Heikki Miettinen

The Homeostasis Model in the San Antonio Heart Study

OBJECTIVE Both insulin resistance and decreased insulin secretion have been shown to predict the development of NIDDM. However, methods to assess insulin sensitivity and secretion are complicated and expensive to apply in epidemiological studies. The homeostasis model assessment (HOMA) has been suggested as a method to assess insulin resistance and secretion from the fasting glucose and insulin concentrations. However, this method has not been extensively evaluated, particularly in different ethnic groups. RESEARCH DESIGN AND METHODS We applied the HOMA model to cross-sectional analyses of the San Antonio Heart Study (n = 2,465). RESULTS HOMA insulin resistance (IR) was very strongly correlated with fasting insulin (r = 0.98) and HOMA β-cell function (β-cell) was moderately correlated with the 30-min increment in insulin concentration over the 30-min increment in glucose concentration (Δ I30/Δ G30) in an oral glucose tolerance test (OGTT) (r = 0.44). NIDDM was characterized by both high HOMA IR and low HOMA β-cell function. In Mexican-Americans, HOMA IR in NIDDM subjects was 9.5 compared with 2.7 in normal glucose tolerance (NGT) subjects. In contrast, HOMA β-cell function showed only small differences in Mexican-Americans (176 NIDDM; 257 NGT). However, the ΔI30/ΔG30 (pmol/mmol) showed much larger differences (75 NIDDM; 268 NGT). When modeled separately, impaired glucose tolerance (IGT) was characterized by high HOMA IR and high HOMA β-cell function. However, when analyzed in the same regression model, high HOMA IR and low HOMA β-cell function characterized subjects with IGT. These results were similar in both ethnic groups. Mexican-Americans had increased insulin resistance (as judged by both HOMA IR and fasting insulin) and insulin secretion (by HOMA β-cell and ΔI30/ΔG30) relative to non-Hispanic whites. CONCLUSIONS We conclude that HOMA provides a useful model to assess insulin resistance and β-cell function in epidemiological studies in which only fasting samples are available and that, further, it is critical to take into account the degree of insulin resistance in assessing insulin secretion by the HOMA model.

Impact of Diabetes on Mortality After the First Myocardial Infarction

OBJECTIVE To study diabetic and nondiabetic patients with their first myocardial infarction to determine overall 1-year mortality, out-of-hospital mortality, 28-day mortality of hospitalized patients, and 1-year mortality of 28-day survivors. RESEARCH DESIGN AND METHODS This study—based on the FINMONICA Myocardial Infarction Register, a part of the Finnish contribution to the WHO MONICA Project (World Health Organization Multinational Monitoring of Trends and Determinants of Cardiovascular Disease)—covered coronary heart disease (CHD) deaths and acute CHD events occurring during hospitalization among residents of Finland aged 25–64 years in three geographically defined areas. The study population comprised 620 diabetic and 3,445 nondiabetic patients who had their first myocardial infarction during the years 1988–1992. RESULTS The age- and area-adjusted mortality rates and hazard ratios (HRs) for diabetic versus nondiabetic patients (95% CI) were as follows: The 1-year mortality rate was 44.2% in diabetic men and 32.6% in nondiabetic men (HR, 1.38; 1.18−1.61) and 36.9% in diabetic women and 20.2% in nondiabetic women (HR, 1.86; 1.40−2.46); the out-of-hospital mortality rate was 28.3% in diabetic men and 22.4% in nondiabetic men (HR, 1.25; 1.03−1.52) and 10.4% in diabetic women and 11.0% in nondiabetic women (HR, 0.95; 0.58−1.54); the 28-day mortality rate of hospitalized patients was 14.4% in diabetic men and 8.8% in nondiabetic men (HR, 1.58; 1.15−2.18) and 21.7% in diabetic women and 7.8% in nondiabetic women (HR, 2.60; 1.71−3.95); and the 1-year mortality rate of 28-day survivors was 9.6% in diabetic men and 5.0% in nondiabetic men (HR, 1.97; 1.25−3.12) and 10.7% in diabetic women and 2.5% in nondiabetic women (HR, 4.17; 2.05−8.51). CONCLUSIONS The high mortality rate of diabetic patients after their first myocardial infarction and the high proportion of out-of-hospital deaths in this group imply that vigorous primary and secondary preventive measures should become an integral part of their medical care.

A prospective analysis of the HOMA model. The Mexico City Diabetes Study.

