Cardiometabolic risk in impaired fasting glucose and impaired glucose tolerance: the Atherosclerosis Risk in Communities Study

OBJECTIVE: We compared and contrasted cardiovascular disease (CVD) risk factors, subclinical manifestations of CVD, incident coronary heart disease (CHD), and all-cause mortality by categories of impaired glucose regulation in nondiabetic individuals. RESEARCH DESIGN AND METHODS: The study included 6,888 participants aged 52-75 years who had no history of diabetes or CVD. All-cause mortality and incident CHD were ascertained over a median of 6.3 years of follow-up. RESULTS: Agreement between fasting and postchallenge glucose impairment was poor: 3,048 subjects (44%) had neither impaired fasting glucose (IFG) nor impaired glucose tolerance (IGT), 1,690 (25%) had isolated IFG, 1,000 (14%) had isolated IGT, and 1,149 (17%) had both IFG and IGT. After adjustment for age, sex, race, and center, subjects with isolated IFG were more likely to smoke, consume alcohol, and had higher mean BMI, waist circumference, LDL cholesterol, and fasting insulin and lower HDL cholesterol than those with isolated IGT, while subjects with isolated IGT had higher mean triglycerides, systolic blood pressure, and white cell counts. Measures of subclinical CVD and rates of all-cause mortality and incident CHD were similar in isolated IFG and isolated IGT. CONCLUSIONS: Neither isolated IFG nor isolated IGT was associated with a more adverse CVD risk profile.     

The Singapore impaired glucose tolerance follow-up study: does the ticking clock go backward as well as forward?

OBJECTIVE: To 1). document the change in glucose tolerance for subjects with normal glucose tolerance (NGT) and impaired glucose tolerance (IGT) over time, 2). identify baseline factors associated with worsening of glucose tolerance, and 3). determine whether cardiovascular disease (CVD) risk factors associated with IGT improved in tandem with glucose tolerance. RESEARCH DESIGN: Subjects with IGT and NGT (matched for age, sex, and ethnic group) were identified from a cross-sectional survey conducted in 1992. Subjects with IGT (297) and NGT (298) (65.0%) were reexamined in 2000. Glucose tolerance (assessed by 75-g oral glucose tolerance test), anthropometric data, serum lipids, blood pressure, and insulin resistance were determined at baseline and at the follow-up examination. RESULTS: For NGT subjects, 14.0% progressed to IGT and 4.3% to diabetes over 8 years. For IGT subjects, 41.4% reverted to NGT, 23.0% remained impaired glucose tolerant, and 35.1% developed diabetes. Obesity, hypertriglyceridemia, higher blood pressure, increased insulin resistance, and lower HDL cholesterol at baseline were associated with worsening of glucose tolerance in both IGT and NGT subjects. Those with IGT who reverted to NGT remained more obese and had higher blood pressure than those with NGT in both 1992 and 2000. However, serum triglyceride, HDL cholesterol, and insulin resistance values in 2000 became indistinguishable from those of subjects who maintained NGT throughout the study period. CONCLUSIONS: Some, but not all, CVD risk factors associated with IGT and with the risk of future diabetes normalize when glucose tolerance normalizes. Continued surveillance and treatment in subjects with IGT, even after they revert to NGT, may be important in the prevention of CVD.     

