Review of methods for measuring ß-cell function: Design considerations from the Restoring Insulin Secretion (RISE) Consortium.

The Restoring Insulin Secretion (RISE) study was initiated to evaluate interventions to slow or reverse the progression of ß-cell failure in type 2 diabetes (T2D). To design the RISE study, we undertook an evaluation of methods for measurement of ß-cell function and changes in ß-cell function in response to interventions. In the present paper, we review approaches for measurement of ß-cell function, focusing on methodologic and feasibility considerations. Methodologic considerations included: (1) the utility of each technique for evaluating key aspects of ß-cell function (first- and second-phase insulin secretion, maximum insulin secretion, glucose sensitivity, incretin effects) and (2) tactics for incorporating a measurement of insulin sensitivity in order to adjust insulin secretion measures for insulin sensitivity appropriately. Of particular concern were the capacity to measure ß-cell function accurately in those with poor function, as is seen in established T2D, and the capacity of each method for demonstrating treatment-induced changes in ß-cell function. Feasibility considerations included: staff burden, including time and required methodological expertise; participant burden, including time and number of study visits; and ease of standardizing methods across a multicentre consortium. After this evaluation, we selected a 2-day measurement procedure, combining a 3-hour 75-g oral glucose tolerance test and a 2-stage hyperglycaemic clamp procedure, augmented with arginine.

Detecting prediabetes among Hispanics/Latinos from diverse heritage groups: Does the test matter? Findings from the Hispanic Community Health Study/Study of Latinos.

The objectives of this analysis were to compare the ability of fasting plasma glucose (FPG), post oral load plasma glucose (2hPG), and hemoglobin A1c (HbA1c) to identify U.S. Hispanic/Latino individuals with prediabetes, and to assess its cardiovascular risk factor correlates. This is a cross-sectional analysis of baseline data from 15,507 adults without self-reported diabetes mellitus from six Hispanic/Latino heritage groups, enrolled in the Hispanic Community Health Study/Study of Latinos, which takes place in four U.S. communities. The prevalence of prediabetes was determined according to individual or combinations of ADA-defined cut points: FPG=5.6-7.0mmol/L, 2hPG=7.8-11.1mmol/L, and HbA1c=5.7%-6.4% (39-46mmol/mol). The sensitivity of these criteria to detect prediabetes was estimated. The prevalence ratios (PRs) for selected cardiovascular risk factors were compared among alternative categories of prediabetes versus normoglycemia [FPG<5.6mmol/L and 2hPG<7.8mmol/L and HbA1c<5.7% (39mmol/mol)]. Approximately 36% of individuals met any of the ADA prediabetes criteria. Using 2hPG as the gold standard, the sensitivity of FPG was 40.1%, HbA1c was 45.6%, and that of HbA1c+FPG was 62.2%. The number of significant PRs for cardiovascular risk factors was higher among individuals with isolated 2hPG=7.8-11.1mmol/L, FPG=5.6-7.0mmol/L+HbA1c=5.7%-6.4%, or those who met the three prediabetes criteria. Assessing FPG, HbA1c, and cardiovascular risk factors in Hispanics/Latinos at risk might enhance the early prevention of diabetes mellitus and cardiovascular complications in this young and growing population, independent of their heritage group.

HEMOGLOBIN A1C, BLOOD PRESSURE, AND LDL-CHOLESTEROL CONTROL AMONG HISPANIC/LATINO ADULTS WITH DIABETES: RESULTS FROM THE HISPANIC COMMUNITY HEALTH STUDY/STUDY OF LATINOS (HCHS/SOL).

