Risk factors for the development of NIDDM in Yonchon County, Korea

Epidemiology of Diabetes Mellitus and Cardiovascular Disease

PURPOSE OF REVIEW

Diabetes mellitus (DM) has become a rising epidemic in the last century, more pressing in the last few decades with the exponential rise of obesity, and has become one of the leading causes of death worldwide.

RECENT FINDINGS

Genetic variants have also been a new field of epidemiology research to determine the underlying genetic component of those risk factors and the association of DM with CVD. In light of its significant prevalence, patients remain unaware of their disease progression that arises from genetic and metabolic risk factors. As compared to non-diabetics, those with type 2 DM carry a higher mortality risk from cardiovascular disease (CVD) across different ethnicity groups and sex. The most common cardiovascular manifestations in those with DM include heart failure, peripheral arterial disease, and coronary heart disease. Although DM does predispose patients to CVD, it in fact is not a risk equivalent, but carries significant heterogeneity in risk for CVD.

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.

Epidemiology in diabetes mellitus and cardiovascular disease

As one of the leading causes of death in the USA, diabetes mellitus (DM) has become an epidemic over the past few decades. Despite the high prevalence of diagnosed DM, close to half of all people with DM are unaware of their disease. The risk of type 2 DM is determined by interplay of genetic and metabolic factors. Patients with type 2 DM have a higher risk of death from cardiovascular causes compared with their nondiabetic counterparts, and the mortality rate of DM associated cardiovascular disease is different among ethnicity groups and sex groups. Because of its adverse effect on people's health, DM also imposes an economic burden on individuals and households affected, as well as on the healthcare system. Current guidelines for cardiovascular disease prevention have focused on lifestyle management, blood pressure control, lipid control, blood glucose control, antiplatelet agent use, and tobacco use cessation.

Incidence and predictors of type 2 diabetes among Koreans: A 12-year follow up of the Korean Genome and Epidemiology Study

AIM

Because the incidence of type 2 diabetes in Korea has not been clearly defined, we examined the incidence of this condition and its association with impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and other risk factors in a 12-year follow-up Korean community-based prospective cohort study.

METHODS

We recruited 7542 subjects aged 40-69years without diabetes at baseline examination from the Korean Genome and Epidemiology Study and followed these subjects for 12years biennially. Diabetes was defined according to the 2010 American Diabetes Association criteria. The incidence of type 2 diabetes and the predictors of progression to diabetes were analyzed according to baseline glucose tolerance.

RESULTS

The overall incidence of type 2 diabetes was 22.1 per 1000person-years. Subjects with combined IFG-IGT at baseline had the highest incidence of diabetes, which was more than two-fold that of individuals with isolated IFG or isolated IGT (114.4 vs. 51.3 vs. 53.1 per 1000person-years). A multivariate Cox proportional hazards model analysis showed that combined IFG-IGT, which were strong predictors of diabetes, as well as age, urban residence, family history of diabetes, smoking status, abdominal obesity, hypertension, high triglycerides and low HDL cholesterols were also independently associated with progression to diabetes.

CONCLUSIONS

The incidence of type 2 diabetes is relatively high in our Korean community-based sample. Combined IFG-IGT are strong predictors of type 2 diabetes. Measurement of 2-hour plasma glucose in addition to fasting plasma glucose is necessary for the detection of individuals at high risk for development of diabetes.

Metabolic syndrome predicts long-term mortality in subjects without established diabetes mellitus in asymptomatic Korean population: A propensity score matching analysis from the Korea Initiatives on Coronary Artery Calcification (KOICA) registry

Despite the different features of diabetes mellitus (DM) in Asian populations compared with Western populations, the impact of metabolic syndrome (MetS) on long-term mortality according to DM status has not yet been elucidated in the Asian population.After performing 1:1 propensity score matching (PSM) using clinical variables including age, gender, smoking, and individual MetS components between DM and non-DM subjects from the data of the Korea Initiatives on Coronary Artery Calcification registry, mortality was evaluated according to DM and MetS in 14,956 asymptomatic Korean subjects.The mean follow-up duration was 53.1 months (interquartile range: 33-80). The overall prevalence of MetS was 60%. DM subjects had higher mortality compared with non-DM subjects (1.2% vs 0.7%, respectively; P = 0.001); the cumulative mortality by Kaplan-Meier analysis was higher in DM subjects than in non-DM subjects (log-rank P = 0.001). DM increased the risk of mortality in PSM participants (hazard ratio [HR] 1.74; P = 0.001). In non-DM subjects, MetS (HR 2.32) and one of its components, central obesity (HR 1.97), were associated with an increased risk of mortality (both P < 0.05). In contrast, there was no significant difference in the risk of mortality according to MetS or its components in DM subjects. After adjusting for confounding risk factors, it was shown that MetS independently increased the risk of mortality in non-DM subjects.Compared with non-DM subjects, DM subjects have an increased risk of long-term mortality among PSM participants. MetS appears to have an independent impact on mortality in subjects without established DM among the asymptomatic Korean population. Our results may not be applicable to the whole subjects with MetS because the PSM using MetS components was performed between subjects with and without DM which was very high risk for adverse clinical events.

Insulin Secretory Capacity and Insulin Resistance in Korean Type 2 Diabetes Mellitus Patients

It is well known that many Korean patients with type 2 diabetes mellitus (T2DM) were non-obese and had decreased insulin secretion in past. However, during the past three decades, lifestyles in Korea have been westernized. As a result, the prevalence of obesity, the main cause of diabetes has increased. Thus, there is still a question as to whether the main pathophysiology of current Korean T2DM is insulin resistance or an insulin secretion defect. Because various anti-diabetes medications having different mechanisms of action are currently used as therapeutics, it is important to understand which of these factors is the main physiology in the development of diabetes in Koreans. In this review, we review changes in obesity prevalence, insulin resistance and insulin secretion defects in Korean T2DM during three decades.

The Association of Metabolic Syndrome with Diabetic Retinopathy: The Korean National Health and Nutrition Examination Survey 2008-2012

Aims

To explore gender differences and associations between metabolic syndrome (MetS) and its components, and diabetic retinopathy (DR) in Korean adults aged 40 years and older with diabetes.

Methods

We analyzed data from the Korean National Health and Nutrition Examination Surveys (2008–2012). In total, 2,576 type 2 diabetic participants, aged 40 and older, were evaluated. Seven standard retinal fundus photographs were obtained after pupil dilation in both eyes. DR was graded using the modified Airlie House classification system. Vision-threatening diabetic retinopathy (VTDR) included proliferative diabetic retinopathy and clinically significant macular edema. MetS was defined according to the Joint Interim Statement, proposed in 2009, by the International Diabetes Federation and the American Heart Association/National Heart, Lung, and Blood Institute. Multivariate logistic regression analysis was used to assess the relationship between MetS and its individual components with DR and VTDR.

Results

After controlling for confounders, MetS was not associated with DR in men or women. Moreover, the risk for DR or VTDR did not increase with increasing MetS components. However, high waist circumference was significantly inversely associated with VTDR (adjusted odds ratio = 0.36; 95% confidence interval = 0.14–0.93) only in men.

Conclusions

MetS was not associated with DR or VTDR in a Korean diabetic population. However, among MetS components, it seems that abdominal obesity was inversely associated with VTDR in Korean diabetic men.

Trends in Diabetes Incidence in the Last Decade Based on Korean National Health Insurance Claims Data

BACKGROUND

Epidemiological data is useful to estimate the necessary manpower and resources used for disease control and prevention of prevalent chronic diseases. We aimed to evaluate the incidence of diabetes and identify its trends based on the claims data from the National Health Insurance Service database over the last decade.

METHODS

We extracted claims data on diabetes as the principal and first additional diagnoses of National Health Insurance from January 2003 to December 2012. We investigated the number of newly claimed subjects with diabetes codes, the number of claims and the demographic characteristics of this population.

