intramural programs of the National Institute of Diabetes and Digestive and Kidney Diseases and the National Institute of Minority Health and Health Disparities of the National Institutes of Health (NIH, Bethesda, Maryland, USA). DBS is supported by the intramural program of the Clinical Center of NIH. The South African Medical Research Council (SAMRC) funded the VMH study with funds from the National Treasury under its Economic Competitiveness and Support Package (MRC-RFA-UFSP-01-2013/VMH Study).

Clinical usefulness of glycated albumin and glycated albumin-to-glycated hemoglobin ratio of gestational diabetes mellitus in late pregnancy for predicting infant complications

BACKGROUND

Gestational diabetes mellitus (GDM) with poorly controlled glycemia is associated with poor pregnancy outcomes. However, adequate markers for glycemic control in GDM have not been fully evaluated.

METHODS

We retrospectively studied 77 patients with GDM and their infants. Mean glycated albumin (GA), glycated hemoglobin (HbA1c), and GA/HbA1c in GDM were compared between two groups stratified by the presence or absence of infant complications (complications or non-complications). We assessed the predictability of infant complications in GA, HbA1c, and GA/HbA1c of women with GDM by receiver operating characteristic analysis (ROC).

RESULTS

In complications and non-complications, GA and GA/HbA1c were significantly associated with neonatal hypoglycemia (13.9% vs. 13.0%, p < 0.001 and 2.49 vs. 2.33, p < 0.001, respectively), respiratory disorders (13.7% vs. 13.2%, p = 0.013 and 2.48 vs. 2.34, p < 0.001, respectively), myocardial hypertrophy (14.5% vs. 13.0%, p < 0.001 and 2.59 vs. 2.33, p < 0.001, respectively), and large for gestational age (14.5% vs. 13.1%, p < 0.001 and 2.58 vs. 2.34, p < 0.001, respectively). Compared with each infant complication in ROC, GA and GA/HbA1c had higher area under the curve than HbA1c. Especially, GA and GA/HbA1c had highest AUC in predicting myocardial hypertrophy and large for gestational age (GA; 0.92 and 0.92, GA/HbA1c; 0.91 and 0.86, respectively). Although statistically significant positive correlations were found between GA and GA/HbA1c and the number of infant complications (GA: r = 0.417, p < 0.001; GA/HbA1c: r = 0.408, p < 0.001), their correlations were weak.

CONCLUSION

Compared with HbA1c, GA and GA/HbA1c of GDM in late pregnancy might be useful for predicting infant complications arising from GDM.

Glycated albumin as biomarker: Evidence and its outcomes

Glycemic control markers are important for the diagnosis and treatment of diabetes. Hemoglobin A1c (A1C) is an important marker that is mandatory in routine medical examinations; however, it is well known that it has some limitations. In this review, we focus on the limitation of A1C and introduce a relatively new marker, glycated albumin (GA), which can be used to complement A1C. First, for a better understanding of the characteristics of each marker, we sort the similarities and differences of glycemic control markers as well as the characteristics of each marker. Second, we point out the limitation of A1C, introduce GA as an alternative indicator, and discuss the limitations of GA. Finally, we summarize important evidence regarding the utility of GA. We hope that this review provides useful information that permits more effective usage of GA as well as other glycemic control markers.

Determinants of Longitudinal Change of Glycated Hemoglobin in a Large Non-Diabetic Population

