Age and sex effects on HbA1c. A study in a healthy Chinese population

Age and Gender Impact on Heart Rate Variability towards Noninvasive Glucose Measurement

Heart rate variability (HRV) parameters can reveal the performance of the autonomic nervous system and possibly estimate the type of its malfunction, such as that of detecting the blood glucose level. Therefore, we aim to find the impact of other factors on the proper calculation of HRV. In this paper, we research the relation between HRV and the age and gender of the patient to adjust the threshold correspondingly to the noninvasive glucose estimator that we are developing and improve its performance. While most of the literature research so far addresses healthy patients and only short- or long-term HRV, we apply a more holistic approach by including both healthy patients and patients with arrhythmia and different lengths of HRV measurements (short, middle, and long). The methods necessary to determine the correlation are (i) point biserial correlation, (ii) Pearson correlation, and (iii) Spearman rank correlation. We developed a mathematical model of a linear or monotonic dependence function and a machine learning and deep learning model, building a classification detector and level estimator. We used electrocardiogram (ECG) data from 4 different datasets consisting of 284 subjects. Age and gender influence HRV with a moderate correlation value of 0.58. This work elucidates the intricate interplay between individual input and output parameters compared with previous efforts, where correlations were found between HRV and blood glucose levels using deep learning techniques. It can successfully detect the influence of each input.

Validation of the traditional Chinese version of the diabetes eating problem survey-revised and study of the prevalence of disordered eating patterns in Chinese patients with type 1 DM

BACKGROUND

Disordered eating behaviours (DEBs) in patients with type 1 diabetes mellitus (T1DM) are associated with an increased risk of complications and mortality. The Diabetes Eating Problem Survey-Revised (DEPS-R) was developed to screen for DEBs in T1DM patients. The objectives of this study were to develop a traditional Chinese version DEPS-R (electronic version) and to measure the prevalence of DEBs in a local population sample.

METHODS

The DEPS-R was translated into traditional Chinese, modified and developed into an electronic version. The psychometric properties of the C-DEPS-R were tested on T1DM patients from 15 to 64 years old. The factor structure of the traditional C-DEPS-R was examined by confirmatory factor analysis (CFA). The C-EDE-Q and the C-DES-20 were used for convergent and divergent validity testing, respectively. Module H of the CB-SCID-I/P was used as a diagnostic tool for eating disorders. A correlation study was conducted with the C-DEPS-R scores obtained and the clinical characteristics. Type 2 diabetic (T2DM) patients on insulin treatment were recruited as controls.

RESULTS

In total, 228 T1DM patients and 58 T2DM patients were recruited. There was good internal consistency of the traditional C-DEPS-R (electronic version), with the McDonald's omega of 0.825 and test-retest reliability of 0.991. A three-factor model of the traditional C-DEPS-R was confirmed by CFA. The cut-off score for the traditional C-DEPS-R was determined to be 24; 13.2% (95% CI 8.8%-17.5%) of T1DM patients were found to score above the cut-off score, while 7.5% (95% CI 4-10.9%) scored above the cut-off by the C-EDE-Q, and 4.4% (95% CI 2.1%-7.9%) were diagnosed with eating disorders by the CB-SCID-I/P Module H. Females with T1DM scored higher on the traditional C-DEPS-R. There was a significant correlation of the C-DEPS-R with BMI, occurrence of DKA, use of a continuous glucose monitoring system and positive diagnosis by the CB-SCID-I/P module H (p < 0.05).

CONCLUSION

The traditional Chinese-DEPS-R (electronic version) demonstrated good psychometric properties. It is a self-rated, time-efficient and reliable tool for the screening of disordered eating behaviours in T1DM patients in the Chinese population of Hong Kong. Disordered eating behaviours, such as insulin omission, are associated with an increased risk of diabetes mellitus-related complications and mortality. Generic screening tools for eating disorders may over- or underestimate such problems in diabetic patients. Type 1 diabetes mellitus patients are at particular risk of developing disordered eating behaviours or eating disorders, yet studies in Chinese populations are limited. This study developed and validated the traditional Chinese (electronic) version of the Diabetes Eating Problem Survey-Revised (DEPS-R). The traditional Chinese-DEPS-R is a self-rated, time-efficient and reliable tool for the screening of disordered eating behaviours in Type 1 diabetes mellitus patients in the Chinese population of Hong Kong. The study also estimated the prevalence of disordered eating behaviours in diabetic patients from the local Chinese population, and the clinical correlations of the symptoms and clinical parameters were explored. The study reflected a higher prevalence of eating problems in the Type 1 diabetes mellitus population and demonstrated significant correlations of eating problems with BMI as well as the occurrence of diabetic ketoacidosis. Correspondence: lcw891@ha.org.hk.

Biomarkers of aging

Aging biomarkers are a combination of biological parameters to (i) assess age-related changes, (ii) track the physiological aging process, and (iii) predict the transition into a pathological status. Although a broad spectrum of aging biomarkers has been developed, their potential uses and limitations remain poorly characterized. An immediate goal of biomarkers is to help us answer the following three fundamental questions in aging research: How old are we? Why do we get old? And how can we age slower? This review aims to address this need. Here, we summarize our current knowledge of biomarkers developed for cellular, organ, and organismal levels of aging, comprising six pillars: physiological characteristics, medical imaging, histological features, cellular alterations, molecular changes, and secretory factors. To fulfill all these requisites, we propose that aging biomarkers should qualify for being specific, systemic, and clinically relevant.

An atlas of robust microbiome associations with phenotypic traits based on large-scale cohorts from two continents

Numerous human conditions are associated with the microbiome, yet studies are inconsistent as to the magnitude of the associations and the bacteria involved, likely reflecting insufficiently employed sample sizes. Here, we collected diverse phenotypes and gut microbiota from 34,057 individuals from Israel and the U.S.. Analyzing these data using a much-expanded microbial genomes set, we derive an atlas of robust and numerous unreported associations between bacteria and physiological human traits, which we show to replicate in cohorts from both continents. Using machine learning models trained on microbiome data, we show prediction accuracy of human traits across two continents. Subsampling our cohort to smaller cohort sizes yielded highly variable models and thus sensitivity to the selected cohort, underscoring the utility of large cohorts and possibly explaining the source of discrepancies across studies. Finally, many of our prediction models saturate at these numbers of individuals, suggesting that similar analyses on larger cohorts may not further improve these predictions.

Naturally Occurring Endocrine Disorders in Non-Human Primates: A Comprehensive Review

Simple Summary

Nonhuman primates (NHP) can become ill due to a variety of diseases and disorders, yet endocrine disorders remain underreported. Therefore, an exhaustive literature search on this subject via widely used academic search systems, peer-reviewed publications, proceedings, and newsletters was performed. Selected major endocrine entities will be described emphasizing clinical signs, morphologic features, concomitant diseases, as well as available treatment options. In most cases, no clinical signs were noted and on gross pathology, the endocrine organs were unremarkable. The diagnosis was frequently made as incidental findings after standard histological examination. Although the findings were frequently incidental many have the potential to impact studies. This review explains that there is no standard procedure for diagnosing, monitoring, or treating endocrine disorders in NHP. More research is needed to evaluate these procedures and establish risk factors.