RESULTS

Total numbers of claimed cases and populations with diabetes continuously increased from 1,377,319 in 2003 to 2,571,067 by 2012. However, the annual number of newly claimed diabetic subjects decreased in the last decade. The total number of new claim patients with diabetes codes decreased as 30.9% over 2005 to 2009. Since 2009, the incidence of new diabetes claim patients has not experienced significant change. The 9-year average incidence rate was 0.98% and 1.01% in men and women, respectively. The data showed an increasing proportion of new diabetic subjects of younger age (<60 years) combined with a sharply decreasing proportion of subjects of older age (≥60 years).

CONCLUSION

There were increasing numbers of newly claimed subjects with diabetes codes of younger age over the last 10 years. This increasing number of diabetic patients will require management throughout their life courses because Korea is rapidly becoming an aging society.

Body composition of women 20-49 years old as a predictor for noncommunicable diseases: a community-based study

BACKGROUND

Obesity increases a person's risk of developing a number of noncommunicable diseases (NCDs), including, type 2 diabetes, coronary heart disease, hypertension, and certain cancers. The bioelectrical impedance analysis (BIA) has been considered as a safe, noninvasive, simple, and least expensive portable method for the evaluation of body composition in clinical practice. However, there is not enough information about its use in community-based surveys to detect the optimal cutoff point for the body fat percent (BF%) that could predict NCDs.

OBJECTIVE

To identify the cutoff point for the BF%, at which NCD risk could be predicted compared with BMI and waist circumference (WC).

METHODS

A community-based study was conducted in a randomly selected cluster located within the catchment area of Cairo University Hospitals. All ever-married women 20-49 years old and not currently pregnant (n=373) in the selected cluster were included in the study. A questionnaire was used for recoding data during the household survey. Portable equipment that estimates body composition (water, fat, protein, and bone) through BIA was used.

RESULTS

Receiver operating characteristic curve analysis showed cutoff point for BF% of 37.5% (P=0.02) at the time of reporting hypertension, with 78% sensitivity and 40% specificity. For diagnosed diabetes, cutoff point for the BF% was 38.5% (P=0.005), with 71% sensitivity and 46% specificity. For diagnosed cardiovascular diseases, cutoff point for BF% was 38.5% (P=0.001) with 86% sensitivity and 47% specificity. For diagnosed joint diseases, cutoff point for BF% was 38.5% (P=0.005), with 67% sensitivity and 48% specificity.

CONCLUSION AND RECOMMENDATIONS

BIA was effective in predicting and suggesting the cutoff points for the BF% associated with four types of NCDs (hypertension, cardiovascular, diabetes, and joint diseases). The use of BIA for women before the age of 20 years could guide strategies for reducing body fat and its risk of NCDs.

Fitness, Body Habitus, and the Risk of Incident Type 2 Diabetes Mellitus in Korean Men

The relative contributions of cardiorespiratory fitness (CRF) and body habitus to predict incident type 2 diabetes mellitus (T2DM) remain unclear. We prospectively investigated the relation of CRF and body habitus on the risk of developing T2DM in men. Participants included 3,770 apparently healthy men who initially presented without baseline evidence of diabetes, cardiovascular disease, and hypertension. Participants were divided into 3 groups as normal weight (18.5 to 24.9 kg/m(2)), obese I (25.0 to 29.9 kg/m(2)), and obese II (≥30.0 kg/m(2)). CRF was directly measured by peak oxygen uptake (VO2peak) and categorized into unfit and fit cohorts based on the median value of age-specific VO2peak. Diabetes was defined as a glycated hemoglobin >6.5% and/or a fasting glucose >126 mg/dl at baseline and follow-up examinations. During a median follow-up of 5 years, 170 men (4.5%) developed diabetes. After adjusting for age and fasting glucose, the relative risk and 95% confidence interval (CI) for incident T2DM were 1.52 (95% CI 1.11 to 2.07) for obese I and 3.11 (95% CI 1.35 to 7.16) for obese II versus normal weight and 0.69 (95% CI 0.51 to 0.95) for fit versus unfit. However, these associations were no longer statistically significant after adjusting for potential confounders with VO2peak (1.32; 95% CI 0.96 to 1.83 for obese I and 1.61, 95% CI 0.64 to 4.06 for obese II vs normal weight) or body mass index (0.75, 95% CI 0.54 to 1.05 for fit vs unfit). In the joint analysis, obese-unfit men had 1.81 times (95% CI 1.22 to 2.69) greater risk of incident T2DM, but obese-fit men were not at increased risk of incident T2DM (0.95, 95% CI 0.57 to 1.58) compared with fit-normal weight men. In conclusion, these results suggest that both CRF and obesity predict the incidence of T2DM independent of potential confounders; however, CRF appears to attenuate the risk of developing diabetes in obese men.

Comparison of 2-year mortality according to obesity in stabilized patients with type 2 diabetes mellitus after acute myocardial infarction: results from the DIAMOND prospective cohort registry

Background

After acute myocardial infarction (AMI), the replicated phenomenon of obesity paradox, i.e., obesity appearing to be associated with increased survival, has not been evaluated in stabilized (i.e., without clinical events within 1 month post AMI) Asian patients with diabetes mellitus (DM).

Methods

Among 1192 patients in the DIabetic Acute Myocardial InfarctiON Disease (DIAMOND) Korean multicenter registry between April 2010 and June 2012, 2-year cardiac and all-cause death were compared according to obesity (body mass index ≥25 kg/m²) in 1125 stabilized DM patients.

Results

Compared with non-obese DM patients (62 % of AMI patients), obese DM patients had: higher incidence of dyslipidemia (31 vs. 24 %, P < 0.01); lower incidence of chronic kidney disease (26 vs. 33 %) (P < 0.01); higher left ventricular ejection fraction after AMI (53 ± 11 vs. 50 ± 12 %, P < 0.001); and lower 2-year cardiac and all-cause death occurrence (0.7 vs. 3.6 % and 1.9 vs. 5.2 %, both P < 0.01) and cumulative incidence in Kaplan–Meier analysis (P < 0.005, respectively). Likewise, both univariate and multivariate Cox hazard regression analyses adjusted for the respective confounders showed that obesity was associated with decreased risk of both cardiac [HR, 0.18 (95 % CI 0.06–0.60), P = 0.005; and 0.24 (0.07–0.78), P = 0.018, respectively] and all-cause death [0.34 (0.16–0.73), P = 0.005; and 0.44 (0.20–0.95), P = 0.038].

Conclusions

In a Korean population of stabilized DM patients after AMI, non-obese patients appear to have higher cardiac and all-cause mortality compared with obese patients after adjusting for confounding factors.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-015-0305-1) contains supplementary material, which is available to authorized users.

Normal Glucose Tolerance with a High 1-Hour Postload Plasma Glucose Level Exhibits Decreased β-Cell Function Similar to Impaired Glucose Tolerance

BACKGROUND

Subjects with normal glucose tolerance (NGT) who have a high 1-hour postload plasma glucose level (≥155 mg/dL; NGT 1 hour-high) have been shown to be at higher risk for type 2 diabetes than subjects with NGT 1 hour-low postload plasma glucose level (<155 mg/dL). We compared β-cell function in subjects with NGT 1 hour-high, NGT 1 hour-low, and impaired glucose tolerance (IGT).

METHODS

We classified subjects into NGT 1 hour-low (n=149), NGT 1 hour-high (n=43), and IGT (n=52). The β-cell function was assessed based on insulinogenic index (IGI), oral disposition index (DI), and insulin secretion-sensitivity index-2 (ISSI-2).

RESULTS

Insulin sensitivity was comparable between the subjects with NGT 1 hour-high and NGT 1 hour-low. The β-cell function with/without adjusting insulin sensitivity was significantly different among the three groups. The IGI (pmol/mmol) was 116.8±107.3 vs. 64.8±47.8 vs. 65.8±80.6 (P=0.141), oral DI was 3.5±4.2 vs. 1.8±1.4 vs. 1.8±3.1 (P<0.001), and ISSI-2 was 301.2±113.7 vs. 213.2±67.3 vs. 172.5±87.5 (P<0.001) in NGT 1 hour-low, NGT 1 hour-high, and IGT, respectively. Post hoc analyses revealed that oral DI and ISSI-2 were significantly different between NGT 1 hour-low and NGT 1 hour-high but comparable between NGT 1 hour-high and IGT.

