Insulin secretion and insulin sensitivity in Japanese subjects with impaired fasting glucose and isolated fasting hyperglycemia

Impaired fasting glucose (IFG) is a subgroup of impaired glucose regulation exhibiting an elevated fasting glucose levels without elevated 2-h glucose levels on oral glucose tolerance test (OGTT). Diabetes mellitus with isolated fasting hyperglycemia (DM/IFH) is a similar subgroup of diabetes having higher fasting glucose levels with 2-h glucose levels within the non-diabetic range. The aim of this study is to profile the characteristics of these subgroups to estimate the factors involved in the development from normal glucose tolerance (NGT) via IFG to DM/IFH. Five hundred and sixty seven Japanese males were classified on the basis of 75 g OGTT into four groups, NGT, IFG, DM/IFH, and isolated impaired glucose tolerance (isolated IGT). Insulin secretion was evaluated by insulinogenic index, insulin sensitivity was evaluated by ISI composite, and insulin secretory patterns were compared additionally. IFG and DM/IFH subjects exhibited both lower insulin secretion and lower insulin sensitivity than NGT subjects. There was an insulin peak in NGT, IFG, and DM/IFH at 60 min, which did not occur in isolated IGT. Impaired early-phase and basal insulin secretion and decreased insulin sensitivity both are estimated as factors in progression from NGT via IFG to DM/IFH in these subjects. IFG and DM/IFH subjects have definite fasting hyperglycemia in contrast to isolated IGT subjects, 2-h glucose levels being maintained within the non-diabetic range partly by the insulin peak at 60 min.     

Diabetes and impaired glucose tolerance prevalences in Turkish patients with impaired fasting glucose

Impaired fasting glucose (IFG) like impaired glucose tolerance (IGT) has increased risk of progressing to diabetes mellitus (DM). The aim of the study was to evaluate prevalance of IGT and type 2 DM with oral glucose tolerance test (OGTT) in Turkish patients who had fasting glucose of 110 and 125 mg/dl. Hundred and forty-eight (67.3%) women and 72 (32.7%) men (30-65 years old with mean age of 51.3 +/- 8.7 year) who had fasting glucose range 110-125 mg/dl were evaluated with OGTT. Seventy-two patients had IGT (32.8%), 74 (33.6%) patients had type 2 diabetes and 74 (33.6%) patients had normal glucose tolerance (NGT). Mean fasting glucose and insulin levels were higher in the IGT group than in the NGT group. Mean level of total cholesterol was higher in DM than that in NGT and IGT groups. Mean triglyceride (TG) (P = 0.476), high-density lipoprotein (HDL) (P = 0.594), low-density lipoprotein (LDL) (P = 0.612), Apoproteine A (P = 0.876), Apoproteine B (P = 0.518), uric acid (P = 0.948) and ferritin (P = 0.314) were found higher in diabetic patients. Lipoproteine a (P = 0.083), fibrinogen (P = 0.175) and hsCRP (P = 0.621) levels were higher in IGT. Mean HOMA S% levels of NGT, IGT and DM were found to be 65.0 +/- 13.0%, 60.9 +/- 16.0% and 50.1 +/- 11.1%, respectively. HOMA B% levels were measured to be 80.4 +/- 29.1% in NGT, 85.3 +/- 14.59% in IGT and 60.1 +/- 10.1% in DM. Significant difference was found between IFG and DM (P = 0.043) groups. The prevalences of diabetes and IGT were found to be 33.63 and 32.7% in IFG, respectively.     