OBJECTIVE Both insulin resistance (IR) and decreased insulin secretion have been shown to predict the development of NIDDM. However, methods to assess insulin sensitivity and secretion are complicated and expensive to apply in epidemiological studies. The homeostasis model assessment (HOMA) has been suggested as a method to assess IR and secretion from the fasting glucose and insulin concentrations. RESEARCH DESIGN AND METHODS We applied the HOMA model in the 3.5-year follow-up of the Mexico City Diabetes Study. RESULTS Out of 1,449 subjects, 97 developed diabetes. When modeled separately insulin resistance but not insulin secretion predicted NIDDM. However, when both variables were entered into the same regression model, both increased IR and decreased β-cell function significantly predicted NIDDM. CONCLUSIONS We conclude that the HOMA provides a useful model to assess ²-cell function in epidemiological studies and that it is important to take into account the degree of IR in assessing insulin secretion.

Insulin resistance syndrome predicts the risk of coronary heart disease and stroke in healthy middle-aged men : The 22-year follow-up results of the Helsinki Policemen Study

The interpretation of conventional multivariate analyses concerning the relation of insulin to the risk of atherosclerotic disease is complex because of correlations of insulin with other risk factors. Therefore, we applied factor analysis to study the clustering of risk factors in the baseline data of the Helsinki Policemen Study (970 healthy men aged 34 to 64 years) and investigated whether these clusterings predict coronary heart disease (CHD) and stroke risk. Areas under the glucose and insulin response curves (AUC glucose and AUC insulin) were used to reflect glucose and insulin levels during oral glucose tolerance tests. During the 22-year follow-up, 164 men had a CHD event, and 70 men had a stroke. Factor analysis of 10 risk factor variables produced 3 underlying factors: insulin resistance factor (comprising body mass index, subscapular skinfold, AUC insulin, AUC glucose, maximal O(2) uptake, mean blood pressure, and triglycerides), lipid factor (cholesterol and triglycerides), and lifestyle factor (physical activity and smoking). In multivariate Cox models, the age-adjusted hazard ratio for insulin resistance factor during the 22-year follow-up was 1.28 (95% CI 1.10 to 1.50) with regard to CHD risk and 1.64 (95% CI 1.29 to 2.08) with regard to stroke risk. Lipid factor predicted the risk of CHD but not that of stroke, and lifestyle factor predicted a reduced CHD risk. Factor analysis including only 6 risk factor variables proposed to be central components of insulin resistance syndrome (body mass index, subscapular skinfold, AUC insulin, AUC glucose, mean blood pressure, and triglycerides) produced only a single insulin resistance factor that predicted the risk of CHD and stroke independently of other risk factors.

Decreased Insulin Secretion and Increased Insulin Resistance Are Independently Related to the 7-Year Risk of NIDDM in Mexican-Americans

The relative importance of insulin resistance and abnormal insulin secretion as risk factors for the development of non-insulin-dependent diabetes mellitus (NIDDM) is still controversial. Few data are available on insulin secretion as a risk factor for the development of NIDDM, especially in subjects with normal glucose tolerance. We examined the relation of fasting insulin (as a markerof insulin resistance) and the ratio of change in insulin to change in glucose during the first 30min after glucose ingestion (ΔI30/ΔG30) (as a marker ofinsulin secretion) as predictors of the 7-year development of NIDDM in 714 initially nondiabetic Mexican-Americans. NIDDM developed in 99 subjects. The relative risk of NIDDM increased with higherquartiles of fasting insulin (quartile 1 [low], 1.0; quartile 2, 1.5; quartile 3, 2.0; and quartile 4 [high], 3.7; P < 0.0001) and lower ΔI30/ΔG30 (quartile 1 [low], 6.9; quartile 2, 1.9; quartile 3, 1.1; quartile 4 [high], 1.0; P < 0.001). Subjects with both increased fasting insulin and decreased ΔI30/ΔG30 had independent increases in NIDDM incidence (P < 0.001). Further, when we stratified subjects by baseline glucose tolerance, both increased fasting insulin and decreased ΔI30/ΔG30 significantly predicted NIDDM in subjects with both impaired and normal glucose tolerance at baseline. We conclude that both decreasedinsulin secretion (as assessed by low ΔI30/ΔG30) and increased insulin resistance (as assessed by fasting insulin) predict the development of NIDDM in Mexican-Americans, a group previously characterized as having hyperinsulinemia and insulin resistance. This study provides the first evidence that decreased insulin secretion predicts the development of NIDDM in subjects with normal glucose tolerance, suggesting that deficient insulin secretion and insulin resistance occur early as a precursor of NIDDM.