CONCLUSION

Among Korean subjects with NGT, those who have a higher 1-hour postload glucose level have a compromised insulin-sensitivity adjusted β-cell function to a similar degree as IGT subjects.

Inverse association between central obesity and arterial stiffness in Korean subjects with metabolic syndrome: a cross-sectional cohort study

BACKGROUND

Metabolic syndrome (MetS) is associated with increased risks of diabetes and atherosclerotic cardiovascular disease. Whether central obesity (CeO) is a prerequisite for the diagnosis of MetS in the International Diabetes Federation (IDF) definition is a substantial issue because it may influence the clinical value of MetS for predicting subclinical atherosclerosis.

METHODS

We investigated the relation between MetS, as defined by the National Cholesterol Education Program-Adult Treatment Panel (NCEP-ATP) III criteria, and arterial stiffness according to CeO status in 2,560 healthy Korean subjects who participated in a community-based cohort study. Arterial stiffness was measured using brachial-ankle pulse wave velocity (baPWV).

RESULTS

The prevalence of MetS was 37%; 84% of MetS subjects had CeO. The prevalence of diabetes was significantly higher in MetS subjects than in non-MetS subjects (30 vs. 8%, p <0.001). The number of MetS components was significantly correlated with baPWV (r = 0.311, p <0.001). In a subgroup analysis of MetS subjects, the prevalence of diabetes was not significantly different in MetS subjects with and without CeO. MetS subjects without CeO had significantly higher baPWV than those with CeO (1654 ± 315 vs. 1578 ± 270 cm/s, p = 0.002). Multiple regression models revealed that waist circumference was independently associated with decreased baPWV in MetS subjects.

CONCLUSIONS

Despite the significant correlation between the number of MetS components and arterial stiffness, there appeared to be an inverse association between CeO and arterial stiffness in MetS subjects. In contrast to the IDF definition, our findings suggest that CeO is not crucial for the diagnosis of MetS in otherwise healthy Koreans having multiple metabolic risk factors with respect to subclinical atherosclerosis reflected in arterial stiffness.

Role of various indices derived from an oral glucose tolerance test in the prediction of conversion from prediabetes to type 2 diabetes

AIMS

The clinical implications of prediabetes for development of type 2 diabetes may differ for Asian ethnicity. We investigated various indices derived from a 2-h oral glucose tolerance test (OGTT) in people with prediabetes to predict their future risk of diabetes.

METHODS

We recruited 406 consecutive subjects with prediabetes from 2005 to 2006 and followed them up every 3-6 months for up to 9 years. Prediabetes was defined as isolated impaired fasting glucose (IFG), isolated impaired glucose tolerance (IGT), combined glucose intolerance (CGI), or isolated elevated HbA1c (5.7-6.4%, 39-46 mmol/mol) without IFG or IGT. The rate of diabetes conversion was compared between prediabetes categories. The association of glycemic indices with development of diabetes was also investigated.

RESULTS

Eighty-one patients were diagnosed with diabetes during the 9-year follow-up (median 46.0 months). The rate of diabetes conversion was higher in subjects with CGI (31.9%), or isolated IGT (18.5%) than in those with isolated IFG (15.2%) or isolated elevated HbA1c (10.9%). Surrogate markers reflecting β-cell dysfunction were more closely associated with diabetes conversion than insulin resistance indices. Subjects with a 30-min postload glucose ≥ 165 mg/dL and a 30-min C-peptide < 5 ng/mL had 8.83 times greater risk (95% confidence interval 2.98-26.16) of developing diabetes than other prediabetic subjects.

CONCLUSIONS

In Asians, at least Koreans, β-cell dysfunction seems to be the major determinant for diabetes conversion. A combination of high glucose and low C-peptide levels at 30 min after OGTT may be a good predictor for diabetes conversion in this population.

Differential association between metabolic syndrome and coronary artery disease evaluated with cardiac computed tomography according to the presence of diabetes in a symptomatic Korean population

BACKGROUND

Metabolic syndrome (MetS) is associated with increased risks of diabetes and coronary artery disease (CAD). Despite the controversial inclusion of established diabetes in MetS, the association between MetS and CAD according to diabetes status has not been elucidated in the Asian population.

METHODS

We evaluated the association between MetS and CAD using the parameters including any plaque, obstructive plaque, and coronary artery calcium score (CACS) >100 according to diabetes status in 2,869 symptomatic Korean subjects who underwent cardiac computed tomographic angiography.

RESULTS

The prevalence of MetS was significantly higher in the diabetic subjects than in the non-diabetic subjects (69% vs. 34%, P <0.001). The incidence of any plaque (64% vs. 43%, P <0.001), obstructive plaque (26% vs. 13%, P = 0.006), and CACS >100 (23% vs. 12%, P = 0.012) was significantly higher in diabetic subjects than in non-diabetic subjects. Among the MetS components, decreased high-density lipoprotein level was significantly associated with any plaque (odds ratio [OR] 1.35), obstructive plaque (OR 1.55), and CACS >100 (OR 1.57) in the non-diabetic subjects (P <0.01, respectively). However, none of the MetS components were associated with all the parameters in the diabetic subjects. Multivariate regression analysis revealed that MetS and the number of MetS components (MetSN) were independently associated with any plaque (MetS: OR 1.55, P <0.001; MetSN: OR 1.22, P <0.001), obstructive plaque (MetS: OR 1.52, P = 0.003; MetSN: OR 1.25, P <0.001), and CACS >100 (MetS: OR 1.46, P = 0.015; MetSN: OR 1.21, P = 0.004) only in the non-diabetic subjects, respectively.

CONCLUSIONS

MetS was independently associated with the presence and severity of CAD only in the non-diabetic subjects among the symptomatic Korean population.

Differential association between obesity and coronary artery disease according to the presence of diabetes in a Korean population

BACKGROUND

Coronary artery disease (CAD) is a major cardiovascular complication in diabetic patients. Despite the significant association between obesity and diabetes, the majority of the diabetic subjects are not obese in an Asian population. This study evaluated the association between obesity and coronary artery disease (CAD) according to the diabetes status in a Korean population.

METHODS

The association between obesity and CAD using the parameters of any plaque, obstructive plaque, and coronary artery calcium score (CACS) >100 according to the presence of diabetes was evaluated in 7,234 Korean adults who underwent multi-detector computed tomography for general health evaluations. Obesity was defined as a body mass index (BMI) ≥25 kg/m(2).

RESULTS

The prevalence of obesity was significantly higher in diabetic subjects than in non-diabetic subjects, but the majority of the diabetic subjects were non-obese (48% vs. 37%, p <0.001). The incidence of any plaque (58% vs. 29%), obstructive plaque (20% vs. 6%), and CACS >100 (20% vs. 6%) were significantly higher in diabetic patients than in non-diabetic subjects (p <0.001, respectively). Incidence of any plaque (33% vs. 26%, p <0.001), obstructive plaque (7% vs. 6%, p = 0.014), and CACS >100 (8% vs. 6%, p = 0.002) was significantly higher in non-diabetic subjects with obesity than in those without obesity, but the incidence of all coronary parameters was not different in diabetic subjects according to the obesity status. After adjusting for confounding risk factors including age, gender, hypertension, dyslipidemia, current smoking, and mild renal dysfunction, obesity was independently associated with increased risks of any plaque (OR 1.14) and CACS >100 (OR 1.31) only in non-diabetic subjects (p <0.05, respectively). Multiple logistic regression models revealed that diabetes was independently associated with all coronary parameters.

CONCLUSION

Despite a significantly higher prevalence of obesity in diabetic subjects than in non-diabetic subjects, obesity is associated with the presence of any plaque and severe coronary calcification only in subjects without established diabetes among Korean population.

Alcohol use behaviors, fat intake and the function of pancreatic β-cells in non-obese, healthy Korean males: findings from 2010 Korea National Health and Nutrition Examination Survey

AIMS

In the present study, we aimed to identify dietary factors related to insulin secretion function especially in healthy, non-obese Korean males.

