Elevated white blood cell count in subjects with impaired glucose tolerance

OBJECTIVE: Impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) differ in their risk of all-cause and cardiovascular mortality, but previous cross-sectional studies have suggested little difference in their levels of lipids or blood pressure. We compared the white blood cell (WBC) count between subjects with IFG and IGT. RESEARCH DESIGN AND METHODS: The subjects were 4,720 nondiabetic Japanese men aged 24-84 years. Based on the 75-g oral glucose tolerance test, the subjects were classified into the following four groups: normal fasting glucose/normal glucose tolerance (n = 3,753), isolated IFG (n = 290), isolated IGT (n = 476), and IFG/IGT (n = 201). We compared the WBC count among the four groups and investigated variables that showed a significant association with the WBC count. RESULTS: The isolated IGT group had a significantly higher WBC count than the isolated IFG group (6,530 vs. 6,210/mm(3), P < 0.05). By stepwise analyses, age, triglycerides, HDL cholesterol, fasting insulin, and 2-h postchallenge plasma glucose (PG) showed an independent association with the WBC count (adjusted R(2) = 0.057). In the analysis stratified by smoking status, the WBC count was independently associated with 2-h PG and triglycerides, irrespective of smoking status. CONCLUSIONS: Individuals with isolated IGT had a significantly higher WBC count than those with isolated IFG. The WBC count was associated with 2-h PG and various components of the metabolic syndrome.     

Predictive properties of impaired glucose tolerance for cardiovascular risk are not explained by the development of overt diabetes during follow-up

OBJECTIVE: To evaluate the relationship of impaired glucose tolerance (IGT) at baseline to coronary heart disease (CHD) incidence, and cardiovascular disease (CVD) and total mortality at follow-up, and to analyze whether the relationship is independent of the subsequent development of diabetes during follow-up. RESEARCH DESIGN AND METHODS: A baseline screening survey for diabetes was performed in 1987 using a 2-h 75-g oral glucose tolerance test. A total of 1234 men and 1386 women aged 45-64 years, who were free of diabetes at baseline, were followed up for 10 years. During the follow-up, 153 subjects had an incident CHD event, 224 died, and 100 deaths were due to cardiovascular causes. Multivariate adjusted (adjusted for age, sex, waist-to-hip ratio, systolic blood pressure, cholesterol, HDL cholesterol, and smoking) hazard ratio (HR) was estimated using Cox regression analysis. RESULTS: In subjects who had IGT at baseline and who did not progress to diabetes during the follow-up, the multivariate adjusted HR (95% CI) was 1.49 (0.95-2.34) for CHD incidence, 2.34 (1.42-3.85) for CVD mortality, and 1.65 (1.13-2.40) for all-cause mortality. CONCLUSIONS: Baseline IGT was an independent risk predictor for cardiovascular morbidity and mortality and for total mortality, which was not confounded by the subsequent development of overt diabetes.     

Different mechanisms for impaired fasting glucose and impaired postprandial glucose tolerance in humans