糖尿病前期尿白蛋白排泄率和微量白蛋白尿患病率的比较

目的　比较糖耐量正常 (NGT)、单纯空腹血糖受损 (I IFG)、单纯糖耐量低减 (I IGT)、糖耐量低减合并空腹血糖受损 (IGT/IFG)、新诊断的 2型糖尿病 (2型DM ) 5种不同糖代谢状态的尿白蛋白排泄率 (UAE)和微量白蛋白尿 (MAU )患病率。方法　根据 75g口服葡萄糖耐量试验 (75gOGTT)结果 ,将 2 93 4例受试者分为 :NGT组 13 3 2例、I IFG组 186例、I IGT组 470例、IGT/IFG组 2 3 6例、新诊断的 2型DM组 710例。用放射免疫法测定过夜 12h尿白蛋白。UAE在 2 0～ 2 0 0μg/min之间定义为MAU。 结果　 (1)UAE水平 [中位数 (四分位数 ) ] ,在新诊断的 2型DM组为8 50 (4 89～ 15 95) μg/min、IGT/IFG组为 6 93 (4 85～ 10 89) μg/min、I IGT组为 6 51(4 0 9～10 74) μg/min ,均高于I IFG组的 5 56(3 70～ 9 2 3 ) μg/min(P值均 <0 0 1) ;I IFG组与NGT组的 5 2 6(3 50～ 8 12 ) μg/min比较差异无显著性 (P >0 0 5) ;MAU的患病率在新诊断的 2型DM组为 2 0 7%、IGT/IFG组为 13 1%、I IGT组为 11 7%、I IFG组为 5 8%、NGT组为 5 6% ,同样呈现上述变化规律。(2 )多元逐步回归分析显示 :UAE与OGTT 2h血糖、舒张压、体重指数呈现独立正相关。logistic回归分析显示 ,导致MAU危险性增加的因素有OGTT 2h血糖、舒张     

Factors responsible for elevation of 1-h postchallenge plasma glucose levels in Japanese men

The 1-h postchallenge plasma glucose (1-h PG) level is considered to be a good index of the development of glucose intolerance and type 2 diabetes as well as of diabetic complications. In some cases, in Japanese, 1-h PG is elevated despite normal fasting glucose during oral glucose tolerance test (OGTT), but the factors responsible remain unclear. In the present study, subjects with normal glucose tolerance (NGT), isolated impaired fasting glucose (IFG), and isolated impaired glucose tolerance (IGT) were divided into subgroups at 1-h PG of 10.0 mM, and the four indices of insulin secretion and insulin sensitivity were compared. In all three categories, the insulinogenic index in subjects with elevated 1-h PG was remarkably lower than in those without elevated 1-h PG. In addition, the insulinogenic index was the strongest factor in elevated 1-h PG according to the multiple regression analysis. Interestingly, one third of the NGT subjects enrolled in this study had elevated 1-h PG. These subjects showed significantly elevated area under the curve of glucose (G-AUC) compared to NGT subjects without 1-h PG elevation. Thus, elevated 1-h PG in Japanese subjects indicates mildly impaired glucose tolerance due to decreased early-phase insulin secretion.     

空腹血糖受损与糖耐量受损患者血管内皮功能的对比研究

目的:应用多普勒超声技术检测空腹血糖受损(IFG)与糖耐量受损(IGT)患者的血管内皮功能,探讨其对动脉粥样硬化的影响。方法:根据口服葡萄糖耐量试验(OGTT)结果,选择血糖正常(NGT)组25例,IFG组24例,IGT组22例,检测TC、TG、LDL-C、HDL-C、空腹血糖(FPG)、空腹胰岛素(FINS)、糖化血红蛋白(HbA1C)、高敏C反应蛋白(hs-CRP)及血管性血友病因子(vWF),OGTT后2h血糖(2hPG)及2h胰岛素(2hINS),以及肱动脉内皮依赖性舒张功能(EDD)。结果:IGT组vWF较IFG组、NGT组明显升高[(170.25±21.76)%∶(155.16±17.19)%、(135.46±15.52)%,P<0.05～0.01],肱动脉EDD较IFG组、NGT组明显降低[(4.86±0.94)%∶(5.47±0.90)%、(6.24±0.97)%,P<0.05～0.01];IFG组vWF较NGT组明显升高[(155.16±17.19)%∶(135.46±15.52)%,P<0.05],肱动脉EDD较NGT组明显降低[(5.47±0.90)%∶(6.24±0.97)%,P<0.05]。多因素逐步回归分析显示,EDD与2hPG、LDL-C明显负相关(r分别为-0.73、-0.59,P<0.05)。结论:IGT较IFG对血管内皮功能危害更大,加强IGT防治对延缓动脉粥样硬化更为重要。     

Prediction of diabetes using ADA or WHO criteria in post-menopausal women: a 10-year follow-up study