Abstract

Literature concerning veterinary medicine of non-human primates is continuously updated, yet endocrine disorders remain underreported. While case or survey reports of individual endocrinopathies are available, a comprehensive review is not. An exhaustive literature search on this subject via widely used academic search systems, (e.g., Google Scholar, PubMed, BioOne complete and Web of Science), and peer-reviewed publications, proceedings, and newsletters was performed. Selected major endocrine entities will be described with emphasis on clinical signs, morphologic appearances, concomitant diseases, as well as available treatment options. Mostly, no clinical signs were noted and on gross pathology, the endocrine organs were unremarkable. An endocrine-related diagnosis was frequently made as an incidental finding after standard histopathological examination. During the review, the pancreas represented the most affected endocrine organ and diabetes mellitus represented the most clinically significant disorder. Currently, no standard procedure for diagnosing, monitoring, or treating endocrine disorders in non-human primates exists.

Variations in glycated haemoglobin with age among individuals with normal glucose tolerance: Implications for diagnosis and treatment-Results from the ICMR-INDIAB population-based study (INDIAB-12)

AIM

To report on glycated haemoglobin (HbA1c) values among individuals with normal glucose tolerance (NGT) at different age groups, using data acquired from a large national survey in India.

MATERIALS AND METHODS

Data on glycaemic parameters at different age groups were obtained from the Indian Council of Medical Research-INdia DIABetes (ICMR-INDIAB) study, in adults aged ≥ 20 years representing all parts of India. Age-wise distribution of HbA1c was assessed among individuals with NGT (n = 14,222) confirmed by an oral glucose tolerance test using the World Health Organization (WHO) criteria. Results were validated in another large epidemiological study (n = 1077) conducted in Chennai, India.

RESULTS

Among NGT individuals, HbA1c increased gradually with age from 5.16 ± 0.71% (33 mmol/mol) in the age group of 20-29 years to 5.49 ± 0.69% (37 mmol/mol) in those aged 70 + years. In the validation study, conducted in another study population, HbA1c was 5.35 ± 0.43% (35 mmol/mol) in age group of 20-29 years and 5.74 ± 0.50% (39 mmol/mol) in those aged 70 and above. In the INDIAB study, for every decadal increase in age, there is a 0.08% increase in HbA1c and this increase was more significant in females (females: 0.10% vs. males: 0.06%) and in urban (urban: 0.10% vs. rural: 0.08%) population.

CONCLUSIONS

HbA1c levels increase steadily with age. This suggests that age-specific cutoffs be used while utilizing HbA1c to diagnose diabetes and prediabetes, so as to minimize the risk of overdiagnosis and unnecessary initiation of treatment in elderly people who could have physiological increase in HbA1c levels.

The effect of age and sex on glycated hemoglobin in dogs

We investigated the effect of age and sex on canine glycated hemoglobin (HbA1c) using a validated capillary electrophoresis assay. Aliquots of EDTA blood samples collected for routine health checks were used. HbA1c was measured using the Capillarys 2 flex-piercing system (Sebia). We included 58 clinically and hematologically healthy, normoglycemic dogs (29 males, 29 females), allocated to 3 age groups: young (14 dogs <1-y-old), adult (31 dogs 1-7.9-y-old), and senior (13 dogs ≥8-y-old). The mean (± SD) HbA1c was not significantly different (p = 0.428) between the age groups (young: 1.68 ± 0.54%; adult: 1.59 ± 0.41%; senior: 1.80 ± 0.57%). The HbA1c was not significantly correlated with age (rho = 0.144, p = 0.280). The median (range) HbA1c was not significantly different (p = 0.391) between male [1.7% (0.5-2.5%)] and female [1.5% (1.0-2.7%)] dogs. Age and sex do not appear to affect canine HbA1c; however, a study of geriatric dogs would be needed to fully exclude an effect of age on HbA1c.

Cardiometabolic risk, biological sex, and age do not share an interactive relationship with cognitive function: A cross-sectional analysis of the Canadian Longitudinal Study on Aging

It is unclear whether cardiometabolic risk shares an interactive relationship with age-associated differences in cognition, and whether this relationship varies by biological sex. We conducted a cross-sectional analyses using baseline data from the Canadian Longitudinal Study on Aging (2010-2015) to examine whether: 1) cardiometabolic risk has an interactive relationship with age-associated cognition; and 2) interactive effects are sex-dependent. We measured memory, executive function, and verbal fluency in the Comprehensive cohort (n=25,830; 45-86 years). Each cognitive domain was modeled using restricted cubic splines for age and each cardiometabolic risk factor (HbA1c, HSCRP, TG, and LDL and HDL cholesterol). Sex was included as a predictor in all models. Wald chi-square statistics were used to determine the relative importance of age, cardiometabolic risk, sex, and their interactive effects on cognition. Age was the most important variable in each model (proportion χ2=34-48%). Biological sex was the second most important variable for memory (proportion χ2=26%), but was unimportant for executive function and verbal fluency (proportion χ2=3-5%). Cardiometabolic risk factors were unimportant predictors in each model (proportion χ2=1-3%). Two and three-way interactions between cardiometabolic risk, age, and sex were also unimportant (proportion χ2=0-2%). Thus, cardiometabolic risk factors did not meaningfully account for age-associated differences in cognition, and these associations (or lack thereof) did not vary by sex. Novelty: Males have poorer age-associated cognitive performance than females Females and males differ in cardiometabolic risk across middle and older adulthood Cardiometabolic risk has a small association with age-associated cognition, and there are no sex differences in this relationship.

Retrospective Evaluation of a Minor Dietary Change in Non-Diabetic Group-Housed Long-Tailed Macaques (Macaca fascicularis)

Macaques in captivity are prone to becoming overweight and obese, which may cause several health problems. A diet that mimics the natural diet of macaques may prevent these problems and improve animal welfare. Adjusting captive diets towards a more natural composition may include increasing fiber content and lowering the glycemic index, i.e., reducing the impact on blood glucose levels. Such a dietary change was implemented in our long-tailed macaque (Macaca fascicularis) breeding colony. The basic diet of monkey chow pellets remained the same, while the supplementary provisioning of bread was replaced by grains and vegetables. This study is a retrospective evaluation, based on electronic health records, that investigated whether this minor dietary change had a beneficial effect on relative adiposity and overweight-related health parameters in 44 non-diabetic, group-housed, female long-tailed macaques. Relative adiposity was measured with a weight-for-height index and blood samples were collected during yearly health checks. Glycemic response and lipid metabolism were evaluated using several biochemical parameters. Relative adiposity and overweight status did not differ after dietary change. Yet, relatively heavy individuals generally lost body weight, while relatively lean individuals gained body weight, leading to a more balanced body weight dynamic. Dietary change did not affect HbA1c and triglyceride levels, while fructosamine and cholesterol levels were significantly reduced. Thus, the minor dietary change had no significant effect on overweight status, but some biochemical parameters related to the risk of diabetes and cardiovascular disease were positively affected. This study emphasizes the importance of evaluating husbandry changes and that critically reviewing husbandry practices can provide valuable insights to improve animal health and welfare.

Fine particulate matter and body weight status among older adults in China: Impacts and pathways

BACKGROUND

Population ageing and air pollution have become two major public health concerns in China. Longitudinal evidence on the body weight impacts of air pollution among older adults is rare. This study aims to investigate the impacts of ambient particulate matter with aerodynamic diameters ≤2.5 μm (PM_2.5) on weight status of older adults in China and the potential behavioral and metabolic pathways through which PM_2.5 influences weight status.

METHODS

The longitudinal data from the China Health and Retirement Longitudinal Study (body mass index-BMI, n = 9053; waist/height ratio-WHR, n = 9064) were linked to the air pollution data at the city-level with a rural-urban distinction. We used mixed-effects linear models to evaluate the impacts of PM_2.5 on individual weight status and multiple mediation analysis to examine potential pathways.