OBJECTIVE: To determine the prevalence of Hispanic/Latino adults with diabetes who meet target hemoglobin A1c, blood pressure (BP), and low-density-lipoprotein cholesterol (LDL-C) recommendations, and angiotensin-converting enzyme (ACE) inhibitors/angiotensin receptor blocker (ARB) and statin medication use by heritage and sociodemographic and diabetes-related characteristics. METHODS: Data were cross-sectional, collected between 2008 and 2011, and included adults age 18 to 74 years who reported a physician diagnosis of diabetes in the Hispanic Community Health Study/Study of Latinos (N = 2,148). Chi-square tests compared the prevalence of hemoglobin A1c, BP, and LDL-C targets and ACE/ARB and statin use across participant characteristics. Predictive margins regression was used to determine the prevalence adjusted for sociodemographic characteristics. RESULTS: The overall prevalence of A1c <7.0% (53 mmol/mol), BP <130/80 mm Hg, and LDL-C <100 mg/dL was 43.0, 48.7, and 36.6%, respectively, with 8.4% meeting all three targets. Younger adults aged 18 to 39 years with diabetes were less likely to have A1c <7.0% (53 mmol/mol) or LDL-C <100 mg/dL compared to those aged 65 to 74 years; younger adults were more likely to have BP <130/80 mm Hg (P<.05 for all). Individuals of Mexican heritage were significantly less likely to have A1c <7.0% (53 mmol/mol) compared to those with Cuban heritage, but they were more likely to have BP <130/80 mm Hg compared to those with Dominican, Cuban, or Puerto Rican heritage (P<.05 for all); there was no difference in LDL-C by heritage. Overall, 38.2% of adults with diabetes were taking a statin, and 50.5% were taking ACE/ARB medications. CONCLUSION: Hemoglobin A1c, BP, and LDL-C control are suboptimal among Hispanic/Latinos with diabetes living in the U.S. With 8.4% meeting all three recommendations, substantial opportunity exists to improve diabetes control in this population. ABBREVIATIONS: A1c = hemoglobin A1c; ABC = hemoglobin A1c, blood pressure, low-density-lipoprotein cholesterol; ACE = angiotensin-converting enzyme; ADA = American Diabetes Association; ARB = angiotensin receptor blocker; BMI = body mass index; BP = blood pressure; CHD = coronary heart disease; CVD = cardiovascular disease; HCHS/SOL = Hispanic Community Health Study/Study of Latinos; LDL-C = low-density-lipoprotein cholesterol; NHANES = National Health and Nutrition Examination Survey; PAD = peripheral artery disease.

IDENTIFYING PROBABLE DIABETES MELLITUS AMONG HISPANICS/LATINOS FROM FOUR U.S. CITIES: FINDINGS FROM THE HISPANIC COMMUNITY HEALTH STUDY/STUDY OF LATINOS.

OBJECTIVE: The aim of this study was to compare the ability of American Diabetes Association (ADA) diagnostic criteria to identify U.S. Hispanics/Latinos from diverse heritage groups with probable diabetes mellitus and assess cardiovascular risk factor correlates of those criteria. METHODS: Cross-sectional analysis of data from 15,507 adults from 6 Hispanic/Latino heritage groups, enrolled in the Hispanic Community Health Study/Study of Latinos. The prevalence of probable diabetes mellitus was estimated using individual or combinations of ADA-defined cut points. The sensitivity and specificity of these criteria at identifying diabetes mellitus from ADA-defined prediabetes and normoglycemia were evaluated. Prevalence ratios of hypertension, abnormal lipids, and elevated urinary albumin-creatinine ratio for unrecognized diabetes mellitus-versus prediabetes and normoglycemia-were calculated. RESULTS: Among Hispanics/Latinos (mean age, 43 years) with diabetes mellitus, 39.4% met laboratory test criteria for probable diabetes, and the prevalence varied by heritage group. Using the oral glucose tolerance test as the gold standard, the sensitivity of fasting plasma glucose (FPG) and hemoglobin A1c-alone or in combination-was low (18, 23, and 33%, respectively) at identifying probable diabetes mellitus. Individuals who met any criterion for probable diabetes mellitus had significantly higher (P<.05) prevalence of most cardiovascular risk factors than those with normoglycemia or prediabetes, and this association was not modified by Hispanic/Latino heritage group. CONCLUSION: FPG and hemoglobin A1c are not sensitive (but are highly specific) at detecting probable diabetes mellitus among Hispanics/Latinos, independent of heritage group. Assessing cardiovascular risk factors at diagnosis might prompt multitarget interventions and reduce health complications in this young population. ABBREVIATIONS: 2hPG = 2-hour post-glucose load plasma glucose ADA = American Diabetes Association BMI = body mass index CV = cardiovascular FPG = fasting plasma glucose HbA1c = hemoglobin A1c HCHS/SOL = Hispanic Community Health Study/Study of Latinos HDL-C = high-density-lipoprotein cholesterol NGT = normal glucose tolerance NHANES = National Health and Nutrition Examination Survey OGTT = oral glucose tolerance test TG = triglyceride UACR = urine albumin-creatinine ratio.

Durable change in glycaemic control following intensive management of type 2 diabetes in the ACCORD clinical trial.