OBJECTIVE: To compare the pathophysiology of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) in a more comprehensive and standardized fashion than has hitherto been done. RESEARCH DESIGN AND METHODS: We studied 21 individuals with isolated IFG (IFG/normal glucose tolerance [NGT]), 61 individuals with isolated IGT (normal fasting glucose [NFG]/IGT), and 240 healthy control subjects (NFG/NGT) by hyperglycemic clamps to determine first- and second-phase insulin release and insulin sensitivity. Homeostasis model assessment (HOMA) indexes of beta-cell function (HOMA-%B) and insulin resistance (HOMA-IR) were calculated from fasting plasma insulin and glucose concentrations. RESULTS: Compared with NFG/NGT, IFG/NGT had similar fasting insulin concentrations despite hyperglycemia; therefore, HOMA-IR was increased approximately 30% (P < 0.05), but clamp-determined insulin sensitivity was normal (P > 0.8). HOMA-%B and first-phase insulin responses were reduced approximately 35% (P < 0.002) and approximately 30% (P < 0.02), respectively, but second-phase insulin responses were normal (P > 0.5). NFG/IGT had normal HOMA-IR but approximately 15% decreased clamp-determined insulin sensitivity (P < 0.03). Furthermore, HOMA-%B was normal but both first-phase (P < 0.0003) and second-phase (P < 0.0001) insulin responses were reduced approximately 30%. IFG/NGT differed from NFG/IGT by having approximately 40% lower HOMA-%B (P < 0.012) and approximately 50% greater second-phase insulin responses (P < 0.005). CONCLUSIONS: Since first-phase insulin responses were similarly reduced in IFG/NGT and NFG/IGT, we conclude that IFG is due to impaired basal insulin secretion and preferential resistance of glucose production to suppression by insulin, as reflected by fasting hyperglycemia despite normal plasma insulin concentrations and increased HOMA-IR, whereas IGT mainly results from reduced second-phase insulin release and peripheral insulin resistance, as reflected by reduced clamp-determined insulin sensitivity.     

Differences in cardiovascular risk factors, insulin resistance, and insulin secretion in individuals with normal glucose tolerance and in subjects with impaired glucose regulation: the Telde Study

OBJECTIVE: To assess the cardiovascular risk profile, the degree of insulin resistance, and beta-cell secretion in a cohort of subjects with different categories of impaired glucose regulation (IGR): impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and combined IFG/IGT. RESEARCH DESIGN AND METHODS: We studied 902 nondiabetic subjects between 30 and 80 years of age, recruited from a cross-sectional population-based study in Telde, Gran Canaria Island, Spain. Categories of glucose tolerance were defined according to 2003 modified American Diabetes Association criteria. Risk factors for cardiovascular disease, the presence of the metabolic syndrome, and indirect measures of both insulin resistance and beta-cell function were analyzed. RESULTS: A total of 132 (14.6%) participants had isolated IFG, 59 (6.5%) isolated IGT, and 48 (5.3%) combined IFG/IGT. Groups with normal glucose tolerance (NGT) and combined IFG/IGT had, respectively, the most favorable and unfavorable levels of cardiovascular risk factors, metabolic syndrome rates, and measures of insulin resistance. Subjects with IFG and IGT showed an intermediate profile between NGT and IFG/IGT categories. We found no significant differences between IFG and IGT in cardiovascular risk factors, metabolic syndrome prevalence, or insulin resistance. The IFG group exhibited a more impaired insulin secretion than those with IGT or IFG/IGT. CONCLUSIONS: Individuals with IGR, especially those with IFG/IGT, have increased values of cardiovascular risk factors and higher indexes of insulin resistance. Groups with isolated IFG and isolated IGT present similar cardiovascular risk profiles. Subjects with IFG are characterized by more defective beta-cell function than other forms of IGR.     

Impaired fasting glucose and impaired glucose tolerance in women with prior gestational diabetes are associated with a different cardiovascular profile

OBJECTIVE: The purpose of this study was to investigate the association of cardiovascular risk factors to impaired glucose tolerance (IGT) and to impaired fasting glucose (IFG) in women with prior gestational diabetes mellitus (GDM). RESEARCH DESIGN AND METHODS: We studied 838 women with prior GDM. Postpartum glucose tolerance status was classified as normal, IFG, IGT, IFG plus IGT, and diabetes according to the World Health Organization criteria. Postpartum BMI, waist circumference, blood pressure, triglyceride, cholesterol, and HDL cholesterol were assessed. RESULTS: BMI and blood pressure were significantly higher in women with IFG than in women with normal glucose status. BMI and waist circumference were significantly higher in women with IFG plus IGT than in women with normal glucose status. No differences were observed between women with IGT and normal glucose status. The prevalence of hypertension and obesity was significantly increased in IFG compared with normal glucose status. The prevalence of obesity and abnormal lipids was significantly increased in IFG plus IGT compared with normal glucose status. IGT showed no increased prevalence of cardiovascular risk factors. CONCLUSIONS: Traditional cardiovascular risk factors have a stronger association with isolated IFG than with isolated IGT in women with prior GDM.     

