Recent population changes in HbA(1c) and fasting insulin concentrations among US adults with preserved glucose homeostasis

Increase in glycemic set point, alongside a decrease in waist circumference, in the non-diabetic population during the Japanese National Intervention Program for metabolic syndrome: A single-center, large-scale, matched-pair analysis

Background

In 2008, the Japanese government implemented a National Intervention Program for metabolic syndrome. Low-risk individuals were not direct targets of this intervention. Nevertheless, they were indirectly enlightened by this massive campaign. Documentation of the metabolic shifts in low-risk individuals following the program launch may inform public health policy regarding approaches to metabolic risks in the general population.

Methods

We conducted a cross-sectional analysis of data from non-diabetic participants who underwent general health check-ups at the Physical Check-up Center of Sumitomo Hospital. Participants during 2007–2008 were pair-matched with those during 2015–2016 with respect to sex, age, smoking status, hemoglobin level, and red blood cell (RBC) count. Each participant was included only once in the study.

Results

Totals of 3,140 men and 2,048 women were pair-matched. The non-diabetic participants showed lower waist circumference, blood pressure, heart rate, and serum lipid concentrations during the second study period. In contrast, the entire distributions of fasting plasma glucose (FPG) concentration in both sexes and glycated hemoglobin (HbA_1c) in women were shifted upwards. In men, Δ FPG was +1.6 mg/dL (P < 0.001) and Δ HbA_1c was ±0% (P = 0.6). In women, Δ FPG was +3.0 mg/dL (P < 0.001), and Δ HbA_1c was +0.1% (P < 0.001). Δ Homeostasis model assessment of β-cell function was −6.6 in men (P < 0.001) and −10.3 in women (P < 0.001). The homeostasis model assessment of insulin resistance did not change significantly.

Conclusions

The “glycemic set point” has increased in non-diabetic people in Japan during recent years. Lifestyle or environmental changes may have caused this metabolic shift through obesity-independent pathways, possibly through effects on pancreatic β-cell function. The underlying mechanism awaits further investigation.

Differences in the prevalence of intermediate hyperglycaemia and the associated incidence of type 2 diabetes mellitus by ethnicity: The HELIUS study

AIMS

We aimed to describe differences in the prevalence of intermediate hyperglycaemia (IH) between six ethnic groups. Moreover, to investigate differences in the association of the classifications of IH with the incidence of T2DM between ethnic groups.

METHODS

We included 3759 Dutch, 2826 African Surinamese, 1646 Ghanaian, 2571 Turkish, 2691 Moroccan and 1970 South Asian Surinamese origin participants of the HELIUS study. IH was measured by fasting plasma glucose (FPG) and HbA1c. We calculated age-, BMI and physical-activity-adjusted prevalence of IH by sex, and calculated age and sex-adjusted hazard ratios (HR)for the association between IH and T2DM in each ethnic group.

RESULTS

The prevalence of IH was higher among ethnic minority groups (68.6-41.7%) than the Dutch majority (34.9%). The prevalence of IH categories varied across subgroups. Combined increased FPG and HbA1c was most prevalent in South-Asian Surinamese men (27.6%, 95 %CI: 24.5-30.9%), and in Dutch women (4.2%, 95 %CI: 3.4-5.1%). The HRs for T2DM for each IH-classification did not differ significantly between ethnic groups. HRs were highest for the combined classification, e.g., HR = 8.1, 95 %CI: 2.5-26.6 in the Dutch.

CONCLUSION

We found a higher prevalence of IH in ethnic minority versus majority groups, but did not find evidence for a differential association of IH with incident T2DM.

The Manitoba Personalized Lifestyle Research (TMPLR) study protocol: a multicentre bidirectional observational cohort study with administrative health record linkage investigating the interactions between lifestyle and health in Manitoba, Canada

INTRODUCTION

Lifestyle factors, such as diet, physical activity and sleep, are associated with the development of many chronic diseases. The objective of The Manitoba Personalized Lifestyle Research study is to understand how these lifestyle factors interact with each other and with other factors, such as an individual's genetics and gut microbiome, to influence health.

METHODS

An observational study of adults, with extensive phenotyping by objective health and lifestyle assessments, and retrospective assessment of early life experiences, with retrospective and prospective utilisation of secondary data from administrative health records.

STUDY POPULATION

A planned non-random convenience sample of 840 Manitobans aged 30-46 recruited from the general population, stratified by sex (equal men and women), body mass index (BMI; 60% of participants with a BMI>25 kg/m²) and geography (25% from rural areas). These stratifications were selected based on Manitoba demographics.