AIMS/HYPOTHESIS: We aimed to determine the persistence of glycaemic control 1 year after a limited period of intensive glycaemic management of type 2 diabetes. METHODS: 4119 ACCORD Trial participants randomised to target HbA1c <6.0% (42 mmol/mol) for 4.0 ± 1.2 years were systematically transitioned to target HbA1c 7.0-7.9% (53-63 mmol/mol) and followed for an additional 1.1 ± 0.2 years. Characteristics of participants with HbA1c <6.5% (48 mmol/mol) or ≥6.5% at transition were compared. Changes in BMI and glucose-lowering medications were compared between those ending with HbA1c <6.5% vs ≥6.5%. Poisson models were used to assess the independent effect of attaining HbA1c <6.5% before transition on ending with HbA1c <6.5%. RESULTS: Participants with pre-transition HbA1c <6.5% were older with shorter duration diabetes and took less insulin but more non-insulin glucose-lowering agents than those with higher HbA1c. A total of 823 participants achieved a final HbA1c <6.5%, and had greater post-transition reductions in BMI, insulin dose and secretagogue and acarbose use than those with higher HbA1c (p < 0.0001). HbA1c <6.5% at transition predicted final HbA1c <6.5% (crude RR 4.9 [95% CI 4.0, 5.9]; RR 3.9 [95% CI 3.2, 4.8] adjusted for demographics, co-interventions, pre-intervention HbA1c, BMI and glucose-lowering medication, and post-transition change in both BMI and glucose-lowering medication). Progressively lower pre-transition HbA1c levels were associated with a greater likelihood of maintaining a final HbA1c of <6.5%. Follow-up duration was not associated with post-transition rise in HbA1c. CONCLUSIONS/INTERPRETATION: Time-limited intensive glycaemic management using a combination of agents that achieves HbA1c levels below 6.5% in established diabetes is associated with glycaemic control more than 1 year after therapy is relaxed.

Arginine is preferred to glucagon for stimulation testing of ß-cell function.

A key aspect of research into the prevention and treatment of type 2 diabetes is the availability of reproducible clinical research methodology to assess ß-cell function. One commonly used method employs nonglycemic secretagogues like arginine (arg) or glucagon (glgn). This study was designed to quantify the insulin response to arg and glgn and determine test repeatability and tolerability. Obese overnight-fasted subjects with normal glucose tolerance were studied on 4 separate days: twice using arg (5 g iv) and twice with glgn (1 mg iv). Pre- and postinfusion samples for plasma glucose, insulin, and C-peptide were acquired. Arg and glgn challenges were repeated in the last 10 min of a 60-min glucose (900 mg/min) infusion. Insulin and C-peptide secretory responses were estimated under baseline fasting glucose conditions (AIRarg and AIRglgn) and hyperglycemic (AIRargMAX AIRglgnMAX) states. Relative repeatability was estimated by intraclass correlation coefficient (ICC). Twenty-three (12 men and 11 women) subjects were studied (age: 42.4 ± 8.3 yr; BMI: 31.4 ± 2.8 kg/m²). Geometric means (95% CI) for baseline-adjusted values AIRarg and AIRglgn were 84 (75-95) and 102 (90-115) µU/ml, respectively. After the glucose infusion, AIRargMAX and AIRglgnMAX were 395 (335-466) and 483 (355-658) µU/ml, respectively. ICC values were >0.90 for AIRarg andAIRargMAX. Glucagon ICCs were 0.83, 0.34, and 0.36, respectively, although the exclusion of one outlier increased the latter two values (to 0.84 and 0.86). Both glgn and arg induced mild adverse events that were transient. Glucagon, but not arginine, induced moderate adverse events due to nausea. Taken together, arginine is preferred to glucagon for assessment of ß-cell function.

Trends in cardiovascular disease risk factors in individuals with and without diabetes mellitus in the Framingham Heart Study.

