Dysmetabolic signals in “metabolically healthy” obesity

Summary 

Background

Obesity is associated with decreased insulin sensitivity, atherogenic dyslipidemia and hypertension, but clinical studies have also identified a “metabolically healthy” obese phenotype.

Objective

To compare the characteristics of so-called “metabolically healthy” obese (MHO), normal weight subjects (MHNW) and obese with insulin resistance in the United States National Health and Nutrition Examination Survey, 1999-2004 (NHANES).

Design, setting and participants

Insulin resistance was defined by a homeostatic model assessment (HOMA) value in the upper tertile for the entire NHANES cohort. “Metabolic health” was defined as the absence of diabetes, insulin resistance, metabolic syndrome, and lipid-lowering therapy. The study evaluated the 314 MHO, 1173 MHNW and 843 insulin-resistant obese from among the 6485 non-diabetic, non-pregnant adults aged 20–79 years.

Main outcome measures

Demographic, metabolic, nutrition and physical activity features.

Results

MHO and MHNW groups were similar regarding age, and fasting glucose and triglyceride levels. MHO had higher insulin (P<0.0001), insulin resistance as measured with the homeostatic model (P<0.0001), non-HDL cholesterol (P=0.002 in females and P=0.049 in males) and C-reactive protein levels (P<0.0001 in females and P=0.038 in males), and lower high-density lipoprotein cholesterol (HDL) levels (P<0.002). In addition, MHO females had higher low-density lipoprotein (LDL) cholesterol levels (P=0.012) and systolic blood pressure (P=0.02), and lower intake of dietary fiber (P=0.0009) and levels of physical activity (P=0.002). Triglycerides levels were normal in the MHO group.

Conclusions

“Metabolically healthy” obese people have multiple dysmetabolic changes that may signal increased risk for coronary artery disease.

Keywords: Obesity, Metabolic Health, HDL-cholesterol, Non-HDL-choleserol, Coronary risk