Retinopathy predicts cardiovascular mortality in type 2 diabetic men and women

OBJECTIVE: To investigate the association of retinopathy with the risk of all-cause, cardiovascular disease (CVD), and coronary heart disease (CHD) mortality in type 2 diabetic subjects in a population-based 18-year follow-up study with particular emphasis on sex differences. RESEARCH DESIGN AND METHODS: Our study cohort comprised 425 Finnish type 2 diabetic men and 399 type 2 diabetic women who were free of CVD at baseline. The findings were classified based on standardized clinical ophthalmoscopy to categories of no retinopathy, background retinopathy, and proliferative retinopathy. The study end points were all-cause, CVD, and CHD mortality. RESULTS: Adjusted Cox model hazard ratios (95% CIs) of all-cause, CVD, and CHD mortality in men were 1.34 (0.98-1.83), 1.30 (0.86-1.96), and 1.18 (0.74-1.89), respectively, for background retinopathy and 3.05 (1.70-5.45), 3.32 (1.61-6.78), and 2.54 (1.07-6.04), respectively, for proliferative retinopathy and in women 1.61 (1.17-2.22), 1.71 (1.17-2.51), and 1.79 (1.13-2.85), respectively, for background retinopathy and 2.92 (1.41-6.06), 3.17 (1.38-7.30), and 4.98 (2.06-12.06), respectively, for proliferative retinopathy. CONCLUSIONS: Proliferative retinopathy in both sexes and background retinopathy in women predicted all-cause, CVD, and CHD death. These associations were independent of current smoking, hypertension, total cholesterol, HDL cholesterol, glycemic control of diabetes, duration of diabetes, and proteinuria. This suggests the presence of common background pathways for diabetic microvascular and macrovascular disease other than those included in the conventional risk assessment of CVD. The sex difference observed in the association of background retinopathy with macrovascular disease warrants closer examination.     

Glucose intolerance and 23-year risk of coronary heart disease and total mortality: the Honolulu Heart Program.

OBJECTIVE: The associations between glucose intolerance measured at the study entry date and the 23-year incidence of coronary heart disease (CHD), CHD mortality, and total mortality were examined at the Honolulu Heart Program. RESEARCH DESIGN AND METHODS: This prospective study followed a cohort of 8,006 Japanese-American men who were 45-68 years old and living on the island of Oahu, HI, in 1965. Baseline glucose was measured in a nonfasting state 1 h after a 50-g glucose load. History and use of medication for diabetes was obtained during an interview. The cohort was divided into four categories of glucose tolerance: low-normal, high-normal, asymptomatic hyperglycemia, and known diabetes. RESULTS: During the 23 years of follow-up, 864 incident cases of CHD, 384 deaths from CHD, and 2,166 total deaths occurred. The relative risks (RRs) were obtained using Cox proportional hazards modeling, with the low-normal category as a reference. The RRs were adjusted for age only, as well as for age, BMI, hypertension, cholesterol, triglycerides, smoking, alcohol, and a Japanese diet index. The age-adjusted and risk factor-adjusted RRs for all outcomes were significant for the asymptomatic hyperglycemic and known diabetes groups (P<0.05). The age-adjusted RRs for CHD incidence and total mortality were marginally significant in the high-normal group, but the RRs were not significant when adjusted for risk factors. CONCLUSIONS: These results suggest a dose-response relation of glucose intolerance at baseline with CHD incidence, CHD mortality, and total mortality, independent of other risk factors, in this cohort of middle-aged and older Japanese-American men.     

Subclinical states of glucose intolerance and risk of death in the U.S

OBJECTIVE: Although clinically evident type 2 diabetes is a well-established cause of mortality, less is known about subclinical states of glucose intolerance. RESEARCH DESIGN AND METHODS: Data from the Second National Health and Nutrition Examination Survey Mortality Study, a prospective study of adults, were analyzed. This analysis focused on a nationally representative sample of 3,174 adults aged 30-75 years who underwent an oral glucose tolerance test at baseline (1976-1980) and who were followed up for death through 1992. RESULTS: Using 1985 World Health Organization criteria, adults were classified as having previously diagnosed diabetes (n = 248), undiagnosed diabetes (n = 183), impaired glucose tolerance (IGT) (n = 480), or normal glucose tolerance (n = 2,263). For these groups, cumulative all-cause mortality through age 70 was 41, 34, 27, and 20%, respectively (P < 0.001). Compared with those with normal glucose tolerance, the multivariate adjusted RR of all-cause mortality was greatest for adults with diagnosed diabetes (RR 2.11, 95% CI 1.56-2.84), followed by those with undiagnosed diabetes (1.77, 1.13-2.75) and those with IGT (1.42, 1.08-1.87; P < 0.001). A similar pattern of risk was observed for cardiovascular disease mortality. CONCLUSIONS: In the U.S., there was a gradient of mortality associated with abnormal glucose tolerance ranging from a 40% greater risk in adults with IGT to a 110% greater risk in adults with clinically evident diabetes. These associations were independent of established cardiovascular disease risk factors.     