METHODS

Data were obtained from the Korea National Health and Nutrition Examination Survey V-1 (KNHANES V-1). Nine hundred and twenty male adults aged >30 years of normal weight were included, excluding those with type 2 diabetes mellitus and liver disease. Alcohol use disorders identification test (AUDIT) score which represents alcohol use behaviors and nutrient intakes was used, and homeostasis model assessment of β-cell function (HOMA-B score) was calculated.

RESULTS

HOMA-B score was associated with age (p < 0.001), AUDIT score (p = 0.030), and percentage of fat from total energy intake (p = 0.002). HOMA-B scores in the problematic AUDIT group were significantly lower than those in the normal AUDIT group. In addition, HOMA-B scores in the lowest fat intake group were significantly lower than those in the medium fat intake group, but similar to those in the highest fat intake group. There was an interaction between alcohol use behaviors and percentage of fat from energy intake in determining HOMA-B score (p for interaction = 0.034).

CONCLUSIONS

Alcohol use behaviors and percentage of fat from energy intake were found to be associated with HOMA-B score in healthy, non-obese Korean males.

Elevated A1C is associated with impaired early-phase insulin secretion rather than insulin resistance in Koreans at high risk for developing diabetes

The purpose of this study is to examine the association of A1C with beta-cell dysfunction, insulin resistance, and cardiovascular risk factors in Koreans with the relatively high risk for the future development of diabetes. This cross-sectional study recruited subjects from the pre-diabetic cohort of the Korea National Diabetes Program. Among study subjects (n = 616) aged 21-77 years with a history of hyperglycemia (fasting plasma glucose (FPG) ≥ 5.5 mmol/mL), analyses were conducted on 504 participants (296 women, 208 men) except for subjects with FPG ≥ 7.0 mmol/L or 120-min post-challenge plasma glucose ≥ 11.1 mmol/L or A1C ≥ 6.5 %. For insulin sensitivity and β-cell function classified by the categories of A1C levels, ∆Ins(30-0)/∆Glu(30-0) was lower in the highest quartile group than other groups. Although there was no significant difference in HOMA-IR according to the A1C categories, even lowest A1C group (≤ 5.3 %) already included many subjects with abnormal glucose tolerance. A1C showed a significant association with hsCRP, number of metabolic syndrome (MetS) components and ∆Ins(30-0)/∆Glu(30-0) after adjusting for age, gender, BMI, and medications whereas HOMA-IR was insignificantly associated with A1C. Stepwise regression analysis for A1C showed that A1C is independently and negatively associated with ∆Ins(30-0)/∆Glu(30-0), and positively associated with hsCRP. Our study showed that higher A1C was associated with impaired early-phase insulin secretion, MetS, and low grade inflammation in Koreans with the relatively high risk for the future development of diabetes.

The clinical course and outcomes of post-transplantation diabetes mellitus after heart transplantation

The aim of this study was to describe in more detail the predisposition, natural course, and clinical impact of post-transplantation diabetes mellitus (PTDM) after heart transplantation (HT). The characteristics and clinical outcomes of 54 patients with PTDM were compared with those of 140 patients without PTDM. The mean age of PTDM patients was significantly higher than controls (48.9 ± 9.3 vs 38.6 ± 13.3 yr, respectively, P = 0.001), and ischemic heart disease was a more common indication of HT (20.4% [11/54] vs 7.1% [10/140], respectively, P = 0.008). In multivariate analysis, only recipient age (odds ratio, 1.80; 95% confidence interval, 1.35-2.40; P = 0.001) was associated with PTDM development. In 18 patients (33%), PTDM was reversed during the follow-up period, and the reversal of PTDM was critically dependent on the time taken to develop PTDM (1.9 ± 1.0 months in the reversed group vs 14.5 ± 25.3 months in the maintained group, P = 0.005). The 5-yr incidence of late infection (after 6 months) was higher in the PTDM group than in the control group (30.4% ± 7.1% vs 15.4% ± 3.3%, respectively, P = 0.031). However, the 5-yr overall survival rate was not different (92.9% ± 4.1% vs 85.8% ± 3.2%, respectively, P = 0.220). In conclusion, PTDM after HT is reversible in one-third of patients and is not a critical factor in patient survival after HT.

The epidemiology of diabetes in Korea

Diabetes is an increasing global health problem worldwide. Diabetes and its complications have become a major cause of morbidity and mortality in Korea. The prevalence of diabetes in Korea has increased six- to seven-fold from 1.5% to 9.9% in the past 40 years. The prevalence of impaired fasting glucose also increased to about 20% in 2009. The International Diabetes Federation has estimated that the prevalence of diabetes will rise to 11.4% in 2030. Possible risk factors for diabetes in Korea are age, male gender, obesity, prediabetes, gestational diabetes, smoking, decreased physical activity, and short sleep duration. With increasing obesity, especially in childhood, and improved longevity, the prevalence of diabetes is expected to dramatically increase more than previously estimated. Therefore, public efforts to introduce healthy lifestyle changes and diabetic prevention programs are necessary to reduce the global epidemic of diabetes.

Racial/ethnic disparities in gestational diabetes mellitus: findings from a population-based survey

PURPOSE

We sought to explore racial/ethnic disparities in the prevalence of gestational diabetes mellitus (GDM) in a population-based sample.

METHODS

Data from the Oregon Pregnancy Risk Assessment Monitoring System (PRAMS), a stratified, random sample of postpartum women who delivered in Oregon in 2004 and 2005 (n = 3,883; weighted response rate, 75.2%) and linked birth certificates were analyzed. Hispanic, non-Hispanic Black, non-Hispanic American Indian, and non-Hispanic Asian/Pacific Islander (API) women were oversampled. We categorized women as having had GDM if they gave an affirmative answer on the birth certificate or the PRAMS survey.

RESULTS

Non-Hispanic API women had the highest prevalence of GDM (14.8%); this was true for women with both a normal and a high body mass index (BMI). Asian women were more likely to have had GDM than Pacific Islander women. On multivariate analysis, non-Hispanic APIs were significantly more likely to have a pregnancy complicated by GDM (adjusted odds ratio, 2.26; 95% confidence interval, 1.23-4.13) than non-Hispanic White women.

CONCLUSION

Non-Hispanic API women, especially Asian women with both normal and high BMI, have increased risk of GDM. Future research should examine the unique risk factors experienced by Asians and health practitioners should be vigilant in screening for GDM regardless of BMI.

The Incretins and Pancreatic beta-Cells: Use of Glucagon-Like Peptide-1 and Glucose-Dependent Insulinotropic Polypeptide to Cure Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is increasing in prevalence worldwide. The complications associated with T2DM result in increased mortality and financial cost for those affected. T2DM has long been known to be associated with insulin resistance in peripheral tissues and a relative degree of insulin deficiency. However, the concept that insulin secretion and insulin sensitivity are not linked through a hyperbolic relationship in T2DM has continuously been demonstrated in many clinical trials. Thus, in order to prevent and treat T2DM, it is necessary to identify the substance(s) that will improve the function and survival of the pancreatic beta-cells in both normal and pathologic conditions, so that production and secretion of insulin can be enhanced. Incretin hormones, such as glucagon-like peptide (GLP)-1 and glucose-dependent insulinotropic polypeptide (GIP), have been shown to lower the postprandial and fasting glucose and the glycated hemoglobin levels, suppress the elevated glucagon level, and stimulate glucose-dependent insulin synthesis and secretion. In this report, we will review the biological actions and mechanisms associated with the actions of incretin hormones, GLP-1 and GIP, on beta-cell health and compare the differences between GLP-1 and GIP.

Metabolic syndrome and alanine aminotransferase: a global perspective from the NAVIGATOR screening population

AIMS

Non-alcoholic fatty liver disease (NAFLD) is associated with features of the metabolic syndrome (MetS) and may be an expression of the syndrome within the liver. Using screening data from the Nateglinide And Valsartan in Impaired Glucose Tolerance Outcomes Research (NAVIGATOR) study (n = 42 149), we examined whether alanine aminotransferase (ALT), a biomarker for NAFLD, clustered with features of MetS and whether the clusters differed across global geographic regions.

