High incidence of type 2 diabetes and increasing conversion rates from impaired fasting glucose and impaired glucose tolerance to diabetes in Mauritius

Left ventricular hypertrophy: an ECG-based study of prevalence and risk factors in a multiethnic population

BACKGROUND

Left ventricular hypertrophy (LVH) is frequently seen in association with arterial hypertension and indicates poor prognosis. This study aimed to determine the prevalence of LVH and associated factors in a multiethnic population from Mauritius.

METHODS

Population-based health surveys were performed in 2009 and 2015 and included in total 8961 individuals aged 35-75 years with recorded 12-lead ECG. LVH was defined according to three criteria: Sokolow-Lyon, Cornell voltage and Cornell product. Data were collected about health and lifestyle behaviour. Anthropometry and blood pressure were measured. Fasting levels of blood lipids and glucose were determined, oral glucose tolerance test was performed in people without glucose-lowering medications.

RESULTS

The age-standardised prevalence of LVH was 9% (n=875) according to any of the three ECG criteria. Individuals with LVH were older, more likely to have hypertension, diabetes, known cardiovascular disease (CVD) and elevated levels of cholesterol and creatinine. Further, they were more likely to be of African descent (Creole) and have lower educational level. In a multivariable model, Creole (OR (95% CI)) (1.56 (1.33 to 1.83)), low educational level (1.49 (1.28 to 1.75)), hypertension (3.01 (2.55 to 3.56)), known CVD (1.42 (1.11 to 1.83)) and elevated creatinine (1.08 (1.03 to 1.14)) remained associated with LVH. Individuals with non-treated or uncontrolled hypertension had a higher risk for LVH (3.09 (95% CI 2.57 to 3.71) and 4.07 (95% CI 3.29 to 5.05), respectively), than individuals with well controlled hypertension or normotension.

CONCLUSION

LVH occurs more frequently in individuals with hypertension, as well as in individuals with African ancestry and/or low education level.

Acupuncture for Impaired Glucose Tolerance in People With Obesity: A Protocol for a Multicenter Randomized Controlled Trial

Background

Impaired glucose tolerance (IGT) is associated with being overweight/obesity and is a powerful risk factor for the disease of diabetes. In addition to lifestyle intervention that shows limited clinical application, acupuncture treatment has been a feasible treatment method for IGT in clinical practice. However, the effectiveness of acupuncture treatment has not been proved in evidence-based practice. Therefore, we design a multicenter randomized controlled trial to evaluate the efficacy and safety of acupuncture treatment for IGT in people with overweight/obesity.

Methods

The trial will be conducted at hospitals in three different sites in China. A total of 196 participants will be recruited and randomly assigned at a ratio of 1:1 to either to the acupuncture group or the sham acupuncture (SA) group. Both groups will receive 30 sessions of treatment for 12 consecutive weeks and will be provided with lifestyle intervention and a 24-week follow-up. The primary outcome will be change in the baseline value of 2-h blood glucose (2hPG) on the 12th week. Additionally, the expectancy of acupuncture, blinding, and safety will also be assessed. All statistical analyses will be performed by two-sided test, and a p-value of less than 0.05 will be considered statically significant.

Discussion

This study aims to provide quantitative clinical evidence of acupuncture effectiveness and safety in treating IGT in people who are overweight/obese.

Clinical Trial Registration

[www.ClinicalTrials.gov], identifier [NCT05347030].

22-year trends in dysglycemia and body mass index: A population-based cohort study in Savitaipale, Finland

AIMS

We describe a 22-year prospective observational population-based study that determined the prevalence and incidence of type 2 diabetes (T2D) and intermediate hyperglycaemia (IH), obesity, hypertension, and disorders of lipid metabolism in a middle-age population in the Finnish municipality of Savitaipale.

METHODS

1151 people participated in the baseline survey in 1996-1999, following two follow-up examinations, in 2007-2008 and 2018-2019. Follow-up studies comprised clinical measurements, 2-h oral glucose tolerance test and other biochemistry, questionnaires, and registry data.

RESULTS

The prevalence of T2D quadrupled to 27% and the proportion of normoglycemic people decreased from 73% to 44% while IH increased only slightly during the 22-year follow-up. A large proportion of people who died between the surveys were diabetic. The mean body mass index (BMI) did not, whereas mean waist circumference increased significantly, by 5-6 cm (P = 0.001) during the 22 years. Systolic blood pressure increased by 13-15 mmHg from baseline (P = 0.0001) but diastolic blood pressure did not. The mean plasma levels of total and LDL-cholesterol decreased 10.8% and 8.9% in women (P = 0.001), 21.5% and 22.2% in men (P = 0.001), respectively, while HDL-cholesterol and triglycerides remained stable. The proportion of those achieving targets in the treatment of dyslipidaemia increased significantly (P < 0.001).

CONCLUSIONS

In this 22-year prospective follow-up study of in middle-aged Europeans with high participation rates, the progression of dysglycaemia to overt diabetes with aging was rapid, even without a significant change in BMI.

Definition and Classification of Diabetes and Prediabetes and Emerging Data on Phenotypes

Diabetes diagnosis has important implications for individuals. Diagnostic criteria for fasting and 2-hour plasma glucose and HbA1c are universally agreed. Intermediate hyperglycemia/prediabetes is a risk factor for diabetes and cardiovascular disease. Because risk is a continuum, determining cut-point is problematic and reflected in significant differences in recommended fasting glucose and HbA1c criteria. Many types of diabetes are recognized. Diabetes classification systems are limited by a lack of understanding of etiopathogenetic pathways leading to diminished β-cell function. The World Health Organization classification system is designed to assist clinical care decisions. Newly recognized phenotypic clusters of diabetes might inform future classification systems.

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.

The Natural Course of Impaired Fasting Glucose

Impaired glucose regulation, including diabetes and prediabetes, poses a huge global problem not only in health but also in the epidemiological and economic areas. These disorders are often detected too late or remain unrecognized. The article aims to provide a review of the prevalence, etiology, and natural history of impaired fasting glucose (IFG). We focus on the progression of isolated IFG to full-fledged type 2 diabetes and the factors conducive to the development of diabetes. The knowledge about it could help design an optimal management program for the prevention of diabetes in patients with IFG; a program that would be patient-tailored and based on the underlying pathophysiology.

Trends in incidence of total or type 2 diabetes: systematic review

OBJECTIVE

To assess what proportions of studies reported increasing, stable, or declining trends in the incidence of diagnosed diabetes.

DESIGN

Systematic review of studies reporting trends of diabetes incidence in adults from 1980 to 2017 according to PRISMA guidelines.

DATA SOURCES

Medline, Embase, CINAHL, and reference lists of relevant publications.

ELIGIBILITY CRITERIA

Studies of open population based cohorts, diabetes registries, and administrative and health insurance databases on secular trends in the incidence of total diabetes or type 2 diabetes in adults were included. Poisson regression was used to model data by age group and year.

RESULTS

Among the 22 833 screened abstracts, 47 studies were included, providing data on 121 separate sex specific or ethnicity specific populations; 42 (89%) of the included studies reported on diagnosed diabetes. In 1960-89, 36% (8/22) of the populations studied had increasing trends in incidence of diabetes, 55% (12/22) had stable trends, and 9% (2/22) had decreasing trends. In 1990-2005, diabetes incidence increased in 66% (33/50) of populations, was stable in 32% (16/50), and decreased in 2% (1/50). In 2006-14, increasing trends were reported in only 33% (11/33) of populations, whereas 30% (10/33) and 36% (12/33) had stable or declining incidence, respectively.

CONCLUSIONS

The incidence of clinically diagnosed diabetes has continued to rise in only a minority of populations studied since 2006, with over a third of populations having a fall in incidence in this time period. Preventive strategies could have contributed to the fall in diabetes incidence in recent years. Data are limited in low and middle income countries, where trends in diabetes incidence could be different.

SYSTEMATIC REVIEW REGISTRATION

Prospero CRD42018092287.

