Metabolically Healthy but Obese Women Have an Intermediate Cardiovascular Risk Profile Between Healthy Nonobese Women and Obese Insulin-Resistant Women

Abstract

Obesity is associated with metabolic and cardiovascular risk factors that include type 2 diabetes, hypertension, and dyslipidemia (1–4). A subset of obese subjects has been identified that appears to be protected from obesity-related metabolic abnormalities (5–11). These subjects, termed metabolically healthy but obese (MHO), are relatively insulin sensitive and have a rather favorable cardiovascular risk profile (5–11). Although the existence of MHO individuals has been recognized, only a few studies have examined in detail the metabolic characteristics associated with their protective profile (5–13). Whereas MHO individuals appear to have a more favorable cardiovascular risk profile than insulin-resistant obese (IRO) individuals, they show early signs of atherosclerosis compared with lean subjects, which could not be explained by alterations in cardiovascular risk factors (12). Among the factors that may account for the early atherosclerosis, insulin-like growth factor (IGF)-1 is a plausible candidate because low plasma IGF-1 concentrations are associated with type 2 diabetes, insulin resistance (14–16), and increased risk of coronary artery disease (17–22). To further characterize the protective profile of MHO individuals, we compared clinical characteristics, including cardiovascular risk factors, plasma IGF-1 levels, and intima-media thickness (IMT) of the common carotid artery, of a group of MHO women from a cohort of nondiabetic Italian Caucasians with those of two age-matched groups comprising healthy nonobese or …