METHODS

Exploratory factor analysis using principle components analysis was applied to data drawn from the NAVIGATOR screening population (n = 41 111). Demographic data, anthropomorphic measurements and blood pressure (BP) collected during the screening visit, as well as blood samples analysed for ALT, total cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein, and fasting and 2-h glucose measures after an oral glucose tolerance test were used for our analysis.

RESULTS

Two factors, interpreted as lipid (Factor 1), and BP/obesity (Factor 2) were identified, explaining approximately 50% of the variance in the overall population. Similar patterns of aggregation were reproducible across all geographic regions except Asia, where fasting glucose loaded more consistently on Factor 1. ALT loaded with mean arterial pressure, fasting glucose and waist circumference except in Asia, where it loaded only with mean arterial pressure and waist circumference.

CONCLUSIONS

ALT aggregated with components of MetS, and the pattern of aggregation of ALT with other features of MetS was similar across regions except Asia, possibly indicating a different pathophysiology for NAFLD in Asia. Predictive models of NAFLD may need to be adjusted for regional and ethnic differences.

The association of sleep duration and type 2 diabetes in Korean male adults with abdominal obesity: the Korean National Health and Nutrition Examination Survey 2005

We used data of 1652 male adults aged 20-60 years from KNHANES III. Short sleep duration was significantly associated with an increased prevalence of type 2 diabetes in Korean male adults without abdominal obesity (OR in sleep duration of <or=5 compared to 7h/day: 2.40 [95% CI, 1.18-4.91]).

Overweight and obesity trends among Japanese adults: a 10-year follow-up of the JPHC Study. Int J Obes (Lond). 2008;32:1861-1867. [PMID: 18957932 DOI: 10.1038/ijo.2008.188]

OBJECTIVE

Limited data are available regarding longitudinal changes in body weight. Here, we describe changes in the prevalences of overweight and obesity and calculated the incidence of these indices during a 10-year follow-up period for a large-scale cohort study in Japan.

DESIGN

Longitudinal analysis of data from a population-based cohort study, the Japan Public Health Center (JPHC) Study.

PARTICIPANTS

A total of 65 095 Japanese men and women, who were between the ages of 40 and 69 years at baseline and participated in the 5th- and 10th-year follow-up surveys of the JPHC, were enroled in the study.

MEASUREMENTS

Mean body mass index (BMI), calculated using self-reported height and weight, and the prevalences of overweight (BMI >or=25 kg/m(2)) and obesity (BMI >or=30 kg/m(2)) at each survey period. Incidences of overweight and obesity during the 10-year period.

RESULTS

On an average, individuals living in Okinawa had much higher BMIs than those living on the Main islands for all sex and age groups. During the follow-up period, the prevalences of overweight and obesity steadily increased in the cohorts aged less than 50 years at baseline in both sexes. Men in younger cohorts had a higher mean BMI than those in the same age group of older cohorts, whereas the opposite trend was observed in women. The incidence of overweight individuals was greater in Okinawa than on the Main islands and among younger generations than among older ones.

CONCLUSION

A longitudinal analysis at the individual level showed that the prevalences of overweight and obesity increased among middle-aged Japanese participants during the follow-up period. Among men, an increasing prevalence of obesity was observed among the younger generations. These findings should be taken into consideration when planning preventive strategies for obesity and its related diseases.

A report on the diagnosis of intermediate hyperglycemia in Korea: A pooled analysis of four community-based cohort studies

Many studies show poor agreement between fasting plasma glucose (FPG)-based and 2-h postchallenge glucose (2-h PG)-based criteria to assess glucose metabolism. We examined the rate of agreement between FPG- and 2-h PG-based criteria in the diagnosis of intermediate hyperglycemia in four representative cohort studies in South Korea and compared the clinical characteristics and biochemical parameters in subjects with impaired fasting glucose (IFG) according to their FPG values. Of 6234 subjects from four population-based studies performed from 1993 to 2000, 4610 individuals with data from a 75g oral glucose tolerance test (OGTT) and no previous history of diabetes were selected. We examined the concordance rate between the FPG and 2-h PG-based criteria. We also investigated the differences in the clinical characteristics and biochemical parameters between individuals with IFG according to their FPG values. The fasting and 2-h PG criteria had large discordance rates in the diagnosis of diabetes and impaired glucose tolerance (IGT) in Korean adults. When individuals with IFG were classified into stage 1 [5.6-6.1mmol/L (100-109mg/dL)] and stage 2 [6.1-7.0mmol/L (110-125mg/dL)] IFG, individuals with stage 2 IFG are more obese and had higher blood pressure and total cholesterol and triglycerides concentrations compared with those with stage 1 IFG. In addition, more individuals with stage 2 IFG were with diabetes as determined by a 2-h PG>or=11.1mmol/L (14.1% vs. 1.9%) (P<0.05). Considering the poorer metabolic profile and higher percentage of people with diabetes by OGTT, these data indicate that, in the Korean population, individuals with stage 2 IFG should be treated differently from those with stage 1 IFG. To detect more cases of diabetes, the OGTT is recommended for all individuals with stage 2 IFG and cases with stage 1 IFG with some additional risk factors for diabetes.

[A prospective cohort study of exercise and the incidence of type 2 diabetes in impaired fasting glucose group]

OBJECTIVES

To determine the relationship between exercise and the incidence of type 2 diabetes in an impaired fasting glucose group.

METHODS

This prospective cohort study was conducted in 19,440 men and 4,297 women, aged 30-69 years, with impaired fasting glucose at baseline who had undergone biennial medical evaluation through the National Health Insurance Corporation from 2000 to 2004. Impaired fasting glucose was defined as fasting glucose of 100 to 125 mg/dl and the subjects were divided into 3 groups depending on weekly exercise frequency. Multivariate logistic regression analysis was used to evaluate the association between the baseline exercise status and incidence of type 2 diabetes.

RESULTS

During the 4-year follow-up, a total of 3,239 men and 283 women developed type 2 diabetes, a cumulative incidence of 16.6% for men, and 6.5% for women. Also, 1,688 men (21.2%) and 127 women (15.2%) developed type 2 diabetes in the obese group. The adjusted relative risk (RR) of developing type 2 diabetes in non-exercising men was significantly higher than exercising men regularly (RR= 1.375, 95% CI=1.236-1.529)(p<0.0001), and the RR for non-exercising women was higher than exercising women regularly (RR=1.124, 95% CI=0.711-1.778). The RR for non-exercise men/women in the obese group was 1.571 (95% CI=1.351-1.827)(p<0.0001)/1.869(95% CI=0.846-4.130).

CONCLUSIONS

Regular exercise is effective in preventing type 2 diabetes in people with impaired fasting glucose, and particularly in obese people. People with risk factors for diabetes should participate in a regular exercise program.

The Collaborative Study of Obesity and Diabetes in Adults (CODA) project: meta-analysis design and description of participating studies

The Collaborative Study of Obesity and Diabetes in Adults (CODA) project was formed to establish an international database of studies of abdominal obesity and type 2 diabetes mellitus (T2DM), and to provide analyses of these associations using individual participant data (IPD) meta-analytic techniques. The collaboration involves obtaining raw data from existing studies. The main objectives of the collaboration are to assess which simple anthropometric indices most closely predict the risk of T2DM in adults, and to investigate ethnicity and other factors that potentially modify that prediction. A second task related to primary prevention of diabetes subsequently evolved, the CODA-2 project, and is concerned with population-based methods to identify people most likely to benefit from diabetes interventions. This article describes the meta-analysis design and the studies involved. The collaboration currently has 37 studies enrolled, providing data on 260,000 participants. The proposed IPD meta-analyses will help resolve several outstanding issues in diabetes.

