THE INSULIN-RESISTANCE SYNDROME (SYNDROME-X) AND RISK-FACTORS FOR CORONARY HEART-DISEASE - AN EPIDEMIOLOGIC OVERVIEW

Recent research has identified several risk factors for coronary heart disease that cluster with greater frequency than would be expected by chance. These risk factors include obesity and a centralized distribu tion of body fat, elevated blood pressure, dyslipidemia, and glucose i ntolerance. An underlying basis for this cluster appears to be disturb ances in insulin-mediated glucose homeostasis as reflected by hyperins ulinemia and/or a resistance to its actions. Whether hyperinsulinemia/ insulin resistance is a necessary and sufficient cause of these metabo lic derangements is uncertain. Many studies conducted in the United St ates and abroad among children, adolescents, and adults have reported hyperinsulinemia/insulin resistance to be associated with an adverse c oronary risk factor profile. Other studies, conducted primarily in old er or noncaucasian adults, have failed to note such relationships. In many in. stances, multivariate analyses of cross-sectional data design ed to address the primacy of insulin resistance in this cluster of ris k factors has introduced more confusion than it has resolved. Only pro spective studies, particularly those that intervene to ''perturb the s ystem,'' can adequately address these questions.