Assessing Abdominal Visceral to Subcutaneous Adiposity in a Rural and Remote Population in the Riverina: A Comparative Analysis of Metabolic and Cardiovascular Risk Markers

Mina Girgis, Juliet Chan, Prof Joseph Suttie

Introduction:

Cardiovascular disease (CVD) is a significant cause of mortality and morbidity globally. However, rural populations experience a higher burden of CVD due to many factors, including limited healthcare access and unique risk profiles. It has recently been shown that the ratio of abdominal visceral to subcutaneous fat (VF/SF ratio) may provide a superior predictive value for CVD and metabolic dysfunction when compared to more traditional metrics like BMI. This study will examine the association between the VF/SF ratio and conventional CVD risk factors and the relationship between the VF/SF ratio and clinical endpoints such as mortality and major adverse cardiac events (MACE) in the rural population of the Riverina.

Objectives:

This study will quantify the volume of abdominal visceral and subcutaneous adipose tissue using CT imaging in a rural population and subsequently calculate VF/SF ratios. This study will also determine the relationship between the VF/SF ratio and conventional cardiovascular risk factors (including age, smoking status, diabetes, hypertension, BMI, dyslipidaemia and rurality). Furthermore, this study will determine the predictive power of the VF/SF ratio in relation to CT angiography findings and coronary CT calcium scores. Finally, this study will examine the relationship between the VF/SF ratio and clinical endpoints such as MACE and mortality.

Methodology:

A retrospective, observational study will be undertaken in the Riverina, reviewing patients from 2013 to 2023 of ages 30-90 years old with intermediate Framingham risk factors. Visceral and subcutaneous abdominal adipose tissue volumes will be measured from CT imaging data, and subsequently, VF/SF ratios will be calculated from these values. Cardiovascular imaging (coronary CT calcium scoring and CT angiography) quantifying atherosclerotic burden and assessing the severity of coronary artery disease will be collected, as well as clinical and anthropometric data (age, sex, BMI, waist circumference, rurality, medical history), lifestyle factors (including smoking status, dietary habits, physical activity levels), biochemical markers (HbA1c, lipid profile, IL-6, CRP) and clinical outcomes (mortality and MACE). Following this, correlation analysis will be conducted between VF/SF ratio and conventional risk factors, multivariate regression modelling will be conducted to assess the independent predictive value of the VF/SF ratio and survival analysis (Kaplan-Meier analysis) will be conducted for mortality and MACE.

Expected results and significance:

We hypothesise that the VF/SF ratio will be a stronger predictor of CVD than more traditional anthropometric markers like BMI. If validated, the VF/SF ratio could be used as a reliable and early metabolic risk indicator, allowing for earlier intervention in rural populations. Furthermore, findings from this study could lead to the future utilisation of abdominal adiposity assessment in cardiovascular risk assessment, which would allow for better identification of high-risk individuals.

Conclusion:

This study aims to provide insight into the association between the distribution of abdominal adipose tissue and CVD in a rural setting. Due to the unique health challenges faced by rural communities, assessing the VF/SF ratio alongside other risk factors could improve patient outcomes and patient risk prediction. If the VF/SF ratio is validated as a superior marker, its routine incorporation into cardiovascular risk assessment could lead to more proactive and targeted healthcare intervention.