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Aims/hypothesis: We aimed to determine associations of regression to normal glucose tolerance (NGT), maintaining impaired glucose tolerance (IGT) or progression to diabetes with subsequent risks of CVD and microvascular disease among Chinese adults with IGT., Methods: We conducted an observational study among 540 participants in the Da Qing Diabetes Prevention Study, a 6 year lifestyle intervention trial in people with IGT, defined by 1985 WHO criteria as fasting plasma glucose <7.8 mmol/l and 2 h post-load plasma glucose ≥7.8 and <11.1 mmol/l. At the end of the trial, the groups that had regressed to NGT, remained with IGT or progressed to diabetes were identified. Participants were then followed for 24 years after completion of the trial, during which we compared the incidence and hazard ratios for CVD and microvascular disease in each group and estimated the differences in their median time to onset from parametric Weibull distribution models., Results: At the end of the 6 year trial, 252 (46.7%) participants had developed diabetes, 114 (21.1%) had remained with IGT and 174 (32.2%) had regressed to NGT. Compared with those who developed diabetes during the trial, the median time to onset of diabetes was delayed by 14.86 years (95% CI 12.49, 17.25) in the NGT and 9.87 years (95% CI 8.12, 11.68) in the IGT groups. After completion of the trial, among those with diabetes, IGT and NGT, the 24 year cumulative incidence of CVD was 64.5%, 48.5% and 45.1%, respectively, and 36.8%, 21.7% and 16.5% for microvascular diseases. Compared with participants who had progressed to diabetes during the trial, those who regressed to NGT had a 37% (HR 0.63; 95% CI 0.47, 0.85) reduction in CVD incidence and a median delay of 7.45 years (95% CI 1.91, 12.99) in onset, and those who remained with IGT had a 34% (HR 0.66; 95% CI 0.47, 0.91) lower CVD incidence with a median delay in onset of 5.69 years (95% CI 1.0, 10.38). Participants with NGT had a 66% (HR 0.34; 95% CI 0.20, 0.56) lower incidence of microvascular diseases and a median delay in the onset of 18.66 years (95% CI 6.08, 31.24), and those remaining with IGT had a 52% (HR 0.48; 95% CI 0.29, 0.81) lower incidence with a median delay of 12.56 years (95% CI 2.49, 22.63)., Conclusions/interpretation: People with IGT who reverted to NGT or remained with IGT at the end of the 6 year trial subsequently had significantly lower incidences of CVD and microvascular disease than those who had developed diabetes.

Background and Aim: We sought to determine the effect of regression to normal glucose tolerance (NGT) or progression to diabetes in early years of impaired glucose tolerance (IGT) on subsequent risk of stroke., Methods: In 1986, 576 adults aged 25 years and older with impaired glucose tolerance in Da Qing, China, were randomly assigned by clinic to control, diet, exercise, or diet plus exercise intervention groups for a six-year period. Subsequently participants received medical care in their local clinics. We tracked participants for additional 17 years to ascertain stroke events and other outcomes., Results: At the end of 6-year intervention trial follow-up, 272 (50.2%) had progressed to diabetes, 169 (31.2%) regressed to normal glucose tolerance, and 101 (18.6%) remained impaired glucose tolerance. During the subsequent 17-year follow-up, 173 (31.9%) developed a stroke, 26.7% of normal glucose tolerances, 30.7% of impaired glucose tolerances, and 36.1% of those with diabetes. After controlling for age, sex, baseline blood pressure, smoking, total cholesterol, previous cardiovascular disease and intervention group, those who developed diabetes in the first six years had a higher incidence of stroke than those who reverted to normal glucose tolerance (HR = 1.49, 95% CI 1.01-2.19, p = 0.04), whereas for those who remained impaired glucose tolerance compared to those who regressed to normal glucose tolerance the HR was 1.25 (95% CI 0.80-1.93; p = 0.30). A 1-mmol/L increase in both fasting and 2-h post-load plasma glucose from entry to end of the six-year trial was significantly associated with a higher risk of development of stroke in the subsequent 17 years, respectively (HR = 1.07, 95% CI 1.03-1.11, p < 0.0001 for fasting glucose, HR = 1.05, 95% CI 1.02-1.09, p = 0.007 for 2-h post-load plasma glucose)., Conclusions: Among Chinese adults with impaired glucose tolerance, early progression to diabetes predicted a higher risk of stroke, compared those who regressed to normal glucose tolerance.