Lowering the criterion for impaired fasting glucose: impact on disease prevalence and associated risk of diabetes and ischemic heart disease

OBJECTIVE: To determine the effect of lowering the fasting plasma glucose (FPG) criterion for impaired fasting glucose (IFG) on the prevalence of IFG, the risks of diabetes, and cardiovascular disease (CVD) associated with IFG. RESEARCH DESIGN AND METHODS: Three studies were used: 1). the 1998 National Health Survey (NHS98), a randomly selected cross-sectional sample of 4723 subjects; 2). the Singapore Impaired Glucose Tolerance (IGT) Follow-up Study, a cohort study comprising 295 IGT and 292 normal glucose tolerance subjects (frequency matched for age, sex, and ethnic group) followed up from 1992 to 2000; and 3). the Singapore CVD Cohort Study, comprising 5920 subjects from three cross-sectional studies in whom the first ischemic heart disease (IHD) event was identified through linkage to registry databases. Risk of diabetes (Singapore IGT Follow-up study) was estimated using logistic regression adjusted for age, sex, and ethnicity. Risk of IHD (Singapore CVD cohort) was estimated using stratified (by study, from which data were derived) Cox's proportional hazards models adjusted for age, sex, and ethnicity. RESULTS: Lowering the criterion for diagnosing IFG to 5.6 mmol/l increased the prevalence of IFG from 9.5 to 32.3% in the NHS98. The lower cutoff identified more subjects at risk of diabetes and IHD, but the relative risk was lower than that for IGT. CONCLUSIONS: Greater efforts to identify those with IGT, or a group at similar risk of diabetes and CVD, may be a more efficient public health measure than lowering the FPG criterion for diagnosing IFG.     

Lack of agreement between the revised criteria of impaired fasting glucose and impaired glucose tolerance in children with excess body weight

OBJECTIVE: The aim of this study was to describe the agreement between impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) in children with excess body weight using the original and the revised definitions of IFG. RESEARCH DESIGN AND METHODS: Obese and overweight children aged 4-17 years were included (n = 533). Anthropometric parameters and biochemical tests (fasting and 2-h glucose tests after an oral glucose load [1.75 g/kg]) were performed. Case subjects with a fasting plasma glucose >/=126 mg/dl were excluded. The diagnostic parameters of the original and the revised definitions of IFG for detecting IGT were estimated. The analysis of agreement between these categories was made using the kappa test. RESULTS: The prevalence of IFG increased from 6.2 to 13.3% using the new criteria. The prevalence of IFG became closer to the prevalence of IGT (14.8%). The revised criteria increased the sensitivity from 26.6 to 36.7%. However, the new IFG definition was not useful for identifying IGT cases. Of the 71 case subjects with IFG, only 29 (40.8%) had IGT. In addition, 50 case subjects with IGT (9.4%) and 13 with diabetes (2.4%) had a fasting glycemia <100 mg/dl. A poor agreement was found between the 2003 IFG definition and abnormal 2-h postchallenge plasma glucose (kappa = 0.359). The proportion of false-positive cases increased (36.3-59.1%) under the new definition. CONCLUSIONS: The new definition modestly increases the sensitivity of IFG for detecting IGT in children with excess body weight. Despite this, more than one-half of these cases are not detected. In addition, the false-positive rate was increased by 61%.     