Heart rate recovery following maximal exercise testing as a predictor of cardiovascular disease and all-cause mortality in men with diabetes

OBJECTIVE: Heart rate recovery (HRR) is an independent prognostic indicator for cardiovascular disease (CVD) and all-cause mortality in healthy men. We examined the association of HRR to CVD-related and all-cause mortality in men with diabetes. RESEARCH DESIGN AND METHODS: In this cohort study we examined 2,333 men with documented diabetes (mean age 49.4 years) that had baseline 5-min HRR measurement following maximal exercise (heart rate(peak) - heart rate(5 min of recovery)) at The Cooper Clinic, Dallas, TX. We identified HRR quartiles as quartile 1 <55, quartile 2 55-66, quartile 3 67-75, and quartile 4 >75 bpm. Hazard ratios (HRs) for cardiovascular and all-cause death were adjusted for age, cardiorespiratory fitness, resting heart rate, fasting blood glucose, BMI, smoking habit, alcohol consumption, total cholesterol, triglyceride, and history of CVD at baseline. RESULTS: During a median of 14.9 years follow-up, there were 142 deaths that were considered CVD related and 287 total deaths. Compared with men in the highest quartile of HRR, adjusted HRs in the first, second, and third quartiles were 2.0 (95% CI 1.1-3.8), 1.5 (0.8-2.7), and 1.5 (0.9-2.8), respectively, for cardiovascular death (P for trend < 0.001). Similarly, for all-cause death, adjusted HRs in the first, second, and third quartiles were 2.0 (1.3-3.2), 1.5 (1.0-2.3), and 1.5 (1.1-2.3) (P for trend < 0.001). CONCLUSIONS: Among men with diabetes, a decreased HRR, even measured as long as 5 min after recovery, was independently predictive of cardiovascular and all-cause death.     

Cross-sectional and prospective associations between proinsulin and cardiovascular disease risk factors in a population experiencing rapid cultural transition.

OBJECTIVE: To examine cross-sectional and prospective associations between proinsulin and cardiovascular disease risk factors using data from a population-based study of type 2 diabetes among Native Canadians. RESEARCH DESIGN AND METHODS: Between 1993 and 1995, 72% of eligible members of a Native Canadian community participated in a baseline diabetes prevalence survey. Fasting samples were collected for glucose, C-peptide, proinsulin, lipids, and apolipoproteins. A 75-g oral glucose tolerance test was administered, and a second sample for glucose was drawn after 120 min. Blood pressure and waist circumference were determined. In the present study, subjects with normal glucose tolerance (NGT) (n = 505) and impaired glucose tolerance (IGT) (n = 74) were included in cross-sectional analyses. In 1998, 95 individuals who had IGT or NGT at baseline with an elevated 2-h glucose concentration (> or = 7.0 mmol/l) participated in a follow-up evaluation using the protocol used at baseline. Cross-sectional and prospective associations between proinsulin and cardiovascular risk factors were assessed using correlation and multiple linear regression analyses. RESULTS: After adjustment for covariates including age, sex, C-peptide, waist circumference, and glucose tolerance status, fasting proinsulin concentration was significantly associated with concurrently measured lipid and apolipoprotein concentrations (triglycerides: r = 0.18, P < 0.0001; total cholesterol: r = 0.10, P = 0.02; LDL cholesterol: r = 0.11, P = 0.01; HDL cholesterol: r = -0.16, P = 0.0002; apolipoprotein (apo) B: r = 0.17, P < 0.0001; apoAI: r = -0.11, P = 0.008). In the adjusted prospective analysis, baseline triglycerides, HDL cholesterol, and apoB were associated with changes over time in proinsulin (r = 0.23, P = 0.04; r = -0.30, P = 0.01; r = 0.23, P = 0.04; respectively). CONCLUSIONS: These results confirm previously reported cross-sectional associations between proinsulin and lipid concentrations. In addition, an unexpected association between baseline lipids and proinsulin change was documented.     

