2-hour Postchallenge Plasma Glucose Research Articles

THU265 A U-Shaped Relationship Between Undiagnosed Diabetes And Thyroid Function

Abstract Disclosure: Z.Z. Alvi: None. R. Karnchanasorn: None. H. Ou: None. L. Chuang: None. A.G. Gianoukakis: None. K.C. Chiu: None. Thyroid dysfunction is present in about 20 million people in the United States, with about 60% percent unaware of their condition. Thyroid hormone is one of the key hormone regulators of energy metabolism, while diabetes mellitus (DM) is a disorder of dysregulated fuel metabolism. Thus, thyroid hormone can affect glucose metabolism. Unfortunately, this area has received little attention over the past few decades. This study investigates the rate of undiagnosed DM in relation to thyroid function. A representative and noninstitutionalized US adult (aged 20 years or older with BMI available) population from the National Health and Nutrition Examination Survey 2007-2012 was used for this study. Subjects with known thyroid diseases and/or diabetes were excluded. This study only included subjects with available TSH, free T4 (FT4), and free T3 (FT3) levels and the defined status of glucose tolerance by HbA1c, fasting, and/or 2-hour post-challenge plasma glucose concentrations (n=6,843). The rates of previously undiagnosed DM were determined for each quintile of TSH, FT4, and FT3 with sample-weighted analysis. The adjusted odds ratio (AOD) with a 95% confidence interval (95%CI) for DM was calculated with the lowest quintile as a reference after consideration of age, gender, BMI, and racial/ethnic groups. Amongst 6,834 subjects in this study, DM was found in 488 subjects. The rates of DM from quintile 1 to quintile 5 were 3.37%, 3.95%, 3.84%, 6.42%, and 7.26 % for TSH quintiles (P<0.0001 by ANOVA); 5.69%, 4.27%, 5.05%, 4.74%, and 6.46% for FT4 quintiles (P<0.0001 by ANOVA); and 4.82%, 4.63%, 5.33%, 5.33%, and 4.93% for FT3 quintiles (P<0.0001 by ANOVA). Although the correlations were imperfect among TSH, FT4, and FT3 quintiles, the U-shaped relationship of DM with thyroid function was confirmed by the lowest AOD of 0.80 (95%CI: 0.80 - 0.80, P<0.0001) for the 3rd quintile of TSH (TSH: 1.321 - 1.771 mIU/L). The association of DM with low thyroid function was confirmed by the AOD of 1.31 (95%CI: 1.30 - 1.32, P<0.0001) for the 5th quintile of TSH (TSH: 2.519 - 80.968 mIU/L). The association of DM with high thyroid function was confirmed by AOD of 2.45 (95%CI: 2.44 - 2.46, P<0.0001) for the 5th quintile of FT3 (FT3: 3.51 - 28.82 pg/mL). FT4 confirmed the U-shaped relationship with the highest AOD of 1.07 (95%CI: 1.07 - 1.08, P<0.0001) for the 5th quintile of FT4 (FT4: 0.91 - 4.80 ng/mL) and the lowest AOD of 0.82 (95%CI: 0.82 - 0.82, P<0.001) for the 2nd quintile of FT4 (FT4: 0.91 - 4.80 ng/mL). Our study revealed a U-shaped relationship between the rates of undiagnosed DM with thyroid function in a representative and noninstitutionalized US adult population without a prior diagnosis of thyroid dysfunction and diabetes. Different underlying mechanisms may be responsible for the association of DM with high and low thyroid function. Further studies are required to elucidate the underlying mechanisms. Presentation: Thursday, June 15, 2023

Glucose Tolerance Test in Clinical Practice is Varied in Basic Research

In diabetic patients, blood glucose levels often elevate markedly after a meal, mainly associated with the progress of diabetic complications. They belong to a category of hyperglycemia which is abnormal but is still not reach the criteria of diabetes mellitus (DM). Generally, they are classified as the impaired glucose tolerance. In clinics, oral glucose tolerance test (OGTT) is widely used to diagnostic for the impaired glucose tolerance (IGT) and/or type-2 DM (T2DM) while IGT is obtained from a 2-hour post-challenge plasma glucose level about 140-200 mg/dl during OGTT.

Glucose patterns during the OGTT and risk of future diabetes in an urban Indian population: The CARRS study.