Rapidly increasing diabetes-related mortality with socio-environmental changes in South Korea during the last two decades

Diabetes mellitus is the result of complex interactions involving many genes and environmental factors, and rapid socio-environmental changes have been strongly associated with the development of diabetes. In this study, we examined the trends in diabetes mortality and associated socio-environmental changes that have occurred in South Korea over the last 20 years. Data from a national database and government reports for the years from 1983 to 2001 were analyzed. The data included mortality, socio-economic changes, physical activity and dietary pattern indicators. Deaths from diabetes per 100,000 people increased from 5.3 in 1983 to 18.4 in 2001. Along with increasing diabetes-related mortality, many socio-economic indices (gross domestic production, proportion of tertiary industry and urbanization rate), proxies for physical activity (numbers of cars and time spent watching television) and diet indices (animal protein intake and fat intake) showed remarkable changes. To counter increasing prevalence of diabetes and its related mortality in South Korea, multidirectional efforts including lifestyle modification should be mandatory features of future public health policy.

Epidemic obesity and type 2 diabetes in Asia

The proportions of people with type 2 diabetes and obesity have increased throughout Asia, and the rate of increase shows no sign of slowing. People in Asia tend to develop diabetes with a lesser degree of obesity at younger ages, suffer longer with complications of diabetes, and die sooner than people in other regions. Childhood obesity has increased substantially and the prevalence of type 2 diabetes has now reached epidemic levels in Asia. The health consequences of this epidemic threaten to overwhelm health-care systems in the region. Urgent action is needed, and advocacy for lifestyle changes is the first step. Countries should review and implement interventions, and take a comprehensive and integrated public-health approach. At the level of primary prevention, such programmes can be linked to other non-communicable disease prevention programmes that target lifestyle-related issues. The cost of inaction is clear and unacceptable.

Heterogeneity of early-onset and ketosis-resistant diabetes in Korean subjects--is it possible to determine cut-off age of early-onset type 2 diabetes?

OBJECTIVE

To investigate the heterogeneity of early-onset and ketosis-resistant diabetes and to define a not-arbitrary cut-off age for early-onset diabetes based on its clinical and metabolic characteristics, and diabetes complications.

METHODS

We classified 1015 early-onset diabetes subjects aged 21-40 into four groups (group I, age at diagnosis 21-25 years; group II, 26-30; group III, 31-35; group IV, 36-40). Familial and diabetic history, statue of insulin secretion, metabolic parameters, and diabetes complications were analyzed.

RESULTS

No significant difference in family history or the rate of diabetic complication was found in the four groups. Subjects with a 21 to a 25-year-old diabetes onset had the lowest serum C-peptide levels, with 50% of the cumulative 24-h urine C-peptide levels of the other three groups (p<0.0001). This group also had the lowest prevalence of hyperlipidemia and arterial hypertension (p<0.01 and <0.0001, respectively). Group III was found to have a higher prevalence of insulin insufficiency and hypertension than group IV.

CONCLUSION

Our data based on insulin secretory function and metabolic factors might suggest that a cut-off age of 26 years might be warranted in Korean patients. Korean early-onset type 2 diabetes patients tend to be non-obese and insulin secretory dysfunction.

Pathophysiologic heterogeneity in the development of type 2 diabetes mellitus in Korean subjects

OBJECTIVE

To investigate the clinical characteristics and predisposing metabolic abnormalities in the development of glucose intolerance and diabetes mellitus in obese and non-obese Korean subjects.

METHODS

Four hundred Korean subjects were classified into five groups according to degree of glucose tolerance by OGTT: NGT, IGT alone, IFG alone, IFG+IGT, and DM. The groups were also subdivided into obese and non-obese group according to body mass index. Insulin resistance was assessed by using homeostasis model assessment of insulin resistance (HOMA-R), and insulinogenic index was used as an index of early-phase insulin secretion.

RESULTS

Impaired early-phase insulin secretion was seen in non-obese IGT alone, IFG alone, and IFG+IGT, though more profound secretory defects were noted in IFG+IGT and DM. No significant difference were found in HOMA-R among non-obese IGT alone, IFG alone, or IFG+IGT, or in terms of early-phase insulin secretion in obese IGT alone, IFG alone, or IFG+IGT. However, the magnitude of insulin resistance differed in the obese group, IFG+IGT and DM being more insulin resistant than IGT alone or IFG alone.

CONCLUSIONS

These results suggest that the predisposing metabolic abnormality in non-obese subjects with IGT alone or IFG alone and in progression to IFG+IGT might be deterioration of early phase insulin secretion, whereas insulin resistance might be the major contributory factor in obese subjects. The predisposing metabolic abnormality leading to diabetes in both obese and non-obese groups was deterioration of early-phase insulin secretion.

Alcohol consumption and other risk factors for self-reported diabetes among middle-aged Japanese: a population-based prospective study in the JPHC study cohort I

AIMS

Few prospective studies have examined the relationship between lifestyle characteristics and the incidence of diabetes mellitus in an Asian general population. This study was undertaken to evaluate the risk factors for Type 2 diabetes in a population-based prospective study of middle-aged Japanese.

METHODS

We investigated 12,913 men and 15,980 women, aged 40-59 years at baseline (year 0), who participated in the Japan Public Health Center-based prospective study on cancer and cardiovascular diseases (JPHC Study) Cohort I. The participants were followed for up to 10 years. Incident cases of diabetes were identified by self-reporting of a physician's diagnosis on two questionnaires sent to each participant, one at year 5 and the second at year 10.

RESULTS

During the 10-year follow-up, 703 men and 482 women reported newly diagnosed diabetes. Age, body mass index (BMI), family history of diabetes and cigarette smoking were independent risk factors in both genders by multivariate analysis. Among men with a BMI < or = 22 kg/m2, a significant positive association was observed between the diabetes incidence and moderate (23.0 < 46.0 g/day) to high (> 46.0 g/day) alcohol consumption, odds ratio 1.91 (95% CI, 1.05-3.46) and 2.89 (1.63-5.11), respectively. Among men with a BMI > 22 kg/m2, a small non-significant increase in odds ratio was observed with alcohol consumption.

CONCLUSIONS

Established risk factors for diabetes in western populations were also identified as predictors of the disease among Japanese. Moderate to high alcohol consumption was positively associated with the incidence of diabetes in Japanese lean (BMI < or = 22 kg/m2) men.

Type 2 diabetes prevalence in Asian Americans: results of a national health survey

OBJECTIVE

Asians are thought to be at high risk for diabetes, yet there is little population-based information about diabetes in Asian Americans. The purpose of this study was to directly compare the prevalence of type 2 diabetes in Asian Americans with other racial and ethnic groups in the U.S. using data from the 2001 Behavioral Risk Factor Surveillance System (BRFSS).

RESEARCH DESIGN AND METHODS

The BRFSS is a population-based telephone survey of the health status and health behaviors of Americans in all 50 states, Guam, Puerto Rico, and the U.S. Virgin Islands. Subjects included 3,071 Asians, 12,561 blacks, 12,153 Hispanics, 2,299 Native Americans, 626 Pacific Islanders, and 129,116 non-Hispanic whites aged >/=30 years. Subjects who reported a physician-diagnosis of diabetes were considered to have type 2 diabetes unless they were diagnosed before age 30.

RESULTS

Compared with whites, odds ratios (95% CIs) for diabetes, adjusted for age and sex, were 1.0 (0.7-1.4) for Asians, 2.3 (2.1-2.6) for blacks, 2.0 (1.8-2.3) for Hispanics, 2.2 (1.6-2.9) for Native Americans, and 3.1 (1.4-6.8) for Pacific Islanders. Results adjusted for BMI, age, and sex were 1.6 (1.2-2.3) for Asians, 1.9 (1.7-2.2) for blacks, 1.9 (1.6-2.1) for Hispanics, 1.8 (1.3-2.5) for Native Americans, and 3.0 (1.4-6.7) for Pacific Islanders.

CONCLUSIONS

Similar proportions of Asian and non-Hispanic white Americans report having diabetes, but after accounting for the lower BMI of Asians, the adjusted prevalence of diabetes is 60% higher in Asian Americans.

Insulin, proinsulin, proinsulin:insulin ratio, and the risk of developing type 2 diabetes mellitus in women

PURPOSE

To assess the associations among baseline levels of fasting insulin and proinsulin, proinsulin:insulin ratio, and the development of type 2 diabetes mellitus in apparently healthy middle-aged women.