RESULTS

After adjusting for relevant socioeconomic and city-level risk factors, significant and robust positive impacts of PM_2.5 on BMI (0.025, 95%CI: 0.018, 0.031) and WHR*100 (0.058, 95%CI: 0.044, 0.072) were found among older adults in China. The PM_2.5-weight status relationship among older adults may be mediated through metabolic and inflammatory dysfunction pathways particularly HbA1c and C-reactive protein (CRP). As PM_2.5 deteriorates, the detrimental impacts tend to be more severe for rural-urban migrants and rural residents, compared to their urban counterparts. The worsening rural PM_2.5 profiles in some areas, such as the northern parts of the Central and the Eastern, may leave them particularly vulnerable to air pollution.

CONCLUSIONS

PM_2.5 has an independent and significant detrimental impact on weight status including BMI and WHR of older adults in China, especially among rural adults and rural-urban migrants. PM_2.5 may affect weight status of older adults through biomarkers such as HbA1c and CRP. More research is needed to confirm our findings.

Hemoglobin A1c Levels Associated with Age and Gender in Taiwanese Adults without Prior Diagnosis with Diabetes

Several studies have reported that Hemoglobin A1c (HbA1c) levels increase with age for people without diabetes. However, HbA1c levels associated with age and gender have not been well investigated for Taiwanese adults. The objective of this study was to investigate the sex-specific association between HbA1c levels and age for Taiwanese adults without diabetes. The data were collected from the Taiwan Biobank database with inclusive criteria being participants without diabetes. The association between HbA1c values and age was conducted by linear regression analysis, HbA1c values between sexes were compared by two-sample t-test, and HbA1c levels among age groups were compared using one-way ANOVA. The results showed that HbA1c levels were positively correlated with age, and the levels for males were significantly higher than for females among all participants. However, there was no significantly positive correlation between HbA1c levels and age in males for age group of 50–70 years. The levels of males were significantly higher than females for age groups of 30–39 and 40–49 years. There were significant differences in HbA1c levels among age groups for all participants, males, and females except for the two age groups of 50–59 and 60–70 years in males. Age and gender were important factors affecting HbA1c levels. Our results suggested that the HbA1c cut-point levels for the diagnosis of diabetes should vary by age and gender.

A Cross-Sectional Study on Ultrasonographic Measurements of Parotid Glands in Type 2 Diabetes Mellitus

Background

Diabetes mellitus is a metabolic disease which is seen increasing globally and is diagnosed and monitored on basis of invasive blood investigations. Salivary glands are affected in diabetes mellitus. The objective of this study was to assess ultrasonographic measurements of parotid glands and correlate with the glycosylated hemoglobin levels in type 2 diabetic mellitus and duration of type 2 diabetic mellitus and treatment regimens.

Materials and Methods

This study was conducted on 50 subjects of type 2 diabetes mellitus and on 50 healthy controls. After HbA_1C analysis of selected individuals, 100 individuals were grouped into group I (above 5.7) and group II (below 5.7). Ultrasonographic measurements (length (L), transverse dimension (TD), depth lateral to the mandible (DLM), and depth dorsal to the mandible (DDM)) of bilateral parotid glands were calculated. Statistical analysis was done using the chi-square test of significance and Spearman correlation coefficients.

Results

On correlation with measurement of right (L, DLM, DDM) and left (TD, DLM, DDM) of parotid glands with duration of type 2 diabetes mellitus, we found a moderate positive relationship, whereas as for right (TD) and left (L), we found a low-positive relationship. Similarly, for right (L, TD, DLM, DDM) and left (TD, DDM) parotid glands with HbA_1C, we found a low-positive relationship, whereas for left parotid gland (L, DLM) with HbA_1C, we found a moderate positive relationship. The mean DLM of right and left parotids in the insulin group was found to be slightly more than that in the combined group which was statistically insignificant.

Conclusion

Ultrasonographic measurements of parotid glands were found to be higher in study subjects as compared to control subjects, and they increased with increased HbA_1C levels; also, there was no difference in treatment regimen. Ultrasonography could be a prospective diagnostic test for detection and monitoring of diabetes mellitus, and still further studies are required for this.

The Influence of Gender and Menopausal Status on Hba1c Variation in a Big Data Study of a Saudi Population

BACKGROUND

Glycated haemoglobin (HbA1c) is the gold standard measurement in the screening, diagnosis and monitoring of diabetes mellitus. Saudi Arabia has a high prevalence of diabetes mellitus that is expected to rise, and the HbA1c test is commonly used in the screening, diagnosis and monitoring of diabetes.

OBJECTIVE

This study aims to assess the impact of age and gender on HbA1c levels, and the influence of menopausal status on HbA1c variation in a large group of Saudis.

METHODS

Age, gender, and HbA1c results of 168,614 Saudi adult individuals were obtained from their medical records. Patients' records were extracted irrespective of their status regarding the presence of diabetes and the status of glycaemic control. Linear regression models were used for predicting HbA1c from age and gender, and their interaction term. HbA1c levels were compared between genders in different age groups and different HbA1c categories.

RESULTS

There was a statistically significant positive correlation between age and HbA1c levels, where for each ten years increase in age, HbA1c increased by 0.35%. Although the overall mean HbA1c in women was significantly lower than in men (P < 0.001), women showed a significant increase in HbA1c with older age compared to men (B = 0.014, P < 0.001). Furthermore, the mean HbA1c levels in the age group > 50 years was significantly higher than before that age (P < 0.001). Thus, HbA1c increased by 1.118% in age > 50 years group compared to age ≤ 50 years, and this increase in HbA1c was significantly higher in women compared to men (B = 0.495, P < 0.001).

CONCLUSION

HbA1c levels are lower in women before the estimated menopausal age, which should be taken into consideration when using HbA1c for screening, diagnosis, and monitoring of diabetes in Saudi adult women. The short lifespan of red blood cells, due to loss of blood through menstruation, in women before menopause age, is a possible reason for these variations.

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.

Phenotypic and lifestyle determinants of HbA1c in the general population-The Hoorn Study

Aim

To investigate the relative contribution of phenotypic and lifestyle factors to HbA_1c, independent of fasting plasma glucose (FPG) and 2h post-load glucose (2hPG), in the general population.

Methods

The study populations included 2309 participants without known diabetes from the first wave of the Hoorn Study (1989) and 2619 from the second wave (2006). Multivariate linear regression models were used to analyze the relationship between potential determinants and HbA_1c in addition to FPG and 2hPG. The multivariate model was derived in the first wave of the Hoorn Study, and replicated in the second wave.

Results

In both cohorts, independent of FPG and 2hPG, higher age, female sex, larger waist circumference, and smoking were associated with a higher HbA_1c level. Larger hip circumference, higher BMI, higher alcohol consumption and vitamin C intake were associated with a lower HbA_1c level. FPG and 2hPG together explained 41.0% (first wave) and 53.0% (second wave) of the total variance in HbA_1c. The combination of phenotypic and lifestyle determinants additionally explained 5.7% (first wave) and 3.9% (second wave).

Conclusions

This study suggests that, independent of glucose, phenotypic and lifestyle factors are associated with HbA_1c, but the contribution is relatively small. These findings contribute to a better understanding of the low correlation between glucose levels and HbA_1c in the general population.