Background: Lifestyle interventions among people with impaired glucose tolerance reduce the incidence of diabetes, but their effect on all-cause and cardiovascular disease mortality is unclear. We assessed the long-term effect of lifestyle intervention on long-term outcomes among adults with impaired glucose tolerance who participated in the Da Qing Diabetes Prevention Study., Methods: The study was a cluster randomised trial in which 33 clinics in Da Qing, China-serving 577 adults with impaired glucose tolerance-were randomised (1:1:1:1) to a control group or lifestyle intervention groups (diet or exercise or both). Patients were enrolled in 1986 and the intervention phase lasted for 6 years. In 2009, we followed up participants to assess the primary outcomes of cardiovascular mortality, all-cause mortality, and incidence of diabetes in the intention-to-treat population., Findings: Of the 577 patients, 439 were assigned to the intervention group and 138 were assigned to the control group (one refused baseline examination). 542 (94%) of 576 participants had complete data for mortality and 568 (99%) contributed data to the analysis. 174 participants died during the 23 years of follow-up (121 in the intervention group vs 53 in the control group). Cumulative incidence of cardiovascular disease mortality was 11.9% (95% CI 8.8-15.0) in the intervention group versus 19.6% (12.9-26.3) in the control group (hazard ratio [HR] 0.59, 95% CI 0.36-0.96; p=0.033). All-cause mortality was 28.1% (95% CI 23.9-32.4) versus 38.4% (30.3-46.5; HR 0.71, 95% CI 0.51-0.99; p=0.049). Incidence of diabetes was 72.6% (68.4-76.8) versus 89.9% (84.9-94.9; HR 0.55, 95% CI 0.40-0.76; p=0.001)., Interpretation: A 6-year lifestyle intervention programme for Chinese people with impaired glucose tolerance can reduce incidence of cardiovascular and all-cause mortality and diabetes. These findings emphasise the long-term clinical benefits of lifestyle intervention for patients with impaired glucose tolerance and provide further justification for adoption of lifestyle interventions as public health measures to control the consequences of diabetes., Funding: Centers for Disease Control and Prevention, WHO, the China-Japan Friendship Hospital, Da Qing First Hospital., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Objective: To evaluate whether impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) are associated with increased risk of mortality and prevalent ischemic heart disease (IHD) and to analyze if the increased risk of death is dependent on subsequent development of diabetes in Pima Indians., Research Design and Methods: A total of 2,993 Pima Indians aged >or=35 years were included. Prevalent IHD, defined by major ischemic electrocardiogram changes, was evaluated according to the following glucose/diabetes categories: normal glucose regulation (NGR), IFG and/or IGT, and diabetic groups by duration. During a median follow-up of 10.4 years, 780 subjects died from natural causes and 156 of these died from IHD. Mortality was analyzed according to the same glucose/diabetes categories at baseline and then as time-dependent variables., Results: Only subjects with diabetes >or=15 years of duration have a higher prevalence of IHD (odds ratio 1.9 [95% CI 1.4-2.5]) relative to NGR. In baseline and time-dependent models, age- and sex-adjusted death rates from natural causes and from IHD were similar among the nondiabetic groups. Among diabetic subjects, natural mortality was higher in those with >or=15 years diabetes duration (death rate ratio [DRR] relative to NGR = 2.6 [95% CI 2.1-3.3]). IHD mortality was higher in subjects with long diabetes duration (DRR for diabetes 10-15 years = 3.8 [1.5-9.5]; DRR for diabetes >or=15 years = 8.6 [3.8-19.4]) in the time-dependent model., Conclusions: Natural and IHD mortality are not increased in Pima Indians with IFG and/or IGT. Only after the onset of diabetes do the rates of these events increase relative to NGR.

Objective: The 1997 American Diabetes Association (ADA) and the 1985 and 1999 World Health Organization (WHO) criteria for diabetes and hyperglycemia differ. The appropriateness of these diagnostic criteria in terms of individuals identified as abnormal and their prognosis has been debated. The purpose of this study is to compare the classifications of people by these criteria and to compare fasting and postload plasma glucose concentrations in the prediction of diabetes., Research Design and Methods: The frequencies of diabetes by the 3 sets of criteria were compared in 5,023 adult Pima Indians not taking hypoglycemic drugs. Among nondiabetic subjects, fasting plasma glucose (FPG) and 2-h postload plasma glucose (2-h PG) concentrations and categories of impaired glucose regulation or diabetes were evaluated as predictors of diabetes defined by 1999 WHO criteria., Results: The frequency of diabetes was 12.5% by 1997 ADA criteria, 14.6% by 1985 WHO criteria, and 15.3% by 1999 WHO criteria. The incidence of diabetes was strongly related to higher FPG and 2-h PG, each of which had very similar predictive powers. Impaired glucose tolerance (IGT) was more common than impaired fasting glucose (IFG) (15 vs. 5%), but the 5-year incidence of diabetes was higher in IFG than IGT (37 vs. 24%)., Conclusions: The prevalence and incidence of diabetes are somewhat lower with the ADA criteria than with the 1985 or 1999 WHO criteria. The intermediate categories of glycemia differ substantially IFG defines a smaller number of people who are at higher risk of developing diabetes than those with IGT. More people at high risk of diabetes could be identified by using either IFG or IGT, as recommended by the 1999 WHO criteria, or by using the FPG concentration alone, but with a lower cutoff value.

Objective: The 1997 American Diabetes Association (ADA) and 1999 World Health Organization (WHO) criteria for diabetes and hyperglycemia were evaluated and compared with respect to prediction of microvascular and macrovascular disease and mortality, Research Design and Methods: The prevalence of retinopathy and nephropathy at baseline and during the subsequent 10 years and mortality rates were examined in relation to baseline fasting plasma glucose (FPG) and 2-h postload plasma glucose (2-h PG) among 5,023 Pima Indian adults and in relation to the cut points defined by the ADA and WHO criteria., Results: The frequencies of retinopathy and nephropathy were directly related to baseline FPG and 2-h PG with approximate thresholds near or below the current diagnostic criteria for diabetes (FPG > or =7.0 and 2-h PG > or = 11.1 mmol/l). The rates of retinopathy were 4.7% in impaired fasting glucose (IFG) and 20.9% in diabetes by ADA criteria; 1.6% for impaired glucose tolerance (IGT) and 19.7% for diabetes by 1985 WHO criteria; and 1.2% for IGT and 19.2% for diabetes by the 1999 WHO criteria. Mortality rates from cardiovascular-renal-related diseases were higher in diabetic individuals (FPG > or =7.0 or 2-h PG > 11.1 mmol/l) than in those with normal FPG and 2-h PG but were not elevated in those with IFG or IGT., Conclusions: Retinopathy and nephropathy were directly related to higher FPG or 2-h PG. FPG, which identifies those at high risk of microvascular disease and mortality, can be used to predict these outcomes and to diagnose diabetes when oral glucose tolerance testing is not practical.