Development of type 2 diabetes mellitus in people with intermediate hyperglycaemia

BACKGROUND

Intermediate hyperglycaemia (IH) is characterised by one or more measurements of elevated blood glucose concentrations, such as impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and elevated glycosylated haemoglobin A1c (HbA1c). These levels are higher than normal but below the diagnostic threshold for type 2 diabetes mellitus (T2DM). The reduced threshold of 5.6 mmol/L (100 mg/dL) fasting plasma glucose (FPG) for defining IFG, introduced by the American Diabetes Association (ADA) in 2003, substantially increased the prevalence of IFG. Likewise, the lowering of the HbA1c threshold from 6.0% to 5.7% by the ADA in 2010 could potentially have significant medical, public health and socioeconomic impacts.

OBJECTIVES

To assess the overall prognosis of people with IH for developing T2DM, regression from IH to normoglycaemia and the difference in T2DM incidence in people with IH versus people with normoglycaemia.

SEARCH METHODS

We searched MEDLINE, Embase, ClincialTrials.gov and the International Clinical Trials Registry Platform (ICTRP) Search Portal up to December 2016 and updated the MEDLINE search in February 2018. We used several complementary search methods in addition to a Boolean search based on analytical text mining.

SELECTION CRITERIA

We included prospective cohort studies investigating the development of T2DM in people with IH. We used standard definitions of IH as described by the ADA or World Health Organization (WHO). We excluded intervention trials and studies on cohorts with additional comorbidities at baseline, studies with missing data on the transition from IH to T2DM, and studies where T2DM incidence was evaluated by documents or self-report only.

DATA COLLECTION AND ANALYSIS

One review author extracted study characteristics, and a second author checked the extracted data. We used a tailored version of the Quality In Prognosis Studies (QUIPS) tool for assessing risk of bias. We pooled incidence and incidence rate ratios (IRR) using a random-effects model to account for between-study heterogeneity. To meta-analyse incidence data, we used a method for pooling proportions. For hazard ratios (HR) and odds ratios (OR) of IH versus normoglycaemia, reported with 95% confidence intervals (CI), we obtained standard errors from these CIs and performed random-effects meta-analyses using the generic inverse-variance method. We used multivariable HRs and the model with the greatest number of covariates. We evaluated the certainty of the evidence with an adapted version of the GRADE framework.

MAIN RESULTS

We included 103 prospective cohort studies. The studies mainly defined IH by IFG_5.6 (FPG mmol/L 5.6 to 6.9 mmol/L or 100 mg/dL to 125 mg/dL), IFG_6.1 (FPG 6.1 mmol/L to 6.9 mmol/L or 110 mg/dL to 125 mg/dL), IGT (plasma glucose 7.8 mmol/L to 11.1 mmol/L or 140 mg/dL to 199 mg/dL two hours after a 75 g glucose load on the oral glucose tolerance test, combined IFG and IGT (IFG/IGT), and elevated HbA1c (HbA1c_5.7: HbA1c 5.7% to 6.4% or 39 mmol/mol to 46 mmol/mol; HbA1c_6.0: HbA1c 6.0% to 6.4% or 42 mmol/mol to 46 mmol/mol). The follow-up period ranged from 1 to 24 years. Ninety-three studies evaluated the overall prognosis of people with IH measured by cumulative T2DM incidence, and 52 studies evaluated glycaemic status as a prognostic factor for T2DM by comparing a cohort with IH to a cohort with normoglycaemia. Participants were of Australian, European or North American origin in 41 studies; Latin American in 7; Asian or Middle Eastern in 50; and Islanders or American Indians in 5. Six studies included children and/or adolescents.Cumulative incidence of T2DM associated with IFG_5.6, IFG_6.1, IGT and the combination of IFG/IGT increased with length of follow-up. Cumulative incidence was highest with IFG/IGT, followed by IGT, IFG_6.1 and IFG_5.6. Limited data showed a higher T2DM incidence associated with HbA1c_6.0 compared to HbA1c_5.7. We rated the evidence for overall prognosis as of moderate certainty because of imprecision (wide CIs in most studies). In the 47 studies reporting restitution of normoglycaemia, regression ranged from 33% to 59% within one to five years follow-up, and from 17% to 42% for 6 to 11 years of follow-up (moderate-certainty evidence).Studies evaluating the prognostic effect of IH versus normoglycaemia reported different effect measures (HRs, IRRs and ORs). Overall, the effect measures all indicated an elevated risk of T2DM at 1 to 24 years of follow-up. Taking into account the long-term follow-up of cohort studies, estimation of HRs for time-dependent events like T2DM incidence appeared most reliable. The pooled HR and the number of studies and participants for different IH definitions as compared to normoglycaemia were: IFG_5.6: HR 4.32 (95% CI 2.61 to 7.12), 8 studies, 9017 participants; IFG_6.1: HR 5.47 (95% CI 3.50 to 8.54), 9 studies, 2818 participants; IGT: HR 3.61 (95% CI 2.31 to 5.64), 5 studies, 4010 participants; IFG and IGT: HR 6.90 (95% CI 4.15 to 11.45), 5 studies, 1038 participants; HbA1c_5.7: HR 5.55 (95% CI 2.77 to 11.12), 4 studies, 5223 participants; HbA1c_6.0: HR 10.10 (95% CI 3.59 to 28.43), 6 studies, 4532 participants. In subgroup analyses, there was no clear pattern of differences between geographic regions. We downgraded the evidence for the prognostic effect of IH versus normoglycaemia to low-certainty evidence due to study limitations because many studies did not adequately adjust for confounders. Imprecision and inconsistency required further downgrading due to wide 95% CIs and wide 95% prediction intervals (sometimes ranging from negative to positive prognostic factor to outcome associations), respectively.This evidence is up to date as of 26 February 2018.

AUTHORS' CONCLUSIONS

Overall prognosis of people with IH worsened over time. T2DM cumulative incidence generally increased over the course of follow-up but varied with IH definition. Regression from IH to normoglycaemia decreased over time but was observed even after 11 years of follow-up. The risk of developing T2DM when comparing IH with normoglycaemia at baseline varied by IH definition. Taking into consideration the uncertainty of the available evidence, as well as the fluctuating stages of normoglycaemia, IH and T2DM, which may transition from one stage to another in both directions even after years of follow-up, practitioners should be careful about the potential implications of any active intervention for people 'diagnosed' with IH.

Overview of trends in cardiovascular and diabetes risk factors in Fiji

CONTEXT

Fiji has undergone an epidemiological transition, characterised by declining infectious disease and childhood mortality, that has been offset by rising cardiovascular disease mortality. Other Pacific Island states are in a comparable situation.

OBJECTIVE

With a focus on Fiji, this study reviews and contextualises research performed by the authors and others that examines cardiovascular disease (CVD) and type 2 diabetes (T2DM) and their risk factors in Pacific Island states.

METHODS

This overview covers evidence for the causes and consequences of CVD risk factors and the epidemiological transition and reflects on biological and evolutionary hypotheses. It is based on studies the authors carried out that synthesised disparate population-based CVD risk factor surveys conducted in Fiji over 1980-2012.

RESULTS

Prevalences of obesity, T2DM and hypertension continue to increase in the Fiji population. Tobacco smoking prevalence has decreased, but remains relatively high in men compared to many developed countries. T2DM and hypertension trends, and CVD consequences related to diet, exercise and tobacco smoking, have placed the Fiji population in a variant of the epidemiological transition manifesting as a plateau in life expectancy similar to that of numerous developed countries during the mid-20th century.

CONCLUSION

There is evidence that risk factors and consequent CVD mortality can be reduced in populations. Obesity and T2DM reductions have been observed only in populations surviving in dire circumstances. Interventions to lower the prevalence of CVD and T2DM risk factors in the Fiji population require multi-faceted approaches, with continual monitoring and evaluation for their impact on these risk factors and morbidity and mortality outcomes.

Prediabetes and diabetes in a cohort of Qatari women screened for polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is associated with an increased risk of type 2 diabetes mellitus (T2DM) but its association with prediabetes and T2DM is unknown in Qatar. A cross sectional analysis of 3,017 Qatari subjects from the Qatar Biobank, identified 749 women aged 18–40 years, 720 of whom were assessed by the National Institute for Health (NIH) Guidelines for PCOS. Prediabetes (HbA1c 5.7–6.4% and/or impaired fasting glucose (IFG): fasting plasma glucose (FPG) 100–125 mg/dL (5.6–6.9 mmol/L)), and T2DM (fasting plasma glucose > 125 mg/dL (≥7 mmol/L), and/or HbA1c ≥ 6.5%) were determined. The prevalence of prediabetes was 10.6% and the prevalence of undiagnosed diabetes was found to be 4.0% in the total population. Overall, 12.1% of 720 women had PCOS, of whom FPG and HbA1c were available in 62 women with PCOS: 19.4% had prediabetes and 9.7% had diabetes. An adverse cardiovascular risk profile for IFG women compared to normal women was found. Women with PCOS alone had a similar adverse cardiovascular profile as those with IFG alone and T2DM. Thus, the risk of prediabetes and diabetes is increased in Qatari women with PCOS, with an adverse cardiovascular risk profile similar to that seen in prediabetes and T2DM.