Reconsidering the HbA1c Cutoff for Diabetes Diagnosis Based on a Large Chinese Cohort

INTRODUCTION

The HbA1c has been considered as the 'gold standard' in diabetes diagnosis and management, however, age, gender and body mass index (BMI) might have certain effects on HbA1c. We are aiming to further investigate the correlation between age and HbA1c, and whether it was affected by gender and BMI.

METHODS

A cross-sectional survey including 135,893 nondiabetic individuals who took the physical examination between 2013 and 2017 was conducted. The subjects were grouped by gender, age and BMI, and the interactive and independent effects of the 3 factors on the HbA1c were detected. The median and 95% confidence interval (CI) of HbA1c levels were calculated.

RESULTS

The HbA1c levels gradually increased along with age, both in female and male, and there is a positive association between BMI and the HbA1c. The difference on HbA1c in gender was associated with both age and BMI, the age-related increase in HbAlc was accentuated in the subgroup with higher BMI, and there was a marked accentuation of the positive association between BMI and HbA1c as age increased. In almost all the young and middle-aged (aged 20-59) subgroups, the 97.5^th percentiles of HbA1c levels were lower than 6.5%, suggesting that the single HbA1c cutoff value is probably not applicable to the young and middle-aged population.

CONCLUSIONS

We recommend that the effects of age, gender and BMI should be taken into consideration when using HbA1c for the diagnosis and management of diabetes, especially in the young and middle-aged population.

Preventing misdiagnosis of diabetes in the elderly: age-dependent HbA1c reference intervals derived from two population-based study cohorts

BACKGROUND

Measurement of gylcated hemoglobin A1c (HbA1c) plays a central role in monitoring quality of antidiabetic therapy and in the diagnosis of diabetes. Several studies report increased levels of HbA1c in nondiabetic elderly. However, this observation did not reach incorporation into daily clinical practice or the respective guidelines. The present study aimed to evaluate HbA1c levels in relation to age in two independent population-based cohorts and to derive age-specific reference intervals.

METHODS

Four thousand two hundred sixty three participants from the Study of Health in Pomerania (SHIP-0) and 4402 participants from the independent study SHIP-Trend were included. HbA1c was determined by means of high-performance liquid chromatography. Multivariable linear regression models were performed. Reference intervals for HbA1c were determined.

RESULTS

Reference intervals were derived from a healthy subpopulation with the upper reference limit (URL) for HbA1c of 42.1 mmol/Mol (6.0%) for individuals aged 20-39 years increasing to 43.2 mmol/Mol (6.1%) for individuals aged 40-59 years. For people aged ≥60 years the URL was 47.5 mmol/Mol (6.5%). In both study populations an increase in HbA1c with age was observed. ANOVA revealed up to 8.5 mmol/Mol (0.77%) or 7.3 mmol/Mol (0.68%) higher estimated mean levels of HbA1c in the oldest compared to the youngest age group in SHIP-0 or SHIP-trend, respectively. Linear regression analyses confirmed the positive associations of HbA1c with age which was independent of BMI CONCLUSION: The present study confirmed the previously observed increase of HbA1c with increasing age in non-diabetic individuals. As a consequence age-dependent reference values for HbA1c were derived from two large and well defined reference populations. Implementation of them into daily practice may improve patient care and diagnosis of diabetes and reduce the risk of misdiagnosis and subsequent overtreatment of diabetes in elderly patients.

Optimal hemoglobin A1C cutoff value for diabetes mellitus and pre-diabetes in Pudong New Area, Shanghai, China

AIMS

Due to the diversity of the Chinese population, it requires considerable research to evaluate HbA1c diagnostic threshold for diagnosis of hyperglycemia.

METHODS

We included 7909 subjects aged ≥15 without known diabetes from the baseline of Pudong community cohort in 2013. Participants took oral glucose tolerance test (OGTT) and HbA1c assay. Receiver operating characteristic curve determined the HbA1c threshold in the diagnosis of hyperglycemia.

RESULTS

The optimal HbA1C threshold for diagnosing newly diagnosed diabetes (NDD) and pre-diabetes in this population was 6.0% (AUC=0.798, 95%CI: 0.779-0.818) and 5.6% (AUC=0.655, 95%CI: 0.638-0.671). When compared with elderly age group (≥70 years), HbA1c for detecting NDD performed better in youth (15-39 years: P=0.003, 40-49 years: P<0.001). There were 13.81% and 13.34% of participants would be newly detected as NDD and pre-diabetes via HbA1c criteria; meanwhile 3.20% and 15.52% diagnosed as NDD and pre-diabetes by OGTT criteria would be missed diagnosis.

CONCLUSIONS

The optimal HbA1c thresholds for NDD and pre-diabetes were lower than ADA criteria. It is necessary to carefully consider whether choose HbA1c as a diagnostic criterion or combine two diagnostic standards. Age-specific diagnostic thresholds should be considered when HbA1c was recommended as diagnostic standard.

Hemoglobin A1c and diagnosis of diabetes

The prevalence of diabetes is increasing markedly worldwide, especially in China. Hemoglobin A1c is an indicator of mean blood glucose concentrations and plays an important role in the assessment of glucose control and cardiovascular risk. In 2010, the American Diabetes Association included HbA1c ≥6.5% into the revised criteria for the diagnosis of diabetes. However, the debate as to whether HbA1c should be used to diagnose diabetes is far from being settled and there are still unanswered questions regarding the cut-off value of HbA1c for diabetes diagnosis in different populations and ethnicities. This review briefly introduces the history of HbA1c from discovery to diabetes diagnosis, key steps towards using HbA1c to diagnose diabetes, such as standardization of HbA1c measurements and controversies regarding HbA1c cut-off points, and the performance of HbA1c compared with glucose measurements in the diagnosis of diabetes.

Effect of age on the diagnostic efficiency of HbA1c for diabetes in a Chinese middle-aged and elderly population: The Shanghai Changfeng Study

Background and aims

Glycated hemoglobin A1c (HbA1c) ≥6.5% (or 48mmol/mol) has been recommended as a new diagnostic criterion for diabetes; however, limited literature is available regarding the effect of age on the HbA1c for diagnosing diabetes and the causes for this age effect remain unknown. In this study, we investigated whether and why age affects the diagnostic efficiency of HbA1c for diabetes in a community-based Chinese population.

Methods

In total, 4325 participants without previously known diabetes were enrolled in this study. Participants were stratified by age. Receiver operating characteristic curve (ROC) was plotted for each age group and the area under the curve (AUC) represented the diagnostic efficiency of HbA1c for diabetes defined by the plasma glucose criteria. The area under the ROC curve in each one-year age group was defined as AUCage. Multiple regression analyses were performed to identify factors inducing the association between age and AUCage based on the changes in the β and P values of age.

Results

The current threshold of HbA1c (≥6.5% or 48mmol/mol) showed low sensitivity (35.6%) and high specificity (98.9%) in diagnosing diabetes. ROC curve analyses showed that the diagnostic efficiency of HbA1c in the ≥75 years age group was significantly lower than that in the 45–54 years age group (AUC: 0.755 vs. 0.878; P<0.001). Pearson correlation analysis showed that the AUCage of HbA1c was negatively correlated with age (r = -0.557, P = 0.001). When adjusting the red blood cell (RBC) count in the multiple regression model, the negative association between age and AUCage disappeared, with the regression coefficient of age reversed to 0.001 and the P value increased to 0.856.

Conclusions

The diagnostic efficiency of HbA1c for diabetes decreased with aging, and this age effect was induced by the decreasing RBC count with age. HbA1c is unsuitable for diagnosing diabetes in elderly individuals because of their physiologically decreased RBC count.