BACKGROUND: Individuals with diabetes mellitus are at 2- to 3-fold increased risk for cardiovascular disease (CVD) relative to those without diabetes. Our objective was to examine CVD risk factor level changes among individuals with and without type 2 diabetes mellitus from 1970 to 2005 in the Framingham Heart Study. METHODS AND RESULTS: We included 4195 participants (3990 with no diabetes and 205 with diabetes) 50 years of age and 3495 participants (3178 with no diabetes and 317 with diabetes) 60 years of age. Contemporaneous CVD risk factor levels were measured; linear regression models were used to assess the interaction between diabetes status and calendar year on CVD risk factor levels. Among 50-year-olds without diabetes mellitus, there was an increase in body mass index of 0.39 kg/m(2) per 10 years, whereas for those with diabetes, there was an increase of 2.52 kg/m(2) (P value for the diabetes-by-calendar year interaction [P for interaction] <0.001). For low-density lipoprotein cholesterol, the mean decrease was -7.43 mg/dL per decade (nondiabetes) and -15.5 mg/dL for diabetes (P for interaction=0.002). For systolic blood pressure, the mean decrease was -3.35 mm Hg per decade (nondiabetes) and -3.50 mm Hg for diabetes (P for interaction=0.97). The direction of the trends for those with diabetes relative to those without diabetes was similar for 60-year-olds. CONCLUSIONS: Compared with individuals without diabetes mellitus, individuals with diabetes experienced a greater increase in body mass index, a greater decrease in low-density lipoprotein cholesterol, and a similar magnitude of decline in systolic blood pressure. Individuals with diabetes mellitus have not experienced the necessary declines in CVD risk factors to overcome their increased risk of CVD. Further efforts are needed to aggressively control CVD risk factors among individuals with diabetes mellitus.

Trends in all-cause and cardiovascular disease mortality among women and men with and without diabetes mellitus in the Framingham Heart Study, 1950 to 2005.

BACKGROUND: Despite population declines in all-cause mortality, women with diabetes mellitus may have experienced an increase in mortality rates compared with men. METHODS AND RESULTS: We examined change in all-cause, cardiovascular, and non-cardiovascular disease mortality rates among Framingham Heart Study participants who attended examinations during an "earlier" (1950 to 1975; n=930 deaths) and a "later" (1976 to 2001; n=773 deaths) time period. Diabetes mellitus was defined as casual glucose > or =200 mg/dL, fasting plasma glucose > or =126 mg/dL, or treatment. Among women, the hazard ratios (HRs) for all-cause mortality in the later versus the earlier time period were 0.59 (95% confidence interval, 0.50 to 0.70; P<0.0001) for those without diabetes mellitus and 0.48 (95% confidence interval, 0.32 to 0.71; P=0.002) for those with diabetes mellitus. Similar results were observed in men. Among women and men, the HR of cardiovascular disease mortality declined among those with and without diabetes mellitus. Non-cardiovascular disease mortality declined among women without diabetes mellitus (HR, 0.76; P=0.01), whereas no change was observed among women with diabetes mellitus or among men with or without diabetes mellitus. Individuals with versus those without diabetes mellitus were at increased risk of all-cause mortality in the earlier (HR, 2.44; P<0.0001) and later (HR, 1.95; P<0.0001) time periods. CONCLUSIONS: Reductions in all-cause mortality among women and men with diabetes mellitus have occurred over time. However, mortality rates among individuals with diabetes mellitus remain approximately 2-fold higher compared with individuals without diabetes mellitus.

Increasing cardiovascular disease burden due to diabetes mellitus: the Framingham Heart Study.

BACKGROUND: Marked reductions in cardiovascular disease (CVD) morbidity and mortality have occurred in the United States over the last 50 years. We tested the hypothesis that the relative burden of CVD attributable to diabetes mellitus (DM) has increased over the past 5 decades. METHODS AND RESULTS: Participants aged 45 to 64 years from the Framingham Heart Study, who attended examinations in an "early" time period (1952 to 1974), were compared with those who attended examinations in a later time period (1975 to 1998). The risk of CVD events (n=133 among those with and 1093 among those without DM) attributable to DM in the 2 time periods was assessed with Cox proportional hazards models; population attributable risk of DM as a CVD risk factor was calculated for each time period. The age- and sex-adjusted hazard ratio for DM as a CVD risk factor was 3.0 (95% CI, 2.3 to 3.9) in the earlier time period and 2.5 (95% CI, 1.9 to 3.2) in the later time period. The population attributable risk for DM as a CVD risk factor increased from 5.4% (95% CI, 3.8% to 6.9%) in the earlier time period to 8.7% (95% CI, 5.9% to 11.4%) in the later time period (P for attributable risk ratio=0.04), although multivariable adjustment resulted in attenuation of these findings (P=0.12); most of these observations were found among men. CONCLUSIONS: The proportion of CVD attributable to DM has increased over the past 50 years in Framingham. These findings emphasize the need for increased efforts to prevent DM and to aggressively treat and control CVD risk factors among those with DM.

Magnesium intake and incidence of metabolic syndrome among young adults.