The significance of impaired fasting glucose versus impaired glucose tolerance: importance of insulin secretion and resistance

OBJECTIVE: The American Diabetes Association recommended substituting 2hBS (glycemia at the second hour of an oral glucose tolerance test [OGTT]) for fasting blood glucose (FBS) in screening for glucose intolerance. It is debated whether these tests measure the same abnormality and relate to defective insulin secretion or resistance. This study examines the diagnostic effectiveness of FBS versus 2hBS and their relationship with insulin secretion and resistance. RESEARCH DESIGN AND METHODS: Based on history or physical findings suggesting glucose intolerance, we enrolled 398 unselected subjects admitted to a general Internal Medicine ward. After 5 days of a weight-maintaining diet, FBS, 2hBS, and insulin were measured during OGTT. The homeostatic model assessment was used to assess beta-cell function and insulin resistance. RESULTS: Excluding 19 patients with diabetes (5%), we identified 284 subjects with normal glucose tolerance (NGT), 22 with isolated impaired fasting glucose (IFG), 59 with isolated impaired glucose tolerance (IGT), and 14 with associated IFG/IGT. The sensitivity of FBS in predicting 2hBS was 19%, specificity 93%. Positive and negative predictive values were 39% and 83%, respectively. Insulin resistance was absent in NGT and IFG and markedly elevated in IGT and IFG/IGT, whereas defective insulin release was significant only in isolated IFG. CONCLUSIONS: In unselected patients, elevated FBS depends primarily on defective insulin secretion, and impaired 2hBS on insulin resistance. Because these tests measure different alterations, they are useful in combination.     

血糖调节异常者血脂代谢的初步研究

目的初步评价血糖调节受损患者血脂代谢异常情况。方法检测糖耐量正常(NGT)、单纯空腹血糖异常(IFG)、单纯糖耐量异常(IGT)、空腹血糖异常合并糖耐量异常(IFG IGT)和糖尿病(DM)患者空腹血糖和餐后2 h血糖及空腹血清总胆固醇(TC)、三酰甘油(TG)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、载脂蛋白A-I(apo A-I)和载脂蛋白B(apo B)水平,计算非高密度脂蛋白胆固醇(non-HDL-C)和血浆致动脉硬化指数(AIP),比较各组间血清脂质成分的差异。结果IFG组血清TC、LDL-C、non-HDL-C和apo B水平较NGT组明显升高(P<0.01),而TG、HDL-C、AIP差异无统计学意义(P>0.05)。IGT组血清TC、TG、LDL-C、non-HDL-C、apo A-I、apo B和AIP水平较NGT组显著升高(P<0.01),前6项指标与IFG IGT组差异无统计学意义(P>0.05)。IFG IGT组与NGT组比较,各指标差异均有统计学意义(P<0.01);HDL-C、non-HDL-C和AIP水平与IFG组比较差异有统计学意义(P<0.01)。DM组表现出典型的DM性脂代谢紊乱伴AIP水平显著异常。non-HDL-C和apo B间存在良好的相关性(P<0.01)。结论血糖调节受损者不同程度的存在血脂代谢异常,主要表现为TC、TG、LDL-C、non-HDL-C和apo B水平的升高和HDL-C、apo A-I的降低,伴不同程度AIP水平的改变。     

Changing the definition of impaired fasting glucose: impact on the classification of individuals and risk definition

OBJECTIVE: This study evaluates the impact of lowering the diagnostic threshold for impaired fasting glucose (IFG) from 6.1 to 5.6 mmol/l as proposed by the American Diabetes Association (ADA) on the prevalence of the condition, classification of individuals, and risk definition. RESEARCH DESIGN AND METHODS: A total of 1,285 employees of the Italian Telephone Company aged 35-59 years without known diabetes underwent an oral glucose tolerance test (OGTT). BMI, serum cholesterol, triglycerides, and blood pressure were measured. Medication use was recorded. RESULTS: With the new ADA criterion, the proportion of people diagnosed with IFG increased from 3.2 to 9.7%. The newly proposed IFG category identified 41% of all subjects with impaired glucose tolerance (IGT) compared with 16.2% identified with the use of the World Health Organization criterion for IFG; the improvement in accuracy has been achieved at the cost of classifying more previously "normal" subjects as having IFG (from 2.3 to 7.3%). Both IFG and IGT were associated with an unfavorable risk profile for diabetes and cardiovascular disease, with a higher estimated risk for IGT than IFG. CONCLUSIONS: Even with the revised diagnostic criterion, IFG and IGT identify distinct groups that have a different background risk. The cost/benefit of preventive measures tested in people with IGT may not apply to the new IFG category.     

