Visceral adiposity and cardiometabolic health in Luxembourg

• Metabolic Diseases
• NutriHealth

Increased visceral adipose tissue as a risk factor of cardiometabolic conditions   

Looking at a sample of individuals representative of the Luxembourgish population, researchers from the LIH Department of Population Health (DoPH) showed that increased visceral adipose tissue (VAT), located inside the abdominal cavity between the organs, is strongly associated with an increased risk of developing cardiometabolic disorders. To study this relationship, the scientists used recently developed and validated anthropometric predictive models of VAT, which distinguished VAT from other forms of adipose tissue. Their findings were published in the April issue of the Nature Publishing Group journal “Scientific Reports”. 

Over the past 20 years there has been a significant global increase in the prevalence of cardiovascular (CVD) and metabolic conditions such as hypertension, type 2 diabetes, hypercholesterolemia, hypertriglyceridemia and metabolic syndrome, with nearly 30% of global deaths being linked specifically to CVD. Visceral adipose tissue accumulation, stored between the organs inside the abdominal cavity, has been recognised as a major independent risk factor for developing chronic conditions, although its accurate measurement remains challenging in the context of clinical or population-based studies. Indeed, commonly used parameters such as waist circumference and waist-to-hip circumference cannot effectively differentiate between VAT and subcutaneous abdominal adipose tissue (SAAT). Moreover, the gold standard measurement of VAT is mainly provided by biomedical imaging techniques (e.g., MRI and CT-scan), which limit its assessment due to high cost and low availability.

In order to provide up-to-date and more exhaustive insights into the cardiometabolic health status of the Luxembourgish population,  Dr Maria Ruiz‑Castell, from the Chronic Diseases & Environmental Epidemiology Custom Group at DoPH, and Co-Authors used recently developed and validated anthropometric predictive models of VAT by Dr Hanen Samouda  (NutriHealth, DoPH).

Dr Ruiz‑Castell and her colleagues  investigated whether anthropometrically predicted visceral adipose tissue was associated with hypertension, prediabetes and diabetes, as well as hypercholesterolemia and hypertriglyceridemia, after adjusting for socio-demographic and lifestyle patterns in a in a sample of 1,529 adults from the 2013-2015 European Health Examination Survey in Luxembourg (EHES-LUX).

The scientists observed an increased risk of all metabolic and cardiovascular disorders, such as hypertension, type 2 diabetes, hypercholesterolemia, hypertriglyceridemia and metabolic syndrome, associated with increasing VAT, in both men and women in Luxembourg (2013-2015), regardless of socioeconomic status and lifestyle characteristics. This association was strongest in men for hypertension, while women reported higher odds of developing combined prediabetes and diabetes, hypercholesterolemia and hypertriglyceridemia.

“Our findings confirm that VAT is a major independent predictor of cardiometabolic risk among the Luxembourgish population”, says Dr Ruiz-Castell, lead author of the publication. “Our results also show that, compared to a previous study carried out in 2007 in Luxembourg, there has been no significant reduction in cardiometabolic disorders over the last decade. On the contrary, the incidence of some conditions, such as diabetes and metabolic syndrome, even increased”, notes Dr Ruiz-Castell. This could explain why cardiovascular diseases were the leading cause of mortality in Luxembourg in 2016, accounting for almost 32% of deaths.

“The relationship between VAT and cardiometabolic conditions can be explained by factors such as the high metabolic activity of VAT and its pro-inflammatory effects. Moreover, compared to other fat deposits, VAT has larger and dysfunctional adipocytes, which have the tendency to store triglycerides and promote the synthesis and release of free fatty acids”, explains Dr Hanen Samouda, second author of the study.

Capable of distinguishing VAT from SAAT, these anthropometric models have also been validated as the most predictive markers of cardiometabolic conditions, cancer and all-cause and specific mortality among 10.000 participants followed over 20 years by the National Health and Nutrition Examination Survey , when biomedical imaging is not available, compared to waist circumference and body mass index.

“VAT predictive models should therefore be leveraged in future epidemiological studies in the absence of biomedical imaging measurements, in order to further explore the impact of VAT on health”, conclude Dr Ruiz-Castell and Dr Samouda.

The current burden of cardiovascular and metabolic conditions in Luxembourg calls for new public health initiatives specifically targeting VAT to improve population health.

The study involved various research groups from DoPH, namely the Chronic Diseases & Environmental Epidemiology Custom Group, the Nutrition and Health Research Group, the Competence Centre for Methodology and Statistics and the Deep Digital Phenotyping Research Unit and the Public Health Research unit, as well as the Schulich School of Medicine and Dentistry of the University of Western Ontario (Canada). It was financed by the Luxembourg National Research Fund through a Core Junior grant to Dr Ruiz-Castell, by the Directorate and Ministry of Health and by the Ministry of Higher Education and Research (MESR).