Although many cross-section studies have assessed the determinants of glycated hemoglobin (HbA_1c), there have been limited studies designed to evaluate the temporal correlates of HbA_1c in non-diabetic patients. This study aimed to identify the major determinants of longitudinal change of HbA_1c in non-diabetic patients. This study included subjects from the 104,451 participants enrolled between 2012 and 2018 in the Taiwan Biobank. We only included participants with complete data at baseline and follow-up (n = 27,209). Patients with diabetes at baseline or follow-up (n = 3983) were excluded. Finally, 23,226 participants without diabetes at baseline and follow-up were selected in this study. △Parameters was defined as the difference between the measurement baseline and follow-up. Multivariable linear regression analysis was used to identify the major determinants of HbA_1c longitudinal change (△HbA_1c). During a mean 3.8 year follow-up, after multivariable analysis, new-onset hypertension (coefficient β: 0.014, p < 0.001), high △heart rate (coefficient β: 0.020, p = 0.002), high △BMI (coefficient β: 0.171, p = 0.028), high △fasting glucose (coefficient β: 0.107, p < 0.001), low △creatinine (coefficient β: −0.042, p < 0.001), high △total cholesterol (coefficient β: 0.040, p < 0.001), high △hemoglobin (coefficient β: 0.062, p < 0.001), high △GPT (coefficient β: 0.041, p = 0.001), and low △albumin (coefficient β: −0.070, p < 0.001) were significantly associated with high △HbA_1c. In non-diabetic population, strategies to decrease the development of new-onset hypertension, resting heart rate, body mass index, fasting glucose, total cholesterol, and GPT and increase serum albumin level might be helpful in slowing the longitudinal change of HbA_1c. In addition, increased hemoglobin and decreased serum creatinine over time also had an impact on the HbA_1c elevation over time in non-diabetic population.

Factors associated with glycated albumin in adults without diabetes

Background and aims

Glycated albumin is a glycemic marker useful in short-term monitoring and in situations when a glycated hemoglobin test is not reliable. This study aims to evaluate glycated albumin levels and its associated factors in normoglycemic adults from Southern Brazil.

Method

136 individuals, without diabetes or pre-diabetes, were included in this cross-sectional study. Levels of glycated albumin, glycated hemoglobin, and other biochemical markers were measured.

Results

Glycated albumin levels ranged from 11.1% to 17.5% (2.5^th and 97.5^th percentiles). Glycated albumin/glycated hemoglobin ratio was 2.8±0.2. Glycated albumin did not differ according to gender and age groups. However, in overweight individuals, levels of glycated albumin and glycated albumin/glycated hemoglobin ratio were lower and weakly and negatively correlated with body mass index.

Conclusions

Glycated albumin levels in Brazilians were similar to those previously described in other populations. Glycated albumin seems to be irrespective of gender or age, but weakly correlated with weight. These aspects should be taken into account in the interpretation of glycated albumin results.

Predictive Performance of Glycated Hemoglobin for Incident Diabetes Compared with Glucose Tolerance Test According to Central Obesity

BACKGROUND

To examine whether glycated hemoglobin (HbA1c) test would be a suitable screening tool for detecting high-risk subjects for diabetes compared to oral glucose tolerance test (OGTT) according to accompanied central obesity.

METHODS

In this prospective population-based cohort study, both OGTT and HbA1c tests were performed and continued every 2 years up to 12 years among individuals with non-diabetic state at baseline (aged 40 to 69 years, n=7,512). Incident diabetes was established by a doctor, HbA1c ≥6.5%, and/or fasting plasma glucose (FPG) ≥126 mg/dL, and/or 2-hour postprandial glucose (2hPG) level based on OGTT ≥200 mg/dL. Discriminative capacities of high HbA1c (≥5.7%) versus high 2hPG (≥140 mg/dL) for predicting incident diabetes were compared using Cox-proportional hazard regression and C-index.

RESULTS

During the median 11.5 years of follow-up period, 1,341 (17.6%) developed diabetes corresponding to an incidence of 22.1 per 1,000 person-years. Isolated high 2hPG was associated with higher risk for incident diabetes (hazard ratio [HR], 4.29; 95% confidence interval [CI], 3.56 to 5.17) than isolated high HbA1c (HR, 2.79; 95% CI, 2.40 to 3.26; P<0.05). In addition, high 2hPG provided better discriminatory capacity than high HbA1c (C-index 0.79 vs. 0.75, P<0.05). Meanwhile, in subjects with central obesity, the HR (3.95 [95% CI, 3.01 to 5.18] vs. 2.82 [95% CI, 2.30 to 3.46]) and discriminatory capacity of incident diabetes (C-index 0.75 vs. 0.75) between two subgroups became comparable.