Elevated risk of cardiovascular disease prior to clinical diagnosis of type 2 diabetes

OBJECTIVE: To examine whether the risk of cardiovascular disease (CVD) is elevated before clinical diagnosis of type 2 diabetes in women. RESEARCH DESIGN AND METHODS: A total of 117,629 female nurses aged 30-55 years who were free of diagnosed CVD at baseline were recruited in 1976 and followed for 20 years. RESULTS: A total of 1,508 women had diagnosed type 2 diabetes at baseline in 1976. During 20 years of follow-up, 110,227 women remained free of diabetes diagnosis and 5,894 women developed type 2 diabetes. During 2.2 million person-years of follow-up, we documented 1,556 new cases of myocardial infarction (MI), 1,405 strokes, 815 fatal coronary heart disease (CHD), and 300 fatal strokes. Among women who developed type 2 diabetes during follow-up, the age-adjusted RRs of MI were 3.75 (95% CI 3.10-4.53) for the period before the diagnosis and 4.57 (3.87-5.39) for the period after the diagnosis, compared with women who remained free of diabetes diagnosis. The multivariate RRs further adjusting for BMI, smoking, and other cardiovascular risk factors were 3.17 (2.61-3.85) and 3.97 (3.35-4.71). The risk of stroke was also significantly elevated before diagnosis of diabetes (multivariate RR = 2.30 [1.76-2.99]). Further adjustment for history of hypertension or hypercholesterolemia did not appreciably alter the results. CONCLUSIONS: Our data indicate a substantially elevated risk of CVD before clinical diagnosis of type 2 diabetes in women. These findings suggest that aggressive management of cardiovascular risk factors is warranted in individuals at increased risk for diabetes.     

Impact of incident diabetes and incident nonfatal cardiovascular disease on 18-year mortality: the multiple risk factor intervention trial experience

OBJECTIVE: To report long-term risks for total, cardiovascular disease (CVD), and coronary heart disease (CHD) mortality associated with incident diabetes (using current diagnostic criteria) and with incident nonfatal CVD (NF-CVD). RESEARCH DESIGN AND METHODS: A total of 11645 participants without diabetes or CVD at baseline from the Multiple Risk Factor Intervention Trial who survived to the end of the trial were grouped by during-trial incident diabetes and/or NF-CVD events: neither diabetes nor NF-CVD, diabetes only, NF-CVD only, or both diabetes and NF-CVD. Incident diabetes was defined by use of hypoglycemic agents or fasting glucose >or=126 mg/dl at any time over the 6 trial years. Proportional hazards models tested group differences in mortality over 18 post-trial years. RESULTS: Among 3859 total deaths were 1846 from CVD and 1277 from CHD, with death rates per 10000 person-years of 203, 97, and 67, respectively. Multivariate-adjusted hazard ratios (HRs) for total mortality were 2.75 (P < 0.0001) for those with NF-CVD and diabetes both, 1.92 (P < 0.0001) for those with NF-CVD only, and 1.49 (P < 0.0001) for those with diabetes only, relative to neither diabetes nor NF-CVD. NF-CVD was associated with a higher hazard of death than diabetes for total (HR 1.29, P = 0.0004), CVD (HR 1.76, P < 0.0001), and CHD (HR 1.88, P < 0.0001) mortality. Only the subgroup of participants on hypoglycemic agents showed an equivalent risk of total mortality relative to participants with NF-CVD (HR 0.93, P = 0.54). CONCLUSIONS: Current diabetes diagnostic criteria conferred significantly increased total, CVD, and CHD mortality risks independent of the impact of NF-CVD. NF-CVD was more strongly predictive of mortality.     