Diabetes self-assessment score and the development of diabetes: A 10-year prospective study

To verify that the Korean Diabetes Score (KDS), a self-assessment, predicts the risk of diabetes in various comprehensive risk models, and to investigate factors that enhance its predictive ability in a large cohort. We analyzed 8735 adults without diabetes in the Korean Genome and Epidemiology Study, an ongoing large community-based 10-year cohort study. Incident diabetes was defined as fasting blood glucose ≥126 mg/dL or postload 2-hour glucose ≥200 mg/dL by 75 g oral glucose tolerance test conducted biennually, or currently taking medication for diabetes. Hazard ratios (HRs) using Cox regression were calculated for relative risk of developing diabetes as associated with the KDS, and performance of risk models was assessed by area under the receiver-operating characteristic curve (AUC). Of 8735 participants, 1497 (17.1%) developed diabetes over 10 years. The prevalence of incident diabetes was 10.3% in people with a KDS <5 and was 21.8% in those with KDS ≥5 (P < .001). Increasing KDS was significantly associated with developing diabetes (adjusted HR: 1.13; 95% confidence interval:1.09,1.18). The comprehensive prediction model with KDS added to fasting glucose, glycated hemoglobin, postload 2-hour glucose, and triglyceride showed a markedly higher AUC (0.782) compared to KDS alone (0.641). A low insulinogenic index (IGI) level, but not insulin resistance, was a significant determinant of developing diabetes in subjects who had baseline KDS < 5. We confirmed that KDS as a 10-year risk model to predict diabetes becomes more potent when added to relevant laboratory parameters. Beta-cell function as assessed by IGI should be taken into account when predicting diabetes using the KDS.

Incidence and risk factors for type 2 diabetes mellitus in transitional Thailand: results from the Thai cohort study

BACKGROUND

Type 2 diabetes mellitus (T2DM) is increasingly prevalent in countries undergoing rapid development, including Thailand. We assessed T2DM incidence over an 8-year period in a nationwide cohort of Thai adults.

METHODS

Thai Cohort Study participants were surveyed in 2005, 2009 and 2013. The analysed cohort members were aged (15-88), did not have diabetes in 2005 and were followed up by questionnaire in 2013 (n=39 507). T2DM was ascertained using self-report, which has been validated using physician interviews. We calculated the 8-year cumulative incidence of T2DM. Multivariable logistic regression assessed associations between potential risk factors and T2DM incidence.

RESULTS

8-year cumulative incidence of T2DM (2005 to 2013) was 177 per 10 000 (95% CI 164 to 190). Crude and age-standardised cumulative incidences of T2DM by sex were 249 per 10 000 (95% CI 226 to 272) and 222 per 10 000 (95% CI 219 to 225) for men; and 119 per 10 000 (95% CI 105 to 133) and 96 per 10 000 (95% CI 94 to 98) for women, respectively. T2DM increased significantly for both sexes with increasing age and body mass index (BMI) (p trend <0.001 for both). Residence in an urban area as a child associated with T2DM among men and women (OR=1.4, 95% CI 1.1 to 1.7 and OR=1.4, 95% CI 1.01 to 1.79); this was no longer statistically significant after adjusting for BMI. Among men, smoking (OR=1.7, 95% CI 1.3 to 2.2) and alcohol intake (OR=1.8, 95% CI 1.1 to 3.0) were associated with T2DM.

CONCLUSIONS

This study found that the sociodemographic and lifestyle changes that have accompanied Thailand's economic development are associated with T2DM risk in a large cohort of Thai adults. Our findings highlight the need to address these transitions to prevent a further increase in the national incidence of T2DM, particularly among Thai men.

Diabetes incidence and projections from prevalence surveys in Fiji

Background

Type 2 diabetes mellitus (T2DM) incidence is traditionally derived from cohort studies that are not always feasible, representative, or available. The present study estimates T2DM incidence in Fijian adults from T2DM prevalence estimates assembled from surveys of 25–64 year old adults conducted over 30 years (n = 14,288).

Methods

T2DM prevalence by five-year age group from five population-based risk factor surveys conducted over 1980–2011 were variously adjusted for urban-rural residency, ethnicity, and sex to previous censuses (1976, 1986, 1996, 2009) to improve representativeness. Prevalence estimates were then used to calculate T2DM incidence based on birth cohorts from the age-period (Lexis) matrix following the Styblo technique, first used to estimate annual risk of tuberculosis infection (incidence) from sequential Mantoux population surveys. Poisson regression of year, age, sex, and ethnicity strata (n = 160) was used to develop projections of T2DM prevalence and incidence to 2020 based on various scenarios of population weight measured by body mass index (BMI) change.

Results

T2DM prevalence and annual incidence increased in Fiji over 1980–2011. Prevalence was higher in Indians and men than i-Taukei and women. Incidence was higher in Indians and women. From regression analyses, absolute reductions of 2.6 to 5.1% in T2DM prevalence (13–26% lower), and 0.5–0.9 per 1000 person-years in incidence (8–14% lower), could be expected in 2020 in adults if mean population weight could be reduced by 1–4 kg, compared to the current period trend in weight gain.

Conclusions

This is the first application of the Styblo technique to calculate T2DM incidence from population-based prevalence surveys over time. Reductions in population BMI are predicted to reduce T2DM incidence and prevalence in Fiji among adults aged 25–64 years.

Electronic supplementary material

The online version of this article (doi:10.1186/s12963-016-0114-0) contains supplementary material, which is available to authorized users.

Factors that could explain the increasing prevalence of type 2 diabetes among adults in a Canadian province: a critical review and analysis

BACKGROUND

The prevalence of diabetes has increased since the last decade in New Brunswick. Identifying factors contributing to the increase in diabetes prevalence will help inform an action plan to manage the condition. The objective was to describe factors that could explain the increasing prevalence of type 2 diabetes in New Brunswick since 2001.

METHODS

A critical literature review was conducted to identify factors potentially responsible for an increase in prevalence of diabetes. Data from various sources were obtained to draw a repeated cross-sectional (2001-2014) description of these factors concurrently with changes in the prevalence of type 2 diabetes in New Brunswick. Linear regressions, Poisson regressions and Cochran Armitage analysis were used to describe relationships between these factors and time.

RESULTS

Factors identified in the review were summarized in five categories: individual-level risk factors, environmental risk factors, evolution of the disease, detection effect and global changes. The prevalence of type 2 diabetes has increased by 120% between 2001 and 2014. The prevalence of obesity, hypertension, prediabetes, alcohol consumption, immigration and urbanization increased during the study period and the consumption of fruits and vegetables decreased which could represent potential factors of the increasing prevalence of type 2 diabetes. Physical activity, smoking, socioeconomic status and education did not present trends that could explain the increasing prevalence of type 2 diabetes. During the study period, the mortality rate and the conversion rate from prediabetes to diabetes decreased and the incidence rate increased. Suggestion of a detection effect was also present as the number of people tested increased while the HbA1c and the age at detection decreased. Period and birth cohort effect were also noted through a rise in the prevalence of type 2 diabetes across all age groups, but greater increases were observed among the younger cohorts.

CONCLUSIONS

This study presents a comprehensive overview of factors potentially responsible for population level changes in prevalence of type 2 diabetes. Recent increases in type 2 diabetes in New Brunswick may be attributable to a combination of some individual-level and environmental risk factors, the detection effect, the evolution of the disease and global changes.