MEASUREMENTS

Lifestyle factors assessed will include dietary pattern, physical activity, cardiovascular fitness, and sleep. Factors such as medical history, socioeconomic status, alcohol and tobacco consumption, cognition, stress, anxiety, and early life experiences will also be documented. A maternal survey will be performed. Body composition and bone density will be measured by dual energy X-ray absorptiometry. Blood pressure, pulse wave velocity, and augmentation index will be measured on two consecutive days. Chronic disease risk biomarkers will be measured in blood and urine samples. DNA will be extracted for genetic analysis. A faecal sample will be collected for microbiome analysis. Participants may provide their Manitoba personal health information number to link their study data with administrative health records.

ETHICS AND DISSEMINATION

Ethics approval has been obtained from the University of Manitoba Health Research Ethics Board (protocol # HS18951; 05/01/2016). Data analysis, release of results and publication of manuscripts are scheduled to start in early 2019. Additional information at www.TMPLR.ca.

TRIAL REGISTRATION NUMBER

NCT03674957; Pre-results.

Evaluation of surrogate measures of insulin sensitivity - correlation with gold standard is not enough

Background

Impaired insulin sensitivity is a key abnormality underlying the development of type 2 diabetes. Measuring insulin sensitivity is therefore of importance in identifying individuals at risk of developing diabetes and for the evaluation of diabetes-focused interventions. A number of measures have been proposed for this purpose. Among these the hyperinsulinemic euglycemic clamp (HEC) is considered the gold standard. However, as the HEC is a costly, time consuming and invasive method requiring trained staff, there is a need for simpler so called surrogate measures.

Main message

A frequently used approach to evaluate surrogate measures is through correlation with the HEC. We discuss limitations with this method. We suggest other aspects to take into consideration, such as repeatability, reproducibility, systematic biases and discrimination ability. In addition, we focus on three frequently used surrogate measures. We argue that they are one-to-one transformations of each other, and therefore question the benefits of further comparison between them. They give the same results in all rank-based methods, for instance Spearman correlations, Mann-Whitney tests and receiver operating characteristic (ROC) analysis.

Conclusions

We suggest investigating further aspects than correlation alone when evaluating a surrogate measure of insulin sensitivity. We recommend choosing one of the three surrogate measures HOMA-IR, QUICKI and FIRI for analysis of a clinical study.

Electronic supplementary material

The online version of this article (10.1186/s12874-018-0521-y) contains supplementary material, which is available to authorized users.

Ethnic Variations in Diabetes and Prediabetes Prevalence and the roles of Insulin Resistance and β-cell Function: The CARRS and NHANES Studies

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We compared the hyperglycemia prevalence in Asian Indians to other ethnic groups.

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The prevalence of diabetes was higher in Indians compared to other ethnic groups.

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The prevalence of prediabetes was lower in Indians compared to other ethnic groups.

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These differences may be driven by impaired β-cell function.

Aims

It is unclear how the prevalence of diabetes in Asian Indians in urban India compares to that of race/ethnic groups in the US that may have different underlying susceptibilities. Therefore, we examined ethnic variations in the prevalence of type 2 diabetes, iIFG, iIGT, IFG + IGT, and the associated risk factors in Asian Indians in Chennai, India, and Whites, Blacks, and Hispanics in the United States.

Methods

Cross-sectional analyses, using representative samples of 4867 Asian Indians aged 20–74 years from Chennai, India, in the Centre for Cardiometabolic Risk Reduction in South-Asia study (CARRS) (2010–2011) and 6512 US Whites, Blacks, and Hispanics aged 20–74 years from the National Health and Nutrition Examination Survey (NHANES) (2007–2012).

Results

The age-adjusted prevalence of type 2 diabetes was highest in Asian Indians (men: 28.4, 95% CI: 25.9, 31.0; women: 30.6, 95% CI, 27.5, 33.9) and lowest in Caucasians (men: 12.2, 95% CI, 10.3, 14.4, women: 9.5, 95% CI, 7.9, 11.5). Asian Indians had the lowest prediabetes prevalence (men: 19.0, 95% CI, 17.2, 20.8; women: 27.2, 95% CI, 22.8, 32.1) and Caucasians had the highest (men; 46.5, 95% CI, 43.5, 49.6, women: 34.4, 95% CI, 31.7, 37.3). However, there were differences in prediabetes prevalence by gender and prediabetes state. The inclusion of HOMA-β in standardized polytomous logistic regression models resulted in a greater odds of diabetes in Blacks and Hispanics compared to Asian Indians.

Conclusions

The high prevalence of diabetes in Asian Indians may be due to innate susceptibilities for β-cell dysfunction in this high risk population.

Association between Inflammation and Biological Variation in Hemoglobin A1c in U.S. Nondiabetic Adults

CONTEXT

Inflammation is associated with higher glycated hemoglobin (HbA1c) levels. Whether the relationship is independent of blood glucose concentration remains unclear.