Prospective study of high-sensitivity C-reactive protein as a determinant of mortality: results from the MONICA/KORA Augsburg Cohort Study, 1984-1998

BACKGROUND: C-reactive protein (CRP), an exquisitely sensitive systemic marker of inflammation, has emerged as an independent predictor of cardiovascular diseases (CVD). Because other chronic diseases are also associated with an inflammatory response, we sought to assess the association of high-sensitivity CRP (hsCRP) with total and cause-specific mortality in a large cohort of middle-aged men. METHODS: We measured hsCRP at baseline in 3620 middle-aged men, randomly drawn from 3 samples of the general population in the Augsburg area (Southern 0Germany) in 1984-85, 1989-90, and 1994-95. Outcome was defined as all deaths, fatal CVD, fatal coronary heart disease (CHD) including sudden cardiac deaths, and cancer deaths. RESULTS: During an average follow-up of 7.1 years, 408 deaths occurred (CVD 196, CHD 129, cancer 127). In multivariable Cox regression analysis, subjects with hsCRP >3 mg/L at baseline showed an almost 2-fold increased risk to die vs those with hsCRP <1 mg/L [hazard ratio (HR) 1.88, 95% CI 1.41-2.52]. HRs were 2.15 (95% CI 1.39-3.34) for fatal CVD, 1.74 (1.04-2.92) for fatal CHD, and 1.65 (1.01-2.68) for cancer mortality. In contrast, neither total nor HDL cholesterol significantly predicted all-cause or cancer mortality, and cholesterol had only modest effects on CVD mortality. CONCLUSIONS: Our results suggest that increased circulating hsCRP concentrations are associated with an increased risk of death from several widespread chronic diseases. Persistently increased hsCRP is a sensitive and valuable nonspecific indicator of an ongoing disease process that deserves serious and careful medical attention.     

Obese women and the relation between cardiovascular risk profile and hormone therapy, glucose tolerance, and psychosocial conditions

OBJECTIVE: To evaluate the relation between cardiovascular disease (CVD) risk factors and hormone therapy, serum hormone levels, glucose tolerance, and psychosocial and psychological conditions in subjectively healthy obese female subjects. RESEARCH DESIGN AND METHODS: The study included 606 women, aged 50-64 years, with BMI 30-40 kg/m(2) and no history of cardiovascular or other severe diseases. One group with a CVD risk profile (n = 473) (i.e., cholesterol >7.0 mmol/l, HDL cholesterol <1.2 mmol/l, triglycerides >2.0 mmol/l, systolic or diastolic blood pressure >140/90 mmHg, or waist-to-hip ratio >0.85) was compared with women without such risk (n = 133). Steroid hormones, leptin, insulin, and oral glucose tolerance tests (OGTTs) were analyzed. A subgroup of women with baseline impaired glucose tolerance (IGT) completed a 2.5-year follow-up OGTT. RESULTS: Fewer obese postmenopausal women with CVD risk had ever used hormone therapy (odds ratio 0.24 [95% CI 0.07-0.75]), after multivariate adjustments. Furthermore, women with CVD risk had a higher testosterone index (1.07 [1.01-1.13]) and more had insulin resistance (1.04 [1.00-1.08]) and IGT (2.92 [1.50-5.69]), while OGTT was similar at follow-up. No differences were observed regarding family history or lifestyle, except that fewer women with CVD risk consumed fruits, boiled vegetables, or whole-grain cereals. More women with CVD risk lived alone (3.26 [1.28-8.31]) and had more mental problems (1.16 [1.05-1.28]). CONCLUSIONS: Previously healthy obese women with a CVD risk profile seemed to have a high risk of diabetes, as well as psychosocial or psychological problems. Hormone therapy was associated with reduced CVD risk. Obesity's growing burden on society makes it more important to further target individuals that are at greatest risk of future health hazards.     

Features of the metabolic syndrome predict higher risk of diabetes and impaired glucose tolerance: a prospective study in Mauritius