Traditionally, fasting and 2-hour post challenge plasma glucose have been used to diagnose diabetes. However, evidence indicates that clinically relevant pathophysiological information can be obtained by adding intermediate time-points to a standard oral glucose tolerance test (OGTT). We studied a population-based sample of 3666 Asian Indians without diabetes from the CARRS-Chennai Study, India. Participants underwent a three-point (fasting, 30-min, and 2-h) OGTT at baseline. Patterns of glycemic response during OGTT were identified using latent class mixed-effects models. After a median follow-up of two years, participants had a second OGTT. Logistic regression adjusted for diabetes risk factors was used to compare risk of incident diabetes among participants in different latent classes. We identified four latent classes with different glucose patterns (Classes 1-4). Glucose values for Classes 1, 2, and 4 ranked consistently at all three time-points, but at gradually higher levels. However, Class 3 represented a distinct pattern, characterized by high 30-min (30minPG), normal fasting (FPG) and 2-h (2hPG) plasma glucose, moderately high insulin sensitivity, and low acute insulin response. Approximately 22% of participants were categorized as Class 3, and had a 10-fold risk of diabetes compared to the group with the most favorable glucose response, despite 92.5% of Class 3 participants having normal glucose tolerance (NGT) at baseline. Elevated 30minPG is associated with high risk of incident diabetes, even in individuals classified as NGT by a traditional OGTT. Assessing 30minPG may identify a subgroup of high-risk individuals who remained unidentified by traditional measures.

Decision tree-based modelling for identification of potential interactions between type 2 diabetes risk factors: a decade follow-up in a Middle East prospective cohort study

ObjectiveThe current study was undertaken for use of the decision tree (DT) method for development of different prediction models for incidence of type 2 diabetes (T2D) and for exploring interactions...

Pre-diabetes tsunami: incidence rates and risk factors of pre-diabetes and its different phenotypes over 9 years of follow-up.

To investigate the incidence of pre-diabetes and its different phenotypes and the related risk factors during 9 years of follow-up. A total of 5879 people (2597 men and 3282 women) aged ≥ 20 years, free of diabetes and pre-diabetes, took part in the study. Multivariable Cox proportional hazard models were used to evaluate hazard ratios (HR) and 95% confidence intervals (CI) for all potential risk factors. Overall, 853 men and 902 women developed pre-diabetes. Incidence rates of pre-diabetes were 46.1 per 1000 person-years in men and 36.8 per 1000 person-years in women, while isolated impaired fasting glucose had the highest incidence rate among all pre-diabetes phenotypes. In both sexes, age, family history of diabetes, fasting plasma glucose and 2-hour post-challenge plasma glucose were related to incident pre-diabetes. Among women, waist-to-height ratio [HR: 1.02 (1.00-1.03)] and being divorced/widowed compared with married [HR: 0.67 (0.52-0.87)] were significant predictors of pre-diabetes; whereas among men, community-based intervention [HR: 0.79 (0.68-0.90)], higher level of education and being single [HR: 0.77 (0.6-0.97)] were protective against progression to pre-diabetes. Moreover, hip circumference among women [HR: 0.95 (0.93-0.98)] and current smoking among men [HR: 1.69 (1.15-2.48)] were related to incident combined impaired fasting glucose and impaired glucose tolerance. More than 4% of the Iranian population develop pre-diabetes each year, emphasizing the important role of socio-economic factors (marital status, education and smoking habits) and community-based intervention in progression to impaired glucose regulations. Thus, emergent intervention is necessary to halt the tsunami of pre-diabetes among the Iranian population.

Obese Patients With a Binge Eating Disorder Have an Unfavorable Metabolic and Inflammatory Profile.

To evaluate whether obese patients with a binge eating disorder (BED) have an altered metabolic and inflammatory profile related to their eating behaviors compared with non-BED obese.A total of 115 White obese patients consecutively recruited underwent biochemical, anthropometrical evaluation, and a 75-g oral glucose tolerance test. Patients answered the Binge Eating Scale and were interviewed by a psychiatrist. The patients were subsequently divided into 2 groups according to diagnosis: non-BED obese (n = 85) and BED obese (n = 30). Structural equation modeling analysis was performed to elucidate the relation between eating behaviors and metabolic and inflammatory profile.BED obese exhibited significantly higher percentages of altered eating behaviors, body mass index (P < 0.001), waist circumference (P < 0.01), fat mass (P < 0.001), and a lower lean mass (P < 0.001) when compared with non-BED obese. Binge eating disorder obese also had a worse metabolic and inflammatory profile, exhibiting significantly lower high-density lipoprotein cholesterol levels (P < 0.05), and higher levels of glycated hemoglobin (P < 0.01), uric acid (P < 0.05), erythrocyte sedimentation rate (P < 0.001), high-sensitive C-reactive protein (P < 0.01), and white blood cell counts (P < 0.01). Higher fasting insulin (P < 0.01) and higher insulin resistance (P < 0.01), assessed by homeostasis model assessment index and visceral adiposity index (P < 0.001), were observed among BED obese. All differences remained significant after adjusting for body mass index. No significant differences in fasting plasma glucose or 2-hour postchallenge plasma glucose were found. Structural equation modeling analysis confirmed the relation between the altered eating behaviors of BED and the metabolic and inflammatory profile.Binge eating disorder obese exhibited an unfavorable metabolic and inflammatory profile, which is related to their characteristic eating habits.