Increased mortality risks of pre-diabetes (impaired fasting glucose) in Taiwan

OBJECTIVE: The objective of this article was to assess mortality risks at different levels of fasting blood glucose (FBG) in Taiwan, with particular attention to those pre-diabetic subjects with impaired fasting glucose (IFG). RESEARCH DESIGN AND METHODS: Governmental employees and schoolteachers were followed up for an average of 11 years. With the use of Cox regression analyses, mortality risks were calculated for 36,386 subjects, aged 40-69. RESULTS: FBG > or =110 mg/dl was associated with increased mortality risks for all causes, cardiovascular diseases (CVD), and diabetes. IFG, when defined as 110-125 mg/dl, was associated with a significant increase for CVD and/or diabetes mortality. These mortality risks remained elevated when known CVD risk factors were adjusted for. The IFG group shared risk factor characteristics more with the FBG > or =126 mg/dl group than with the FBG <110 mg/dl group. When IFG was defined as 100-125 mg/dl, the number of subjects quadrupled, but mortality risks diminished substantially because of the inclusion of 100-109 mg/dl group. The lowest FBG group, 50-75 mg/dl, had a significant 2-fold risk from all causes. CONCLUSIONS: There was an overall J-shaped relationship between all-cause mortality and FBG. IFG, when defined as 110-125 mg/dl, is an independent risk factor and should be aggressively treated as a disease because its subsequent mortality risks for CVD and diabetes were significantly increased. The newly defined IFG at 100-125 mg/dl did not have the predictive power for later increases in CVD or diabetes mortality.     

Impaired glucose tolerance and impaired fasting glucose share similar underlying pathophysiologies

Both impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) are pre-diabetic states. IGT was defined as having normal fasting plasma glucose (< 6.1 mmol/l) and abnormal 2-hr post-challenge plasma glucose. IFG was defined as having abnormal fasting plasma and normal 2-hr post-challenge plasma glucose (< 7.8 mmol/l). To explore whether these two abnormalities share similar underlying pathophysiologies, we evaluated risk factors of IGT and IFT using the models of factor analysis. The present study included 107 subjects with IGT and 52 with IFG. An oral glucose tolerance test and insulin suppression test, which could quantify insulin resistance, were performed on separate days. The risk factors include waist-to-hip ratio (WHR), triglycerides, high-density lipoprotein (HDL)-cholesterol, blood pressure, and fasting plasma glucose, which are associated with metabolic syndrome and insulin resistance. Factor analysis is a commonly used statistical method that could reduce a large number of risk factors into smaller numbers of groups, also called dimension. Accordingly, the complicated data could be interpreted more easily, since the related risk factors are grouped in one dimension. The results showed that the risk factors of IGT and IFG have similar grouping patterns. Triglyceride, insulin resistance, and HDL-cholesterol were grouped in one dimension (the lipid dimension), while WHR, mean blood pressure and fasting plasma glucose were grouped in another dimension (the metabolic dimension). In conclusion, except for WHR, the grouping patterns of the components in both IGT and IFG were nearly identical. These results suggest that IGT and IFG may share similar pathophysiologies.     