The metabolic characteristics of type 2 diabetes, insulin resistance, and diminished insulin secretion are costly to measure directly. To evaluate the utility of several simple indices derived from insulin and glucose measurements, the indices were examined from 1982 to 1997 with respect to correlation with more sophisticated measures of insulin sensitivity and secretion in Pima Indians in the Gila River Indian Community of Arizona. Ability to predict the incidence of diabetes in 1,731 persons was also examined. Indices were calculated from fasting and 2-hour glucose (G0, G120) and insulin (I0, I120) concentrations obtained during an oral glucose tolerance test. Fasting serum insulin concentration and the insulin sensitivity index (10(4)/(I0 x G0)) each showed a moderate correlation with the estimate of insulin sensitivity derived from the hyperinsulinemic-euglycemic clamp (absolute value r approximately 0.60). They also strongly predicted the incidence of diabetes (incidence rate ratio comparing the most and least insulin-resistant tertile groups approximately 3.0). Corrected insulin response (I120/(G120 x (G120 - 70))) was modestly correlated with insulin secretion as measured by an intravenous glucose tolerance test (r = 0.35). Impaired insulin secretion assessed by this index predicted incidence of diabetes, particularly after control for insulin sensitivity index (incidence rate ratio = 1.6). Thus, simple indices of insulin sensitivity and secretion may be reasonable surrogates for more sophisticated measures in epidemiologic studies.

The effect of plasma glucose concentration on overall and cause-specific mortality was examined in 1,745 Pima Indians (725 men, 1,020 women) > or = 15 years old with type 2 diabetes. During a median follow-up of 10.6 years (range 0.1-24.8), 533 subjects (275 men, 258 women) died; 113 of the deaths were attributable to cardiovascular disease, 96 to diabetes-related diseases (diabetic nephropathy for 92 of these), 249 to other natural causes, and 75 to external causes. After adjusting for age, sex, duration of diabetes, and BMI in a generalized additive proportional hazards model, higher baseline 2-h postload plasma glucose concentration predicted deaths from cardiovascular disease (P = 0.007) and diabetes-related diseases (P = 0.003), but not from other natural causes (P = 0.73). An increment of 5.6 mmol/l (100 mg/dl) in the 2-h plasma glucose concentration was associated with 1.2 times (95% CI 1.1-1.4) the death rate from cardiovascular disease, 1.3 times (95% CI 1.1-1.5) the death rate from diabetes-related diseases, and almost no change in the death rate from other natural causes (rate ratio = 1.0; 95% CI 0.94-1.1). In Pima Indians with type 2 diabetes, higher plasma glucose concentration predicts deaths from cardiovascular and diabetes-related diseases but has little or no effect on deaths from other natural or external causes.

Objective: To examine hyperinsulinemia, insulin secretion, and beta-cell function in Pima Indians, South Asians, and whites, populations at varying risk of diabetes., Research Design and Methods: We investigated 136 Pima Indian, 98 Asian, and 80 white nondiabetic and 172 Pima Indian, 40 Asian, and 49 white diabetic subjects. Highly specific assays for insulin, intact proinsulin, and des 31,32 proinsulin were used. Insulin secretion was assessed using ratio of increment (0 to 30 min) in insulin to glucose concentrations during an oral glucose tolerance test (OGTT)., Results: Nondiabetic Pima Indians were significantly more obese than Asians and whites. Pima Indian subjects had significantly higher (P < 0.01) fasting insulin concentrations (median 109 pmol/l, range 40-250) than Asian (37 pmol/l, range 17-91) and white (30 pmol/l, range 10-82) subjects. These differences remained significant when controlled for obesity. Nondiabetic Pima Indians also had higher fasting C-peptide concentrations and higher early insulin secretion during an OGTT. Fasting concentrations of intact proinsulin and des 31,32 proinsulin were also significantly higher in Pima Indians (P < 0.01). However, the proportion of proinsulin-like molecules was significantly lower (P < 0.01) in Pima Indians (median 7.9% vs. 12.7% for South Asians and 12.2% for whites). Subjects with diabetes from the three ethnic groups showed significantly higher fasting insulin concentrations but lower 30-min insulin and lower ratios of increment (0-30 min) in insulin to glucose concentrations than did nondiabetic subjects. The proportion of proinsulin-like molecules was not significantly different in diabetic subjects from the three ethnic groups., Conclusions: These specific assays for insulin indicate that after adjusting for obesity nondiabetic Pima Indians are truly hyperinsulinemic, which is consistent with their insulin resistance as measured by other methods. Hyperinsulinemia in this population with a high risk of diabetes is likely to be due to enhanced insulin secretion. Furthermore, in Pima Indians, the predominant beta-cell secretory product is insulin and not its precursors. We conclude that the differences in the risk of diabetes among these three groups are not due to differences in insulin secretion or insulin processing. Subjects with type 2 diabetes have defective early insulin secretion during OGTTs but show fasting hyperinsulinemia even when specific assays for insulin are used.