Circulation : Clinical Summaries

<i>Circulation</i> : Clinical Summaries

Prehypertension Tsunami: A Decade Follow-Up of an Iranian Adult Population.

ObjectivePrehypertension is associated with cardiovascular disease (CVD). There is no study to examine the incidence and risk factors of prehypertension in a sex stratified setting. The aim of this study was to examine the effect modification of sex for different risk factors which predicts the progression from normotension to prehypertension in a Middle East population-based cohort, during a median follow-up of 9.2 years.MethodsA multivariate Cox analysis was performed among 1466 and 2131 Iranian men and women, respectively, who were free of prehypertension, hypertension, CVD and diabetes at baseline and free of incident hypertension without preceding prehypertension at follow-up. Incident prehypertension at follow-up was defined as systolic blood pressure (SBP) of 120–139 mmHg and/or diastolic blood pressure (DBP) of 80–89 mmHg.ResultsOverall, 1440 new cases of prehypertension were identified resulting in an incidence rate of 593/10000 person-years; the corresponding values for women and men were 489/10000 and 764/10000person-years, respectively. There were significant interactions between gender with age, DBP, waist-to-hip-ratio (WHpR) and estimated glomerular filtration rate (eGFR) (all P-values <0.05) in multivariate analysis. Strong associations were found between age, body mass index (BMI) and SBP with incident prehypertension in both genders. However, the effect of DBP and WHpR was significant among women and 2-hour post challenge plasma glucose (2h-PCPG)was an independent risk factor for men. In the sex-adjusted analysis, glomerular hyperfiltration [Hazard ratio (HR) and 95%CI: 1.01 (1.00–1.01), P-value = 0.02], age, BMI, WHpR, SBP and DBP had higher risks while being female [HR (95%CI): 0.81(0.69–0.94), P-value = 0.01] had a lower risk for incident prehypertension.ConclusionAccording to this study results, among Iranian population with high incidence of prehypertension, general adiposity and glomerular hyperfiltration in total, 2h-PCPG in men and central adiposity in women should be emphasized as risk factors for prehypertension.

Wrist Circumference as a Novel Predictor of Diabetes and Prediabetes: Results of Cross-Sectional and 8.8-Year Follow-up Studies

Our objective was to examine whether wrist circumference is associated with incident type 2 diabetes mellitus, independently of general (body mass index [BMI]) or central (waist circumference [WC]) adiposity measures in a cohort of an Iranian adult population. A total of 9330 subjects ≥ 20 years of age were included in the cross-sectional study. For prospective analysis, subjects with prevalent diabetes were excluded, leaving 6393 subjects (2716 males and 3677 females). The standard 2-hour postchallenge plasma glucose test was performed at baseline and during follow-up. Cox regression analysis was used to estimate the hazard ratio of diabetes for wrist circumference. During a mean follow-up of 8.8 years, 649 new cases of diabetes occurred. At baseline, using linear regression models, we showed significant linear associations between wrist circumference and diabetes risk factors in both genders, and this association remained significant after controlling for BMI or WC among females. In prospective evaluation, wrist circumference was significantly associated with incident diabetes (multivariable-adjusted hazard ratio = 1.17 [1.03-1.32] and 1.31 [1.18-1.45] for males and females, respectively). After controlling for the subjects' BMI or WC, wrist circumference was an independent predictor of diabetes only among females. Wrist circumference was an independent predictor of metabolic syndrome only among women even after adjustment for BMI, WC, or both. Wrist circumference is a significant predictor of diabetes in both genders of adult population. However, its predictability is independent of BMI or WC only among females. Because of its simple and easy-to-detect nature, wrist circumference could be considered as a new anthropometric assessment for prediction of type 2 diabetes and metabolic syndrome.