Investigation of Genetic Variation Underlying Central Obesity amongst South Asians

South Asians are 1/4 of the world's population and have increased susceptibility to central obesity and related cardiometabolic disease. Knowledge of genetic variants affecting risk of central obesity is largely based on genome-wide association studies of common SNPs in Europeans. To evaluate the contribution of DNA sequence variation to the higher levels of central obesity (defined as waist hip ratio adjusted for body mass index, WHR) among South Asians compared to Europeans we carried out: i) a genome-wide association analysis of >6M genetic variants in 10,318 South Asians with focused analysis of population-specific SNPs; ii) an exome-wide association analysis of ~250K SNPs in protein-coding regions in 2,637 South Asians; iii) a comparison of risk allele frequencies and effect sizes of 48 known WHR SNPs in 12,240 South Asians compared to Europeans. In genome-wide analyses, we found no novel associations between common genetic variants and WHR in South Asians at P<5x10-8; variants showing equivocal association with WHR (P<1x10-5) did not replicate at P<0.05 in an independent cohort of South Asians (N = 1,922) or in published, predominantly European meta-analysis data. In the targeted analyses of 122,391 population-specific SNPs we also found no associations with WHR in South Asians at P<0.05 after multiple testing correction. Exome-wide analyses showed no new associations between genetic variants and WHR in South Asians, either individually at P<1.5x10-6 or grouped by gene locus at P<2.5x10-6. At known WHR loci, risk allele frequencies were not higher in South Asians compared to Europeans (P = 0.77), while effect sizes were unexpectedly smaller in South Asians than Europeans (P<5.0x10-8). Our findings argue against an important contribution for population-specific or cosmopolitan genetic variants underlying the increased risk of central obesity in South Asians compared to Europeans.

Determinants of incident prediabetes and type 2 diabetes in a 7-year cohort in a developing country: The Isfahan Cohort Study

BACKGROUND

This study aimed to identify determinants of new onset type-2 diabetes (T2D) and prediabetes in a region with high rate of T2D but scarcity of evidence.

METHODS

Participants free of T2D were identified in a population-based study of adults older than 35 years living in the rural and urban areas of three districts in Iran in 2001 and were re-examined after 7 years. Biochemical measurements, anthropometric data, blood pressure, smoking status and dietary intake were determined at both measurement points through identical protocols and procedures. Data analysis was done using multivariate ordered logistic regressions.

RESULTS

Incidence rate of prediabetes and T2D was 32.3 (95%CI, 29.7-35.1) and 18.9 (17.1-20.9) per 1000 person-year, respectively. Odds of progression to prediabetes and T2D were increased with ageing, living in rural area (OR = 1.28), unhealthy diet (OR = 1.32), overweight (OR = 1.45), obesity (OR = 1.97), waist gain (OR = 1.37), high waist-to-hip ratio (OR = 1.35), hypertension (OR = 1.35), and hypertriglyceridemia (OR = 1.50); but reduced with higher education (OR = 0.76) and weight loss (OR = 0.67) in the adjusted models. In those with prediabetes at baseline, parental history of T2D (OR = 2.26), obesity (OR = 2.59), high waist circumference (OR = 2.03), and hypertriglyceridemia (OR = 1.94) were associated with developing T2D. No factor was found to be associated with regression from prediabetes to normoglycemia in adjusted models.

CONCLUSIONS

Current data endorses proposed statistical projections for the future trend of diabetes, and highlights the potential role of obesity specifically visceral type.

High consumption of pulses is associated with lower risk of abnormal glucose metabolism in women in Mauritius

AIMS

To investigate if consumption of pulses was associated with a reduced risk of developing abnormal glucose metabolism, increases in body weight and increases in waist circumference in a multi-ethnic cohort in Mauritius.

METHODS

Population-based surveys were performed in Mauritius in 1992 and in 1998. Pulse consumption was estimated from a food frequency questionnaire in 1992 and outcomes were measured in 1998. At both time points, anthropometry was undertaken and an oral glucose tolerance test was performed.

RESULTS

Mauritian women with the highest consumption of pulses (highest tertile) had a reduced risk of developing abnormal glucose metabolism [odds ratio 0.52; 95% CI 0.27, 0.99) compared with those with the lowest consumption, and also after multivariable adjustments. In women, a high consumption of pulses was associated with a smaller increase in BMI.

CONCLUSIONS

High consumption of pulses was associated with a reduced risk of abnormal glucose metabolism and a smaller increase in BMI in Mauritian women. Promotion of pulse consumption could be an important dietary intervention for the prevention of Type 2 diabetes and obesity in Mauritius and should be examined in other populations and in clinical trials.

The performance of diabetes risk prediction models in new populations: the role of ethnicity of the development cohort

It is believed that diabetes risk scores need to be ethnic specific. However, this prerequisite has not been tested. We examined the performance of several risk models, developed in various populations, in a Europid and a South Asian population. The performance of 14 published risk prediction models were tested in two prospective studies: the Australian Diabetes, Obesity and Lifestyle (AusDiab) study and the Mauritius non-communicable diseases survey. Eight models were developed in Europid populations; the remainder in various non-Europid populations. Model performance was assessed using area under the receiver operating characteristic curves (discrimination), Hosmer-Lemeshow tests (goodness-of-fit) and Brier scores (accuracy). In both AusDiab and Mauritius, discrimination was highest for a model developed in a mixed population (non-Hispanic white and African American) and lowest for a model developed in a Europid population. Discrimination for all scores was higher in AusDiab than in Mauritius. For almost all models, goodness-of-fit was poor irrespective of the ethnicity of the development cohort, and accuracy was higher in AusDiab compared to Mauritius. Our results suggest that similarity of ethnicity or similarity of diabetes risk may not be the best way of identifying models that will perform well in another population. Differences in study methodology likely account for much of the difference in the performance. Thus, identifying models which use measurements that are clearly described and easily reproducible for both research and clinical settings may be more important.

Plasma levels of soluble interleukin 1 receptor accessory protein are reduced in obesity

CONTEXT

Adipokines actuate chronic, low-grade inflammation through a complex network of immune markers, but the current understanding of these networks is incomplete. The soluble isoform of the IL-1 receptor accessory protein (sIL1RAP) occupies an important position in the inflammatory pathways involved in obesity. The pathogenetic and clinical influences of sIL1RAP are unknown.

OBJECTIVE

The objective of the study was to elucidate whether plasma levels of sIL1RAP are reduced in obesity, using affluent clinical, biochemical, and genetic data from two diverse cohorts.

DESIGN, SETTING, AND PARTICIPANTS

The study was conducted in two cohorts: the San Antonio Family Heart Study (n = 1397 individuals from 42 families) and South Asians living in Mauritius, n = 230).

MAIN OUTCOME MEASURES

Plasma sIL1RAP levels were measured using an ELISA. The genetic basis of sIL1RAP levels were investigated using both a large-scale gene expression profiling study and a genome-wide association study.

RESULTS

A significant decrease in plasma sIL1RAP levels were observed in obese subjects, even after adjustment for age and sex. The sIL1RAP levels demonstrated a strong inverse association with obesity measures in both populations. All associations were more significant in females. Plasma sIL1RAP levels were significantly heritable, correlated with IL1RAP transcript levels (NM_134470), showed evidence for shared genetic influences with obesity measures and were significantly associated with the rs2885373 single-nucleotide polymorphism (P = 6.7 × 10(-23)) within the IL1RAP gene.

CONCLUSIONS

Plasma sIL1RAP levels are reduced in obesity and can potentially act as biomarkers of obesity. Mechanistic studies are required to understand the exact contribution of sIL1RAP to the pathogenesis of obesity.

Approaching pre-diabetes

As the global epidemic of type 2 diabetes continues to rise, the time has come to revisit our approach to pre-diabetes. Recently, much ado has been made about screening, diagnosis, pathophysiology and clinical interventions in pre-diabetes, and all for good reason as the key to reversing the diabetes epidemic likely lies therein. The somewhat controversial term "pre-diabetes" represents collective dysglycemic states intermediate between normal glucose regulation (NGR) and diabetes. Not all people with pre-diabetes will develop diabetes, but the majority will. In fact, up to 70% of those with pre-diabetes may acquire the disease over their lifetime. Furthermore, even when overt diabetes is delayed or prevented, both micro- and macrovascular disease appears more prevalent in those with pre-diabetes compared to their normoglycemic peers. Hence, there is growing consensus that NGR should be the goal for people with pre-diabetes. Nevertheless, there is much to consider in that pursuit. Herein, we provide an update on the global burden of pre-diabetes, its underlying pathophysiology and discuss clinical considerations in these individuals at high risk of developing diabetes.