HbA1c and Risks of All-Cause and Cause-Specific Death in Subjects without Known Diabetes: A Dose-Response Meta-Analysis of Prospective Cohort Studies

Whether HbA_1c levels are associated with mortality in subjects without known diabetes remains controversial. Moreover, the shape of the dose–response relationship on this topic is unclear. Therefore, a dose–response meta-analysis was conducted. PubMed and EMBASE were searched. Summary hazard ratios (HRs) were calculated using a random-effects model. Twelve studies were included. The summary HR per 1% increase in HbA_1c level was 1.03 [95% confidence interval (CI) = 1.01–1.04] for all-cause mortality, 1.05 [95% CI = 1.02–1.07) for cardiovascular disease (CVD) mortality, and 1.02 (95% CI = 0.99–1.07) for cancer mortality. After excluding subjects with undiagnosed diabetes, the aforementioned associations remained significant for CVD mortality only. After further excluding subjects with prediabetes, all aforementioned associations presented non-significance. Evidence of a non-linear association between HbA_1c and mortality from all causes, CVD and cancer was found (all P_{non-linearity} < 0.05). The dose–response curves were relatively flat for HbA_1c less than around 5.7%, and rose steeply thereafter. In conclusion, higher HbA_1c level is associated with increased mortality from all causes and CVD among subjects without known diabetes. However, this association is driven by those with undiagnosed diabetes or prediabetes. The results regarding cancer mortality should be treated with caution due to limited studies.

Association between glycated hemoglobin A1c levels with age and gender in Chinese adults with no prior diagnosis of diabetes mellitus

The present cross-sectional study consisted of 18,265 Chinese patients not previously diagnosed with diabetes mellitus, and who underwent physical examination at the Third People's Hospital of Shenzhen between June 2014 and May 2015 (mean patient age, 51.312±15.252 years). The study was composed of 11,770 males and 6,495 females. The aim was to investigate the association between glycated hemoglobin A1c (HbA1c) levels, gender and age. HbA1c values were measured using a Bio-Rad VARIANT™ II HbA1c Reorder Pack. All data was collected for analysis of the HbA1c levels in different gender and age groups, in order to investigate the association between HbA1c levels and age. Analysis of the 18,265 total cases and 16,734 cases with HbA1c levels <6.5%, demonstrated a positive correlation between levels of HbA1c and patient age. Linear regression for patient age and HbA1c levels demonstrated that HbA1c (%) = 0.020 × age (years) + 4.523 (r=0.369, P<0.0001) and HbA1c (%) = 0.014 × age (years) + 4.659 (r=0.485, P<0.0001), respectively. HbA1c levels of the male group were significantly higher than those of the female group (P<0.0001). Furthermore, in different gender groups, HbA1c levels gradually rose with increasing age. Therefore, HbA1c levels are associated with age and gender in Chinese populations, and this should be considered when selecting HbA1c as a criterion for future diabetes screening.

High-risk glycated hemoglobin trajectories established by mid-20s: findings from a birth cohort study

OBJECTIVE

To describe the natural history of glycemia (as measured by glycated hemoglobin (HbA1c)) over 12 years using group-based trajectory modeling (GBTM), and to examine baseline predictors of trajectory.

RESEARCH DESIGN AND METHODS

HbA1c data collected at ages 26, 32 and 38 in the long-running, prospective Dunedin Multidisciplinary Health and Development Study were used to assign study members (n=893) to trajectories applying GBTM. A generalization of the model allowed the statistical linking of baseline demographic, smoking and anthropometric characteristics to group membership probability.

RESULTS

Mean HbA1c increased with age, as did prevalence of prediabetes, diabetes and dysglycemia. The greatest increase occurred between ages 26 and 32. Glycemic health status at age 26 predicted glycemic health status at age 38. 3 HbA1c trajectory groups were identified: 'low' (n=98, 11.0%); 'medium' (n=482, 54.0%); and 'high' (n=313, 35.0%) with mean HbA1c of 29.6, 34.1, and 38.7 mmol/mol, respectively, at age 38. High waist circumference (≥880 mm for women and ≥1020 mm for men), high waist-height ratio (≥0.50), and being a smoker at age 26 predicted membership of the least favorable trajectory over the next 12 years. High body mass index (≥30) at age 26 did not predict of trajectory.

CONCLUSIONS

Trajectories of HbA1c are established relatively early in adulthood. HbA1c levels, waist circumference, waist-height ratio, and smoking status at age 26 are valid clinical predictors for future dysglycemic risk. The identification of HbA1c trajectories and their predictors introduces the possibility of an individualized approach to prevention at an earlier stage than is currently done.

Association between Self-Reported Smoking and Hemoglobin A1c in a Korean Population without Diabetes: The 2011-2012 Korean National Health and Nutrition Examination Survey

Background

Several Western studies have revealed that among non-diabetics, glycosylated hemoglobin A1c (HbA1c) levels are higher in smokers than non-smokers. While studies conducted in Western populations consistently support this association, a recent meta-analysis reported that studies carried out in non-Western populations, including studies of Chinese, Egyptian, and Japanese-Americans, did not detect any significant differences in HbA1c levels between smokers and non-smokers.

Objectives

We assessed the association between smoking habits and HbA1c levels in the general Korean adult population using data from the Korean National Health and Nutrition Examination Survey (KNHANES) performed in 2011–2012.

Methods

A total of 10,241 participants (weighted n=33,946,561 including 16,769,320 men and 17,177,241 women) without diabetes were divided into four categories according to their smoking habits: never smokers (unweighted n/ weighted n= 6,349/19,105,564), ex-smokers (unweighted n/ weighted n= 1,912/6,207,144), current light smokers (<15 cigarettes per day, unweighted n/ weighted n=1,205/5,130,073), and current heavy smokers (≥15 cigarettes per day, unweighted n/ weighted n=775/3,503,781).

Results

In age- and gender-adjusted comparisons, the HbA1c levels of each group were 5.52 ± 0.01% in non-smokers, 5.49 ± 0.01% in ex-smokers, 5.53 ± 0.01% in light smokers, and 5.61 ± 0.02% in heavy smokers. HbA1c levels were significantly higher in light smokers than in ex-smokers (p = 0.033), and in heavy smokers compared with light smokers (p < 0.001). The significant differences remained after adjusting for age, gender, fasting plasma glucose, heavy alcohol drinking, hematocrit, college graduation, and waist circumference. Linear regression analyses for HbA1c using the above-mentioned variables as covariates revealed that a significant association between current smoking and HbA1c (coefficient 0.021, 95% CI 0.003–0.039, p = 0.019).

Conclusions

Current smoking was independently associated with higher HbA1c levels in a cigarette exposure-dependent manner in a representative population of Korean non-diabetic adults. In this study, we have observed an association between smoking status and HbA1c levels in non-diabetics drawn from a non-Western population, consistent with previous findings in Western populations.

Glycosylated hemoglobin testing in the National Social Life, Health, and Aging Project

OBJECTIVES

Longitudinal biomeasures of health are still new in nationally representative social science survey research. Data measuring blood sugar control provide opportunities for understanding the development of diabetes and its complications in older adults, but researchers must be aware that some of the differences across time can be due to variations in measurement procedures. This is a well-recognized issue whenever all samples cannot be assayed at the same time and we sought to present the analytic methods to quantify and adjust for the variation.

METHOD

We collected and analyzed HbA1C, glycated hemoglobin, a biomeasure of average blood sugar concentrations within the past few months. Improvements were made in the collection protocol for Wave 2, and assays were performed by a different lab.