Non-linear contribution of glucose measures to cardiovascular diseases and mortality: Reclassifying the Framingham's risk categories: A decade follow-up from the Tehran lipid and glucose study

BackgroundWe investigated non-linear contribution of fasting plasma glucose (FPG) and 2-hour post-challenge plasma glucose (2h-PCPG) to the risk of CVD and mortality. We hypothesized that glucose measures improve risk-stratification made by the Framingham's general CVD risk algorithm. MethodsAmong participants aged ≥30 (n=8071), not taking glucose-lowering agents, 6169 (3477 women) remained eligible. Non-linear contribution of FPG and 2h-PCPG to incident CVD and mortality were assessed using Cox models incorporating restricted cubic splines functions. Risk reclassification improvement conferred by FPG and 2h-PCPG was examined using an extended version of net reclassification index (NRI) that takes into account the censoring nature of survival data. ResultsWe documented 465 incident CVD events (402 CHD), 212 deaths from any cause (94 CVD deaths). Excluding the contribution of the 2h-PCGP to mortality (that was linear) dose–response relationships between glucose measures and CVD and mortality were curvilinear with nadirs below which decreasing levels of glucose were unlikely to offer any benefit. These nadirs were assigned to FPG of 4.9–5.3 and 2h-PCPG of 6.0mmol.l−1. Glucose measures added to the predictive ability of the Framingham's general CVD risk algorithm with cutpoint-free NRIs ranging from 19 to 54%. ConclusionGlucose measures contributed to the risk of CVD and mortality in a curvilinear fashion, we observed increased risk below glucose thresholds currently used to define diabetes, supporting criteria for the diagnosis of impaired fasting glycemia and impaired glucose tolerance. Glucose measures were observed to add to predictive ability of the predictive model which included established cardiovascular risk factors.

Effects of exercise on insulin sensitivity, inflammatory cytokines, and serum tartrate-resistant acid phosphatase 5a in obese Chinese male adolescents

The benefits of exercise on glucose metabolism, inflammation, and serum tartrate-resistant acid phosphatase 5a (TRACP 5a) protein levels in Chinese male adolescents have not been extensively analyzed. Therefore, we examined the effects of a 12-week exercise program on weight, adiposity, insulin sensitivity (IS), and inflammatory marker expression, including the novel macrophage marker TRACP 5a, in obese Chinese male adolescents. A total of 106 male adolescents were recruited from the Army Academy in Taiwan and classified as lean (body mass index [BMI], 20.9 ± 0.2 kg/m 2) or obese (BMI, 27.7 ± 0.2 kg/m 2). Body composition, IS, and inflammatory markers were measured in both groups at baseline and in the obese group after completion of a 12-week exercise program. Body weight, BMI, waist circumference, body fat mass and percentage, homeostasis model assessment for insulin resistance, fasting plasma glucose, fasting serum insulin, 2-hour postchallenge plasma glucose concentration, interleukin-6, C-reactive protein, and serum TRACP 5a were significantly higher in the obese group as compared with the lean group. In addition, serum TRACP 5a was positively correlated with body mass and fat indices. After completion of the exercise program, significant reductions in all anthropometric, metabolic, and inflammatory indicators, with the exception of serum TRACP 5a were observed. Although the obese participants remained obese, exercise training significantly improved IS and reduced interleukin-6 and C-reactive protein. Tartrate-resistant acid phosphatase 5a remained unaffected by exercise training, consistent with our hypothesis that it is associated with increased adipose tissue in obese individuals.

Intima-Media Thickness of Lower-Limb Arteries Associated with Fasting and Post-Challenge Plasma Glucose Levels