OBJECTIVE

The hemoglobin glycation index (HGI) was used to test the hypothesis that interindividual variation in HbA1c is associated with inflammation.

PARTICIPANTS

This study used nondiabetic adults from the National Health and Nutrition Examination Survey (1999-2008).

MAIN OUTCOME MEASURES

A subsample of participants was used to estimate the linear regression relationship between HbA1c and fasting plasma glucose (FPG). Predicted HbA1c were calculated for 7323 nondiabetic participants by inserting FPG into the equation, HbA1c = 0.017 × FPG (mg/dL) + 3.7. HGI was calculated as the difference between the observed and predicted HbA1c and the population was divided into low, moderate, and high HGI subgroups. Polymorphonuclear leukocytes (PMNL), monocytes, and C-reactive protein (CRP) were used as biomarkers of inflammation.

RESULTS

Mean HbA1c, CRP, monocyte, and PMNL levels, but not FPG, progressively increased in the low, moderate, and high HGI subgroups. There were disproportionately more Blacks than whites in the high HGI subgroup. CRP (ß, 0.009; 95% confidence interval [CI], 0.0001-0.017), PMNL (ß, 0.036; 95% CI, 0.010-0.062), and monocyte count (ß, 0.072; 95% CI, 0.041-0.104) were each independent predictors of HGI after adjustment for age, sex, race, triglycerides, hemoglobin level, mean corpuscular volume, red cell distribution width, and obesity status.

CONCLUSIONS

HGI reflects the effects of inflammation on HbA1c in a nondiabetic population of U.S. adults and may be a marker of risk associated with inflammation independent of FPG, race, and obesity.

A rightward shift of the distribution of fasting and post-load glucose in northern Sweden between 1990 and 2009 and its predictors. Data from the Northern Sweden MONICA study

AIMS

Most Swedish studies show stable diabetes prevalence despite increasing obesity, but glucose levels may shift upwards below the diagnostic threshold for diabetes. Our aim was to explore trends in glucose distribution in northern Sweden; whether these trends were uniformly distributed throughout the spectrum of glucose concentrations; and to relate trends to traditional risk factors and the obesity-related adipokine leptin.

METHODS

The project consisted of four cross-sectional surveys between 1990 and 2009, with 7069 participants aged 25-64 years. The overall participation rate was 74.4%. Trend analyses of glucose concentrations along the entire distribution and linear regression in relation to survey years and risk markers were used.

RESULTS

Fasting and post-load glucose increased in women (both P < 0.001) and post-load glucose in men (P = 0.004). The increase was seen in most deciles of glucose concentrations. The prevalence of impaired glucose tolerance doubled in women to 14.5% and tripled in men to 10.1% (both P = 0.004). The prevalence of impaired fasting glucose rose in women from 4.5 to 7.7% (P < 0.001). The prevalence of diabetes was unchanged-6.4% in 2009. In men, leptin, together with traditional risk factors, explained 7.8 and 10.8% of the variance in fasting (P = 0.008) and post-load (P < 0.001) glucose, respectively.

CONCLUSIONS

Increasing fasting and post-load glucose concentrations were seen in most deciles of the glucose distribution, indicating a shift in the entire population. Leptin was significantly associated with fasting and post-load glucose in men.

Pharmacogenetics in primary care: the promise of personalized medicine and the reality of racial profiling

Many anticipate that expanding knowledge of genetic variations associated with disease risk and medication response will revolutionize clinical medicine, making possible genetically based Personalized Medicine where health care can be tailored to individuals, based on their genome scans. Pharmacogenetics has received especially strong interest, with many pharmaceutical developers avidly working to identify genetic variations associated with individual differences in drug response. While clinical applications of emerging genetic knowledge are becoming increasingly available, genetic tests for drug selection are not as yet widely accessible, and many primary care clinicians are unprepared to interpret genetic information. We conducted interviews with 58 primary care clinicians, exploring how they integrate emerging pharmacogenetic concepts into their practices. We found that in their current practices, pharmacogenetic innovations have not led to individually tailored treatment, but instead have encouraged use of essentialized racial/ethnic identity as a proxy for genetic heritage. Current manifestations of Personalized Medicine appear to be reinforcing entrenched notions of inherent biological differences between racial groups, and promoting the belief that racial profiling in health care is supported by cutting-edge scientific authority. Our findings raise concern for how pharmacogenetic innovations will actually affect diverse populations, and how unbiased treatment can be assured.