OBJECTIVE: To assess the independent and joint effects of the components of the metabolic syndrome, including leptin, which is a recently proposed addition to this syndrome, in predicting the cumulative incidence of impaired glucose tolerance (IGT) and diabetes among individuals with normal glucose tolerance. RESEARCH DESIGN AND METHODS: This prospective study involved 2,605 residents of Mauritius with normal glucose tolerance who were followed for 5 years for IGT or diabetes onset in relation to total and regional adiposity (BMI, waist-to-hip ratio [WHR]), fasting and 2-h 75-g oral glucose load glucose and insulin, total and HDL cholesterol, blood pressure, serum uric acid, triglyceride, and leptin levels. RESULTS: A multivariate logistic regression model adjusted for age, sex, ethnicity, and diabetes family history showed a significantly higher linear increase in risk of IGT and diabetes in association with the following variables only: fasting glucose (odds ratio 1.89 [95% CI 1.51-2.34]), 2-h glucose (1.68 [1.50-1.88]), WHR (1.30 [1.10-1.52]), BMI (1.04 [1.00-1.08]), and serum uric acid (1.37 [1.20-1.57]). However, a nonlinear increase was seen with serum triglyceride and plasma leptin concentrations. No risk factors resulted in joint effects that were greater than expected from combining individual effects. CONCLUSIONS: Metabolic syndrome features independently predict a higher risk of diabetes or IGT in normoglycemic subjects but in combination confer no higher-than-expected risk of these outcomes. At higher concentrations of triglycerides and leptin, risk plateaus and even declines slightly.     

Cardiovascular disease risk factors predict the development of type 2 diabetes: the insulin resistance atherosclerosis study

OBJECTIVE: In a few previous studies, cardiovascular disease (CVD) risk factors (RFs) have been shown to predict diabetes. Our objective was to determine whether the presence of CVD RFs predict the eventual development of diabetes after controlling for known RFs, such as directly measured insulin resistance and obesity. RESEARCH DESIGN AND METHODS: We studied 872 participants with normal or impaired glucose tolerance (IGT) who were enrolled at baseline in the Insulin Resistance Atherosclerosis Study (IRAS). Of these, 143 (16%) developed type 2 diabetes in 5 years. Using these participants, a series of logistic regression models were fit to address the question. RESULTS: Significant RFs for developing type 2 diabetes included high plasminogen activator inhibitor-1, hypertension, high triglycerides, low levels of HDL cholesterol, and IGT. The 5-year cumulative incidence of type 2 diabetes by the number of RFs (0-5) was as follows: no RFs, 11 of 230 = 5%; one RF, 31 of 278 = 11%; two RFs, 36 of 202 = 18%; three RFs, 41 of 110 = 37%; four RFs, 19 of 42 = 45%; and five RFs, 5 of 10 = 50% (P < 0.001). The odds ratio (OR) for conversion to type 2 diabetes for each additional RF was 2.1 (95% CI 1.78-2.46) after adjusting for age, sex, ethnicity, and center. After further adjustment for insulin resistance, determined by the frequently sampled intravenous glucose tolerance test and waist circumference, each additional CVD RF increased the risk of type 2 diabetes significantly (OR 1.81, 95% CI 1.49-2.20). CONCLUSIONS: Individuals with multiple CVD RFs are at increased risk of type 2 diabetes, which is only partially mediated by insulin resistance or central adiposity. This information should be useful for identifying high-risk patients for developing diabetes through RF assessments.     

Non-HDL cholesterol and apolipoprotein B predict cardiovascular disease events among men with type 2 diabetes

OBJECTIVE: To evaluate the role of non-HDL cholesterol and apolipoprotein (apo)B, markers of all potentially atherogenic lipoproteins, as predictors of cardiovascular disease (CVD) in comparison with LDL cholesterol in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: We prospectively followed 746 diabetic men in the Health Professionals' Follow-up Study who were aged 46-81 years and free of CVD or cancer at the time of blood draw in 1993-1994. During 6 years of follow-up, we ascertained 103 incident CVD cases. RESULTS: We used Cox proportional hazard modeling to estimate the relative risk (RR) of CVD. After adjustment for age, BMI, and other lifestyle risk factors, the multivariate RR of CVD (the highest versus the lowest quartile) was 2.34 (95% CI 1.26-4.32) for non-HDL cholesterol, 2.31 (1.23-4.35) for apoB, and 1.74 (0.99-3.06) for LDL cholesterol. Comparisons of nested models indicate that non-HDL cholesterol, but not apoB, adds significantly to the prediction of CVD risk beyond LDL cholesterol. The area under the receiver operating characteristic curve was 0.685, 0.691, 0.695, and 0.722 for the CVD risk-prediction model with LDL cholesterol, apoB, non-HDL cholesterol, and total cholesterol-to-HDL cholesterol ratio (or the non-HDL-to-HDL cholesterol ratio), respectively. CONCLUSIONS: Non-HDL cholesterol and apoB are more potent predictors of CVD incidence among diabetic men than LDL cholesterol. Statistically, the ratio of total to HDL cholesterol is the best predictor of CVD in this cohort of diabetic men.     