CONCLUSION

Even though the overall inferior predictive capacity of HbA1c test than OGTT, HbA1c test might plays a complementary role in identifying high risk for diabetes especially in subjects with central obesity with increased sensitivity.

Recent Updates and Advances in the Use of Glycated Albumin for the Diagnosis and Monitoring of Diabetes and Renal, Cerebro- and Cardio-Metabolic Diseases

Diabetes mellitus is a heterogeneous and dysmetabolic chronic disease in which the laboratory plays a fundamental role, from diagnosis to monitoring therapy and studying complications. Early diagnosis and good glycemic control should start as early as possible to delay and prevent metabolic and cardio-vascular complications secondary to this disease. Glycated hemoglobin is currently used as the reference parameter. The accuracy of the glycated hemoglobin dosage may be compromised in subjects suffering from chronic renal failure and terminal nephropathy, affected by the reduction in the survival of erythrocytes, with consequent decrease in the time available for glucose to attach to the hemoglobin. In the presence of these renal comorbidities as well as hemoglobinopathies and pregnancy, glycated hemoglobin is not reliable. In such conditions, dosage of glycated albumin can help. Glycated albumin is not only useful for short-term diagnosis and monitoring but predicts the risk of diabetes, even in the presence of euglycemia. This protein is modified in subjects who do not yet have a glycemic alteration but, as a predictive factor, heralds the risk of diabetic disease. This review summarizes the importance of glycated albumin as a biomarker for predicting and stratifying the cardiovascular risk linked to multiorgan metabolic alterations.

Improved Detection of Abnormal Glucose Tolerance in Africans: The Value of Combining Hemoglobin A1c With Glycated Albumin

OBJECTIVE

In African-born Blacks living in America, we determined by BMI category 1) prevalence of abnormal glucose tolerance (Abnl-GT) and 2) diagnostic value and reproducibility of hemoglobin A_1c (HbA_1c), fructosamine, and glycated albumin (GA).

RESEARCH DESIGN AND METHODS

Participants (n = 416; male, 66%; BMI 27.7 ± 4.5 kg/m² [mean ± SD]) had an oral glucose tolerance test with HbA_1c, GA, and fructosamine assayed. These glycemic markers were repeated 11 ± 7 days later. Abnl-GT diagnosis required 0 h ≥5.6 mmol/L (≥100 mg/dL) and/or 2 h ≥7.8 mmol/L (≥140 mg/dL). Thresholds for HbA_1c, GA, and fructosamine were the values at the 75th percentile for the population (39 mmol/mol [5.7%], 14.2%, and 234 μmol/L, respectively).

RESULTS

Abnl-GT prevalence in the nonobese was 34% versus 42% in the obese (P = 0.124). Reproducibility was excellent for HbA_1c and GA (both κ ≥ 0.8), but moderate for fructosamine (κ = 0.6). Focusing on HbA_1c and GA in the nonobese, we found as single tests the sensitivities of HbA_1c and GA were 36% versus 37% (P = 0.529). Combining HbA_1c and GA, sensitivity increased to 58% because GA identified 37% of Africans with Abnl-GT not detected by HbA_1c (P value for both tests vs. HbA_1c alone was <0.001). For the obese, sensitivities for HbA_1c, GA, and the combined tests were 60%, 27%, and 67%, respectively. Combined test sensitivity did not differ from HbA_1c alone (P = 0.25) because GA detected only 10% of obese Africans with Abnl-GT not detected by HbA_1c.

CONCLUSIONS

Adding GA to HbA_1c improves detection of Abnl-GT in nonobese Africans.