Atherosclerosis is a systemic disease with focal cardiovascular events. Although the accelerated development of peripheral arterial disease in diabetic patients is well known, the pathogenic mechanism of site-specific susceptibility to glycemia is uncertain. To investigate the association of fasting and post-challenge glucose levels with intima-media thickness (IMT) at different arterial sites. Forty consecutive middle-aged volunteers aged 37 to 53 years were recruited to define the association of IMT with cardiovascular risk factors at 12 carotid and 6 lower-limb arterial sites. A linear mixed model was used to regress the primary outcome measures, which were repeated measures of IMT at multiple arterial sites (18 sites per participant), on fixed-effect predictors of various conventional cardiovascular risk factors, while accounting for the interdependence of repeated measures taken from the same participant with unstructured covariance. Carotid IMTs were associated independently with waist circumference and systolic blood pressure, whereas lower-limb IMTs were associated with waist circumference, low-density lipoprotein cholesterol (LDL-C), glycated hemoglobin A1C (HbA1C), and fasting and 2-hour post-challenge plasma glucose levels; these associations were stronger in overall arteries. Independent associations of ALT and smoking with IMT appeared only in overall arteries. In a middle-aged, nonclinical sample, lower-limb but not carotid IMTs are associated independently with HbA1C, and fasting and 2-hour post-challenge plasma glucose levels.

Fasting and postchallenge hyperglycemia and risk of cardiovascular disease in Chinese: The Chin-Shan Community Cardiovascular Cohort study

Whether fasting glucose is superior to postchallenge glucose or insulin level for prediction of cardiovascular disease (CVD) remains controversial. The aim of our study was to compare fasting, postchallenge glucose and other markers as predictors of CVD in a community-based prospective cohort study among 2,165 adult participants. A standard 75-g oral glucose tolerance test was performed, with measurements of fasting and 2-hour postchallenge plasma glucose and insulin levels. We defined the CVD outcome as incident coronary heart disease and stroke. Cox regression model was used to estimate the relative risk (RR) for CVD. A total of 166 individuals developed major CVD events during 10.5 years of follow-up. Both fasting and postchallenge glucose were significantly associated with CVD risk (adjusted RR in the highest quartile vs the lowest quartile 1.74, 95% confidence interval [CI] 1.06-2.86 for fasting glucose; RR in highest quartile 2.05, 95% CI 1.23-3.42 for postchallenge glucose). Postchallenge and fasting glucose had similar areas of receiver operative characteristics curves (0.65, 95% CI 0.58-0.72 for postchallenge glucose; 0.65, 95% CI 0.58-0.72 for fasting glucose). In mutually adjusted models, fasting and postchallenge glucose remained significant risk factors for CVD, whereas insulin resistance variables became nonsigificant. These findings show that fasting and postchallenge glucose concentrations are independent predictors of CVD risk among ethnic Chinese in Taiwan.

Contribution of nonesterified fatty acids to insulin resistance in the elderly with normal fasting but diabetic 2-hour postchallenge plasma glucose levels: the Baltimore Longitudinal Study of Aging

Isolated postchallenge hyperglycemia (IPH) with normal fasting plasma glucose <100 mg/dL and plasma glucose with diabetic 2-hour plasma glucose ≥200 mg/dL after an oral glucose tolerance test (OGTT) is a common occurrence in the elderly. We sought to understand what unique characteristics this population might have that puts it at risk for this particular metabolic finding. We therefore conducted a longitudinal study of volunteers in the Baltimore Longitudinal Study of Aging (BLSA). All volunteers had an OGTT performed (75 g) on 2 or more occasions. We measured plasma levels of glucose, insulin, C-peptide, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), ghrelin, leptin, adiponectin, resistin, C-reactive protein, cytokines, and their soluble receptors, as well as nonesterified free fatty acids (NEFAs). We determined that 22 subjects in BLSA had IPH, accounting for 2.1% of the BLSA population. All 22 were older than 65 years. They were then matched by age, sex, and body mass index to 12 subjects who had isolated impaired glucose tolerance (IGT) and 15 subjects with normal glucose tolerance (NGT). All subjects had normal fasting glucose levels <100 mg/dL in accordance with the American Diabetes Association Expert Committee on the Classification and Diagnosis of Diabetes Mellitus criteria (2003). We found that subjects with IPH had similar plasma insulin levels to the other 2 groups, except at the 2-hour time when their insulin levels were higher than NGT ( P < .05). Although there was a clear trend for differences in the insulinogenic index, the areas under the curves for insulin, systolic blood pressure, adiponectin, and C-reactive protein across the glucose tolerance categories revealed no statistical significance. Cytokines and their soluble receptors, gut hormones, and adipokines were similar in all 3 groups. The NEFA levels were significantly elevated in the fasting state ( P < .05) in the IPH compared with NGT, with IGT intermediate between the other 2 groups. The rate of clearance of NEFAs after the OGTT decreased progressively from the NGT to the IPH group (in micromoles per liter per minute: NGT, 11.9 vs IGT, 7.6 vs IPH, 3.0). We conclude that the rate of suppression of lipolysis in the elderly determines the sensitivity of glucose uptake to insulin after OGTT.