Objective: To evaluate 2-h plasma glucose (2HPG), fasting plasma glucose (FPG), glycosylated hemoglobin (HbA1), a combination of FPG and HbA1 (FPG-HbA1), and other factors as screening tests for identifying high-risk subjects for a clinical trial of prevention of NIDDM and to identify strategies to minimize the total number of oral glucose tolerance tests (OGTTs) required to recruit eligible subjects to the trial., Research Design and Methods: One thousand, one hundred and eight nondiabetic Pima Indians aged 25-64 years were followed for up to 5 years, and factors predicting NIDDM, defined by World Health Organization criteria (2HPG > or = 11.1 mmol/l), were assessed using Cox's proportional hazards analysis. Various threshold values of FPG, HbA1, and FPG-HbA1 were determined, which, when combined with an OGTT, identified subjects with impaired glucose tolerance (IGT) (2HPG > or = 7.8 and < 11.1 mmol/l) at a number of specified risks for developing NIDDM in 5 years. The value of each of the three tests was then assessed by calculating (for each threshold) the numbers to be screened, the numbers requiring an OGTT, and the sample size of IGT subjects needed to detect a 33% reduction in NIDDM by an experimental intervention at a power of 80%., Results: During a median of 4.3 years of follow-up, 91 (8.2%) of the 1.108 nondiabetic subjects developed NIDDM. The estimated 5-year cumulative incidence rate was 13.5%. Each of the variables, 2HPG, FPG, HbA1, FPG-HbA1, BMI, IGT, and systolic (sBP), diastolic (dBP), and mean (MBP) blood pressures, predicted NIDDM (P < 0.05 for each) when controlled for age and sex. In a stepwise proportional hazards analysis model, 2HPG and FPG-HbA1 (P < 0.001 for each) were selected as the best set of predictors of NIDDM and of fasting hyperglycemia (FPG > or = 7.8 mmol/l)., Conclusions: A two-step strategy, in which high-risk individuals are first identified by FPG or FPG-HbA1 and then the OGTT is used to select subjects with IGT, requires fewer OGTTs than when using 2HPG as the initial screening test without substantially increasing the numbers that would need to be screened. Such a strategy also offers the advantage of reducing the necessary sample size and is therefore an effective, efficient, and convenient method of identifying eligible subjects for a clinical trial of prevention of NIDDM.

Metabolic abnormalities antedate the development of non-insulin-dependent diabetes mellitus (NIDDM) by some years. How these metabolic abnormalities relate to the genetic component of the disease and to the subsequent prediction of diabetes is unknown. The present study was designed to examine the association of parental diabetes with relative weight, fasting and 2-h plasma glucose and fasting and 2-h serum insulin in childhood, and to identify which of these variables were most predictive of subsequent NIDDM. Subjects comprised 1258 Pima Indians aged 5-19 years with normal glucose tolerance participating in a longitudinal population-based study. Age-sex-adjusted values of relative weight, fasting and 2-h glucose and fasting and 2-h insulin were positively associated with parental diabetes. Only one of 138 subjects with two non-diabetic parents developed diabetes. Among 1120 subjects with at least one diabetic parent, 101 (9.0%) developed diabetes during a mean follow up of 8.4 years. Fasting insulin was a significant predictor of diabetes, but did not add to the predictive value of relative weight. Relative weight and 2-h and fasting plasma glucose were the variables most predictive of NIDDM in childhood and adolescence. Against a background of parental diabetes, high fasting insulin concentrations predict diabetes, compatible with the hypothesis that insulin resistance is an early metabolic abnormality leading to NIDDM. In this study, however, its predictive power did not add significantly to that of relative weight, with which it was correlated.(ABSTRACT TRUNCATED AT 250 WORDS)

Objective: To compare the ability of tests measuring two hour plasma glucose, fasting plasma glucose, and glycated haemoglobin concentrations in predicting the specific microvascular complications of non-insulin dependent diabetes mellitus., Design: Cross sectional and longitudinal analysis of the relation between complications and concomitant results of the three tests., Setting: Gila River Indian Community, Arizona., Subjects: Pima Indians (cross sectional, n = 960), aged 25 years or above who were not receiving insulin or oral hypoglycaemic treatment at the baseline examination., Main Outcome Measures: Development of retinopathy and nephropathy., Results: Cross sectionally, frequency distributions of logarithms of the three sets of results were bimodal, with the prevalence of retinopathy and nephropathy being, respectively, 12.0-26.7 and 3.9-4.2 times as high above as below cut off points which minimised overlap (two hour plasma glucose concentration 12.6 mmol/l; fasting plasma glucose concentration 9.3 mmol/l; glycated haemoglobin (HbA1c) concentration 7.8%). Longitudinally, each of the three measures of glycaemia significantly predicted the development of retinopathy (P < 0.0001) and nephropathy (P < 0.05). Receiver operating characteristic curves showed that two hour plasma glucose concentration was superior to fasting plasma glucose concentration (P < 0.05) for prevalent cases of retinopathy, but otherwise no variable had a significant advantage for detecting incident or prevalent cases of either complication., Conclusions: These findings suggest that determination of glycated haemoglobin or fasting plasma glucose concentrations alone may be acceptable alternatives to measuring glucose concentration two hours after challenge with 75 g glucose for the diagnosis of diabetes.