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.

The association between self-rated health and impaired glucose tolerance in Swedish adults: a cross-sectional study

OBJECTIVE

To investigate gender differences in the association between self-rated health (SRH) and impaired glucose tolerance (IGT) in subjects unaware of their glucose tolerance.

DESIGN

A cross-sectional population-based study.

SETTING

The two municipalities of Vara and Skövde in south-western Sweden.

SUBJECTS

A total of 2502 participants (1301 women and 1201 men), aged 30-75, were randomly selected from the population.

MAIN OUTCOME MEASURES

IGT was regarded as the outcome measure and SRH as the main risk factor.

RESULTS

The prevalence of IGT was significantly higher in women (11.9%) than in men (10.1%), (p = 0.029), as was the prevalence of low SRH (women: 35.4%; men: 22.1%, p = 0.006). Both men and women with low SRH had a poorer risk factor profile than those with high SRH, and a statistically significant crude association between SRH and IGT was found in both men (OR = 2.8, 95% CI 1.8-4.4) and women (OR = 1.5, 95% CI 1.0-2.2, p = 0.033). However, after controlling for several lifestyle factors and biomedical variables, the association was attenuated and remained statistically significant solely in men (OR = 2.3, 95% CI 1.2-4.3).

CONCLUSION

The gender-specific associations found between SRH and IGT suggest that SRH may be a better indicator of IGT in men than in women. Future studies should evaluate the utility of SRH in comparison with objective health measures as a potential aid to health practitioners when deciding whether to screen for IGT and T2DM.

Comparison of the clinical manifestations of type 2 diabetes mellitus between rhesus monkey (Macaca mulatta lasiotis) and human being

OBJECTIVES

Type 2 diabetes mellitus (T2DM) is the most common form of diabetes. To determine the similarities of development of T2DM between rhesus monkey [Macaca mulatta lasiotis (M. m. lasiotis)] and human being, the clinical parameters were determined during a period of 2 years in 60 adult male rhesus monkeys (M. m. lasiotis).

METHODS

Sixty male monkeys whose fasting plasma glucose (FPG) level less than or equal to 5 mmol/L (90 mg/dL) were enrolled in this study. Of these, 50 monkeys aged 7 to 20 years were fed with high-fat diet and 10 aged 4 to 10 years fed with standard diet as normal monkeys. Body weight, body mass index, FPG, fasting plasma insulin, and hemoglobin A1c levels were measured and calculated. The responses of insulin and glucose levels to intravenous glucose tolerance test were analyzed.

RESULTS

Of 50 monkeys fed with high-fat diet, 8 developed overt T2DM, 26 experienced impaired glucose tolerance and impaired fasting glucose, and FPG of 16 monkeys was normal. All monkeys with impaired glucose tolerance experienced obesity, compensatory increase of fasting plasma insulin, significant decline of postprandial glucose clearance rate (KGluc5-20), and decreased insulin secretion.

CONCLUSIONS

In conclusion, rhesus monkey (M. m. lasiotis) has many similarities with human beings in terms of clinical manifestations and risk factors at different diabetes stages.

All-cause cancer mortality over 15 years in multi-ethnic Mauritius: the impact of diabetes and intermediate forms of glucose tolerance

There are accumulating data describing the association between diabetes and cancer mortality from Westernised populations. There are no data describing the relationship between diabetes and cancer mortality in African or South Asian populations from developing countries. We explored the relationship of abnormal glucose tolerance and diabetes on cancer mortality risk in a large, multi-ethnic cohort from the developing nation of Mauritius. Population-based surveys were undertaken in 1987, 1992 and 1998. The 9559 participants comprised 66% of South Asian (Indian), 27% of African (Creole), and 7% of Chinese descent. Cox's proportional hazards model with time varying covariates was used to obtain hazard ratios (HRs) and 95% confidence intervals (95% CI) for risk of cancer mortality, after adjustment for confounding factors. In men, but not women, cancer mortality risk increased with rising 2h-PG levels with HR for the top versus bottom quintile of 2.77 (95%CI: 1.28 to 5.98). South Asian men with known diabetes had a significantly greater risk of cancer mortality than those with normal glucose tolerance (NGT) HR: 2.74 (95%CI: 1.00-7.56). Overall, impaired glucose tolerance was associated with an elevated risk of cancer mortality compared to NGT (HR: 1.47, 95% CI: 0.98-2.19), though this was not significant. We have shown that the association between abnormal glucose tolerance and cancer extends to those of African and South Asian descent. These results highlight the importance of understanding this relationship in a global context to direct future health policy given the rapid increase in type 2 diabetes, especially in developing nations.

The influence of hip circumference on the relationship between abdominal obesity and mortality

BACKGROUND

Higher waist circumference and lower hip circumference are both associated with increased cardiovascular disease (CVD) risk, despite being directly correlated. The real effects of visceral obesity may therefore be underestimated when hip circumference is not fully taken into account. We hypothesized that adding waist and hip circumference to traditional risk factors would significantly improve CVD risk prediction.

METHODS

In a population-based survey among South Asian and African Mauritians (n = 7978), 1241 deaths occurred during 15 years of follow-up. In a model that included variables used in previous CVD risk calculations (a Framingham-type model), the association between waist circumference and mortality was examined before and after adjustment for hip circumference. The percentage with an increase in estimated 10-year cumulative mortality of >25% and a decrease of >20% after waist and hip circumference were added to the model was calculated.

RESULTS

Waist circumference was strongly related to mortality only after adjustment for hip circumference and vice versa. Adding waist and hip circumference to a Framingham-type model increased estimated 10-year cumulative CVD mortality by >25% for 23.7% of those who died and 15.7% of those censored. Cumulative mortality decreased by >20% for 4.5% of those who died and 14.8% of those censored.

CONCLUSIONS

The effect of central obesity on mortality risk is seriously underestimated without adjustment for hip circumference. Adding waist and hip circumference to a Framingham-type model for CVD mortality substantially increased predictive power. Both may be important inclusions in CVD risk prediction models.

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.

Genome-wide association study in individuals of South Asian ancestry identifies six new type 2 diabetes susceptibility loci

We carried out a genome-wide association study of type-2 diabetes (T2D) in individuals of South Asian ancestry. Our discovery set included 5,561 individuals with T2D (cases) and 14,458 controls drawn from studies in London, Pakistan and Singapore. We identified 20 independent SNPs associated with T2D at P < 10(-4) for testing in a replication sample of 13,170 cases and 25,398 controls, also all of South Asian ancestry. In the combined analysis, we identified common genetic variants at six loci (GRB14, ST6GAL1, VPS26A, HMG20A, AP3S2 and HNF4A) newly associated with T2D (P = 4.1 × 10(-8) to P = 1.9 × 10(-11)). SNPs at GRB14 were also associated with insulin sensitivity (P = 5.0 × 10(-4)), and SNPs at ST6GAL1 and HNF4A were also associated with pancreatic beta-cell function (P = 0.02 and P = 0.001, respectively). Our findings provide additional insight into mechanisms underlying T2D and show the potential for new discovery from genetic association studies in South Asians, a population with increased susceptibility to T2D.

Neuropathy and impaired glucose tolerance: an updated review of the evidence

There has been considerable interest in the possible association between impaired glucose tolerance (IGT) and neuropathy. A systematic literature search (Medline) and review was here performed. Twenty-three studies were evaluated. Fourteen investigated for the presence of neuropathy in patients with IGT. Nine studied patients with chronic idiopathic axonal polyneuropathy (CIAP), for the prevalence of IGT. The findings suggest that a significant proportion of patients with IGT may have neuropathy, particularly of the small-fibre and painful type. Similarly, a significant percentage of patients without another identifiable cause for painful axonal neuropathy may have IGT. This may however not be applicable to all populations. There are issues relating to the reproducibility, reliability and timing of a single glucose tolerance test (GTT) in establishing a diagnosis of IGT. Furthermore, it is possible neuropathic damage may occur at lower glucose levels than those defining IGT. In conclusion, further prospective long-term study of large IGT cohorts with known prestudy IGT duration is required to confirm and answer the many remaining questions about this presumed association. However, at present time, consideration of IGT as potential cause of painful small-fibre neuropathy appears justified, especially as patients may benefit from dietary and physical exercise interventions.