Age - a significant independent factor of A1C levels. Evidence from the National Health and Nutrition Examination Survey 1999-2014

AIM

The aim of our study is to examine the association between age and A1C levels in nondiabetic subjects and develop the age-adjusted A1C levels for screening and diagnosis of prediabetes and diabetes.

METHODS

Participants from National Health and Nutrition Examination Survey (NHANES) -1999-2014 with age over 12 years were examined. Individuals with previous diagnosed diabetes, baseline anemia, established hemoglobinopathies, known liver or chronic kidney disease, and abnormal liver function tests or creatinine levels were excluded. Total 16949 subjects consisting of 8651 female subjects and 8298 male subjects were included in the analyses. Linear regression and multivariate regression analyses were performed to assess the relationship between A1C levels and age. Age adjusted A1C levels were determined.

RESULTS

Significant positive correlation between A1C and age was found in both female and male subjects in the fasting plasma glucose (FPG) interval between 4.4-7mmol/L (80-126mg/dL) (P<0.0001). There was a linear correlation between A1C levels and age. Linear regression analysis suggested A1C levels rose by 0.009% (about 0.09mmol/mol) in female and by 0.008% (about 0.08mmol/mol) in male per year in subjects without abnormality in glucose homeostasis (p<0.0001).

CONCLUSIONS

Our study concluded that age is a significant independent factor of A1C levels.

Review of methods for detecting glycemic disorders

Prediabetes (intermediate hyperglycemia) consists of two abnormalities, impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) detected by a standardized 75-gram oral glucose tolerance test (OGTT). Individuals with isolated IGT or combined IFG and IGT have increased risk for developing type 2 diabetes (T2D) and cardiovascular disease (CVD). Diagnosing prediabetes early and accurately is critical in order to refer high-risk individuals for intensive lifestyle modification. However, there is currently no international consensus for diagnosing prediabetes with HbA1c or glucose measurements based upon American Diabetes Association (ADA) and the World Health Organization (WHO) criteria that identify different populations at risk for progressing to diabetes. Various caveats affecting the accuracy of interpreting the HbA1c including genetics complicate this further. This review describes established methods for detecting glucose disorders based upon glucose and HbA1c parameters as well as novel approaches including the 1-hour plasma glucose (1-h PG), glucose challenge test (GCT), shape of the glucose curve, genetics, continuous glucose monitoring (CGM), measures of insulin secretion and sensitivity, metabolomics, and ancillary tools such as fructosamine, glycated albumin (GA), 1,5- anhydroglucitol (1,5-AG). Of the approaches considered, the 1-h PG has considerable potential as a biomarker for detecting glucose disorders if confirmed by additional data including health economic analysis. Whether the 1-h OGTT is superior to genetics and omics in providing greater precision for individualized treatment requires further investigation. These methods will need to demonstrate substantially superiority to simpler tools for detecting glucose disorders to justify their cost and complexity.

Influence of Sex Hormones on the Relationship Between Body Fat and Glycated Albumin Levels

BACKGROUND

Previous studies have reported that glycated albumin (GA) is affected by body fat distribution. Sex hormones are reported to play an important role in fat metabolism.

AIM

This study aimed to explore the influence of sex hormones on the relationship between body fat and GA in a community population.

METHODS

We recruited 763 middle-aged and elderly subjects with normal glucose tolerance from communities. GA was determined using the enzyme method, and serum estradiol (E₂), total testosterone, and sex hormone-binding globulin (SHBG) were detected using chemiluminescent microparticle immunoassays.

OUTCOME

There was a statistically significant association between SHBG and GA remained after adjusting for body fat in both men and women.