BACKGROUND: Studies suggest that magnesium intake may be inversely related to risk of hypertension and type 2 diabetes mellitus and that higher intake of magnesium may decrease blood triglycerides and increase high-density lipoprotein (HDL) cholesterol levels. However, the longitudinal association of magnesium intake and incidence of metabolic syndrome has not been investigated. METHODS AND RESULTS: We prospectively examined the relations between magnesium intake and incident metabolic syndrome and its components among 4637 Americans, aged 18 to 30 years, who were free from metabolic syndrome and diabetes at baseline. Metabolic syndrome was diagnosed according to the National Cholesterol Education Program/Adult Treatment Panel III definition. Diet was assessed by an interviewer-administered quantitative food frequency questionnaire, and magnesium intake was derived from the nutrient database developed by the Minnesota Nutrition Coordinating Center. During the 15 years of follow-up, 608 incident cases of the metabolic syndrome were identified. Magnesium intake was inversely associated with incidence of metabolic syndrome after adjustment for major lifestyle and dietary variables and baseline status of each component of the metabolic syndrome. Compared with those in the lowest quartile of magnesium intake, multivariable-adjusted hazard ratio of metabolic syndrome for participants in the highest quartile was 0.69 (95% confidence interval [CI], 0.52 to 0.91; P for trend <0.01). The inverse associations were not materially modified by gender and race. Magnesium intake was also inversely related to individual component of the metabolic syndrome and fasting insulin levels. CONCLUSIONS: Our findings suggest that young adults with higher magnesium intake have lower risk of development of metabolic syndrome.

Metabolic syndrome and cardiovascular disease in older people: The cardiovascular health study.

OBJECTIVES: To assess the prospective association between metabolic syndrome (MetS) and cardiovascular disease (CVD) in older people and to evaluate the effect of lowering the threshold for impaired fasting glucose (IFG) on the prevalence of IFG and MetS and the risk of CVD. DESIGN: Prospective cohort study. SETTING: Four field centers in U.S. communities. PARTICIPANTS: Three thousand five hundred eighty-five subjects in the Cardiovascular Health Study free of diabetes mellitus and CVD at baseline (mean age 72, 62% female, 14% black). MEASUREMENTS: Baseline measures of MetS components and adjudicated incident CVD events. MetS (2001) was defined first using the original criteria from the Third Adult Treatment Panel Report of the National Cholesterol Education Program (> or =3 of the following: large waist circumference (women >88 cm, men >102 cm), elevated triglycerides (> or =1.70 mmol/L), low high-density lipoprotein cholesterol (men <1.04 mmol/L, women <1.30 mmol/L), elevated fasting glucose (6.1-6.9 mmol/L), and high blood pressure (> or =130/85 mmHg or self-reported use of medications for hypertension). Subjects were also classified according to the revised definition of the MetS (2005) that applies the lower threshold for fasting glucose (5.6-6.9 mmol/L). RESULTS: During follow-up (median 11 years), 818 coronary heart disease (CHD), 401 stroke, and 554 congestive heart failure (CHF) events occurred. Age- and race-adjusted hazard ratios (HRs) for CHD, stroke, and CHF were 1.30 (95% confidence interval (CI) = 1.07-1.57), 0.94 (95% CI = 0.73-1.21), and 1.40 (95% CI = 1.12-1.76) for women and 1.35 (95% CI = 1.10-1.66), 1.51 (95% CI = 1.08-2.12), and 1.47 (95% CI = 1.14-1.90) for men, respectively. Overall, women and men with MetS (2005) were 20% to 30% more likely to experience any CVD event than subjects without MetS (2005). Using the lower cut-point for IFG resulted in a near tripling in IFG prevalence (16% to 46%) and an additional 9% classified with MetS (2005) but HRs similar to those estimated from the original MetS (2001) criteria. High blood pressure was the component most strongly associated with incident CHD. CONCLUSION: Results from this study of an elderly, population-based cohort provide support for earlier investigations in primarily middle-aged populations that link the presence of MetS with the development of CVD and further underscore the importance of recognizing and treating its individual components, particularly high blood pressure.

Metabolic and inflammation variable clusters and prediction of type 2 diabetes: factor analysis using directly measured insulin sensitivity.