Insulin resistance in treated HIV infection

Insulin resistance (IR) was one of the first metabolic complications reported with highly active antiretroviral therapy for HIV infection. It continues to be of concern despite the introduction of newer antiretrovirals with safer metabolic profiles and is associated with inflammation and the development of diabetes mellitus. As the HIV-infected population ages, the prevalence of IR is likely to rise. Specific antiretrovirals can increase insulin resistance through two principal mechanisms, either directly by interfering with insulin signalling at the cellular level or indirectly as a consequence of defects in lipid metabolism (lipotoxocity) arising from antiretroviral toxicities such as the IR observed in those with HIV-associated lipodystrophy. There is considerable overlap between different antiretrovirals in their propensity to cause IR making it more difficult to attribute development of IR to a particular antiretroviral medication. In addition, in the setting of a generalised epidemic of obesity that exists in many populations worldwide, HIV-infected patients may be more prone to the consequences of antiretroviral-induced insulin resistance and diabetes mellitus. Optimal screening and treatment strategies for IR in treated HIV infection have not been established. In this article we review current opinion on insulin resistance in HIV and identify potential areas for future research.

The Evaluation of Screening and Early Detection Strategies for Type 2 Diabetes and Impaired Glucose Tolerance (DETECT-2) update of the Finnish diabetes risk score for prediction of incident type 2 diabetes

AIMS/HYPOTHESIS

The Finnish diabetes risk questionnaire is a widely used, simple tool for identification of those at risk for drug-treated type 2 diabetes. We updated the risk questionnaire by using clinically diagnosed and screen-detected type 2 diabetes instead of drug-treated diabetes as an endpoint and by considering additional predictors.

METHODS

Data from 18,301 participants in studies of the Evaluation of Screening and Early Detection Strategies for Type 2 Diabetes and Impaired Glucose Tolerance (DETECT-2) project with baseline and follow-up information on oral glucose tolerance status were included. Incidence of type 2 diabetes within 5 years was used as the outcome variable. Improvement in discrimination and classification of the logistic regression model was assessed by the area under the receiver-operating characteristic (ROC) curve and by the net reclassification improvement. Internal validation was by bootstrapping techniques.

RESULTS

Of the 18,301 participants, 844 developed type 2 diabetes in a period of 5 years (4.6%). The Finnish risk score had an area under the ROC curve of 0.742 (95% CI 0.726-0.758). Re-estimation of the regression coefficients improved the area under the ROC curve to 0.766 (95% CI 0.750-0.783). Additional items such as male sex, smoking and family history of diabetes (parent, sibling or both) improved the area under the ROC curve and net reclassification. Bootstrapping showed good internal validity.

CONCLUSIONS/INTERPRETATION

The predictive value of the original Finnish risk questionnaire could be improved by adding information on sex, smoking and family history of diabetes. The DETECT-2 update of the Finnish diabetes risk questionnaire is an adequate and robust predictor for future screen-detected and clinically diagnosed type 2 diabetes in Europid populations.

Incidence of type 2 diabetes using proposed HbA1c diagnostic criteria in the european prospective investigation of cancer-norfolk cohort: implications for preventive strategies

OBJECTIVE

To evaluate the incidence and relative risk of type 2 diabetes defined by the newly proposed HbA(1c) diagnostic criteria in groups categorized by different baseline HbA(1c) levels.

RESEARCH DESIGN AND METHODS

Using data from the European Prospective Investigation of Cancer (EPIC)-Norfolk cohort with repeat HbA(1c) measurements, we estimated the prevalence of known and previously undiagnosed diabetes at baseline (baseline HbA(1c) ≥6.5%) and the incidence of diabetes over 3 years. We also examined the incidence and corresponding odds ratios (ORs) by different levels of baseline HbA(1c). Incident diabetes was defined clinically (self-report at follow-up, prescribed diabetes medication, or inclusion on a diabetes register) or biochemically (HbA(1c) ≥6.5% at the second health assessment), or both.

RESULTS

The overall prevalence of diabetes was 4.7%; 41% of prevalent cases were previously undiagnosed. Among 5,735 participants without diabetes at baseline (identified clinically or using HbA(1c) criteria, or both), 72 developed diabetes over 3 years (1.3% [95% CI 1.0-1.5]), of which 49% were identified using the HbA(1c) criteria. In 6% of the total population, the baseline HbA(1c) was 6.0-6.4%; 36% of incident cases arose in this group. The incidence of diabetes in this group was 15 times higher than in those with a baseline HbA(1c) of <5.0% (OR 15.5 [95% CI 7.2-33.3]).

CONCLUSIONS

The cumulative incidence of diabetes defined using a newly proposed HbA(1c) threshold in this middle-aged British cohort was 1.3% over 3 years. Targeting interventions to individuals with an HbA(1c) of 6.0-6.4% might represent a feasible preventive strategy, although complementary population-based preventive strategies are also needed to reduce the growing burden of diabetes.

Epidemiology of prediabetes

Identifying individuals at increased risk of developing diabetes has assumed increasing importance with the expansion of the evidence from clinical trials on the prevention or delay of type 2 diabetes using lifestyle modification and medication. The epidemiology of prediabetes depends on the diagnostic method used. Glucose measures defining impaired glucose tolerance and impaired fasting glucose levels identify about 10% of the adults to have prediabetes, whereas glycated hemoglobin-based criteria identify a significantly lower proportion of the population. Increasingly, multifactorial risk tools are being used and cut-points set to identify approximately 15% of the population as being at high risk.

Effect of bezafibrate on monocyte cytokine release and systemic inflammation in patients with impaired fasting glucose

This study assessed the effect of bezafibrate on monocyte secretory function and systemic inflammation in patients with impaired fasting glucose (IFG), comparing this effect with that produced by bezafibrate in mixed dyslipidemic subjects. The study included 28 patients with IFG, 29 individuals with mixed dyslipidemia, and 24 age-, sex- and weight-matched control subjects without lipid and glucose metabolism abnormalities. Compared with the control group, in both IFG and mixed dyslipidemic subjects, monocyte release of monocyte chemoattractant protein-1 (MCP-1), interleukin-6, tumor necrosis factor-α (TNF-α), and interleukin-1β was increased, which was accompanied by higher plasma levels of high-sensitivity C-reactive protein (hsCRP). Despite affecting plasma lipids in both treatment groups, bezafibrate administration (200 mg twice daily for 90 days) reduced fasting plasma glucose levels, the homeostasis model assessment index, and glycated hemoglobin only in IFG subjects. Bezafibrate treatment normalized monocyte release of MCP-1, interleukin-6, TNF-α, and interleukin-1β and also normalized plasma hsCRP levels in mixed dyslipidemic subjects, whereas in IFG individuals the drug reduced only MCP-1 and interleukin-6 release. This study shows that IFG is associated with the presence of systemic inflammation and abnormal monocyte secretory function. Compared with patients with mixed dyslipidemia, IFG patients who are administered bezafibrate experience a stronger effect on glucose metabolism and weaker anti-inflammatory and monocyte-suppressing actions.

Mortality, all-cause and cardiovascular disease, over 15 years in multiethnic mauritius: impact of diabetes and intermediate forms of glucose tolerance

OBJECTIVE

Little information is available on the impact of abnormal glucose tolerance on mortality in South Asian and African populations in the developing world. We explored this issue in a large, multiethnic cohort from the developing nation of Mauritius.

RESEARCH DESIGN AND METHODS

Population-based surveys were undertaken in 1987, 1992, and 1998. The 9,559 participants (20-82 years old) comprised 66% South Asian (Indian), 27% Creole (African), and 7% Chinese descent. Mortality was ascertained in 2007.

RESULTS

Over a median 15.1-year follow-up, 1,557 participants died. Compared with those with normal glucose tolerance, the all-cause mortality hazard ratios (HR) for known diabetes, newly diagnosed diabetes, and impaired glucose tolerance were 3.35 (95% CI 2.77-4.04), 2.11 (1.73-2.57), and 1.53 (1.26-1.87) in South Asians and 2.14 (1.65-2.79), 1.41 (1.06-1.88), and 1.08 (0.83-1.40) in Africans, respectively. Those with impaired fasting glucose were not at increased risk in either ethnicity. In the Chinese, only those with known diabetes were at increased risk of mortality with HR 3.68 (1.87-7.25).