Among Pima Indians with Type 2 (non-insulin-dependent) diabetes mellitus the relationships between glycated haemoglobin (HbA1), fasting or 2-h post-load plasma glucose and diabetic retinopathy were examined by cross-sectional and prospective analyses, and the strengths of the associations were directly compared by receiver operating characteristic analysis. In the cross-sectional analysis, HbA1, fasting and 2-h plasma glucose were each significantly related to retinopathy among 789 diabetic subjects by separate logistic models. In a stepwise multiple logistic model in which HbA1, fasting and 2-h plasma glucose were included, HbA1 was selected as having the strongest association with retinopathy and neither fasting nor 2-h plasma glucose contributed significantly to the model once HbA1 was entered. Similarly, in the prospective analysis, HbA1, fasting and 2-h plasma glucose all predicted retinopathy in 227 diabetic subjects by separate proportional-hazards models. In a stepwise proportional-hazards model with HbA1, fasting and 2-h plasma glucose available to the model, HbA1 was again selected as having the strongest association with the incidence of retinopathy, and neither fasting nor 2-h plasma glucose significantly added to the prediction of retinopathy. A receiver operating characteristic analysis was used to determine if HbA1 was statistically significantly better than fasting or 2-h plasma glucose in assessing the risk for retinopathy. In neither the cross-sectional nor the prospective data did the area under the receiver operating characteristic curve for HbA1 differ significantly from that for fasting or 2-h plasma glucose (p > 0.05 for each).(ABSTRACT TRUNCATED AT 250 WORDS)

Objective: Fasting hyperinsulinemia in the presence of normoglycemia usually indicates insulin resistance and is characteristic of populations at high risk for developing NIDDM. Hyperinsulinemia predicts the development of impaired glucose tolerance and NIDDM in Pima Indians, a population with a high incidence of NIDDM. Insulin concentrations in population-based samples of children who have different risks of developing NIDDM later in life have not been reported previously., Research Design and Methods: We compared fasting insulin concentrations in two populations of nondiabetic children, 6-19 yr of age: Pima Indians from southern Arizona and Caucasians from Minnesota., Results: Insulin concentration varied with age, sex, glucose concentration, and relative weight. Mean fasting insulin concentration was 140.3 pM in Pima Indian males, 94.4 pM in Caucasian males, 171.5 pM in Pima Indian females, and 107.1 pM in Caucasian females. For each sex, the mean fasting insulin concentration, controlled for age, glucose, and relative weight, was significantly higher in the Pima Indians than in the Caucasians (P < 0.001)., Conclusions: From a young age, Pima Indian children have higher fasting insulin concentrations than Caucasian children. As hyperinsulinemia predicts subsequent NIDDM, these data suggest that the susceptibility to NIDDM is manifest at a young age as fasting hyperinsulinemia.

Insulin action in vivo varies widely in nondiabetic Pima Indians. Not all of this variance is attributable to individual differences in obesity, physical fitness, sex, or age, and after correcting for these co-variates, measures of insulin action aggregate in families. Insulin action at maximally stimulating insulin concentrations has a trimodal frequency distribution, particularly among obese individuals. This is consistent with the hypothesis that a codominantly inherited autosomal gene, unrelated to obesity, determines MaxM in the population. Preliminary sib-pair linkage analyses indicated the possibility of linkage between MaxM and the GYPA/B locus (encoding the MNSs red cell surface antigens) on chromosome 4q. To confirm and extend these findings, 10 additional loci on 4q were typed in 123 siblings and many of their parents from 46 nuclear families. The results indicate significant (P < 0.001) linkage of the FABP2 and ANX5 loci on 4q with MaxM, and of FABP2 with fasting insulin concentration. No linkage was found between the 4q markers and obesity. Our findings indicate that a gene on 4q, near the FABP2 and ANX5 loci, contributes to in vivo insulin action in Pima Indians.

Objective: To determine the prevalence of IGT and diabetes and identify the occurrence of CVD and its risk factors., Research Design and Methods: This study was a population-based, cross-sectional study of 110,660 residents, 25-74 yr of age of DaQing, Hei Long Jiang Province, China., Results: Using 1985 WHO criteria, 577 (5.5/1000) subjects with IGT and 630 (6.0/1000) with newly diagnosed diabetes were identified. In addition, 190 (1.7/1000) with previously known diabetes were identified. Hypertension, obesity, and abnormal albumin excretion were twice as frequent in those with IGT as in 279 men and 240 women of similar age and sex distribution who had normal OGTTs. Plasma cholesterol and TGs were higher, and HDL cholesterol was lower in subjects with IGT than in nondiabetic subjects. Those with IGT had a prevalence of electrocardiographically recognized CHD 9.5-fold greater than the normoglycemic subjects. Subjects with IGT had higher plasma insulin concentrations, but the 1-h insulin-glucose ratio after the 75-g glucose load was lower. In a forward stepwise multiple logistic regression analysis, IGT itself remained an independent factor associated with CHD after adjustment for age, sex, cigarette smoking, plasma cholesterol, BP, and obesity., Conclusions: Therefore, in China, IGT may occur with almost as high a frequency as diabetes and is accompanied by an increased frequency of CVD and its risk factors. Estimates from this study indicate that > 12.0% of all ECG-indicated CHD in the Da Qing population occurs in individuals with IGT and NIDDM. The IGT subjects identified in this survey form the cohort for a long-term follow-up and intervention study.