Aims/hypothesis. To study the risk of women with impaired fasting glucose (IFG) as against impaired glucose tolerance (IGT) developing diabetes.¶Methods. Oral glucose tolerance tests (75 g) were done in 265 women selected at random at baseline (age 55–57 years) and at a 10-year follow-up. Of the women 42 had IFG/NGT (fasting glucose 6.1–6.9 mmol/l, 2-h glucose < 7.8 mmol/l), 66 IGT/NFG (2-h glucose 7.8–11.0 mmol/l, fasting glucose < 6.1 mmol/l), 30 IGT/IFG and 127 NFG/NGT.¶Results. The 10-year progression to diabetes was similar in IGT/NFG (12.1 %) and IFG/NGT groups (11.9 %, p = 0.97). In IGT/IFG, 20.0 % had developed diabetes, which was not significantly higher than in IFG/NGT and IGT/NFG (p = 0.53). In NFG/NGT at baseline, only 3.9 % had developed diabetes, which was lower than in the other groups (p = 0.023).¶Conclusion/interpretation. Fasting and 2-h glucose concentrations are equally good in predicting diabetes development over a 10-year period in Caucasian postmenopausal women. Because IGT is more common than IFG, measuring only fasting glucose concentrations would, however, result in missing a prediabetic stage in a large group of people at risk for diabetes and cardiovascular diseases. [Diabetologia (2000) 43: 1224–1228]     

空腹血糖异常、糖耐量减低患者血清胰岛素水平的变化及其意义

目的 观察空腹血糖异常(IFG)、糖耐量减低(IGT)患者血清胰岛素水平的变化。方法 对50例空腹血糖和糖耐量正常者(NGT)、40例IFC和80例IGT患者行口服葡萄糖耐量试验(0GTT)，用氧化酶法检测血糖，用放免法测定血清空腹及餐后2小时胰岛素。结果 IFG、IGT组空腹血糖、空腹胰岛素水平及胰岛素敏感指数较NGT组明显升高(P＜0.05或P＜0．01)，IFG组胰岛素敏感指数与IGT组比较无显著性差异(P＞0．05)。结论 在IFG、IGT状态下已经存在胰岛素抵抗，而且在程度上两者间并没有显著性差异，应早期干预治疗。     

不同糖耐量者血清超敏C-反应蛋白表达及与胰岛素抵抗的相关性研究

目的探讨不同糖耐量者血清超敏C-反应蛋白(hs-CRP)的表达及与胰岛素抵抗的相关性。方法对2004年10月至2005年4月中国医科大学附属第一医院体检中心90名体检者(男53名,女37名),根据标准75g口服葡萄糖耐量试验(OGTT)分为正常糖耐量(NGT)组、单纯空腹血糖受损(IFG)组、单纯糖耐量异常(IGT)组、同时合并IFG/IGT组及2型糖尿病(T2DM)组,采用酶联免疫吸附(ELISA)法分别检测各组血清hs-CRP,并与稳态模型胰岛素抵抗指数(HOMA-IR)作相关分析。结果IFG组、IFG/IGT组及T2DM组hs-CRP均明显高于NGT组,并与糖代谢指标及HOMA-IR呈正相关。结论T2DM患者早在IFG阶段就已经存在炎症状态,炎症可能参与了T2DM的发生与发展。     

Impaired fasting glucose and impaired glucose tolerance in urban population in India.

AIMS: To study prevalence of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) in urban Indians and their demographic and anthropometric characteristics. METHODS: Data on capillary blood glucose (OGTT), anthropometric and demography details were available in 10 025 subjects (M : F 4711 : 5314) aged > or = 20 years. Glucose tolerance was categorized as normal, isolated IFG, isolated IGT, IFG + IGT and diabetes using the fasting and 2-h blood glucose (2hBG; 75-g glucose load) values. Subjects with known diabetes were excluded. RESULTS: Age-standardized prevalences of IFG, IGT and newly detected diabetes were 8.7%, 8.1% and 13.9%, respectively. IFG was more prevalent in women (9.8%) than in men (7.4%) (chi2 = 13.62, P = 0.0002), while the gender differences in IGT (men 8.4%, women 7.9%) and diabetes (men 13.3%, women 14.3%) were not significant. Body mass index and waist circumference were higher in glucose-intolerant groups than in normal glucose tolerance (NGT). Prevalence of diabetes, IGT and IFG + IGT increased with age. Among the IFG, 4% had diabetes and 27.1% had IGT using 2hBG criteria. In IFG, the fasting and 2hBG values were not correlated. CONCLUSIONS: Prevalences of IFG and IGT were similar in urban Indians and an overlap occurred in only less than half of these subjects. IFG was more common in women. Subjects with IFG were older and had more adverse anthropometric characteristics in comparison with NGT. IFG did not show an increasing trend with age.     