Insulin secretion and insulin sensitivity pattern is different in isolated impaired glucose tolerance and impaired fasting glucose: the risk factor in Impaired Glucose Tolerance for Atherosclerosis and Diabetes study

OBJECTIVE: Isolated impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) are two risk categories for type 2 diabetes. This study compared both categories with respect to the degree of insulin secretion abnormalities and insulin resistance. RESEARCH DESIGN AND METHODS: This is a crossover comparison of a population at high risk for type 2 diabetes. The subjects were recruited from the Risk Factor in Impaired Glucose Tolerance for Atherosclerosis and Diabetes (RIAD) study. They underwent a 75-g oral glucose tolerance test, with measurement of specific insulin, C-peptide, proinsulin, and free fatty acids at baseline and every 30 min after load for 2 h. Factor analysis was performed to evaluate the importance of insulin resistance and secretion abnormalities in both categories. RESULTS: All categories of prediabetic hyperglycemia had a higher cardiovascular risk factor level when adjusted for sex, age, and BMI compared to control subjects with normal glucose tolerance. Subjects with isolated IFG were more insulin resistant than those with IGT. By contrast, subjects with isolated IGT exhibited a more severe deficit in early- and late-phase insulin secretion versus IFG subjects. As shown with factor analysis, in IFG the insulin resistance factor explained 28.4% of the variance, whereas in IGT the insulin secretion factor was dominant, explaining 31.1% of the total variance. CONCLUSIONS: Our cross-sectional data from the RIAD study demonstrate that isolated IFG and isolated IGT are different with respect to the degree of insulin resistance and anomalies in insulin secretion, and that subjects with IGT exhibit a deficit in the early and late phases of insulin secretion. This finding may be important for a differential approach in primary prevention of type 2 diabetes.     

Contributions of beta-cell dysfunction and insulin resistance to the pathogenesis of impaired glucose tolerance and impaired fasting glucose

Impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) are intermediate states in glucose metabolism that exist between normal glucose tolerance and overt diabetes. Epidemiological studies demonstrate that the two categories describe distinct populations with only partial overlap, suggesting that different metabolic abnormalities characterize IGT and IFG. Insulin resistance and impaired beta-cell function, the primary defects observed in type 2 diabetes, both can be detected in subjects with IGT and IFG. However, clinical studies suggest that the site of insulin resistance varies between the two disorders. While subjects with IGT have marked muscle insulin resistance with only mild hepatic insulin resistance, subjects with IFG have severe hepatic insulin resistance with normal or near-normal muscle insulin sensitivity. Both IFG and IGT are characterized by a reduction in early-phase insulin secretion, while subjects with IGT also have impaired late-phase insulin secretion. The distinct metabolic features present in subjects with IFG and IGT may require different therapeutic interventions to prevent their progression to type 2 diabetes.     

Screening for impaired glucose tolerance. Results from a population-based study in 21,057 individuals

OBJECTIVE: To study the distribution of fasting plasma glucose and impaired glucose tolerance (IGT) in a large general population and explore their possible implications for large-scale screening. The study focuses especially on the relation to age, obesity, and heredity background of diabetes. RESEARCH DESIGN AND METHODS: A total of 21,057 men and women aged 30-60 years were used for this cross-sectional study. Individuals with known diabetes and individuals with a fasting plasma glucose > or = 7 mmol/l were excluded. A physical examination, including blood sampling and an oral glucose tolerance test, was conducted. RESULTS: The relative risk for IGT increased more than fourfold among obese subjects compared with normal-weight subjects, yet only 25% of IGT subjects were obese. Similarly, IGT subjects more frequently reported having first-degree relatives with diabetes than did subjects with normal glucose tolerance. Nonetheless, > 70% of IGT subjects reported no heredity background of diabetes. Subjects with IGT showed higher mean values of BMI, blood pressure, and triglycerides. Only 13% of the men and 19% of the women having impaired fasting glucose (IFG) fulfilled the criteria of IGT. CONCLUSIONS: The present study shows that a high-risk screening strategy for IGT targeted solely toward subjects with obesity and/or heredity background of diabetes will fail to detect the majority of subjects with IGT in the general population. The new concept of IFG may not replace the concept of IGT as a risk marker for worsening to diabetes.     