RESULTS

The average serum GA levels were 13.40 ± 1.10% in the 298 men and 465 postmenopausal women included in this study. GA presented a significant downward trend with increasing quartiles of total fat mass (FM), limb FM, and trunk FM in both men and women (all P for trend < .01). In men, total testosterone, free testosterone, and SHBG were positively correlated with GA (both P < .01), and the correlation between SHBG and GA remained after adjusting for body fat (P < .01). In women, E2, free testosterone, bioactive testosterone, and SHBG were correlated with GA (all P < .01); furthermore, the positive correlation between SHBG and GA and the inverse correlation between E2 and GA remained after adjusting for body fat (both P < .05). Multivariate linear regression analyses showed that in addition to trunk FM, SHBG was positively correlated with GA in both men and women (standardized β = 0.136, P = .035; standardized β = 0.101, P = .033); however, E2 was not independently correlated with GA in women.

CLINICAL IMPLICATIONS

SHBG may contribute to the influence of body fat, especially trunk fat on GA levels.

STRENGTHS & IMPLICATIONS

This study used an automated bioelectrical impedance analyzer to measure segmental body composition including limb FM and trunk FM and further investigated the role of segmental body fat in the correlation between SHBG and GA. Sex hormones may explain in part why body fat content and distribution can alter GA levels.

CONCLUSION

SHBG is positively correlated with serum GA levels, and this correlation is independent of total or segmental body fat. Xu Y, Ma X, Shen Y, et al. Influence of Sex Hormones on the Relationship Between Body Fat and Glycated Albumin Levels. J Sex Med 2020;17:903-910.

Associations Between Thyroid Hormones and Glycated Albumin in Euthyroid and Subclinical Hypothyroid Individuals: Results of an Observational Study

PURPOSE

Although overt thyroid dysfunction has been found to influence the level of glycated albumin (GA), the associations between thyroid hormones and GA in individuals with euthyroidism and subclinical hypothyroidism (SHypo) are still unknown. The present study aimed to investigate whether thyroid hormones were related to GA in euthyroid and SHypo individuals.

METHODS

We recruited 685 euthyroid and 103 SHypo subjects with normal weight from communities in Shanghai. Electrochemiluminescence immunoassay was used to detect the serum levels of free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone. GA was detected by the enzymatic method. Glycated hemoglobin (HbA_1c) was detected by high-performance liquid chromatography.

RESULTS

Among the 788 subjects (age range 31-81 years old), 307 were men and 481 were women. In the Spearman correlation analysis and multiple stepwise regression analysis, FT3 was negatively correlated with both GA and GA/HbA_1c in euthyroid subjects (all P < 0.05). The values of GA and GA/HbA_1c were reduced by approximately 0.30 and 0.05, respectively, for each 0.50 pmol/L increment in FT3. In SHypo subjects, FT4 was negatively associated with both GA and GA/HbA_1c (all P < 0.05). The values of GA and GA/HbA_1c were reduced by approximately 0.23 and 0.03, respectively, for each 1.00 pmol/L increment in FT4.

CONCLUSION

In euthyroid and SHypo subjects, more attention should be paid to the potential effects of individual differences in thyroid hormones on GA.

Increasing waist circumference is associated with decreased levels of glycated albumin

BACKGROUND

Glycated albumin (GA) levels are affected by body fat and its distribution. We explored the association of waist circumference (WC) with GA and to assess the extent to which WC influences GA.

METHODS

We recruited 1799 subjects (age 26-82 y) from communities. GA was determined using the enzyme method, and glycated hemoglobin A_1c (HbA_1c) was detected using high-performance liquid chromatography.

RESULTS

Subjects with central obesity had lower GA and GA/HbA_1c than those without (both P < .01). GA and GA/HbA_1c were negatively correlated with central obesity (both P < .01), whereas HbA_1c was not correlated (P = .833). In the euglycemic and hyperglycemic subpopulations, GA and GA/HbA_1c showed decreasing trends as WC levels increased (both P for trends <0.01). WC was a significant negative determinant of GA (P < .05). In the hyperglycemic subpopulation, the GA value decreased by approximately 0.15% for each 5 cm increment in WC regardless of the presence of central obesity.

CONCLUSIONS

The GA value was reduced by approximately 0.15% for each 5 cm increment in WC, suggesting that more attention should be paid to actual blood glucose underestimated by GA in obese people.