脑梗死患者糖耐量减低与颈动脉粥样硬化的相关性研究

目的探讨脑梗死患者糖耐量减低(IGT)与颈动脉粥样硬化的关系。方法将120例急性脑梗死患者根据病史和口服葡萄糖耐量试验(OGTT)结果分为糖尿病(DM)组、IGT组、糖耐量正常组(NGT组)。对3组患者进行颈动脉超声检查,测定各组生化指标。结果与NGT组相比,IGT组和DM组的体重指数(BMI)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)、空腹血糖(FPG)、餐后2h血糖(2hPG)、颈动脉内中膜厚度(CIMT)、斑块检出率及斑块积分均显著增高(P<0.05);Spearman相关性分析显示,CIMT与年龄、TC、LDL-C、2hPG呈正相关(P<0.05或P<0.01)。结论脑梗死患者在IGT阶段已经发生颈动脉粥样硬化改变,早期控制血糖,可减轻脑血管病变的严重程度、减少血管事件发生。     

不同糖耐量状态者血清SICAM-1和SVCAM-1水平与炎症相关性研究

按口服葡萄糖耐量试验结果,将研究对象分为正常糖耐量(NGT)组、单纯空腹血糖受损(IFG)组、单纯糖耐量受损(IGT)组、IFG与IGT并存(IFG/ICT)组及2型糖尿病(DM)组。采用酶联免疫吸附法(ELISA)分别检测上述人群的血清可溶性细胞间黏附分子1(SICAM-1)、可溶性血管细胞黏附分子1(SVCAM-1)和超敏C反应蛋白水平(hr-CRP),并与糖脂代谢指标和稳态模型胰岛素抵抗指数(HOMA- IR)作相关性分析。结果显示,血清SICAM-1、SVCAM-1和hs-CRP水平按分组顺序逐组升高,提示2型DM的发病过程与内皮细胞损伤和炎症状态有关。     

1193例住院高血压病患者胰岛素分泌和敏感性情况

目的用口服葡萄糖耐量试验中各点血糖和胰岛素的值来计算反映胰岛素敏感性及β细胞功能的参数,回顾性研究住院高血压病人糖代谢情况。方法根据WHO和美国糖尿病协会标准计算血糖分布情况,去除新诊断的糖尿病病人后,分成正常血糖(NGT)、单纯性空腹血糖升高(IFG)、单纯性餐后血糖升高(IGT)和空腹、餐后血糖均升高(IFG,／IGT)组进行比较。再分别以口服75g葡萄糖后30min或60min血糖正常值为标准对NGT组和IGT组进行分组。用HOMA-IR和Composite胰岛素敏感性指数(ISI)计算胰岛素敏感性,HOMA-B和△I／AG计算β细胞功能。结果1193例住院的原发性高血压病人中,新诊断的糖尿病病人为11．1％,其中57．9％仅有餐后血糖升高。IGT、和IFG／ICT组的HOMA-IR高于NGT组,Composite ISI和AI／AG低于NGT组。无论是否30min或60min血糖升高,IGT组的Composite ISI均低于30min和60min血糖正常的NGT组。30min和(或)60min血糖升高的NGT组△I／AG低于30min和60min血糖正常的NGT组。结论IGT或IFG／IGT的高血压患者同时存在空腹和总体胰岛素敏感性的下降和糖负荷后早期β细胞分泌功能的受损。30min和(或)60min血糖升高的NGT高血压病人存在糖负荷后早期β细胞分泌功能的受损。     

Assessment of factors associated with pre-diabetes in HCV infection including direct and dynamic measurements of insulin action