Proteinuria Predicts Stroke and Other Atherosclerotic Vascular Disease Events in Nondiabetic and Non–Insulin-Dependent Diabetic Subjects

BACKGROUND AND PURPOSE Increased urinary albumin and protein excretion is associated with cardiovascular disease mortality independent of other cardiovascular risk factors in subjects with non-insulin-dependent diabetes mellitus (NIDDM). We assessed the relationship between the different degrees of proteinuria at baseline and the incidence of stroke, as well as other atherosclerotic vascular disease events, in a prospective study of nondiabetic and NIDDM subjects. METHODS Our study was based on the 7-year follow-up of cohorts of nondiabetic (n = 1375) and NIDDM (n = 1056) subjects in Finland. The urinary protein concentration at baseline was stratified into three categories: no proteinuria (< 150 mg/L), borderline (150 to 300 mg/L), and clinical proteinuria (> 300 mg/L). RESULTS The association between the different degrees of proteinuria and the atherosclerotic vascular events was similar in nondiabetic and NIDDM subjects. Cardiovascular disease mortality was higher both in nondiabetic and NIDDM subjects with clinical proteinuria than in those without proteinuria. The incidence of stroke was 1.6% in nondiabetic subjects without proteinuria, 3.2% in subjects with borderline proteinuria, and 8.5% in subjects with clinical proteinuria (P < .001 for trend). In NIDDM patients, the corresponding rates were 7.2%, 11.1%, and 23.0%, respectively (P < .001 for trend). The association between clinical proteinuria and the incidence of stroke remained significant both in nondiabetic and in NIDDM subjects after adjustment for other cardiovascular risk factors. Clinical proteinuria was also associated with the incidence of coronary heart disease events and that of lower-extremity amputation. NIDDM independently increased the risk of atherosclerotic vascular disease events regardless of the proteinuria status. CONCLUSIONS Clinical proteinuria significantly predicted stroke and other atherosclerotic vascular disease events independent of other cardiovascular risk factors. This finding is compatible with the view that increased urinary protein excretion rate may be associated with widespread vascular damage.

Insulin Resistance Implications for Type II Diabetes Mellitus and Coronary Heart Disease

PURPOSE To review information on the implications of insulin resistance for type II diabetes mellitus (non-insulin-dependent diabetes mellitus) and coronary heart disease, and to derive guidance from this information for the management of these conditions. DATA SOURCES A MEDLINE search of English-language articles published between 1985 and July 1996, and review of the bibliographies of articles obtained through the MEDLINE search and textbooks. STUDY SELECTION Primary research articles, reviews and perspectives on the epidemiology of diabetes and cardiovascular diseases and on intervention outcomes in these diseases. DATA EXTRACTION Study design and quality were assessed, with particular attention to methods, study population size and other characteristics. Conclusions of review articles and perspectives were analyzed critically. DATA SYNTHESIS Type II diabetes is associated with a two- to fourfold excess of coronary heart disease, compared to nondiabetic populations. In most studies, glycemia and duration of clinical diabetes were found to be only weak risk factors for coronary heart disease. Conventional coronary heart disease risk factors such as dyslipidemia and hypertension have been associated with coronary heart disease in type II diabetes subjects. Hyperinsulinemia and insulin resistance have been predictive of the development of type II diabetes and, in some studies, of coronary heart disease. CONCLUSION Strategies to prevent the development of coronary heart disease in diabetic and possibly prediabetic subjects should emphasize a multifactorial approach, including: a) improved glycemic control; b) aggressive treatment of risk factors for coronary heart disease, including insulin resistance; c) primary prevention of NIDDM; and d) use of glucose lowering agents that improve insulin sensitivity and cardiovascular risk factors.

Randomized Comparison of Final Kissing Balloon Dilatation Versus No Final Kissing Balloon Dilatation in Patients With Coronary Bifurcation Lesions Treated With Main Vessel Stenting The Nordic-Baltic Bifurcation Study III