Insulin resistance,the metabolic syndrome,and risk of incident cardiovascular disease in nondiabetic american indians: the Strong Heart Study

OBJECTIVE: Insulin resistance (IR) and the metabolic syndrome (MS) are associated with type 2 diabetes and adverse cardiovascular disease (CVD) risk factor profiles. Whether IR and MS predict CVD independently of diabetes and other CVD risk factors is not known. This study examines whether IR and/or presence of MS are independently associated with CVD in nondiabetic American Indians (AI). RESEARCH DESIGN AND METHODS: We examined 2283 nondiabetic AI who were free of CVD at the baseline examination of the Strong Heart Study (SHS). CVD risk factors were measured, IR was quantified using the homeostasis model assessment (HOMA), and MS as defined by the National Cholesterol Education Program Adult Treatment Panel (ATP III) was assessed for each participant. Incident CVD and diabetes were ascertained during follow-up. RESULTS: MS was present in 798 individuals (35%), and 181 participants (7.9%) developed CVD over 7.6 +/- 1.8 years of follow-up. Age, BMI, waist circumference, and triglyceride levels increased and HDL cholesterol decreased across tertiles of HOMA-IR. Risk of diabetes increased as a function of baseline HOMA-IR (6.3, 14.6, and 30.1%; P < 0.001) and MS (12.8 vs. 24.5%). In Cox models adjusted for CVD risk factors, risk of CVD did not increase either as a function of baseline HOMA-IR or MS, but individual CVD risk factors predicted subsequent CVD. CONCLUSIONS: Among nondiabetic AI in the SHS, HOMA-IR and MS both predict diabetes, but neither predicts CVD independently of other established CVD risk factors.     

Adiponectin in a native Canadian population experiencing rapid epidemiological transition

OBJECTIVE: Adiponectin is emerging as an important protein in the etiology of obesity and related metabolic disorders. The objectives of this study were to determine cross-sectional and prospective associations of adiponectin concentration with adiposity, type 2 diabetes, and cardiovascular disease (CVD) risk factors in a population-based study of Native Canadians, a group experiencing dramatic increases in diabetes and CVD. RESEARCH DESIGN AND METHODS: During the 1993-1995 baseline survey, samples for glucose, insulin, adiponectin, and lipids were collected after an overnight fast. Waist circumference and percent body fat were measured, and a 75-g oral glucose tolerance test was administered: n = 505 with normal glucose tolerance (NGT), 74 with impaired glucose tolerance (IGT), and 149 with diabetes. In 1998, 95 high-risk subjects, defined as those who, at baseline, had either IGT or NGT with an elevated 2-h glucose concentration (>/==" BORDER="0">7.0 mmol/l), participated in a follow-up examination using the protocol used at baseline. RESULTS: After adjustment for covariates including percent body fat and homeostasis model assessment of insulin resistance (HOMA-IR), adiponectin concentrations were significantly lower among men versus women (10.8 vs. 15.0 micro g/ml, P < 0.0001) and among diabetic versus NGT subjects (11.1 vs. 13.1 micro g/ml, P < 0.05). Adiponectin was inversely correlated with percent body fat, waist circumference, HOMA-IR, and triglyceride and positively correlated with HDL (r = |0.30|-|0.44|, all P < 0.0001). In multivariate linear regression analysis in nondiabetic subjects, HDL and percent body fat were significantly related to adiponectin variation among both men and women (R(2) = 28-29%). Factor analysis returned three underlying factors among these variables, with adiponectin loading on the second factor along with insulin, waist circumference, triglyceride, and HDL. In the follow-up study, higher adiponectin at baseline was significantly associated with increases in HDL (r = 0.24, P = 0.03) and decreases in HOMA-IR (r = -0.29, P = 0.009) after adjustment for covariates, including age, adiposity, and diabetes status at baseline and follow-up. CONCLUSIONS: These population-based findings support the hypothesis that low circulating levels of adiponectin are an important determinant of risk of CVD.     