The long-term effects on offspring of abnormal glucose tolerance detected during pregnancy were examined in 552 Pima Indian offspring 5-24 yr of age. Fasting hyperinsulinemia, presumably reflecting increased insulin resistance, occurred at an earlier age in the offspring of women who had abnormal glucose tolerance during pregnancy, and these offspring were more obese and had higher rates of abnormal glucose tolerance. When confounding factors were controlled, a 1 mM higher 2-h postload glucose concentration during pregnancy resulted in a significantly higher prevalence of diabetes in the offspring (odds ratio = 162). Maternal 2-h glucose concentration during pregnancy was also a significant predictor of glucose concentration during pregnancy in the offspring (P = 0.011). Thus, the metabolic abnormalities associated with the diabetic pregnancy result in long-term effects on the offspring, including insulin resistance, obesity, and diabetes, which in turn may contribute to transmission of risk for developing the same problems in the next generation.

Previous studies show that children of women who are diabetic during pregnancy are more obese and have a higher prevalence of non-insulin-dependent diabetes mellitus (NIDDM) than children of women who first developed NIDDM greater than 1 yr after the pregnancy (prediabetic mothers) and children of women who have never developed diabetes (nondiabetic mothers). To determine whether lean and obese children of glucose-intolerant pregnancies can be distinguished from similar children of glucose-tolerant pregnancies, we measured body composition, abdominal and gluteal adipocyte size, fasting free fatty acid (FFA), and fasting and stimulated glucose and insulin concentrations during an oral glucose tolerance test in prepubertal children of glucose-intolerant and prediabetic mothers. Each group ranged in adipocity from 6 to 40% body fat. Age, weight, height, and percentage of body fat were similar in the two groups. There were no significant differences in adipocyte size or in glucose, FFA, C-peptide, and insulin concentrations between the groups. The correlation between abdominal adipocyte size and fasting insulin concentration (r = .91 and .18, t = 2.8, P = .01) was stronger in children from glucose-intolerant than from glucose-tolerant pregnancies, respectively. In terms of the parameters we measured, there are no major differences between children of glucose-intolerant and glucose-tolerant pregnancies.

The risks of microvascular complications over periods of 3 and 6 years in relation to baseline plasma glucose concentrations were estimated in Pima Indians of Arizona aged 25 years or more and who were not taking hypoglycaemic medicine at their initial examinations. Retinopathy (microaneurysms, haemorrhages, or neovascularisation) developed within 3 years in 1% of 181 subjects with initial fasting plasma glucose concentrations less than 140 mg/dl (1 mg/dl = 0.0555 mmol/l) and in 13% of 39 subjects with higher initial fasting plasma glucose levels. No one with an initial 2 h glucose concentration less than 200 mg/dl had retinopathy within 3 years, but the rate was 12% in 60 subjects with higher glucose concentrations. Retinopathy developed within 6 years in 1% of 446 subjects whose 2 h post-load glucose concentrations were less than 200 mg/dl and in 20% of 113 subjects with higher levels. Subsequent development of heavy proteinuria (urine protein/creatinine ratio at least 1.0) was less common than that of retinopathy, but was similarly related to the initial fasting and 2 h plasma glucose concentrations. The finding that these microvascular complications rarely appeared in individuals with fasting plasma glucose concentrations less than 140 mg/dl or 2 h plasma glucose concentrations less than 200 mg/dl supports the validity of these concentrations as part of the new diagnostic criteria for diabetes mellitus.

Glucose tolerance and the prevalence of impaired glucose tolerance (IGT) and diabetes in the Polynesian populations of Rarotonga and Niue were studied in 1980. Both Rarotongans and Niueans have been considerably influenced by sociocultural modernization and (in the case of Rarotonga) tourism. In both populations, the prevalence of abnormal glucose tolerance exceeded 10% in men and 15% in women. There was an association between glucose tolerance and age and obesity in both sexes, but not between glucose tolerance and physical activity. Glucose tolerance did not differ between Rarotongans and Niueans after allowing for differences in age and obesity. Comparisons between normal subjects, those with impaired glucose tolerance (IGT) and diabetic subjects with respect to factors that are traditionally associated with glucose intolerance provided some support for IGT as a truly intermediate diagnostic category of glucose tolerance.

The frequency distributions of both the fasting and two-hour post-load plasma glucose levels were bimodal in the Pima Indian population aged 25 years and over. The hyperglycaemic component of this distribution represents those with diabetes mellitus, as some 30 percent of this group had evidence of the specific vascular complications of the disease, whereas these abnormalities were virtually absent in those with lower glucose levels. The bimodal characteristics of the frequency distributions were utilized to define optimal criteria to separate those with and without diabetes. The sensitivity and specificity of these criteria for fasting and two-hour glucose levels were compared and were found to be similar. The fasting glucose determination, however, was more reproducible and stable, as well as being easier to obtain, indicating that it is the better measurement for diagnostic purposes. The optimal level for diagnosis of 7.5 mmol/l (136 mg/dl) for the fasting glucose and the equivalent two-hour value of 14 mmol/l (250 mg/dl), were higher than many previously recommended diagnostic levels. Nevertheless, there was no evidence that subjects with lower levels were at appreciable risk of developing the specific complications of diabetes. Subjects with impaired glucose tolerance (IGT), but without fasting hyperglycaemia, should not be diagnosed as having diabetes mellitus.