Background— It is unknown whether the preferred 1-stent bifurcation stenting approach with stenting of the main vessel (MV) and optional side branch stenting using drug-eluting stents should be finalized by a kissing balloon dilatation (FKBD). Therefore, we compared strategies of MV stenting with and without FKBD. Methods and Results— We randomized 477 patients with a bifurcation lesion to FKBD (n=238) or no FKBD (n=239) after MV stenting. The primary end point was major adverse cardiac events: cardiac death, non–procedure-related index lesion myocardial infarction, target lesion revascularization, or stent thrombosis within 6 months. The 6-month major adverse cardiac event rates were 2.1% and 2.5% (P=1.00) in the FKBD and no-FKBD groups, respectively. Procedure and fluoroscopy times were longer and more contrast media was needed in the FKBD group than in the no-FKBD group. Three hundred twenty-six patients had a quantitative coronary assessment. At 8 months, the rate of binary (re)stenosis in the entire bifurcation lesion (MV and side branch) was 11.0% versus 17.3% (P=0.11), in the MV was 3.1% versus 2.5% (P=0.68), and in the side branch was 7.9% versus 15.4% (P=0.039) in the FKBD versus no-FKBD groups, respectively. In patients with true bifurcation lesions, the side branch restenosis rate was 7.6% versus 20.0% (P=0.024) in the FKBD and no-FKBD groups, respectively. Conclusions— MV stenting strategies with and without FKBD were associated with similar clinical outcomes. FKBD reduced angiographic side branch (re)stenosis, especially in patients with true bifurcation lesions. The simple no-FKBD procedures resulted in reduced use of contrast media and shorter procedure and fluoroscopy times. Long-term data on stent thrombosis are needed. Clinical Trial Registration— URL: http://clinicaltrials.gov. Unique identifier: NCT00914199.

Relationship of Socioeconomic Status to the Incidence and Prehospital, 28-Day, and 1-Year Mortality Rates of Acute Coronary Events in the FINMONICA Myocardial Infarction Register Study

BACKGROUND Low socioeconomic status (SES) is associated with increased coronary heart disease mortality rates. There are, however, very little data on the relation of SES to the incidence, recurrence, and prognosis of myocardial infarction (MI) events. METHODS AND RESULTS The FINMONICA MI Register recorded detailed information on all MI events among men and women aged 35 to 64 years in 3 areas of Finland during the period of 1983 to 1992. We carried out a record linkage of the MI register data with files of Statistics Finland to obtain information on indicators of SES, such as taxable income and education, for each individual who is registered. In the analyses, income was grouped into 3 categories (low, middle, and high), and education was grouped into 2 categories (basic and secondary or higher). Among men with their first MI event (n=6485), the adjusted incidence rate ratios were 1.67 (95% CI 1.57 to 1.78) and 1.84 (95% CI 1.73 to 1.95) in the low- and middle-income categories compared with the high-income category. For 28-day mortality rates, the corresponding rate ratios were 3.18 (95% CI 2.82 to 3.58) and 2.33 (95% CI 2.03 to 2.68). Significant differentials were observed for prehospital mortality rates, and they remained similar up to 1 year after the MI. Findings among the women were consistent with those among the men. CONCLUSIONS The excess coronary heart disease mortality and morbidity rates among persons with low SES are considerable in Finland. To bring the mortality rates of low- and middle-SES groups down to the level of that of the high-SES group constitutes a major public health challenge.

Risk of Harboring an Unruptured Intracranial Aneurysm

BACKGROUND AND PURPOSE The purpose of the present study was to calculate the prevalence and relative risk of unruptured incidental intracranial aneurysms (IAs) among families with IA case(s) compared with the general population in one geographically defined area in East Finland and to identify the risk group that could benefit most from screening for IAs. We compared these results with our earlier study results of familial IA (FIA) cases, with two or more known IA cases in the same family. METHODS The study groups were collected from the catchment area of the University Hospital of Kuopio in East Finland. The inclusion criteria were age 30 to 70 years and unruptured incidental IAs > or =3 mm. Patients with previous subarachnoid hemorrhage or in whom a ruptured IA was found to be the cause of death were excluded from all study groups. During routine forensic autopsies the circle of Willis was studied for IAs to estimate the number of IAs in the general population. In the families with one known IA case and in FIA families, MR angiography was used as a preliminary screening method for IAs, followed by intra-arterial angiography to verify suspected IAs. Study populations were age and sex adjusted for the statistical calculations. RESULTS The relative risk for IAs among first-degree relatives in FIA families was 4.2 (95% confidence interval, 2.2 to 8.0) and among first-degree relatives in families with only one affected family member was 1.8 (95% confidence interval, 0.7 to 4.8) compared with the general population in East Finland. CONCLUSIONS First-degree relatives in FIA families constitute a high-risk group for incidental IAs, and this group would benefit from screening studies for IAs. Screening for IAs in families with only one affected member or in the general population is not recommended.