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

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

The metabolic syndrome and 11-year risk of incident cardiovascular disease in the atherosclerosis risk in communities study

OBJECTIVE: To assess the magnitude of the association between the National Cholesterol Education Program's Third Adult Treatment Panel Report (ATP III) definition of the metabolic syndrome and cardiovascular disease (CVD). RESEARCH DESIGN AND METHODS: Cox regression was used to estimate the relative risk of incident coronary heart disease (CHD) and stroke among 12,089 black and white middle-aged individuals in the Atherosclerosis Risk in Communities (ARIC) study. RESULTS: The metabolic syndrome was present in approximately 23% of individuals without diabetes or prevalent CVD at baseline. Over an average of 11 years of follow-up, 879 incident CHD and 216 ischemic stroke events occurred. Among the components of the metabolic syndrome, elevated blood pressure and low levels of HDL cholesterol exhibited the strongest associations with CHD. Men and women with the metabolic syndrome were approximately 1.5 and 2 times more likely to develop CHD than control subjects after adjustment for age, smoking, LDL cholesterol, and race/ARIC center (sex interaction P < 0.03). Similar associations were found between the metabolic syndrome and incident ischemic stroke. Comparison of receiver operating characteristic curves indicated that the metabolic syndrome did not materially improve CHD risk prediction beyond the level achieved by the Framingham Risk Score (FRS). CONCLUSIONS: Individuals without diabetes or CVD, but with the metabolic syndrome, were at increased risk for long-term cardiovascular outcomes, although statistical models suggested that most of that risk was accounted for by the FRS. Nevertheless, identification of individuals with the metabolic syndrome may provide opportunities to intervene earlier in the development of shared disease pathways that predispose individuals to both CVD and diabetes.     

HOMA-estimated insulin resistance is an independent predictor of cardiovascular disease in type 2 diabetic subjects: prospective data from the Verona Diabetes Complications Study

OBJECTIVE: To evaluate whether homeostasis model assessment-estimated insulin resistance (HOMA-IR) is an independent predictor of cardiovascular disease (CVD) in type 2 diabetes. RESEARCH DESIGN AND METHODS: Conventional CVD risk factors (sex, age, smoking, plasma lipids, blood pressure, and metabolic control) and insulin resistance (estimated by HOMA) were evaluated at baseline in 1,326 patients with type 2 diabetes examined within the Verona Diabetes Complications Study. At baseline and after a mean follow-up of 4.5 years, CVD was assessed by medical history, physical examination, electrocardiography, and echo-Doppler of carotid and lower limb arteries. Death certificates and medical records of subjects who died during the follow-up were carefully scrutinized to identify cardiovascular deaths. In statistical analyses, CVD was an aggregate end point including both fatal and nonfatal coronary, cerebrovascular, and peripheral vascular disease as well as ischemic electrocardiographic abnormalities and vascular lesions identified by echo-Doppler. RESULTS: At baseline, 441 subjects were coded positive for CVD (prevalent cases). Incident cases numbered 126. Multiple logistic regression analyses showed that, along with sex, age, smoking, HDL/total cholesterol ratio, and hypertension, HOMA-IR was an independent predictor of both prevalent and incident CVD. A 1-unit increase in (log)HOMA-IR value was associated with an odds ratio for prevalent CVD at baseline of 1.31 (95% CI 1.10-1.56, P = 0.002) and for incident CVD during follow-up of 1.56 (95% CI 1.14-2.12, P < 0.001). CONCLUSIONS: HOMA-IR is an independent predictor of CVD in type 2 diabetes. The improvement of insulin resistance might have beneficial effects not only on glucose control but also on CVD in patients with type 2 diabetes.     

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

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