METHODS

In a nested case-control study involving a nationwide cohort of 27,628 participants from the Women's Health Study, 126 women with diabetes diagnosed during a 4-year follow-up period were compared with 225 age-matched controls. Fasting insulin level and proinsulin:insulin ratio were assessed in quartiles, and proinsulin level was assessed in categories (< or =4.0 pmol/L, 4.01 to 6.99 pmol/L, > or =7.0 pmol/L). The risk of developing type 2 diabetes was determined using conditional logistic regression analysis that adjusted for body mass index and other diabetes risk factors.

RESULTS

Baseline insulin and proinsulin levels and proinsulin:insulin ratios were significantly higher among cases than among controls. Women with elevated insulin levels in the highest as compared with the lowest quartile were more likely to develop diabetes (odds ratio [OR] = 5.6; 95% confidence interval [CI]: 1.8 to 17.6), as were women with elevated (> or =7.0 pmol/L vs. < or =4.0 pmol/L) proinsulin levels (OR = 16.4; 95% CI: 5.8 to 46.8) and women with proinsulin:insulin ratios in the highest quartile (OR = 9.6; 95% CI: 3.1 to 30.8). Similar results were observed among women with a baseline hemoglobin A(1c) level < or =6.0%. In time-trend analyses, fasting insulin was a consistent predictor of long-term risk. Proinsulin and proinsulin:insulin ratio, although predictive throughout the study, were especially strong predictors of rapid progression to type 2 diabetes.

CONCLUSION

Elevated fasting insulin and proinsulin levels and proinsulin:insulin ratio are associated with an increased risk of developing type 2 diabetes in apparently healthy middle-aged women.

High incidence of tacrolimus-associated posttransplantation diabetes in the Korean renal allograft recipients according to American Diabetes Association criteria

OBJECTIVE

The incidence of posttransplantation diabetes mellitus (PTDM) has been reported to vary according to different study populations or different definitions. In this study, using American Diabetes Association criteria, the incidence and clinical characteristics of PTDM in Korean renal allograft recipients undergoing tacrolimus-based immunosuppression were examined.

RESEARCH DESIGN AND METHODS

A total of 21 patients taking tacrolimus as primary immunosuppressant were recruited and tested with a serial 75-g oral glucose tolerance test at 0, 1, 3, and 6 months after renal transplantation.

RESULTS

The cumulative incidence of PTDM was 52.4% at 1 month and 57.1% at 3 and 6 months. The baseline characteristics of the PTDM group were old age (especially >40 years), a high BMI, a high fasting glucose level, a high plasma insulin level, and increased insulin resistance. Among these parameters, old age was the only independent risk factor. The insulin secretory capacity in the PTDM group was maximally suppressed 3 months after transplantation. Thereafter, it was gradually restored along with dose reduction of tacrolimus.

CONCLUSIONS

Routine screening for PTDM is necessary in patients over 40 years of age who are undergoing a relatively higher dose tacrolimus therapy during the early course of postrenal transplantation.

Factor analysis of the metabolic syndrome among elderly Koreans--the South-west Seoul Study

AIMS

To examine the relationship between the components of the metabolic syndrome and to explore whether insulin resistance unifies the clustering of components of the metabolic syndrome among urban elderly Koreans using exploratory factor analysis.

METHODS

We included 1314 non-diabetic subjects over the age of 60 years, selected from a cross-sectional study, which was conducted in 1999 in Seoul, Korea. Factor analysis was carried out using the principle components analysis with Varimax orthogonal rotation of the components of the metabolic syndrome.

RESULTS

We found four major factors of cardiovascular disease risk variables in our study subjects. Impaired glucose tolerance, dyslipidaemia, hypertension and obesity aggregated as the major domain. Obesity and dyslipidaemia variables were closely related and loaded on the same factor. However, hypertension was not linked closely with other factors of the metabolic syndrome.

CONCLUSIONS

Insulin resistance is not the only contributor to the metabolic syndrome among urban elderly Koreans. Although the components of the metabolic syndrome were closely related, the finding of more than one factor suggests that more than one pathophysiological mechanism underlies full expression of the metabolic syndrome among elderly Koreans.

Increased proinsulin levels and decreased acute insulin response independently predict the incidence of type 2 diabetes in the insulin resistance atherosclerosis study

Previous studies have indicated that beta-cell dysfunction predicts the development of diabetes, although it is unknown whether the use of combinations of insulin secretory measures further improves prediction. The Insulin Resistance Atherosclerosis Study is a prospective, multicenter, epidemiological study of the relationship between insulin sensitivity and the risk of diabetes and cardiovascular disease. At baseline, fasting concentrations of insulin, intact proinsulin (PI), and split PI were measured, and acute insulin response (AIR) was determined during a frequently sampled intravenous glucose tolerance test (FSIGTT). Subjects who were nondiabetic at baseline (n = 903) were reexamined after 5 years of follow-up; 148 had developed diabetes. In separate logistic regression models adjusted for age, sex, clinic, and ethnicity, 1 SD differences in measures of beta-cell dysfunction were associated with diabetes incidence (AIR: odds ratio [OR] 0.37, 95% CI 0.27-0.52; intact PI: OR 1.90, 95% CI 1.57-2.30; split PI: OR 1.94, 95% CI 1.63-2.31). After additional adjustment for BMI, impaired glucose tolerance, and insulin sensitivity, these measures continued to be significantly associated with risk of diabetes (all P < 0.0001). Furthermore, in models that included both PI and AIR, each was an independent predictor, and individuals who had combined low AIR and high PI experienced the highest diabetes risk. In conclusion, both low AIR and high PI independently predicted diabetes in a well-characterized multiethnic population. Although fasting PI is simpler to assess, determining AIR from an FSIGTT may further improve prediction. If pharmacological agents to prevent diabetes are proved to be efficacious in ongoing clinical trials, then it may be beneficial to perform FSIGTTs to identify better (for intensive intervention) prediabetic subjects who would ultimately require lifelong pharmacological therapy.

Incidence of diabetes in American Indians of three geographic areas: the Strong Heart Study

OBJECTIVE

To estimate incidence rates of diabetes and associated risk factors among participants of the Strong Heart Study.

RESEARCH DESIGN AND METHODS

Of the 4,549 Strong Heart Study participants examined at baseline, 3,638 returned for a similar examination after an average of 4 years. The 1985 World Health Organization criteria for diabetes were used to identify new diabetes cases. Rates of diabetes among participants who did not have diabetes at baseline examination were determined. The relationships between the incidence rates of diabetes and a number of risk factors measured at baseline examination were studied.

RESULTS

Significant variables associated with the development of diabetes included triglycerides, obesity, fasting plasma glucose, insulin, and degree of American Indian blood among participants with NGT at baseline. For those with IGT at baseline, significant predictors included fasting plasma glucose, 2-h glucose, BMI, degree of American Indian blood, and albuminuria.

CONCLUSIONS

The high incidence rates found in this study were alarming. To slow down the rapid increase of this disease in the American Indian population, preventive programs must be designed and implemented. Patients with IGT should be treated with diabetes medication or put on a rigid weight-reduction program to reduce the risk of progression to diabetes.

Incidence and predictors of drug-treated diabetes in elderly French subjects. The PAQUID Epidemiological Survey

AIMS

To estimate the incidence and predictors of drug-treated diabetes in elderly subjects.

METHODS

The PAQUID epidemiological survey, a population-based study, has followed up 3,777 subjects older than 65 years since 1988. At each visit (baseline, 1, 3, 5 and 8 years), treatment regimen was used to identify new drug-treated diabetic subjects. Potential predictors of drug-treated diabetes were collected during the baseline visit (body mass index (BMI), educational level, cigarette smoking and wine consumption, physical activity, depressive symptomatology, subjective health, treatment, and hypertension) and analysed by using a multivariate backward stepwise regression Cox model with delayed entry.