The occurrence of retinopathy and its relationship to diabetes in 1,640 Pima Indians age 15 and over has been determined. Eighteen per cent of those with two-hour postload plasma glucose levels of equal to or greater than 200 mg./dl. had some evidence of retinopathy. Of those with retinopathy and diabetes, 7 per cent were found to have proliferative or neovascular changes, the remainder having microaneurysms and/or exudates. The frequency of retinopathy increased from 3 per cent among newly diagnosed diabetics to 47 per cent among those with diabetes of 10 or more years duration. No relationship was found with sex, age at diagnosis of diabetes, or age at time of examination when duration of diabetes was taken into account. The occurrence of retinopathy was confined largely to those who fell into the second or hyperglycemic component of the frequency distribution of plasma glucose levels in the population, indicating the significance of the bimodal glucose tolerance frequency distribution.

The effects of disturbances in carbohydrate metabolism during gestation were studied in the offspring of 1049 Pima Indian women who had no previous diagnosis of diabetes. Rates of fetal and maternal complications of pregnancy among women with diabetes first diagnosed during the pregnancy were similar to those among women in whom diabetes was recognized before gestation. Offspring, aged 5-19 yr, of women with abnormal glucose tolerance during pregnancy had a higher mean percent desirable weight and a higher mean postchallenge plasma glucose concentration than did offspring of women with normal glucose tolerance. Percent desirable weight and glucose concentration, however, were both lower than found in offspring of women with diabetes diagnosed before the pregnancy. Thus, metabolic events during pregnancy, as indicated by the detection of abnormal glucose tolerance during gestation, appear to have long-term effects on obesity and glucose tolerance in the offspring.

In a multinational study, fasting plasma glucose values in 3583 diabetic patients, aged 34-56 years, were related to the characteristics of these subjects and to the presence and severity of microangiopathy as ascertained by standardised methods. The patients were from nine different populations and ranged in number from 193 to 686 per population (London, Warsaw, Berlin (FRG), New Delhi, Tokyo, Havana, Oklahoma Indians, Arizona Pima Indians, and a national sample in Switzerland). In the total group, mean fasting plasma glucose was 8.1 mmol/l for those on diet alone, 9.7 mmol/l for those on oral agents, and 12.7 mmol/l for insulin-treated patients, of whom 25% had values exceeding 16.5 mmol/l. Since many variables were measured in each patient, it was possible to take into account many confounding factors in evaluating the relationship of plasma glucose levels to retinopathy and nephropathy.

As part of a continuing epidemiological study of non-insulin dependent diabetes among Pima Indians 154 subjects who had had a transient impairment of glucose tolerance were followed up for 1.2-16.9 (median 5.8) years after their glucose tolerance had returned to normal. Of these, 49 subsequently developed diabetes; 26 subsequently developed impaired glucose tolerance; and 79 had normal glucose tolerance at the last examination. The cumulative incidence of diabetes was 16% and 48% at five and 10 years of follow up respectively, compared with 3% and 8% for a control group of 1245 members of the same population. After adjustment for age, sex, body mass index, and plasma glucose concentration two hours after glucose loading the incidence of diabetes among the subjects who had had transient impaired glucose tolerance was 3.0 times that among the controls (95% confidence interval 2.1 to 4.3). Proportional hazards function analysis indicated that obesity was the most important predictor of subsequent development of diabetes. The results suggest that transient impairment of glucose tolerance indicates, at least in some subjects, a predisposition to diabetes and should not be considered clinically unimportant.

The definition of prediabetes by genetic criteria alone has limitations since not all such subjects progress to overt diabetes. Sequential oral glucose tolerance testing in a population has enabled the identification of 14 "true prediabetic" subjects with baseline two-hour plasma glucose levels smaller than 160 mg. per 100 ml. who subsequently developed unequivocal diabetes (two-hour plasma glucose level larger than 275 mg. per 100 ml.). All but one were matched for baseline two-hour plasma glucose and relative weight with a subject whose glucose tolerance remained unchanged during a mean follow-up period of 4 years. Fasting insulin levels and responses at 1/2, 1, and 2 hour sampling times were similar in both group and matched pair analysis at baseline. No evidence was found that subjects destined to develop diabetes have either excessive or diminished insulin secretion.

The prevalence of physician-diagnosed diabetes and of undiagnosed diabetes and impaired glucose tolerance (IGT) that meet National Diabetes Data Group (NDDG) and World Health Organization (WHO) criteria have been estimated for the U.S. population aged 20-74 yr from the 1976-1980 National Health and Nutrition Examination Survey. This survey included a demographic/medical history questionnaire administered in the participant's home and a detailed examination composed of a physician's exam, special clinical procedures, other tests, and collection of blood and urine specimens. Survey participants were selected from 1970 census data through a stratified multistage probability sampling scheme. Of 17,390 eligible residents aged 20-74 yr, 15,357 (88.3%) participated in the interview and are the basis for estimates of diagnosed diabetes; 11,858 (68%) participated in the exam. A half sample of 5901 examinees was selected to receive a 75-g oral glucose tolerance test (OGTT) performed in the morning after an overnight 10- to 16-h fast. Of these examinees, valid OGTT data were obtained for 3772 people without a medical history of diabetes, and these are the basis for estimates of undiagnosed diabetes and IGT. The major reasons for incomplete OGTT data were inability of participants to attend the examination center in the morning and lack of adherence to the fasting instructions. Despite the relatively low response rates, evidence is presented that data on both the interviewed sample and those receiving the OGTT, when adjusted for the 1970-1980 census characteristics by age, race, sex, income, and geographic location, are representative of the U.S. population. Extrapolation of these data to the U.S. population aged 20-74 yr indicates a total diabetes prevalence of 6.6% by NDDG criteria, or more than 8 million people with diabetes. The prevalence of undiagnosed diabetes (3.2%) was almost equal to that of previously diagnosed diabetes (3.4%). Total rates of diabetes increased with age, from 2.0% at age 20-44 yr to 17.7% at age 65-74 yr. Rates were approximately equal by sex but were greater in Blacks than in Whites. The prevalence of undiagnosed diabetes by WHO criteria (3.4%) was similar to that by NDDG criteria, but the rate of impaired glucose tolerance (11.2%) was more than twice the NDDG estimate (4.6%). Both obesity and parental history of diabetes were associated with significantly higher rates of diabetes and IGT. Fasting plasma glucose was relatively insensitive to age, but 1-h and 2-h post-75-g glucose values increased significantly with age.