CONCLUSIONS

This is the first study in a developing country of the impact of glucose intolerance on mortality in an African population, and one of the first studies of a South Asian population. It shows that the impact on mortality in these populations in Mauritius is comparable to that seen in developed countries. These results are important in a global context for future health policy in light of the impact of the rapid increase in prevalence of diabetes, especially in developing nations.

Incidence of type 2 diabetes in Aboriginal Australians: an 11-year prospective cohort study

BACKGROUND

Diabetes is an important contributor to the health inequity between Aboriginal and non-Aboriginal Australians. This study aims to estimate incidence rates of diabetes and to assess its associations with impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) among Aboriginal participants in a remote community.

METHODS

Six hundred and eighty six (686) Aboriginal Australians aged 20 to 74 years free from diabetes at baseline were followed for a median of 11 years. During the follow-up period, new diabetes cases were identified through hospital records. Cox proportional hazards models were used to assess relationships of the incidence rates of diabetes with IFG, IGT and body mass index (BMI).

RESULTS

One hundred and twenty four (124) new diabetes cases were diagnosed during the follow up period. Incidence rates increased with increasing age, from 2.2 per 1000 person-years for those younger than 25 years to 39.9 per 1000 person-years for those 45-54 years. By age of 60 years, cumulative incidence rates were 49% for Aboriginal men and 70% for Aboriginal women. The rate ratio for developing diabetes in the presence of either IFG or IGT at baseline was 2.2 (95% CI: 1.5, 3.3), adjusting for age, sex and BMI. Rate ratios for developing diabetes were 2.2 (95% CI: 1.4, 3.5) for people who were overweight and 4.7 (95% CI: 3.0, 7.4) for people who were obese at baseline, with adjustment of age, sex and the presence of IFG/IGT.

CONCLUSIONS

Diabetes incidence rates are high in Aboriginal people. The lifetime risk of developing diabetes among Aboriginal men is one in two, and among Aboriginal women is two in three. Baseline IFG, IGT and obesity are important predictors of diabetes.

Diabetes and impaired fasting glucose in Mongolian population, Inner Mongolia, China

AIMS

The aims of this study is to assess the prevalence of diabetes and IFG and compare the risk factors between diabetes and IFG in the Mongolian population, China.

METHODS

Data on demographic characteristics, lifestyle risk factors, family history of hypertension, medical history and fasting plasma glucose were obtained and analyzed for all individuals.

RESULTS

Total 2589 Mongolians aged 20 years or more were recruited as study subjects. The overall prevalence of diabetes and IFG was 3.7% (males 3.9%; females 3.5%) and 18.5% (males 17.7%; females 19.0%), respectively. Multivariate logistic analysis showed that diabetes was significantly associated with age (odds ratio: 1.26), overweight (1.86), high triglycerides (1.96), family history of hypertension (1.86), heart rate (1.05) and high C-reactive protein (3.59), and IFG significantly associated with age (odds ratio: 1.11), low high-density lipoprotein-cholesterol (1.80), family history of hypertension (1.60), heart rate (1.03) and high C-reactive protein (2.73).

CONCLUSIONS

IFG were common among Mongolian people living in the northeast of China. IFG has partly same risk factors as diabetes, and prevalence of some cardiovascular risk factors and number of risk factor in diabetes were higher than that in IFG.

Risk prediction models for the development of diabetes in Mauritian Indians

AIMS

To develop risk prediction models of future diabetes in Mauritian Indians.

METHODS

Three thousand and ninety-four Mauritian Indians (1141 men, aged 20-65 years) without diabetes in 1987 or 1992 were followed up to 1992 or 1998. Subjects underwent repeated oral glucose tolerance tests and diabetes was diagnosed according to 2006 World Health Organization/International Diabetes Federation criteria. Cox regression models for interval censored data were performed using data from 1544 randomly selected participants. Predicted probabilities for diabetes were calculated and validated in the remaining 1550 subjects.

RESULTS

Over 11 years of follow-up, there were 511 cases of diabetes. Among variables tested, family history of diabetes, obesity (body mass index, waist circumference) and glucose were significant predictors of diabetes. Predicted probabilities derived from a simple model fitted with sex, family history of diabetes and obesity ranged from 0.05 to 0.64 in men and 0.03 to 0.49 in women. To predict the onset of diabetes, area under the receiver operating characteristic (ROC) curve (AROC) of predicted probabilities was 0.62 (95% confidence interval, 0.56-0.68) in men and 0.64 (0.59-0.69) in women. At a cut-off point of 0.12, the sensitivity and specificity were 0.72 (0.71-0.74) and 0.47 (0.45-0.49) in men and 0.77 (0.75-0.78) and 0.50 (0.48-0.52) in women, respectively. Addition of fasting plasma glucose (FPG) to the model improved the prediction slightly [AROC curve 0.70 (0.65-0.76) in men, 0.71 (0.67-0.76) in women].

CONCLUSIONS

A diabetes prediction model based on obesity and family history yielded moderate discrimination in Mauritian Indians, which was slightly inferior to the model with the FPG but may be useful in low-income countries to promote identification of people at high risk of diabetes.

Genetic influences on type 2 diabetes and metabolic syndrome related quantitative traits in Mauritius

Epidemiological studies report a high prevalence of type 2 diabetes and metabolic syndrome in the island nation of Mauritius. The Mauritius Family Study was initiated to examine heritable factors that contribute to these high rates of prevalence and consists of 400 individuals in 24 large extended multigenerational pedigrees. Anthropometric and biochemical measurements relating to the metabolic syndrome were undertaken in addition to family and lifestyle based information for each individual. Variance components methods were used to determine the heritability of the type 2 diabetes and metabolic syndrome related quantitative traits. The cohort was made up of 218 females (55%) and 182 males with 22% diagnosed with type 2 diabetes and a further 30% having impaired glucose tolerance or impaired fasting glucose. Notably BMI was not significantly increased in those with type 2 diabetes (P= .12), however a significant increase in waist circumference was observed in these groups (P= .02). The heritable proportion of trait variance was substantial and greater than values previously published for hip circumference, LDL and total cholesterol, diastolic and systolic blood pressure and serum creatinine. Height, weight and BMI heritabilities were all in the upper range of those previously reported. The phenotypic characteristics of the Mauritius family cohort are similar to those previously reported in the Mauritian population with a high observed prevalence rate of type 2 diabetes. A high heritability for key type 2 diabetes and metabolic syndrome related phenotypes (range 0.23 to 0.68), suggest the cohort will have utility in identifying genes that influence these quantitative traits.

Population-based incidence of Type 2 diabetes and its associated risk factors: results from a six-year cohort study in Iran

Background

The Middle East is estimated to have the largest increase in prevalence of diabetes by 2030; yet there is lack of published data on the incidence of Type 2 diabetes in this region. This study aimed to estimate Type 2 diabetes incidence and its associated risk factors in an Iranian urban population.

Methods

Among 3307 non-diabetics ≥ 20 years (mean age 42 ± 13 years, 42% males), glucose tolerance test was performed at baseline in 1999–2001 and at two consecutive phases in 2001–2005 and 2005–2008. Diabetes and glucose tolerance status were defined according to the ADA 1997 criteria. Logistic regression was used to determine the independent variables associated with incident diabetes and their odds ratios (OR).

Results

After median follow-up of 6 years, 237 new cases of diabetes were ascertained corresponding to an age and sex standardized cumulative incidence of 6.4% (95%CI: 5.6–7.2) and incidence rate of 10.6 (9.2–12.1) per 1000 person years. Besides classical diabetes risk factors, female sex and low education level significantly increased risk of diabetes in age adjusted models. In full model, the independent predictors were age [OR, 95%CI: 1.2 (1.1–1.3)], family history of diabetes [1.8 (1.3–2.5)], body mass index ≥ 30 kg/m² [2.3 (1.5–3.6)], abdominal obesity [1.9 (1.4–2.6)], high triglyceride [1.4 (1.1–1.9)], Isolated impaired fasting glucose (IFG) [7.4 (3.6–15.0)], Isolated impaired glucose tolerance (IGT) [5.9 (4.2–8.4)] and combined IFG and IGT [42.2 (23.8–74.9)].

Conclusion

More than 1% of the Iranian urban population older than 20 years develops Type 2 diabetes each year. Combination of IFG and IGT was the strongest predictor of incident diabetes among the modifiable risk factors.