Factor analysis, a multivariate correlation technique, has been used to provide insight into the underlying structure of the metabolic syndrome. The majority of previous factor analyses, however, have used only surrogate measures of insulin sensitivity; very few have included nontraditional cardiovascular disease (CVD) risk factors such as plasminogen activator inhibitor (PAI)-1, fibrinogen, and C-reactive protein (CRP); and only a limited number have assessed the ability of factors to predict type 2 diabetes. The objective of this study was to investigate, using factor analysis, the clustering of metabolic and inflammation variables using data from 1,087 nondiabetic participants in the Insulin Resistance Atherosclerosis Study (IRAS) and to determine the association of these clusters with risk of type 2 diabetes at follow-up. This study includes information on directly measured insulin sensitivity (S(i)) from the frequently sampled intravenous glucose tolerance test among African-American, Hispanic, and non-Hispanic white subjects aged 40-69 years. Principal factor analysis of data from nondiabetic subjects at baseline (1992-1994) identified three factors, which explained 28.4, 7.4, and 6% of the total variance in the dataset, respectively. Based on factor loadings of >or= 0.40, these factors were interpreted as 1) a "metabolic" factor, with positive loadings of BMI, waist circumference, 2-h glucose, log triglyceride, and log PAI-1 and inverse loadings of log S(i) + 1 and HDL; 2) an "inflammation" factor, with positive loadings of BMI, waist circumference, fibrinogen, and log CRP and an inverse loading of log S(i) + 1; and 3) a "blood pressure" factor, with positive loadings of systolic and diastolic blood pressure. The results were similar within strata of ethnicity, and there were only subtle differences in sex-specific analyses. In a prospective analysis, each of the factors was a significant predictor of diabetes after a median follow-up period of 5.2 years, and each factor remained significant in a multivariate model that included all three factors, although this three-factor model was not significantly more predictive than models using either impaired glucose tolerance or conventional CVD risk factors. Factor analysis identified three underlying factors among a group of inflammation and metabolic syndrome variables, with insulin sensitivity loading on both the metabolic and inflammation variable clusters. Each factor significantly predicted diabetes in multivariate analysis. The findings support the emerging hypothesis that chronic subclinical inflammation is associated with insulin resistance and comprises a component of the metabolic syndrome.

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

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

The association of fasting glucose levels with congestive heart failure in diabetic adults > or =65 years: the Cardiovascular Health Study.

OBJECTIVES: The purpose of this study was to determine if fasting glucose levels are an independent risk factor for congestive heart failure (CHF) in elderly individuals with diabetes mellitus (DM) with or without coronary heart disease (CHD). BACKGROUND: Diabetes mellitus and CHF frequently coexist in the elderly. It is not clear whether fasting glucose levels in the setting of DM are a risk factor for incident CHF in the elderly. METHODS: A cohort of 829 diabetic participants, age > or =65 years, without prevalent CHF, was followed for five to eight years. The Cox proportional hazards modeling was used to determine the risk of CHF by fasting glucose levels. The cohort was categorized by the presence or absence of prevalent CHD. RESULTS: For a 1 standard deviation (60.6 mg/dl) increase in fasting glucose, the adjusted hazard ratios for incident CHF among participants without CHD at baseline, with or without an incident myocardial infarction (MI) or CHD event on follow-up, was 1.41 (95% confidence interval 1.24 to 1.61; p < 0.0001). Among those with prevalent CHD at baseline, with or without another incident MI or CHD event on follow-up, the corresponding adjusted hazard ratio was 1.27 (95% confidence interval 1.02 to 1.58; p < 0.05). CONCLUSIONS: Among older adults with DM, elevated fasting glucose levels are a risk factor for incident CHF. The relationship of fasting glucose to CHF differs somewhat by the presence or absence of prevalent CHD.

Fasting and 2-hour postchallenge serum glucose measures and risk of incident cardiovascular events in the elderly: the Cardiovascular Health Study.

BACKGROUND: The contributions of fasting and 2-hour postchallenge glucose level to cardiovascular events remain ill-defined, especially for nondiabetic adults. This study examined the relative predictive power of fasting and 2-hour glucose level on cardiovascular event risk. METHODS: A total of 4014 community-dwelling adults 65 years or older who participated in the baseline visit of the Cardiovascular Health Study and who were without treated diabetes or previous myocardial infarction or stroke were eligible for analyses. Participants with treated diabetes at baseline were excluded. Incident myocardial infarction or stroke, or coronary death, was the outcome of interest. Age-, sex-, and race-adjusted proportional hazards regression models described individual and joint associations between baseline measures of fasting and 2-hour postchallenge glucose level and event risk. RESULTS: There were 764 incident cardiovascular events during 8.5 years of follow-up. Fasting glucose level of 115 mg/dL (6.4 mmol/L) or more was associated with an increased cardiovascular risk (hazard ratio [HR], 1.66 [95% confidence interval (CI), 1.39-1.98]) in adjusted analyses compared with fasting glucose level less than 115 mg/dL. Two-hour glucose level was associated with a linear risk (HR, 1.02 [95% CI, 1.00-1.04] per 10 mg/dL [0.6 mmol/L]) that included an additional increase in risk for 2-hour glucose level of 154 mg/dL (8.5 mmol/L) or more (HR, 1.29 [95% CI, 1.04-1.59]) in adjusted analyses. In joint fasting and 2-hour glucose models, only 2-hour glucose level remained predictive of event risk. CONCLUSIONS: Two-hour glucose level was better than fasting glucose level alone at identifying older adults at increased risk of major incident cardiovascular events.

