Metabolically Healthy, but Obese Individuals and Associations with Echocardiographic Parameters and Inflammatory Biomarkers: Results from the CARLA Study

Abstract

Introduction

The research on heterogeneity among obese individuals has identified the metabolically healthy, but obese (MHO) phenotype as a distinct group that does not experience the typical cardiovascular-related diseases (CVD). It is unclear if this group differs with regard to preconditions for CVDs. Our aim was to assess differences in echocardiographic parameters and inflammatory biomarkers between MHO and metabolically healthy, normal weight individuals (MHNW).

Methods

The analyses used data from 1412 elderly participants from a German population-based cohort study (CARLA), which collected detailed information on demographic, biochemical, and echocardiographic variables. Participants were subdivided into four groups (MHNW, MHO, MUNW (metabolically unhealthy, normal weight) and MUO (metabolically unhealthy, obese)) based on BMI≥30 kg/m² (obese or normal weight) and presence of components of the metabolic syndrome. The clinical characteristics of the 4 groups were compared with ANOVA or Chi-Square test, in addition to two linear regression models for 16 echocardiographic parameters. The difference in inflammatory biomarkers (hsCRP, IL-6 and sTNF-RI) between the groups was examined with a multinomial logistic regression model.

Results

The MHO individuals were on average 64.2±8.4 years old, with a higher proportion of women (71.6%), low percentage of smokers, larger waist circumference (109.3±10.5 cm vs 89.1±10.8 cm, p<0.0001) and higher odds ratios for hsCRP, IL-6 and sTNF-RI compared to MHNW individuals. Linear regression models revealed greater left atrial (LA) diameter (2.73 (95% CI: 1.35–4.11) mm), LA volume (7.86 (95% CI: 2.88–12.83) mL), and left ventricular mass index (LVMI) (11.82 (95% CI: 4.43–19.22) g/m^1.7) in the MHO group compared to the MHNW group.

Conclusion

The MHO phenotype is associated with echocardiographic markers of cardiac remodeling (LA diameter, volume and LVMI) and higher odds ratios for inflammatory biomarkers.

Keywords:

• obesity phenotypes
• visceral adipose tissue
• cardiac remodeling
• inflammatory biomarkers

Acknowledgments

We are thankful to all participants, study nurses, clerical staff and medical professionals who made the CARLA study possible. The authors also wish to thank Jens Höpner and Sandra Steensels for helpful discussions during the preparation of the manuscript. We acknowledge the financial support of the Open Access Publication Fund of the Martin-Luther-University Halle-Wittenberg.

Disclosure

The Authors declare no conflicts of interest in this work.

Additional information

Funding

The CARLA study was supported by a grant from the German Research Foundation (DFG) as part of the Collaborative Research Project 598 “Heart failure in the elderly—cellular mechanisms and therapy” at the Medical Faculty of the Martin-Luther-University Halle-Wittenberg. Additional funding was obtained from the Wilhelm-Roux Programme of the Martin-Luther-University Halle-Wittenberg (FKZ 14/41, 16/19), the Ministry of Education and Cultural Affairs of Saxony-Anhalt (MKCARLA-MLU-2011), and the German Federal Employment Office.