RESULTS

The HbA1C data obtained during Wave 1 and Wave 2 are consistent with the expected population distributions for differences by gender, age, race/ethnicity, and diabetes status. Age-adjusted mean HbA1C declined slightly from Wave 1 to Wave 2 by -0.19 (95% confidence interval [CI]: -0.27, -0.10), and the average longitudinal change was -0.12 (95% CI: -0.18, -0.06).

DISCUSSION

Collection of HbA1C in Wave 2 permits researchers to examine the relationship between HbA1C and new health and social measures added in Wave 2, and to identify factors related to the change in HbA1C. Changes in collection protocol and labs between waves may have yielded small systematic differences that require analysts to carefully interpret absolute HbA1C values. We recommend analytic methods for cross wave differences in HbA1C and steps to ensure cross wave comparability in future studies.

Hemoglobin A1c, fasting plasma glucose, and 2-hour plasma glucose distributions in U.S. population subgroups: NHANES 2005-2010

PURPOSE

Although mean concentrations of hemoglobin A1c (A1C), fasting plasma glucose, and 2-hour plasma glucose differ by demographics, it is unclear what other characteristics of the distributions may differ, such as the amount of asymmetry of the distribution (skewness) and shift left or right compared with another distribution (shift).

METHODS

Using kernel density estimation, we created smoothed plots of the distributions of fasting plasma glucose (N = 7250), 2-hour plasma glucose (N = 5851), and A1C (N = 16,209) by age, race-ethnicity, and sex in the 2005-2010 National Health and Nutrition Examination Survey, a nationally representative sample of U.S. adults including people with and without diabetes. We tested differences in distributions using cumulative logistic regression.

RESULTS

The distributions were generally unimodal and right-skewed. All distributions were shifted higher and more right-skewed for older age groups (P < .001 for each marker). Compared with non-Hispanic whites, the distribution of fasting plasma glucose was shifted higher for Mexican-Americans (P = .01), whereas the distribution of A1C was shifted higher for non-Hispanic blacks (P < .001). The distribution of fasting plasma glucose was shifted higher for men (P < .001) and the distribution of 2-hour plasma glucose was shifted higher for women (P = .01).

CONCLUSIONS

We provide a graphic reference for comparing these distributions and diabetes cut-points by demographic factors.

The diagnostic threshold of HbA1c and impact of its use on diabetes prevalence-a population-based survey of 6898 Han participants from southern China

OBJECTIVE

The objective of this study is to determine the diagnostic threshold of HbA1c for diabetes and the impact of using it on diabetes prevalence.

METHODS

A population-based stratified study was conducted in 2010 among community-dwelling adults aged ≥35years in southern China. Participants without previously-diagnosed diabetes (PDD) took oral glucose tolerance test (OGTT) and HbA1c assay. HbA1c diagnostic threshold was determined by receiver operating characteristic curve.

RESULTS

A total of 6989 participants with mean age of 52years were recruited. The area under curve of HbA1c was 0.903 (95% CI: 0.883-0.922), with optimal cut-off value at 6.25% (sensitivity 75.6% and specificity 91.9%). There were 449 (6.42%) patients with PDD and 422 (6.04%), 815 (11.66%) and 918 (13.13%) new cases diagnosed by OGTT, HbA1c ≥6.25% or either, respectively. When either HbA1c or OGTT was used, newly-diagnosed diabetes prevalence increased by 117.4%.

CONCLUSIONS

Diabetes is prevalent in southern China. Near half of the patients go undetected with current diagnostic criteria. HbA1c ≥6.25% may be the diagnostic threshold value but needs further verification. The introduction of HbA1c threshold into diabetes diagnosis in China will cause a substantial increase in diabetes prevalence and great challenge on the public healthcare system.

HbA1c for screening and diagnosis of diabetes mellitus

HbA1c has become the gold standard for monitoring glycemic control in patients with diabetes mellitus. The use of this test has been expanded to diagnose and screen for diabetes mellitus with the endorsement of influential diabetes societies and the World Health Organization. The literature on the use of HbA1c for the diagnosis and screening of diabetes mellitus was critically examined. There is substantial recent literature on this topic with strong advocates for the use of HbA1c to diagnose and screen for diabetes and equally strong detractors for its use. Advocates of the use of HbA1c cite challenges in respect of patient compliance and the analysis of glucose and inconsistency of diagnosis with glucose-based diabetes diagnosis with the elimination or reduction in these challenges in HbA1c-based diagnosis. Detractors of its use cite increased cost, concerns about the availability of HbA1c testing, and the influence of demographic and clinical factors on HbA1c results that make the use of a single-threshold values questionable for different ethnic and age groups. Despite the recommendation of many international diabetes societies that HbA1c be used for screening and diagnosis of diabetes mellitus, there is a wide divergence of opinion on this use.

Effects of age and sex in the diagnosis of type 2 diabetes using glycated haemoglobin in Japan: the Yuport Medical Checkup Centre study

BACKGROUND

We examined how the prevalence of individuals diagnosed with diabetes differs by age and sex using the diagnostic criteria of fasting plasma glucose (FPG) and/or glycated haemoglobin (HbA1c) in a large Japanese population.

METHODS

We conducted a cross-sectional study using a dataset of 33,959 people (16,869 men and 17,090 women) without known diabetes who underwent health checkups from 1998 to 2006. We divided the age range of the participants into six groups of similar numbers. We compared the prevalence of diabetes using the criteria of FPG ≥7.0 mmol/l (126 mg/dl), HbA1c ≥48 mmol/mol (6.5%), or both, in men and women in each age group.

RESULTS

Men had higher prevalence of diabetes than women using the criterion of either FPG or HbA1c (7.5% men vs. 3.4% women, P<0.001), or both (4.3% men vs. 1.8% women, P<0.001). HbA1c increased steadily in women through the six age groups. In the oldest group (≥66 years), the proportion of women among those diagnosed with diabetes was as high as 42.3% (215/508) using the criterion of either FPG or HbA1c, and 41.6% (116/279) using both criteria.

CONCLUSIONS

Using either FPG or HbA1c, the prevalence of people diagnosed with diabetes would almost double compared to using the criterion of both scores, and this would include more elderly women than men. The impact of introducing HbA1c for diabetes diagnosis should be considered in terms of age and sex.

The age associations of blood pressure, cholesterol, and glucose: analysis of health examination surveys from international populations

BACKGROUND

The age association of cardiovascular disease may be in part because its metabolic risk factors tend to rise with age. Few studies have analyzed age associations of multiple metabolic risks in the same population, especially in nationally representative samples. We examined worldwide variations in the age associations of systolic blood pressure (SBP), total cholesterol (TC), and fasting plasma glucose (FPG).

METHODS AND RESULTS

We used individual records from 83 nationally or subnationally representative health examination surveys in 52 countries to fit a linear model to risk factor data between ages 30 and 64 years for SBP and FPG, and between 30 and 54 years for TC. We report the cross-country variation of the slope and intercept of this relationship. We also assessed nonlinear associations in older ages. Between 30 and 64 years of age, SBP increased by 1.7 to 11.6 mm Hg per 10 years of age, and FPG increased by 0.8 to 20.4 mg/dL per 10 years of age in different countries and in the 2 sexes. Between 30 and 54 years of age, TC increased by 0.2 to 22.4 mg/dL per 10 years of age in different surveys and in the 2 sexes. For all risk factors and in most countries, risk factor levels rose more steeply among women than among men, especially for TC. On average, there was a flattening of age-SBP relationship in older ages; TC and FPG age associations reversed in older ages, leading to lower levels in older ages than in middle ages.

