Obesity Abstracts

Background: Not all obese individuals exhibit abnormal cardiometabolic parameters. These are termed as being metabolically healthy obese (MHO). Conversely some normal weight individuals exhibit adverse cardiometabolic parameters and are described as being metabolically unhealthy normal weight (MUHNW). Visceral adiposity is known to be strongly associated with cardiometabolic risk than subcutaneous adiposity. Furthermore, there are gender differences in distribution of fat and in the prevalence of overweight and obesity. This study explored gender differences in the prevalence of adiposity-metabolic health phenotypes (expressed as BMI and presence or absence of certain cardiometabolic parameters) in a nationally representative sample of Maltese subjects. We also investigated gender differences in anthropometric measures and cardiometabolic parameters and in the relationship between BMI categories and metabolic health.

Methods: This was a cross-sectional study. Median age was 41± 5 years. Subjects with a BMI <24.9 kg/m² were normal weight and subjects with BMI ≥25 kg/m² were overweight or obese. Metabolic health was defined as presence of ≤1 parameters of the metabolic syndrome as per NCEP ATPIII criteria and classified into one of the following body composition phenotypes: Metabolically healthy normal weight (MUHNW); metabolically unhealthy normal weight (MUHNW); Metabolically healthy overweight/obese (MHO); metabolically unhealthy obese (MUHO)

Results: A higher percentage of males exhibited the unhealthy metabolic phenotypes (41.3% vs 27.8%). 10.3% of normal weight men and 6.3% of normal weight women were metabolically unhealthy. Despite males having a higher median BMI, there was a lower proportion of males having an abnormally high waist circumference then females. Significant gender differences in biochemical and life-style parameters were noted for each body composition phenotype.

Discussion: Males were more likely to be insulin resistant and to exhibit a metabolically unhealthy profile than females despite exhibiting an abnormal waist circumference less frequently and having similar waist index. This suggests that the currently used cut-off for waist circumference should be revised downwards in men. Normal weight men were more often metabolically unhealthy then normal weight women, thus, BMI cut-offs may also need to be lowered in men. The gender divergence between metabolic risk factors is consistent with gender differences in the pathogenesis of cardiovascular disease.