Metabolic characteristics in individuals with impaired glucose homeostasis

We sought to clarify whether impaired fasting glucose (IFG), impaired glucose tolerance (IGT) or both (IFG/IGT) represent the most severe impairment in insulin resistance (IR) and insulin secretion. Among the 159 Chinese subjects, 21 were diagnosed as having IFG, 103 as having IGT and 35 as having both. IR and beta-cell function were assessed using homeostatic model assessment (HOMA) and an insulin-suppression test (IST). No differences were evident between the groups in blood pressure, body mass index, plasma insulin fasting levels and lipid profiles. However, plasma 2-h insulin levels were higher in the IGT and IFG/IGT groups. Beta-cell functions were not different between these groups. But, the result of glucose tolerance was different, in which the IFG/IGT and IFG groups displayed higher insulin sensitivity than IGT via HOMA instead of no difference via IST in the three patient groups.     

The prevalence of diabetes and impaired glucose tolerance in Sivas, Central Anatolia, Turkey

OBJECTIVE: The aim of this study was to determine type 2 diabetes, impaired glucose tolerance (IGT), and impaired fasting glucose (IFG) prevalence in Sivas, Turkey. RESEARCH DESIGN AND METHODS: This cross-sectional study was conducted in the city center of Sivas. The study population of 771 subjects was selected by the cluster sampling method from 115,998 individuals aged > or =30 years. Participants with fasting venous plasma glucose concentrations <100 mg/dl were classified as "normal." Diabetes was diagnosed in participants if they had fasting blood glucose levels > or =126 mg/dl. An oral glucose tolerance test (OGTT) was performed in subjects with fasting blood glucose levels > or =100 mg/dl and <126 mg/dl. RESULTS: According to the fasting blood glucose levels of the 771 subjects, 44 (5.7%) had diabetes. OGTTs were performed in 80 (10.4%) subjects. According to OGTT results, there were 5 subjects with diabetes, 20 subjects with IGT (2.6%), and 55 subjects with IFG (7.1%). The combined prevalence of IFG and IGT was 9.7%. After OGTT, the total number of diabetic subjects was determined to be 49 (6.4%). Twenty-four (3.1%) of the subjects had a previous diagnosis of diabetes. Multivariate analyses showed that age, sex, hypertension, cigarette smoking, obesity, and family history of diabetes were risk factors for type 2 diabetes (P < 0.05). CONCLUSIONS: Diabetes incidence increases with changes in dietary habits and lifestyle. Education is particularly important for public health, as the community may then have required knowledge about the disease and its risk factors.     

Abnormal glucose tolerance and increased risk for cardiovascular disease in Japanese-Americans with normal fasting glucose

OBJECTIVE: To compare the American Diabetes Association (ADA) fasting glucose and the World Health Organization (WHO) oral glucose tolerance test (OGTT) criteria for diagnosing diabetes and detecting people at increased risk for cardiovascular disease (CVD). RESEARCH DESIGN AND METHODS: Study subjects were 596 Japanese-Americans. Fasting insulin, lipids, and C-peptide levels; systolic and diastolic blood pressures (BPs); BMI (kg/m2); and total and intra-abdominal body fat distribution by computed tomography (CT) were measured. Study subjects were categorized by ADA criteria as having normal fasting glucose (NFG), impaired fasting glucose (IFG), and diabetic fasting glucose and by WHO criteria for a 75-g OGTT as having normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and diabetic glucose tolerance (DGT). RESULTS: Of 503 patients with NFG, 176 had IGT and 20 had DGT These patients had worse CVD risk factors than those with NGT . The mean values for NGT, IGT, and DGT, respectively, and analysis of covariance P values, adjusted for age and sex, are as follows; intra-abdominal fat area by CT 69.7, 95.0, and 101.1 cm2 (P < 0.0001); total CT fat area 437.7, 523.3, and 489.8 cm2 (P < 0.0001); fasting triglycerides 1.40, 1.77, and 1.74 mmol/l (P = 0.002); fasting HDL cholesterol 1.56, 1.50, and 1.49 mmol/l (P = 0.02); C-peptide 0.80, 0.90, 0.95 nmol/l (P = 0.002); systolic BP 124.9, 132.4, and 136.9 mmHg (P = 0.0035); diastolic BP 74.8, 77.7, and 78.2 mmHg (P = 0.01). CONCLUSIONS: NFG patients who had IGT or DGT had more intra-abdominal fat and total adiposity; higher insulin, C-peptide, and triglyceride levels; lower HDL cholesterol levels; and higher BPs than those with NGT. Classification by fasting glucose misses many Japanese-Americans with abnormal glucose tolerance and less favorable cardiovascular risk profiles.     