CONCLUSIONS

The rise with age of major metabolic cardiovascular disease risk factors varied substantially across populations, especially for FPG and TC. TC rose more steeply in high-income countries and FPG in the Oceania countries, the Middle East, and the United States. The SBP age association had no specific income or geographical pattern.

Implications of the new definition of diabetes for health disparities

In July 2009, an international committee announced a new diagnostic criterion for diabetes based on hemoglobin Alc (HbA1c) values. Our objective was to estimate how the new diabetes diagnostic criterion will affect the prevalence of diabetes among different race, age, and gender subpopulations, compared to the previously used fasting plasma glucose (FPG) criterion. We analyzed nationally representative data from The National Health and Nutrition Examination Survey (NHANES), aggregated from 1999 to 2006. We estimated the prevalence of known diabetes (prevalence static across either diagnostic criterion), unknown, and no diabetes (prevalence variable by criterion). We tested statistical significance of prevalence differences for unknown diabetes between the prior diagnostic criterion--FPG of at least 126 mg/dL--and the new diagnostic criterion--HbA1c of at least 6.5%--using conditional logistic regression. We further tested the association of these differences with demographic factors. The new HbA1c diagnostic criterion differentially affects different racial/ethnic groups. For non-Hispanic whites, the prevalence of undiagnosed diabetes was more than halved from 2.6% (95% confidence interval [CI], 2.2-3.1) with FPG diagnosis to 1.3% (95% CI, 1.0-1.7), P<.001 with HbAic diagnosis. For Hispanics and non-Hispanic blacks, the differences in prevalence by the 2 criteria were smaller and nonsignificant. Racial differences by diagnostic criteria were most pronounced among people aged over 55 years. Overall, the new definition of diabetes differentially affects ethnic groups, especially for older people. If the new criterion is widely adopted, over time, we may see an apparent widening of racial/ethnic disparities in diabetes prevalence.

Alterations in HbA(1c) with advancing age in subjects with normal glucose tolerance: Chandigarh Urban Diabetes Study (CUDS)

OBJECTIVE

To study the alterations in HbA(1c) with advancing age in subjects with normal glucose tolerance.

METHODS

Community-based cross-sectional study involving 2368 subjects aged ≥ 20 years from Chandigarh, India. All the subjects underwent an oral glucose tolerance test with 75 g anhydrous glucose and were classified as having normal glucose tolerance, pre-diabetes or diabetes according to World Health Organization 1999 criteria. HbA(1c) was measured on a National Glycohemoglobin Standardization Program-certified Bio-Rad D-10 system and the data were available for 1972 subjects.

RESULTS

Out of 1972 subjects, 1317 (67%) subjects had normal glucose tolerance. There was a significant positive correlation between mean HbA(1c) and age in these subjects (r = 0.308, P(trend) < 0.001). The increase in HbA(1c) with each advancing year was 0.01% above the age of 20 years and corrected HbA(1c) (%) for age was 5.09 + 0.01 (age). The 95th percentile of HbA(1c) exceeded 6.5% (48 mmol/mol) (the American Diabetes Association cut-off for diagnosis of diabetes) in subjects aged ≥ 70 years. A significantly higher number (6.5%, 21/325) of subjects had HbA(1c) of ≥ 6.5% (48 mmol/mol) in those above the age of 50 years compared with those below the age of 50 years (1.7%, 17/992) in the group with normal glucose tolerance (P < 0.001). On multivariate regression analysis, after adjusting for BMI, fasting plasma glucose and 2-h plasma glucose post-glucose load, the correlation of HbA(1c) with age still remained significant (r = 0.241, P < 0.01).

CONCLUSION

HbA(1c) increases with advancing age independent of glycaemia, suggesting caution when seeking to achieve the recommended HbA(1c) targets in the elderly population.

Identifying dysglycemic states in older adults: implications of the emerging use of hemoglobin A1c

CONTEXT

Hemoglobin A1c (A1c) was recently added to the diagnostic criteria for diabetes and prediabetes.

OBJECTIVE

Our objective was to examine performance of A1c in comparison with fasting plasma glucose (FPG) in diagnosing dysglycemia in older adults.

DESIGN AND SETTING

We conducted a cross-sectional analysis of data from the Health, Aging, and Body Composition study at yr 4 (2000-2001) when FPG and standardized A1c measurements were available.

PARTICIPANTS

Of 3075 persons (aged 70-79 yr, 48% men, 42% Black) at study entry, 1865 participants without known diabetes who had appropriate measures were included.

MAIN OUTCOME MEASURES

Sensitivity and specificity of A1c-based diagnoses were compared with those based on FPG and the proportion of participants identified with dysglycemia by each measure.

RESULTS

Of all participants, 2.7 and 3.1% had undiagnosed diabetes by FPG≥126 mg/dl and A1c≥6.5%, respectively. Among the remaining participants, 21.1% had prediabetes by impaired fasting glucose (≥100 mg/dl) and 22.2% by A1c≥5.7%. Roughly one third of individuals with diabetes and prediabetes were identified by either FPG or A1c alone and by both tests simultaneously. Sensitivities and specificities of A1c compared with FPG were 56.9 and 98.4% for diabetes and 47.0 and 84.5% for prediabetes, respectively. Blacks and women were more likely to be identified with dysglycemia by A1c than FPG.

CONCLUSIONS

In this older population, we found considerable discordance between FPG- and A1c-based diagnosis of diabetes and prediabetes, with differences accentuated by race and gender. Broad implementation of A1c to diagnose dysglycemic states may substantially alter the epidemiology of these conditions in older Americans.

Effect of aging on A1C levels in individuals without diabetes: evidence from the Framingham Offspring Study and the National Health and Nutrition Examination Survey 2001-2004

OBJECTIVE

Although glycemic levels are known to rise with normal aging, the nondiabetic A1C range is not age specific. We examined whether A1C was associated with age in nondiabetic subjects and in subjects with normal glucose tolerance (NGT) in two population-based cohorts.

RESEARCH DESIGN AND METHODS

We performed cross-sectional analyses of A1C across age categories in 2,473 nondiabetic participants of the Framingham Offspring Study (FOS) and in 3,270 nondiabetic participants from the National Health and Nutrition Examination Survey (NHANES) 2001-2004. In FOS, we examined A1C by age in a subset with NGT, i.e., after excluding those with impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT). Multivariate analyses were performed, adjusting for sex, BMI, fasting glucose, and 2-h postload glucose values.

RESULTS

In the FOS and NHANES cohorts, A1C levels were positively associated with age in nondiabetic subjects. Linear regression revealed 0.014- and 0.010-unit increases in A1C per year in the nondiabetic FOS and NHANES populations, respectively. The 97.5th percentiles for A1C were 6.0% and 5.6% for nondiabetic individuals aged <40 years in FOS and NHANES, respectively, compared with 6.6% and 6.2% for individuals aged >or=70 years (P(trend) < 0.001). The association of A1C with age was similar when restricted to the subset of FOS subjects with NGT and after adjustments for sex, BMI, fasting glucose, and 2-h postload glucose values.

CONCLUSIONS

A1C levels are positively associated with age in nondiabetic populations even after exclusion of subjects with IFG and/or IGT. Further studies are needed to determine whether age-specific diagnostic and treatment criteria would be appropriate.