Although hepatitis C (HCV) is associated with diabetes, few studies have examined pre-diabetes in this population. We aimed to evaluate factors associated with pre-diabetes in HCV-infected patients, including direct measurement of insulin action. Ninety-seven non-cirrhotic, non-diabetic and HCV-infected patients underwent clinical evaluation and oral glucose tolerance testing (OGTT). Insulin sensitivity was measured directly by steady-state plasma glucose (SSPG) concentration during insulin suppression test. Early phase and total insulin secretion were determined using OGTT. Rates of pre-diabetes were as follows: 21% impaired fasting glucose (IFG), 7% impaired glucose tolerance (IGT) and 9% combined IFG/IGT. Twelve percent of Caucasians, 50% of African Americans and 70% of Latinos had pre-diabetes (P = 0.002). Patient characteristics among the glucose metabolism categories were similar except those with combined IFG/IGT had a higher body mass index (BMI) vs normal glucose tolerance (NGT) (30 vs 26 kg/m(2), P = 0.007) and lower LDL vs NGT and IGT (74, 104 and 112 mg/dL, respectively, P ≤ 0.01). On multivariable analysis, non-Caucasian race (OR 23.1, P = 0.003), BMI (OR 3.4, P = 0.02) and greater liver inflammation (OR 7.9, P = 0.03) predicted IFG, whereas non-Caucasian race (OR 14.8, P = 0.01) and SSPG (OR 1.1 per 10 units, P = 0.01) predicted IGT. Early and total insulin secretion adjusted for the degree of insulin resistance was decreased in pre-diabetes compared with NGT (P = 0.01 and P = 0.02, respectively). Pre-diabetes is highly prevalent among HCV-infected patients, and in some instances, coincides with host responses to the virus. In most cases, however, factors that are associated with pre-diabetes in HCV-infected patients are similar to those observed in the non-HCV population.     

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 75 g 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 [5.6–6.1 mmol/L (100–109 mg/dL)] and stage 2 [6.1–7.0 mmol/L (110–125 mg/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 ≥ 11.1 mmol/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.     

社区自然人群糖调节受损者5年转归及其影响因素

目的 探讨糖调节受损人群发生糖尿病的危险性及其影响因素.方法 2002年6月至8月,采用抽样分层横断面现场调查方法于上海市浦东新区社区中检出192例糖调节受损者.2007年同期进行随访,观察单纯糖耐量受损、单纯空腹血糖受损、糖耐量受损合并空腹血糖受损、糖尿病人群比例,变化.使用t检验、方差分析、卡方检验进行统计学分析.结果 5年中死亡5例,存活的187例中79例发生糖尿病,糖尿病年转化率为8.4%(79/187/5年).基线单纯糖耐量受损者糖尿病年转化率为8.2%(47/114/5年),基线单纯空腹血糖受损者精尿病年转化率为6.3%(12/38/5年),基线糖耐量受损合并空腹血糖受损者糖尿病年转化率为11.4%(20/35/5年).正常糖耐量年转化率为6.3%(59/187/5年).单纯糖耐量受损者和糖耐量受损合并空腹血糖受损者发生糖尿病的风险分别是单纯空腹血糖受损者的1.4倍(95%可信区间为0.753～2.508,P=0.29)和107倍(95%可信区间为1.021～2.80,P=0.028).转化为糖尿病者较未转化为精尿病者高血压、肥胖的比例增高,基线年龄、体重指数、腰围、腰臀比和2 h血精明显升高,随访结束时体重指数和收缩压较基线时增高.结论 上海市浦东新区糖耐量受损合并空腹血糖受损者糖尿病转化率最高.多种代谢异常可促进糖调节受损人群向糖球病转化.     