Limited overlap between intermediate hyperglycemia as defined by A1C 5.7-6.4%, impaired fasting glucose, and impaired glucose tolerance

OBJECTIVE

We compared the prevalences and overlap between intermediate hyperglycemia (IH), defined by a hemoglobin A_1c (A1C) 5.7–6.4%, impaired fasting glucose (IFG), and impaired glucose tolerance (IGT).

RESEARCH DESIGN AND METHODS

Oral glucose tolerance test results and A1C measurements were evaluated as markers of IH in an unselected cohort of 486 nondiabetic adults from Finland.

RESULTS

The overall prevalence of IH was 34%. Prevalences of isolated A1C 5.7–6.4%, IGT, and IFG were 8.0, 13.2, and 4.5%, respectively. Overlap between these three markers was uncommon. Isolated A1C 5.7–6.4% was associated with a higher BMI compared with isolated IFG and IGT and with a more adverse lipid profile compared with isolated IFG.

CONCLUSIONS

Prevalence of isolated IH was high, with limited overlap between the definitions. Differences in cardiovascular disease risk factors were observed among the groups. This study demonstrates that an A1C of 5.7–6.4% detects, in part, different individuals with IH compared with IFG and IGT.Hemoglobin A_1c (A1C) at a range of 5.7–6.4% was proposed as an indicator of increased risk for type 2 diabetes (1) in addition to the currently used criteria of intermediate hyperglycemia (IH) as follows: impaired fasting glucose (IFG) and impaired glucose tolerance (IGT).The use of A1C in a nondiabetic range may detect a different prevalence of IH compared with IFG or IGT (2). However, the degree of overlap between these markers is not well reported. Recent studies from diabetic populations have yielded conflicting data regarding differences in cardiovascular disease (CVD) risk factor profiles among those diagnosed by A1C ≥6.5% and oral glucose tolerance test (OGTT) (3,4). Studies comparing CVD risk factor profiles among individuals with IH diagnosed by A1C 5.7–6.4% and OGTT are lacking.We hypothesized that these three different markers of IH, in part, detect different individuals and that individuals with A1C 5.7–6.4% would be characterized by a more unfavorable CVD risk profile than individuals diagnosed by OGTT. To this aim, we conducted a population-based observational study to compare 1) diagnosis of IH based on A1C 5.7–6.4% with OGTT and 2) differences in CVD risk factors among the three groups.     

空腹血糖及糖化血红蛋白用于筛查糖耐量减退的比较性研究

目的比较空腹血糖（FPG）和糖化血红蛋白（HbAlc）在筛查糖耐量减退（IGT）中的应用价值。方法到我院门诊为明确有无血糖异常而就诊者336人，测定空腹血糖、糖化血红蛋白，并行口服葡萄糖耐量试验（OGTT）。结果按照1999年WHO的DM诊断标准，本研究人群空腹血糖〈6．1者124例，≥6．1-〈7．0者56例，≥7．0者156例；糖化血红蛋白〈6．1者84例，≥6．1者252例；OGTT2 hPG〈7．8者92例，≥7．8-〈11．1者99例，≥11．1者145例。结论糖化血红蛋白和空腹血糖均不适用于筛查IGT人群，但糖化血红蛋白比空腹血糖提示病人是否存在血糖异常更敏感。