The relationship between age and carotid artery intima-media thickness, hemoglobin A1c in nondiabetic, healthy geriatric population

The aim of the study was to investigate a casual relationship between age and carotid artery intima-media thickness (IMT) and hemoglobin A1c (HbA1c) levels and to assess the effects of possible risk factors in healthy nondiabetic elderly. Seventy-two healthy, well-educated, nondiabetic, healthy elderlies (mean age: 71.5+/-5.01 years; 43 male, 29 female) were enrolled in the study. Comprehensive assessments including a battery of psychosocial and functional performance tests were performed to all subjects. All of them were also asked about health prevention topics including exercise, dietary habits, smoking, vaccination, cholesterol screening, etc. Carotid artery IMT was measured by ultrasound. Blood samples were obtained for fasting glucose, HbA1c, cholesterol, triglyceride and fibrinogen. The mean carotid artery IMT was 0.94+/-0.13 mm and the mean HbA1c level was 5.29+/-0.65 mg/dl. There was no significant correlation between age and carotid artery IMT (r(s)=0.15), HbA1c levels (r(s)=-0.08) and other possible atherosclerosis risk factors. Also there was no correlation between carotid artery IMT and HbA1c levels (r(s)=0.14). Our data indicated that the carotid artery IMT, HbA1c and age are not associated in a geriatric healthy, well-educated population. Comparative studies done on the elderly who do not benefit from preventive health care programs are needed to establish if preventive health care measures and risk factor modification are important in the elderly age group.

Effects of postmenopausal hormone replacement therapy on HbA(1c) levels

OBJECTIVE

Estrogen seems to contribute to glucose homeostasis in women. The objective of this study was to examine the effects of hormone replacement therapy (HRT) on HbA(1c) levels in Japanese postmenopausal women and to determine whether the effects varied with age.

RESEARCH DESIGN AND METHODS

We studied 99 postmenopausal women taking HRT (mean +/- SD age 56.5 +/- 6.9 years, BMI 21.5 +/- 2.3 kg/m(2)) and 101 postmenopausal women not on HRT (51.4 +/- 6.1 years, 21.3 +/- 2.4 kg/m(2)). HRT consisted of continuous conjugated equine estrogen (CEE; 0.625 mg/day) and medroxyprogesterone acetate (MPA; 2.5 mg/day) for >2 years.

RESULTS

HbA(1c) levels are positively associated with age and BMI in women who use HRT as well as in those who do not use HRT. After adjusting for age and BMI, HRT showed no effects on HbA(1c) levels. However, HbA(1c) levels were significantly lower in postmenopausal women aged 40-49 years who were taking HRT than in women of similar age who were not taking HRT (mean +/- SE 4.776 +/- 0.092 vs. 5.096 +/- 0.078%, P < 0.05). No differences in HbA(1c) levels between women who did and did not use HRT were observed in those older than 50 years.

CONCLUSIONS

Oral HRT involving CEE combined with MPA may decrease HbA(1c) levels in women aged 40-49 years and is likely to have no adverse effects on HbA(1c) levels in women older than 50 years.

[Metabolic control of diabetes mellitus en relation to the quality of the medical records]

OBJECTIVE

To investigate whether there is a relationship between the quality of the clinical history (CH) in primary care and metabolic control of patients with diabetes (DM).

DESIGN

Retrospective and observational.

SETTING

15 health centres in the Segovia Area.

PATIENTS

315 diabetic patients, selected at random from among those with a record of the type of DM, date and outcome of at least one HbA1c and treatment at the time of the most recent HbA1c.

RESULTS

The quality of the clinical histories was measured through the mean of recording of the following items in the 13 months previous to the most recent HbA1c: weight and height, peripheral pulses, sensitivity, foot examination, creatinine, proteinuria, microalbuminuria, glucaemia levels, back of eye, ECG, and diet, tobacco and alcohol counselling. Other variables that could condition the HbA1c, chronic pathologies and those related to DM, were gathered too. Of patients treated with diet or oral diabetic drugs, patients with a clinical history of < or = 49% quality had a mean HbA1c of 7.40%, whereas those with CH of > or = 50% quality had an average of 6.94% (0.46 difference; 95% CI, 0.03-0.90; p = 0.038). This drop was not attributable to age, gender, years of evolution or BMI differences. The risk of having an HbA1c > or = 7.5% is double in patients with a CH of < or = 49% quality than in those with CH of > or = 50% quality (OR = 2.06; 95% CI, 1.14-3.72). In insulin-treated patients, no association between CH quality and HbA1c was found.

CONCLUSIONS

Follow-up of the recommendations for clinical action is associated with better metabolic control in diabetics treated with diet--oral diabetic drugs. This association was not found in insulin-treated patients.

Association between glycated hemoglobin and diet and other lifestyle factors in a nondiabetic population: cross-sectional evaluation of data from the Potsdam cohort of the European Prospective Investigation into Cancer and Nutrition Study

BACKGROUND

Glycation reactions of proteins and other compounds, depending on blood glucose concentrations, have a detrimental effect on health.

OBJECTIVE

The association of diet and other lifestyle factors with glycated hemoglobin (Hb A(1c)) values was examined in a nondiabetic population.

DESIGN

This was a cross-sectional study of 1773 middle-aged men and women. Mean Hb A(1c) values were calculated for categories of diet and lifestyle factors, and odds ratios (ORs) for the highest versus lowest tertiles of Hb A(1c) were determined and compared.

RESULTS

The OR of being in the highest Hb A(1c) tertile compared with the lowest increased with greater age [age 40-44 y compared with >60 y: men (OR: 2.86; 95% CI: 1.60, 5.20) and women: (6.11; 3.15, 12.30)] and greater obesity [body mass index (in kg/m(2)) >25 and waist-hip ratio >1.0 in men and >0.8 in women): men (2.80; 1.48, 5.45) and women (1.73; 1.15, 2.61)]. High energy and energy-adjusted saturated fat intakes were associated with increased risk of being in the highest tertile of Hb A(1c) [highest compared with lowest quintile: (1.53; 1.04, 2.26; P for trend = 0.013) and (1. 98; 1.33, 2.95; P for trend = 0.003), respectively]. No significant associations were observed for intakes of carbohydrates, protein, dietary fiber, or beta-carotene; however, some of the associations were nearly significant. Alcohol, vitamin C, and vitamin E intakes were inversely related to risk [highest compared with lowest quintile: (0.56; 0.38, 0.83; P for trend = 0.001), (0.50; 0.33, 0. 74; P for trend = 0.003), and (0.65; 0.43, 0.96; P for trend = 0. 036), respectively].

CONCLUSION

Hb A(1c) values might be modifiable by diet and other lifestyle factors.

Differences in rates of glycation (glycation index) may significantly affect individual HbA1c results in type 1 diabetes

Ten type 1 diabetic patients recorded their daily home blood glucose values, pre- and post-prandially, for 12 weeks. Blood was collected weekly for HbA1c and total haemoglobin measurement. A rolling 28-day mean of all blood glucose values and a glycation index (the ratio of the HbA1c to the rolling mean blood glucose) were calculated. In the pooled patients' data, there was a large scatter of results about the HbA1c versus mean blood glucose regression line. There was less variation in the results of individual patients. The glycation indices showed marked inter-individual variation, and in 60% of patients there was an inverse relationship between glycation index and mean blood glucose, suggesting a non-linear relationship between mean blood glucose and HbA1c. Patients should be monitored on the basis of their own previous results, and in some patients blood HbA1c may be a less sensitive index of mean blood glucose concentration at higher glucose levels.