Insulin Resistance, the Metabolic Syndrome, and Risk of Incident CVD
Insulin Resistance, the Metabolic Syndrome, and Risk of Incident CVD
Objectives: The goal was to clarify if insulin resistance (IR) would predict cardiovascular disease (CVD) independent of the metabolic syndrome (MetSyn).
Background: Although the cause of MetSyn is not well defined, IR has been proposed to be an important cause. Only a small number of population-based studies have sought to clarify if IR predicts CVD independent of MetSyn.
Methods: This was a prospective Danish population-based study of 2,493 men and women, age 41 to 72 years, without major CVD at baseline. We defined MetSyn according to both the International Diabetes Foundation (IDF) and the National Cholesterol Education Program (NCEP) criteria, and we quantified IR by the homeostasis model assessment (HOMA-IR). Prevalence of MetSyn was 21% according to IDF criteria and 16% according to NCEP criteria. Accordingly, we defined IDF-HOMA-IR as belonging to the highest 21% of the HOMA-IR distribution, and NCEP-HOMA-IR as belonging to the highest 16% of the HOMA-IR distribution.
Results: Over a median follow-up of 9.4 years, the incidence of CV end points (CV death, nonfatal ischemic heart disease, and nonfatal stroke) amounted to 233 cases. In proportional hazard models, adjusting for age, gender, smoking, and low-density lipoprotein cholesterol, and with IDF-HOMA-IR and IDF-MetSyn included in the same model, the relative risk of an end point was 1.67 (95% confidence interval [CI] 1.22 to 2.29) for IDF-HOMA-IR and 1.16 (95% CI 0.84 to 1.60) for IDF-MetSyn. The corresponding figures for NCEP-HOMA-IR and NCEP-MetSyn included in the same model were 1.49 (95% CI 1.07 to 2.07) and 1.56 (95% CI 1.12 to 2.17).
Conclusions: In this Danish study, both HOMA-IR and NCEP-MetSyn were independent predictors of incident CVD.
Although others had proposed similar concepts before 1988, the Reaven Banting lecture from that year, introducing the concept of syndrome X as a fundamental factor in the pathogenesis and clinical course of what are often referred to as the diseases of Western civilization–type 2 diabetes, hypertension, and atherosclerotic cardiovascular disease (CVD)–received much attention. Reaven's syndrome X originally consisted of resistance to insulin-stimulated glucose uptake, hyperinsulinemia, hyperglycemia, an increased concentration of very-low-density lipoprotein triglyceride, a decreased concentration of high-density lipoprotein cholesterol (HDL-C), and high blood pressure. Reaven proposed that insulin resistance (IR) with compensatory hyperinsulinemia was the culprit in syndrome X.
Reaven's work inspired much research interest in the area. Reaven did not offer specific criteria for having syndrome X, and he did not include obesity or visceral obesity as a criterion. Later, others, including leading organizations and associations working in primary and secondary prevention of CVD, added measures of visceral obesity and offered specific criteria to define the metabolic syndrome (MetSyn). Recently, however, the importance of the MetSyn as a risk factor of CVD and the role of IR as a cause of the MetSyn has become an issue for discussion.
The purpose of the present study was to present an analysis of data from a large Danish population-based study dealing with some of the latest issues regarding the MetSyn and risk of CVD. We were particularly interested in clarifying if IR would predict incident CVD independent of the MetSyn, and how 2 different definitions of the MetSyn would affect the risk of CVD associated with the MetSyn and IR. We used the homeostasis model assessment (HOMA) to assess IR, and we defined the MetSyn according to both the International Diabetes Foundation (IDF) criteria and the National Cholesterol Education Program (NCEP) criteria.
Abstract and Introduction
Abstract
Objectives: The goal was to clarify if insulin resistance (IR) would predict cardiovascular disease (CVD) independent of the metabolic syndrome (MetSyn).
Background: Although the cause of MetSyn is not well defined, IR has been proposed to be an important cause. Only a small number of population-based studies have sought to clarify if IR predicts CVD independent of MetSyn.
Methods: This was a prospective Danish population-based study of 2,493 men and women, age 41 to 72 years, without major CVD at baseline. We defined MetSyn according to both the International Diabetes Foundation (IDF) and the National Cholesterol Education Program (NCEP) criteria, and we quantified IR by the homeostasis model assessment (HOMA-IR). Prevalence of MetSyn was 21% according to IDF criteria and 16% according to NCEP criteria. Accordingly, we defined IDF-HOMA-IR as belonging to the highest 21% of the HOMA-IR distribution, and NCEP-HOMA-IR as belonging to the highest 16% of the HOMA-IR distribution.
Results: Over a median follow-up of 9.4 years, the incidence of CV end points (CV death, nonfatal ischemic heart disease, and nonfatal stroke) amounted to 233 cases. In proportional hazard models, adjusting for age, gender, smoking, and low-density lipoprotein cholesterol, and with IDF-HOMA-IR and IDF-MetSyn included in the same model, the relative risk of an end point was 1.67 (95% confidence interval [CI] 1.22 to 2.29) for IDF-HOMA-IR and 1.16 (95% CI 0.84 to 1.60) for IDF-MetSyn. The corresponding figures for NCEP-HOMA-IR and NCEP-MetSyn included in the same model were 1.49 (95% CI 1.07 to 2.07) and 1.56 (95% CI 1.12 to 2.17).
Conclusions: In this Danish study, both HOMA-IR and NCEP-MetSyn were independent predictors of incident CVD.
Introduction
Although others had proposed similar concepts before 1988, the Reaven Banting lecture from that year, introducing the concept of syndrome X as a fundamental factor in the pathogenesis and clinical course of what are often referred to as the diseases of Western civilization–type 2 diabetes, hypertension, and atherosclerotic cardiovascular disease (CVD)–received much attention. Reaven's syndrome X originally consisted of resistance to insulin-stimulated glucose uptake, hyperinsulinemia, hyperglycemia, an increased concentration of very-low-density lipoprotein triglyceride, a decreased concentration of high-density lipoprotein cholesterol (HDL-C), and high blood pressure. Reaven proposed that insulin resistance (IR) with compensatory hyperinsulinemia was the culprit in syndrome X.
Reaven's work inspired much research interest in the area. Reaven did not offer specific criteria for having syndrome X, and he did not include obesity or visceral obesity as a criterion. Later, others, including leading organizations and associations working in primary and secondary prevention of CVD, added measures of visceral obesity and offered specific criteria to define the metabolic syndrome (MetSyn). Recently, however, the importance of the MetSyn as a risk factor of CVD and the role of IR as a cause of the MetSyn has become an issue for discussion.
The purpose of the present study was to present an analysis of data from a large Danish population-based study dealing with some of the latest issues regarding the MetSyn and risk of CVD. We were particularly interested in clarifying if IR would predict incident CVD independent of the MetSyn, and how 2 different definitions of the MetSyn would affect the risk of CVD associated with the MetSyn and IR. We used the homeostasis model assessment (HOMA) to assess IR, and we defined the MetSyn according to both the International Diabetes Foundation (IDF) criteria and the National Cholesterol Education Program (NCEP) criteria.
Source...