Risk factors for the metabolic syndrome: the Coronary Artery Risk Development in Young Adults (CARDIA) study, 1985-2001.

OBJECTIVE: The aim of this study was to describe the association of the metabolic syndrome with demographic characteristics and to identify modifiable risk factors for development of the metabolic syndrome. RESEARCH DESIGN AND METHODS: Men and women (55%) aged 18-30 years from the Coronary Artery Risk Development in Young Adults (CARDIA) study without the metabolic syndrome at baseline (n = 4,192, 49% black) were followed-up from 1985 to 2001. Incident metabolic syndrome, defined according to the National Cholesterol Education Program Adult Treatment Panel III criteria, was ascertained 7, 10, and 15 years after baseline. Risk factors were measured via clinical examination and standardized questionnaires. RESULTS: The age-adjusted rate of metabolic syndrome was 10 per 1,000 person-years (n = 575). Metabolic syndrome risk increased with age and was higher among black participants and those with less than a high school education. Higher baseline BMI, no alcohol intake (versus one to three drinks per day), higher intake of dietary carbohydrates, and lower intake of crude fiber were each associated with an increased risk for the metabolic syndrome (relative risk [RR] ranging from 1.3 to 1.9), and physical activity was protective (RR 0.84 [95% CI 0.76-0.92]). In models adjusting simultaneously for all factors, black participants and women were less likely to develop metabolic syndrome. Risk for metabolic syndrome increased 23% (20-27%) per 4.5 kg (10 lb) of weight gained, whereas regular physical activity over time versus low activity was protective (RR 0.49 [0.34-0.70]). CONCLUSIONS: BMI and weight gain are important risk factors for the metabolic syndrome. Regular physical activity may counter this risk.

The relationship of fasting serum radioimmune insulin levels to incident coronary heart disease in an insulin-treated diabetic cohort.

It is not known whether insulin levels, in the setting of insulin treatment, are an independent risk factor for coronary heart disease (CHD). We studied a cohort of 116 insulin-treated individuals, 65 yr or older, who were followed for 5.6-9 yr. All were free of CHD at baseline. There were 47 incident CHD events. In Cox proportional hazards modeling, with fasting immune-reactive insulin levels as a continuous variable, the hazard ratio for CHD was statistically significant (P < 0.0001). When insulin levels were divided into intervals, those in the third interval [43-150 microU/ml (258-900 pmol/liter)] had an adjusted 30% increased relative risk (95% confidence interval, 0.57, 2.98) compared with those in the first interval [<20 microU/ml (<120 pmol/liter)]. Those in the fourth interval [151-400 microU/ml (906-2400 pmol/liter)] had an adjusted 5.6-fold increased risk (2.3-13.1; P < 0.0001). Approximately 15% of the cohort had such elevated insulin levels. Immune-reactive insulin levels were strongly correlated with specific insulin, proinsulin, and insulin antibody levels. Markedly elevated fasting immune-reactive insulin levels were an independent risk factor for CHD in this study of insulin-treated older adults. These observational findings should be confirmed through larger prospective studies, given their implications for insulin therapy.

Glucose, blood pressure, and lipid control in older people with and without diabetes mellitus: the Cardiovascular Health Study.

