Body fat levels in the normal weight metabolically obese phenotype: A cross-sectional analysis of the Peruvian population

Introduction: The relationship between body composition and the metabolically obese, normal weight phenotype (MONW), characterized by metabolic issues in individuals with a normal BMI, is still not well understood. Although BMI is widely used to assess the impact of overweight and obesity on metabolic health, it has limitations in distinguishing between fat and lean mass. The aim of this study was to analyze the association between estimated body fat percentage (%BF) using skinfold thickness and the diagnosis of MONW in the Peruvian population. Methodology: This cross-sectional analytical study used data from the PERU MIGRANT cohort. Participants with a BMI between 18.5 and 24.9 kg/m² with no history of diabetes or hypertension were included. MONW was defined as having ≥2 cardiometabolic risk factors. The optimal cut-off point for %BF was determined using ROC curves and the area under the curve with 95% confidence intervals (CI), stratified by sex, and using the Youden index. A generalized linear model with a log link and Poisson family was used for regression analysis, obtaining crude and adjusted prevalence ratios (PRc and PRa) with 95%CI. Results: A total of 321 participants were included in the study. 54.52% were women, and 9.66% were ≥60 years old. The prevalence of MONW was 32.09% and varied significantly by sex, age group, and %BF. The optimal %BF cutoff points for MONW were 20.70% in men and 32.45% in women. Multiple regression analysis revealed that a high %BF significantly increased the PR by 3.09 (95%CI: 2.04-4.67) times after adjusting for covariates. Conclusions: This study confirms the relationship between the estimated %BF using skinfold thickness and the diagnosis of MONW. It underscores the importance of comprehensively assessing body composition, even in lean individuals, to effectively prevent associated metabolic alterations.