多囊卵巢综合征患者糖代谢异常发生率及其特点

目的 探讨多囊卵巢综合征患者糖代谢异常特点及其发生率.方法 回顾性分析2006年6月1日至2009年2月1日广州中山大学孙逸仙纪念医院妇产科收治的初诊多囊卵巢综合征患者654例(青春期101例,成人553例),以120名年龄匹配的健康志愿者为对照组(青春期40名,成人80名).病例和对照组均行口服葡萄糖耐量试验和胰岛素释放试验,比较病例组和对照组、成人多囊卵巢综合征与青春期多囊卵巢综合征、不同体重指数亚组中糖代谢异常的特点及其发生率.结果 多囊卵巢综合征患者糖代谢异常的发生率为24.5%(160/654),显著高于对照组的3.3%(4/120)(χ2=27.11,P<0.0001);成人病例组糖代谢异常的发生率高于青春期病例组(分别为26.6%、12.9%,χ2=8.688,P=0.003),青春期病例组代谢异常的发生率高于青春期对照组(分别为12.9%、0%,χ2=5.671,P=0.02).多囊卵巢综合征患者糖代谢异常主要表现为糖耐量受损(62.5%),其次为空腹血糖受损(43.8%),糖尿病仅占少数(8.1%);糖尿病13例,仅4例(30.8%)空腹血糖>7.0 mmol/L,9例(69.2%)通过口服葡萄糖耐量试验筛查发现.多囊卵巢综合征组糖代谢异常的发生率随体重指数升高而升高(χ2=53.71,P<0.0001).结论 多囊卵巢综合征患者为糖代谢异常的高危人群,其糖代谢异常以糖耐量受损为主,空腹血糖受损次之.多囊卵巢综合征患者(尤其是肥胖者)应行口服葡萄糖耐最试验,以早期发现其糖代谢异常.     

不同状态的糖调节受损患者胰岛素分泌和胰岛素敏感性的差异

目的评估初发的单纯空腹血糖受损（IFG）和单纯糖耐量受损（IGT）患者的胰岛素分泌以及胰岛素敏感性（IS）特征。方法北京市东城区既往无糖尿病史的2388名受试者行葡萄糖耐量试验,同时行胰岛素释放试验,本文纳入2244例,其中糖耐量正常（NGT）1608例,IFG240例,IGT243例,IFG＋IGT 153例。比较各组胰岛素抵抗指数（HOMA-IR）、IS指数（Matsudaindex）、B细胞功能指数（1相Stumvoll index、△I30／△G30）。结果与NGT组比较,其余三组HOMA-IR显著升高,Matsuda指数及B细胞功能指数均显著降低（P均〈0．01）;IFG组HOMA-IR及Matsuda指数均高于IGT组;IFG组△I30／△G30高于IGT组,而Stumvoll指数低于IGT组（P〈0．01）;与IFG组、IGT组比较,IFG＋IGT组HOMA-IR显著升高,Matsuda指数、1相Stumvoll指数显著降低（P均〈0．01）。结论糖尿病前期人群存在不同程度的胰岛素分泌缺陷和IR,IFG组肝IR较重,而IGT组肌肉IR较重。     

Early insulin secretion failure leads to diabetes in Chinese subjects with impaired glucose regulation

Background Both beta‐cell dysfunction and decreased insulin sensitivity are involved in the pathogenesis of impaired glucose tolerance (IGT) and impaired fasting glucose (IFG), while their relative contribution in the progression to type 2 diabetes still remains controversial. The aim of the present study is to clarify this process in Chinese subjects by using cross‐sectional method. Methods 2975 Chinese subjects were classified into: normal glucose tolerance (NGT), impaired glucose regulations (IGR), and diabetes mellitus (DM) based on oral glucose tolerance test (OGTT). The IGR group was sub‐classified as isolated IFG, isolated IGT and combined glucose intolerance (CGI). The DM group was sub‐classified as normal fasting plasma glucose and 2‐hour hyperglycemia (N0D2), fasting hyperglycemia and normal 2‐hour plasma glucose (D0N2), and both fasting and 2‐hour hyperglycemia (D0D2). Results As far as insulinogenic index (IGI) was concerned, there was no difference between IFG and IGT in either gender, however, HOMA2‐B% (homeostasis model assessment for beta‐cell function) of IGT was higher than that of IFG and CGI in both male and female (P < 0.05). In the diabetic sub‐groups, IGI of N0D2 was higher than that of D0N2, and both deteriorated compared with those of IGT and IFG, respectively. HOMA2‐B% of N0D2 was still higher than that of D0N2 and D0D2. No significant difference was detected in OGIS and HOMA2‐S% (homeostasis model assessment for insulin sensitivity) between IFG and IGT, and this was the case between N0D2 and D0N2. OGIS and HOMA‐IR of IGR sub‐groups were not different from those of their diabetic counterparts. Conclusion Failure of beta‐cell function might be the main reason for both IGT and IFG developing into diabetes instead of aggravated insulin resistance. Copyright © 2008 John Wiley & Sons, Ltd.     

