Nonlinear Association between Obesity Severity and Left Ventricular Morphology: Impact of Adiposity Phenotypes on Cardiac Remodeling

INTRODUCTION: Obesity is a well-known risk factor for cardiac remodeling; however, there may not be a direct correlation between obesity severity and cardiac structure. Moreover, the role of adiposity phenotypes, reflecting fat distribution patterns, remains incompletely understood. This study aimed to evaluate the association between obesity severity, adiposity indices, and body composition phenotypes with left ventricular mass index (LVMI).
METHODS: Based on body mass index, 229 people were categorized as overweight, mild, moderate, or severely obese. Cardiac morphometry parameters were assessed using echocardiography. Body adiposity index (BAI), body roundness index (BRI), waist-to-height ratio (WHtR), body shape index, and waist-to-hip ratio (WHR) were among the adiposity indices that were computed. Using BRI- and BAI-based methods, participants were further divided into adiposity phenotypes (visceral, peripheral, mixed, and low-risk). Group comparisons were performed using the Kruskal––Wallis H test, and multivariable linear regression was conducted to identify independent predictors of LVMI.
RESULTS: LVMI differed significantly across obesity categories (p<0.001), demonstrating a non-linear pattern, with lower values observed in mild and moderate obesity compared to the overweight group, and a relative increase in severe obesity. Similar non-linear trends were observed across all adiposity indices (BAI, BRI, WHtR, WHR; all p<0.001). In multivariable analysis, age was independently associated with LVMI (β=0.004, p<0.001), whereas sex was not. Compared to the low-risk phenotype, only mixed obesity was independently associated with increased LVMI (β=0.064, p<0.001), while visceral and peripheral obesity alone were not significant predictors. The overall model was significant (adjusted R2=0.178, p<0.001).
DISCUSSION AND CONCLUSION: Obesity severity alone cannot adequately account for the non-linear association between obesity and cardiac remodeling. Compared with isolated fat distribution patterns, the adiposity phenotype – especially mixed obesity – seems to be a stronger predictor of elevated LVMI. These results emphasize how crucial it is to take phenotype-based classification and fat distribution into account when assessing cardiovascular risk.

Keywords: Left ventricular mass index, obesity severity, adiposity phenotype, cardiac remodeling, body fat distribution