RESULTS

The prevalence rate of drug-treated diabetes was 7.5% at baseline and 7.1% after 8 years' follow-up. The incidence rate of drug-treated diabetes was 3.8/1,000 person-years, 5.9/1,000 person-years in men and 2.4/1,000 person-years in women, with no significant variation according to age group. Male sex (relative risk (RR) 2.4, 95% confidence interval (CI) 1.4-4.0, P < 0.001, attributable risk (AR) 0.36), elevated BMI (for one point increase, RR 1.1, 95% CI 1.1-1.1, P < 0.001, > or = 25 vs. < 25, RR 2.1, 95% CI 1.2-3.5, AR 0.33), thiazide diuretics used alone (RR 5.9, 95% CI 1.8-19.6, P = 0.02), and poorer subjective health ('the same' vs. 'better' RR 1.8, 95% CI 1.0-3.1, P = 0.04; 'worse' vs. 'better' RR 2.3, 95% CI 0.9-5.7, P = 0.06) were independent predictors of drug-treated diabetes in this population.

CONCLUSIONS

In older French individuals, men seem to be particularly exposed to drug-treated diabetes although being overweight was found to be a strong predictor as in younger populations.

Comparison of glucose tolerance categories in the Korean population according to World Health Organization and American Diabetes Association diagnostic criteria

OBJECTIVES

To compare the prevalence and metabolic profiles of glucose tolerance categories according to World Health Organization(WHO) and 1997 American Diabetes Association(ADA) fasting criteria for the diagnosis of diabetes mellitus and impaired glucose metabolism in the Korean population.

METHODS

2251 subjects without previous history of diabetes, who participated in the Yonchon diabetes epidemiology survey in 1993, were classified according to both criteria. The prevalence of glucose tolerance categories and the agreement across all categories of glucose tolerance were calculated. Metabolic characteristics of different glucose tolerance categories were compared.

RESULTS

The prevalence of diabetes and impaired fasting glucose(IFG) according to ADA fasting criteria was similar to those of diabetes and impaired glucose tolerance(IGT) according to WHO criteria, respectively. However, 35.5% of the subjects who were diagnosed as diabetes by WHO criteria were reclassified as either IFG or normal fasting glucose (NFG), and 38.5% of diabetic patients according to ADA fasting criteria were IGT or normal glucose tolerance (NGT) by WHO criteria. Only 31.3% of IGT subjects remained as IFG and 62.1% were reclassified as NFG. Similarly, 69.4% of IFG subjects were NGT by WHO criteria. The agreement between the two criteria was poor (K = 0.31). Discordant diabetes groups had higher WHR, systolic and diastolic blood pressure, cholesterol and triglyceride levels than concordant non-diabetes group. Non-diabetes(WHO)/diabetes(ADA) group had higher WHR than diabetes (WHO)/non-diabetes(ADA) group. There were no differences in other metabolic characteristics between the two discordant diabetes groups. IGT/NFG and NGT/IFG group showed higher BMI, WHR, systolic and diastolic blood pressure, cholesterol and triglyceride levels than NGT/NFG group. Metabolic characteristics of IGT/NFG group were not different from those of NGT/IFG group except IGT/NFG subjects were older than NGT/IFG subjects.

CONCLUSION

The agreement between WHO and ADA fasting criteria was poor. ADA fasting criteria can detect new diabetic patients and subjects with impaired glucose metabolism who are not classified as diabetes or IGT by WHO criteria. However, a substantial number of subjects, who may have increased cardiovascular risk and/or increased risk for the development of diabetes and its complication, will be missed when using ADA fasting criteria.

Evidence that the mitochondrial genome is the thrifty genome

Although mitochondrial DNA (mtDNA) abnormalities are known to cause insulin deficiency, insulin resistance and diabetes mellitus, it's quantitative aspect was not addressed well. In this review, mitochondrial genome hypothesis of thrifty phenomenon is proposed, based on the data and review of literatures. From a population based epidemiologic study, it was found that mtDNA quantity was decreased in the peripheral blood of diabetic subjects, and also in those subjects who will convert to diabetes mellitus within 2 years. In this population, low mtDNA subjects were found to have higher blood pressure and high waist hip ratio. These findings suggested mtDNA status might be quantitatively linked to the insulin resistance syndrome. As quantitative relationships between peripheral blood mtDNA levels and insulin requirement, and energy utilization pattern (fat and carbohydrate oxidation during hyperinsulinemic clamp studies) were observed in a group of male students; and maternal mtDNA content (peripheral blood) correlated with birth weight and peripheral blood mtDNA content of the offspring in another study, possibility of thrifty phenotype phenomena might be due to the low mitochondrial status arose. As thrifty phenotype phenomenon shows the quantitatively continuous relationship between involved parameters and characteristics of 'imprinting', a possible mechanism is suggested.

Heterogeneous relationship of early insulin response and fasting insulin level with development of non-insulin-dependent diabetes mellitus in non-diabetic Japanese subjects with or without obesity

The aim of this study was to investigate the association of insulin secretion and insulin resistance with the development of non-insulin-dependent diabetes mellitus (NIDDM) in obese (body mass index (BMI) > or = 25 kg/m2) and non-obese Japanese. Subjects were selected from persons participating a health survey, and a 100 g oral glucose tolerant test was performed. A total of 1604 non-diabetic subjects were followed for 2-8 years (mean 4.5 years). The fasting insulin level and the homeostasis model insulin resistance index (HOMA-R = fasting glucose [mmol/l] x fasting insulin [microU/ml]/22.5) were used as the index of insulin resistance, and insulinogenic index (the ratio of increment of insulin to that of blood glucose 30 min after glucose load) as a measure of early insulin response. Cox's proportional hazards analysis in the whole group showed that BMI, fasting blood glucose (FBG) and 2-h blood glucose (2-h BG) were positive predictors, and age and insulinogenic index were negative predictors of diabetes. Sex, family history, fasting insulin level and HOMA-R were not predictive of developing diabetes. In subgroup analysis, the same variables as in the whole group were predictors in non-obese, whereas only FBG and 2-h BG predicted diabetes in obese subjects. Fasting insulin level and HOMA-R were not predictive of diabetes both in non-obese and obese subjects. Eleven obese subjects, who developed diabetes despite a normal initial insulinogenic index, had significantly higher BMI, fasting insulin level and HOMA-R, compared with 258 obese subjects who did not develop diabetes. We conclude that most cases of diabetes in Japanese begin with decreased insulin secretion, but a small group of diabetes patients may start with insulin resistance, especially obese subjects.

Decreased mitochondrial DNA content in peripheral blood precedes the development of non-insulin-dependent diabetes mellitus

Qualitative changes in mitochondrial DNA (mtDNA), such as mutations and deletions, have been implicated in the pathogenesis of diabetes mellitus. In addition to the qualitative changes, mtDNA is subject to quantitative changes, and is vulnerable to oxidative stress, resulting in both qualitative and quantitative changes. This study was performed to investigate whether quantitative changes in mtDNA occur in non-insulin-dependent diabetes mellitus (NIDDM) patients and also in pre-diabetic subjects. MtDNA content from peripheral blood was measured by slot-blot analysis in 55 NIDDM patients and 29 age- and sex-matched control subjects. We have also analysed the mtDNA copies by quantitative polymerase chain reaction (PCR) method in 23 pre-diabetic subjects who converted to diabetic in 2 years and 22 age- and sex-matched control subjects who remained non-diabetic. Mean mtDNA quantity measured by slot blot method was 35% lower in patients with NIDDM than in control subjects (12.3+/-8.1 vs. 19.1+/-8.2 AU/microg DNA; P < 0.05). MtDNA quantities did not correlate with age, body mass index, duration of diabetes or HbA1c levels. We have also found that the mtDNA copies in subjects who converted to diabetes in 2 years were lower than in controls even before the development of diabetes (102.8+/-41.5 vs. 137.8+/-67.7 copies/pg template DNA P < 0.05). Inverse correlations were noted between mtDNA content and baseline waist hip circumference ratio (WHR) (r = -0.31, P < 0.05), and fasting glucose level (r = - 0.35, P < 0.05), diastolic blood pressure (r = -0.36, P < 0.05), and WHR (r = -0.40, P < 0.01) after development of diabetes. In conclusion, we demonstrate that the content of mtDNA decreases in peripheral blood of patients with NIDDM and the lower mtDNA levels precede the development of diabetes.