Insulin secretion and insulin sensitivity on the oral glucose tolerance test (OGTT) in middle-aged Japanese

The aim of this study was to assess the changes in insulin secretion and insulin sensitivity in relation to fasting and 2-hour plasma glucose (PG) levels and to assess the independent contributions of their impairments to non-diabetic hyperglycemia. A total of 2157 Japanese workers (mean age 52.6±7.3 years and mean BMI 23.9±3.2 kg/m(2)) underwent an oral glucose tolerance test (OGTT). Of these subjects, 1125 had normal glucose tolerance (NGT), 525 subjects had isolated impaired fasting glucose (IFG), 159 subjects had isolated impaired glucose tolerance (IGT), 263 subjects had combined IFG and IGT, and 85 subjects had newly diagnosed type 2 diabetes. Insulinogenic index and Matsuda insulin sensitivity index (ISI) were significantly attenuated in subjects with normal but slightly elevated fasting PG, or in subjects with normal but slightly elevated 2-hour PG. Whereas, InsAUC(120)/GluAUC(120) was not significantly decreased in those subjects, and significant decrease of it was observed exclusively in subjects with abnormal fasting PG (≥ 106 mg/dL) or abnormal 2-hour PG (≥ 221 mg/dL). Using multiple regression analyses, both Matsuda ISI and insulinogenic index were independently correlated with PG concentrations in subjects with IFG and/or IGT, while Matsuda ISI alone was independently correlated with fasting PG concentrations in normoglycemic subjects. In conclusion, both insulinogenic index and Matsuda ISI were significantly attenuated in subjects with normal but slightly elevated PG. Lowering of Matsuda ISI was likely to be a strong contributor to 'elevation of fasting PG within the normal range' in this population.     

Hyperglycemia rapidly suppresses flow-mediated endothelium-dependent vasodilation of brachial artery.

OBJECTIVES: We examined whether endothelial dysfunction occurs when acute hyperglycemia is induced by oral glucose loading. BACKGROUND: Endothelial dysfunction has been shown to occur in patients with diabetes mellitus (DM), and chronic hyperglycemia is implicated as a cause of endothelial dysfunction. However, in many patients with Type 2 DM and in those with impaired glucose tolerance (IGT), fasting blood glucose may be within normal limits, and hyperglycemia occurred only post-prandially. METHODS: With ultrasound technique, we measured flow-mediated endothelium-dependent vasodilation during oral glucose tolerance test in 58 subjects: (17 patients with normal glucose tolerance [NGT], 24 with IGT, and 17 with type 2 DM). In addition, we measured the levels of thiobarbituric acid reactive substances (TBARS) and nitrite/nitrate. RESULTS: Flow-mediated vasodilation decreased after glucose loading (NGT: 7.53+/-0.40, 4.24+/-0.28 and 6.35+/-0.40, in fasting, at 1- and 2-h, respectively, IGT: 6.50+/-0.48, 1.40+/-0.41** and 4.00+/-0.47*, respectively; DM: 4.77+/-0.37, 1.35+/-0.38** and 1.29+/-0.29%**, respectively; *p < 0.01 vs. fasting, **p < 0.005 vs. fasting). The TBARS concentration increased in parallel with plasma glucose level in each group (NGT: 1.43+/-0.07, 2.03+/-0.12 and 1.80+/-0.12, respectively; IGT: 1.65+/-0.11, 2.46+/-0.12** and 1.94+/-0.08*, respectively; DM: 1.73+/-0.07, 2.34+/-0.08** and 2.47+/-0.09** nmol/ml, respectively; *p < 0.05 vs. fasting, **p < 0.01 vs. fasting). Glucose loading did not change nitrite/nitrate concentration in any of the groups. CONCLUSIONS: Hyperglycemia in response to oral glucose loading rapidly suppresses endothelium-dependent vasodilation, probably through increased production of oxygen-derived free radicals. These findings strongly suggest that prolonged and repeated post-prandial hyperglycemia may play an important role in the development and progression of atherosclerosis.