Genetic variation in KCNQ1 associates with fasting glucose and beta-cell function: a study of 3,734 subjects comprising three ethnicities living in Singapore

OBJECTIVE

The potassium voltage-gated channel, KQT-like subfamily, member 1 (KCNQ1) has been found through a genome-wide association study to be a strong candidate for conferring susceptibility to type 2 diabetes in East Asian and European populations. Our objective was to describe the association between polymorphisms at the KCNQ1 locus with insulin resistance, beta-cell function, and other type 2 diabetes-related traits in a sample of Chinese, Malays, and Asian Indians living in Singapore.

RESEARCH DESIGN AND METHODS

We examined the associations between four previously reported KCNQ1 single-nucleotide polymorphisms (SNPs) with type 2 diabetes-related traits in 3,734 participants from the population-based 1998 Singapore National Health Survey cohort (2,520 Chinese, 693 Malay, and 521 Asian Indians). Insulin resistance was calculated from fasting insulin and glucose using the homeostasis model assessment method, whereas pancreatic beta-cell function was assessed using the corrected insulin response at 120 min (CIR(120)).

RESULTS

SNPs rs2237897, rs2237892, and rs2283228 were significantly associated with type 2 diabetes (odds ratio [OR] 1.48, P = 3 x 10(-4); OR 1.38, P = 0.002; OR 1.31, P = 0.012, respectively). Within the Chinese population, the risk alleles for rs2237897, rs2237892, and rs2283228 were significantly associated with higher fasting glucose levels (P = 0.014, 0.011, and 0.034, respectively) and reduced CIR(120)(P = 0.007, 0.013, and 0.014, respectively). A similar trend was observed among the Malay and Asian Indian minority groups, although this did not reach statistical significance because of limited sample sizes.

CONCLUSIONS

The increased risk for type 2 diabetes associated with KCNQ1 is likely to be caused by a reduction in insulin secretion. Further studies will be useful to replicate these findings and to fully delineate the role of KCNQ1 and its related pathways in disease pathogenesis.

Progression to impaired glucose regulation and diabetes in the population-based Inter99 study

OBJECTIVE

The purpose of this study was to estimate the progression rates to impaired glucose regulation (impaired fasting glucose or impaired glucose tolerance) and diabetes in the Danish population-based Inter99 study and in a high-risk subpopulation, separately.

RESEARCH DESIGN AND METHODS

From a population-based primary prevention study, the Inter99 study, 4,615 individuals without diabetes at baseline and with relevant follow-up data were divided into a low- and a high-risk group based on a risk estimate of ischemic heart disease or the presence of risk factors (smoking, hypertension, hypercholesterolemia, obesity, or impaired glucose tolerance). High-risk individuals (57.1%) were examined with an oral glucose tolerance test at 1 and 3 years, and all of the participants were reexamined at the 5-year follow-up. Person-years at risk were calculated. Progression rates to impaired glucose regulation and diabetes were estimated directly from baseline to the 5-year follow-up for all the participants and from baseline through the 1- and 3- to 5-year follow-up examinations for the high-risk individuals, separately.

RESULTS

In the combined low- and high-risk group, 2.1 individuals per 100 person-years progressed from normal glucose tolerance (NGT) to impaired glucose regulation or diabetes. Among high-risk individuals, 5.8 per 100 person-years with NGT progressed to impaired glucose regulation or diabetes, and 4.9 per 100 person-years progressed from impaired glucose regulation to diabetes.

CONCLUSIONS

Progression rates to impaired glucose regulation using the current World Health Organization classification criteria were calculated for the first time in a large European population-based study. The progression rates to diabetes show the same pattern as seen in the few similar European studies.

BMI compared with central obesity indicators as a predictor of diabetes incidence in Mauritius

The aim of the study was to compare BMI with waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-stature ratio (WSR) as a predictor of diabetes incidence. A total of 1,841 men and 2,104 women of Mauritian Indian and Mauritian Creole ethnicity, aged 25-74 years, free of diabetes, hypertension, cardiovascular disease, and gout were seen at baseline in 1987 or 1992, and follow-up in 1992 and/or 1998. At all time points, participants underwent a 2 h 75 g oral glucose tolerance test. Hazard ratios for diabetes incidence were estimated applying an interval-censored survival analysis using age as timescale. Six hundred and twenty-eight individuals developed diabetes during the follow-up period. Multivariable adjusted hazard ratios for diabetes incidence corresponding to a 1 s.d. increase in baseline BMI, WC, WHR, and WSR for Mauritian Indians were 1.49 (1.31-1.71), 1.58 (1.38-1.81), 1.54 (1.37-1.72), and 1.61 (1.41-1.84) in men and 1.33 (1.17-1.51), 1.35 (1.19-1.53), 1.39 (1.24-1.55), and 1.38 (1.21-1.57) in women, respectively; and for Mauritian Creoles they were 1.86 (1.51-2.30), 2.07 (1.68-2.56), 1.92 (1.62-2.26), and 2.17 (1.76-2.69) in men and 1.29 (1.06-1.55), 1.27 (1.04-1.55), 1.24 (1.04-1.48), and 1.27 (1.04-1.55) in women. Paired homogeneity tests showed that there was no difference between BMI and each of the central obesity indicators (all P > 0.05). The relation of BMI with the development of diabetes was as strong as that for indicators of central obesity in this study population.

Central obesity as a precursor to the metabolic syndrome in the AusDiab study and Mauritius

Evidence from epidemiologic studies that central obesity precedes future metabolic change and does not occur concurrently with the appearance of the blood pressure, glucose, and lipid abnormalities that characterize the metabolic syndrome (MetS) has been lacking. Longitudinal surveys were conducted in Mauritius in 1987, 1992, and 1998, and in Australia in 2000 and 2005 (AusDiab). This analysis included men and women (aged > or = 25 years) in three cohorts: AusDiab 2000-2005 (n = 5,039), Mauritius 1987-1992 (n = 2,849), and Mauritius 1987-1998 (n = 1,999). MetS components included waist circumference, systolic blood pressure, fasting and 2-h postload plasma glucose, high-density lipoprotein (HDL) cholesterol, triglycerides, and homeostasis model assessment of insulin sensitivity (HOMA-S) (representing insulin sensitivity). Linear regression was used to determine which baseline components predicted deterioration in other MetS components over 5 years in AusDiab and 5 and 11 years in Mauritius, adjusted for age, sex, and ethnic group. Baseline waist circumference predicted deterioration (P < 0.01) in four of the other six MetS variables tested in AusDiab, five of six in Mauritius 1987-1992, and four of six in Mauritius 1987-1998. In contrast, an increase in waist circumference between baseline and follow-up was only predicted by insulin sensitivity (HOMA-S) at baseline, and only in one of the three cohorts. These results suggest that central obesity plays a central role in the development of the MetS and appears to precede the appearance of the other MetS components.

Diabetes increases large artery diseases, but not small artery diseases in the brain

BACKGROUND

It is established that diabetes causes various systemic micro- and macro-vascular complications. Little has been, however, studied on the differential effects of diabetes on the large artery diseases (LAD) or small artery disease (SAD) in the brain. The purpose of this study was to examine an association of diabetes on the incidence of underlying LAD versus SAD in ischemic stroke patients.

METHODS

We prospectively collected 523 acute ischemic stroke patients without cardioembolic causes or other determined causes of stroke. Using brain MRI, the cerebral LAD (extracranial and intracranial arterial stenosis of 50 % or more) and the cerebral SAD (old lacunar infarction, microbleeds and leukoaraiosis) findings were assessed. Information regarding vascular risk factor was also collected.

RESULTS

Among the patients (male, n = 342; diabetes, n = 200), diabetes was not associated with the presence of LADs or SADs in female subjects, but strongly with the presence of intracranial LAD in male subjects (p < 0.01). The association remained significant (OR 2.09, 95 %CI 1.25-3.51) after adjusting for major confounders. A similar association was also found in intracranial LAD and insulin resistance. There was, however, no significant association of diabetes with SAD in male nor in female patients.

CONCLUSIONS

Our results showed that diabetes is associated with the frequency of intracranial LAD, especially in males. Out study may be regarded as evidence of differential biological effects of diabetes on cerebral vasculature.