Response to Letter Regarding Article, “Low Birth Weight, a Risk Factor for Cardiovascular Diseases in Later Life, Is Already Associated With Elevated Fetal Glycosylated Hemoglobin at Birth”

We thank Harder et al for their interest in our work.1 We would like to reply to the issues raised on a point-to-point basis: 1. Glycosylated hemoglobins (eg, total glycosylated hemoglobin [TGH]) are established, validated measures of average glucose levels during the preceding 6 to 8 weeks, and they are significantly correlated with fasting plasma glucose and 2-hour postchallenge plasma glucose.2,3 Insulin secretion and sensitivity determine glycosylated hemoglobin in diabetic patients.4 An association between glycosylated hemoglobin and insulin resistance also has been observed in a nondiabetic cohort.5 We suggest that these findings in adults can be extrapolated to newborns. However, for technical and ethical reasons, this link was not directly proven in newborns—as we state explicitly in our paper. …

Magnesium Intake Is Related to Improved Insulin Homeostasis in the Framingham Offspring Cohort

Objective: Higher dietary intake of magnesium may protect against development of type 2 diabetes. The aim of this study was to examine the association between dietary magnesium intake and metabolic risk factors for diabetes.Methods: We examined cross-sectional associations between magnesium intake and fasting glucose and insulin, 2-hour post-challenge plasma glucose and insulin, and insulin resistance assessed by the homeostasis model (HOMA-IR) in 1223 men and 1485 women without diabetes from the Framingham Offspring cohort. Magnesium intake was assessed by a food frequency questionnaire and magnesium intake was categorized into quintile categories. Geometric mean insulin, glucose, 2-hour post challenge plasma glucose and insulin concentrations and HOMA-IR were estimated across quintile categories of magnesium intake using Generalized Linear Models.Results: After adjustment for potential confounding factors, magnesium intake was inversely associated with fasting insulin (mean: 29.9 vs 26.7 μU/mL in the lowest vs highest quintiles of magnesium intake; P trend <0.001), post-glucose challenge plasma insulin (86.4 vs 72 μU/mL; P trend <0.001), and HOMA-IR (7.0 vs 6.2; P trend <0.001). No significant association was found between magnesium intake and fasting glucose or 2-hour post challenge glucose.Conclusions: Improved insulin sensitivity may be one mechanism by which higher dietary magnesium intake may reduce the risk of developing type 2 DM.

Diagnostic and therapeutic implications of relationships between fasting, 2-hour postchallenge plasma glucose and hemoglobin a1c values.

Increased fasting plasma glucose (FPG) and 2-hour postchallenge plasma glucose (PCPG) levels with normal hemoglobin A1c (HbA1c) levels are recognized as risk factors for cardiovascular disease. We undertook this study to determine the relationships between FPG and 2-hour PCPG levels over the normal HbA1c range and to assess the need to control FPG and 2-hour PCPG levels to achieve HbA1c targets recommended by the American Diabetes Association (ADA), International Diabetes Federation (IDF), and American College of Endocrinology (ACE). The data of all healthy individuals with HbA1c values less than 7.0% (N = 457) who underwent oral glucose tolerance tests between 1986 and 2002 for either screening as potential research volunteers (93%) or diagnostic purposes (7%) were analyzed. Of 404 individuals with normal HbA1c levels (<6.0%), 60% had normal glucose tolerance, 33% had impaired glucose tolerance, 1% had isolated impaired FPG, and 6% had type 2 diabetes mellitus. Of 161 individuals without normal glucose tolerance, 80% had normal FPG levels. Both FPG and 2-hour PCPG levels increased as HbA1c increased and were significantly correlated (r = 0.63, P<.001), but the 2-hour PCPG level increased at a rate 4 times greater than FPG and accounted for a greater proportion of HbA1c. People who met the IDF and ACE HbA1c targets (<6.5%) had significantly lower 2-hour PCPG levels than those who met the ADA target (<7.0%) (P =.03), whereas FPG levels were similar. Most individuals with HbA1c values between 6.0% and 7.0% have normal FPG levels but abnormal 2-hour PCPG levels, suggesting that an upper limit of normal for FPG at 110 mg/dL (6.11 mmol/L) is too high and that attempts to lower HbA1c in these individuals will require treatment preferentially directed at lowering postprandial glucose levels.