The prevalence of abnormal urinary albumin excretion, defined by a urine albumin to creatinine ratio greater than or equal to 30 mg/g (approximately equivalent to an albumin excretion rate of greater than or equal to 30 mg/24 h), was determined in 2728 Pima Indians aged greater than or equal to 15 years from the Gila River Indian Community in Arizona, a population with a high prevalence of Type 2 (non-insulin-dependent) diabetes mellitus. Excessive albumin excretion was present in 8% of subjects with normal glucose tolerance, 15% of those with impaired glucose tolerance, and 47% of subjects with diabetes. The intermediate prevalence of abnormal albuminuria in those with impaired glucose tolerance suggests that hyperglycaemia even at levels below those diagnostic of diabetes is associated with renal abnormalities in some subjects and that these abnormalities may precede the onset of diabetes. Abnormal albuminuria at levels not reliably detected by the usual dipstick methods was commonly observed in Pima Indians with diabetes, even those with diabetes of recent onset. Associations were found with age, duration of diabetes, level of glycaemia, blood pressure, and treatment with insulin.

Increased in vivo resistance to insulin-mediated glucose disposal has been observed in obese subjects with normal glucose tolerance and in nonobese subjects with glucose intolerance. To determine whether the insulin resistance of glucose-intolerant obese subjects can be accounted for by obesity alone, insulin-mediated glucose disposal was measured in 14 glucose-intolerant and 21 nondiabetic. Southwestern American Indians with similar degrees of obesity. A mixture of insulin, glucose, and somatostatin was infused which delivered the same quantity of glucose and achieved similar plasma insulin concentrations in all subjects. Despite similar steady state plasma insulin levels, the mean steady state plasma glucose concentration was higher in the glucose-intolerant subjects than in weight-matched subjects with normal glucose tolerance (226 +/- 10 vs. 136 +/- 13 mg/dl; P < 0.0001). This increased resistance to insulin action was found in the presence of similar insulin binding to mononuclear cells (measured in 8 glucose-intolerant subjects and 9 subjects with normal glucose tolerance). In obese Southwestern American Indians with glucose intolerance, abnormalities beyond the site of insulin binding to its receptor may explain the observed increase in in vivo insulin resistance.

In 9 of the 14 national samples of diabetic patients assembled for the WHO Multinational Study of Vascular Disease in Diabetes additional laboratory data made it possible to relate manifestations of macrovascular disease to blood glucose concentrations as well as to diabetes duration and to other potential determinants. In five of the samples, serum triglyceride concentrations were also measured and were included in simple and multivariate analyses. Ischemic heart disease defined from Minnesota-coded EKGs and standardized WHO questionnaires was more strongly associated with serum triglyceride concentrations than with serum cholesterol concentrations, an association less notable in non-insulin-dependent diabetic patients. Ischemic heart disease was not related to the single fasting plasma glucose estimated for this study. Stroke and amputation were much more strongly related to the known duration of diabetes than was ischemic heart disease, and they were both related to blood glucose concentration measured at the time of study. Despite major variation in arterial disease prevalence rates between collaborating centers, risk for diabetic women appeared to equal that for diabetic men. The major variation in arterial disease prevalence between national groups could be accounted for only in part by the risk factors studied. Other factors, genetic or more likely environmental, are likely to contribute to the variation in arterial disease susceptibility and, if definable, may be potentially preventable.

In many population and screening studies of diabetes, the one-hour glucose level of the GTT has been used to define the diabetic status of subjects. The one-hour postglucose load determination has been preferred over the two-hour value by many investigators primarily because of convenience and justified on the basis of the high correlation between the two values. Venous plasma glucose levels, one and two hours after 75-gm. carbohydrate load, were determined on over 1600 Pima Indians. In most sex and age groups, the frequency distributions of both the one-hour and two-hour glucose levels were clearly bimodal. By the logarithms of the glucose values these distributions were consistent with a model of two overlapping Gaussian distributions. The data indicate that for the Pima the amount of overlap of the distributions was greater for the one-hour than for the two-hour values. For each sex and decade the probabilities of misclassification of a normal as "hyperglycemic" and vice versa were smaller for the two-hour than for the one-hour values. Such misclassifications for the two-hour levels averaged 6.6 per cent and 11.6 per cent for the one-hour levels. The reproducivility of the GTT taken one to three weeks apart in a sample of ninety-nine Pima Indians showed that the two-hour level was superior to the one-hour level as measured by the mean values of the absolute difference between log GTT levels for test and retest values. The one-hour measurements also gave more disagreements between the classifications of diabetic status than the two-hour test values. If a single measure of glucose tolerance is to be selected for the diagnosis of diabetes among Pima Indians, these data provide a mathematical rationale for preferring the two-hour level to the one-hour determination.