Does Menopause Increase Diabetes Risk? Strategies for Diabetes Prevention in Midlife Women

Menopause is a significant milestone for midlife women. The characteristic changes in sex hormones and associated symptoms mark a time of increased risk for chronic disease, most notably cardiovascular disease. The diabetes epidemic, combined with recent epidemiologic studies linking sex hormone profiles with incident diabetes risk, have recently raised the possibility that the menopause may increase diabetes risk as well. This report reviews studies of menopause and diabetes risk, as well as the potential mechanisms through which menopause might affect traditional and more novel diabetes risk factors. Diabetes risk appears to be more strongly linked with factors associated with chronological aging and sex hormones rather than changes in menopausal status per se. Strategies to reduce diabetes risk, namely lifestyle changes, hormone therapy and other pharmacologic interventions are also discussed vis à vis midlife women and menopause.

Explaining the increase of diabetes prevalence and plasma glucose in Mauritius

OBJECTIVE

Secular trends in the epidemiology of diabetes are best described by studying the same population over time, but few such studies exist. Using surveys from Mauritius in 1987 and 2009, we examined 1) the change in the prevalence of diabetes, 2) the extent to which changes in traditional diabetes risk factors explained the increase, and 3) the change in the distribution of plasma glucose levels over time.

RESEARCH DESIGN AND METHODS

Independent population-based surveys were undertaken in Mauritius in 1987 and 2009 using similar methodology in adults aged 20-74 years. Physical measurements and fasting blood samples were taken, and an oral glucose tolerance test was performed at both surveys.

RESULTS

The age-standardized prevalence of diabetes in 2009 was 22.3% (95% CI 20.0-24.6) among men and 20.2% (18.3-22.3) among women, representing an increase since 1987 of 64 and 62% among men and women, respectively. Concurrent changes in the distribution of age, ethnicity, waist circumference, BMI, physical activity, smoking, family history of diabetes, and hypertension explained more of the increase in the prevalence of diabetes in men than in women. Increases in plasma glucose (especially fasting glucose) were seen across the population but were greater at the upper levels.

CONCLUSIONS

In Mauritius, there has been a marked increase in diabetes prevalence over 22 years. This mainly results from changes in traditional risk factors, leading to population-wide increases in plasma glucose levels. Interventions to control this escalation of diabetes should focus on population-wide strategies.

Long-term and recent progress in blood pressure levels among U.S. adults with diagnosed diabetes, 1988-2008

OBJECTIVE

To examine whether there were long-term (between 1988-1994 and 2001-2008) and recent (between 2001-2004 and 2005-2008) changes in blood pressure (BP) levels among U.S. adults with diagnosed diabetes.

RESEARCH DESIGN AND METHODS

Using data from National Health and Nutrition Examination Surveys (NHANES), we examined changes in BP distributions, mean BPs, and proportion with BP<140/90 mmHg.

RESULTS

Between 1988-1994 and 2001-2008, for adults with diabetes, mean BPs decreased from 135/72 mmHg to 131/69 mmHg (P<0.01) and the proportion with BP<140/90 mmHg increased from 64 to 69% (P=0.01). Although hypertension prevalence increased, hypertension awareness, treatment, and control improved. However, there was no evidence of improvement for adults 20-44 years old. Between 2001-2004 and 2005-2008, there were no significant changes in BP levels.

CONCLUSIONS

BP levels among adults with diabetes improved between 1988-1994 and 2001-2008, but the progress stalled between 2001-2004 and 2005-2008. The lack of improvement among young adults is concerning.

Unrecognized glucose intolerance is common in pulmonary arterial hypertension

BACKGROUND

Animal and human data suggest insulin resistance is common in pulmonary arterial hypertension (PAH). Although routine assessment of insulin resistance is difficult, hemoglobin A(1c) (HbA(1c)) is a sensitive test to detect diabetes mellitus (DM) and those at high risk for DM. We aimed to define the prevalence of elevated HbA(1c) in PAH patients and to correlate HbA(1c) levels with functional assessment.

METHODS

HbA(1c) was measured in 41 PAH patients without a diagnosis of DM, along with demographic, functional, and hemodynamic data. Using published criteria, HbA(1c) ≤ 5.9% defined normal, 6.0% to 6.4% was glucose intolerance, and ≥ 6.5% was DM.

RESULTS

Twenty-three patients (56%) had HbA(1c) ≥ 6.0%, and 6 (15%) had unrecognized DM (HbA(1c) ≥ 6.5%). Age and body mass index were similar in patients with HbA(1c) ≥ 6.0% vs < 6.0%. There was a trend towards lower mean 6-minute walk distance in patients with elevated HbA(1c) (331.0 ± 126.6 vs 413.6 ± 74.9 meters, p = 0.07). The 6-month event-free survival was not significantly different in patients with elevated HbA(1c).

CONCLUSIONS

Unrecognized glucose intolerance as assessed by HbA(1c) is common in PAH. Further studies are needed to discern if glucose or insulin dysregulation mediates PAH pathogenesis or is secondary to advanced PAH.