OBJECTIVES: To determine the prevalence of cardiovascular risk-factor treatment and control in older adults with normal fasting glucose, impaired fasting glucose, and diabetes mellitus and whether those with diabetes mellitus had better risk factor control than older adults with normal fasting glucose. DESIGN: Secondary analysis of data from population-based, prospective cohort study of risk factors for cardio-vascular and cerebrovascular disease in older people (Cardiovascular Health Study). SETTING: Community-based. PARTICIPANTS: Community-dwelling adults aged 65 and older. MEASUREMENTS: Fasting plasma glucose, serum cholesterol and its subfractions, systolic and diastolic blood pressures, and body mass index. RESULTS: There were 579 (18%) cohort members with diabetes mellitus (77% receiving antidiabetic medication, 23% with fasting glucose > or =126 mg/dL and no treatment), 213 (6%) with impaired fasting glucose, and 2,582 (77%)with normal fasting glucose. Of diabetic participants, 12% had recommended fasting glucose levels of less than 110 mg/dL. Of participants with hypertension, a larger proportion of diabetic participants than nondiabetic participants (89% versus 75%, P < .01) was treated with antihypertensive agents, but a smaller proportion of diabetic participants had recommended blood pressure levels of 129/85 mmHg or lower than nondiabetic participants had recommended blood pressure levels of 139/89 mmHg or lower (27% vs 48%, P < .01). Diabetic dyslipidemic participants were treated less often with lipid-lowering therapy (26% versus 55%, P < .01) and achieved recommended low-density lipoprotein goals less often (8%versus 54%, P < .01) than nondiabetic dyslipidemic participants. CONCLUSIONS: Overall, treatment and control of cardiovascular risk factors were suboptimal in this older population, especially among those with diabetes mellitus. Optimizing risk-factor control can improve health outcomes in older adults with and without diabetes mellitus.

Trends in cardiovascular complications of diabetes.

CONTEXT: Despite reductions in cardiovascular disease (CVD) mortality over the past few decades, it is unclear whether adults with and without diabetes have experienced similar declines in CVD risk. OBJECTIVE: To determine whether adults with and without diabetes experienced similar declines in incident CVD in 1950-1995. DESIGN, SETTING, AND PARTICIPANTS: Participants aged 45-64 years from the Framingham Heart Study original and offspring cohorts who attended examinations in 1950-1966 ("earlier" time period; 4118 participants, 113 with diabetes) and 1977-1995 ("later" time period; 4063 participants, 317 with diabetes). Incidence rates of CVD among those with and without diabetes were compared between the earlier and later periods. MAIN OUTCOME MEASURES: Myocardial infarction, coronary heart disease death, and stroke. RESULTS: Among participants with diabetes, the age- and sex-adjusted CVD incidence rate was 286.4 per 10,000 person-years in the earlier period and 146.9 per 10,000 in the later period, a 49.3% (95% confidence interval [CI], 16.7%-69.4%) decline. Among participants without diabetes, the age- and sex-adjusted incidence rate was 84.6 per 10,000 person-years in the earlier period and 54.3 per 10,000 person-years in the later period, a 35.4% (95% CI, 25.3%-45.4%) decline. Hazard ratios for diabetes as a predictor of incident CVD were not different in the earlier vs later periods. CONCLUSIONS: We report a 50% reduction in the rate of incident CVD events among adults with diabetes, although the absolute risk of CVD is 2-fold greater than among persons without diabetes. Adults with and without diabetes have benefited similarly during the decline in CVD rates over the last several decades. More aggressive treatment of CVD risk factors and further research on diabetes-specific factors contributing to CVD risk are needed to further reduce the high absolute risk of CVD still experienced by persons with diabetes.

Hemoglobin A1c, fasting plasma glucose, and 2-hour plasma glucose distributions in U.S. population subgroups: NHANES 2005-2010.

PURPOSE: Although mean concentrations of hemoglobin A1c (A1C), fasting plasma glucose, and 2-hour plasma glucose differ by demographics, it is unclear what other characteristics of the distributions may differ, such as the amount of asymmetry of the distribution (skewness) and shift left or right compared with another distribution (shift). METHODS: Using kernel density estimation, we created smoothed plots of the distributions of fasting plasma glucose (N = 7250), 2-hour plasma glucose (N = 5851), and A1C (N = 16,209) by age, race-ethnicity, and sex in the 2005-2010 National Health and Nutrition Examination Survey, a nationally representative sample of U.S. adults including people with and without diabetes. We tested differences in distributions using cumulative logistic regression. RESULTS: The distributions were generally unimodal and right-skewed. All distributions were shifted higher and more right-skewed for older age groups (P < .001 for each marker). Compared with non-Hispanic whites, the distribution of fasting plasma glucose was shifted higher for Mexican-Americans (P = .01), whereas the distribution of A1C was shifted higher for non-Hispanic blacks (P < .001). The distribution of fasting plasma glucose was shifted higher for men (P < .001) and the distribution of 2-hour plasma glucose was shifted higher for women (P = .01). CONCLUSIONS: We provide a graphic reference for comparing these distributions and diabetes cut-points by demographic factors.