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Increased fat quantity and decreased fat attenuation can be linked to a worsening of cardiovascular disease (CVD) risk factors, according to research published in the Journal of the American College of Cardiology.
Drawing from the Framingham Heart Study, researchers from the Division of Intramural Research at the National Heart, Lung, and Blood Institute and the Division of Endocrinology at Brigham and Women’s Hospital and Harvard Medical School in Boston, and colleagues established a cohort of 1106 participants (44.1% women; mean baseline age: 45.1 years) to examine how changes in abdominal fat quality and quantity affect CVD risk factors.
After undergoing multidetector computed tomography (CT) scans, CVD risk factor profiles were analyzed for each participant, including body mass index (BMI); obesity was defined as BMI ≥30 kg/m2. Weight and height, waist circumference, smoking status, alcohol use, post-menopausal status, and use of hormone replacement therapy were also documented.
The researchers found that during 6.1 years of follow-up, weight, BMI, and waist circumference all increased (2.4 kg, 1.1 kg/m2, and 3.7 cm, respectively). Participants gained an average of 602 cm3 of subcutaneous adipose tissue (SAT) volume and 703 cm3 of visceral adipose tissue (VAT), with average fat attenuation decreasing by 5.5 Hounsfield units (HU) and increasing by 0.07 HU for SAT and VAT, respectively.
Additional increases in fat volume of 500 cm3 were associated with incident hypertension (odds ratio [OR]: 1.21 for SAT; OR: 1.30 for VAT), hypertriglyceridemia (OR: 1.15 for SAT; 1.56 for VAT), and metabolic syndrome (OR: 1.43 for SAT; OR: 1.82 for VAT; all P <.05). Associations remained significant after taking into account changes in BMI, waist circumference, and abdominal adipose tissue volumes. Longitudinal changes in abdominal fat value were also associated with adverse CVD risk factor profile changes over time (P ≤.0005).
Secondary analyses were performed to explore the links between incident CVD risk factors and both SAT and VAT volumes and attenuation change over time.
“We identified an interesting signal in our study results, in which several CVD risk factors, including hypercholesterolemia and low [high-density lipoprotein] cholesterol, were associated only with VAT volume change, but not with SAT volume change,” the researchers noted. “These findings correspond to the previous findings that higher VAT is detrimental, whereas higher SAT is protective of the cardiometabolic risk factors profile.”
“Further studies are warranted to elucidate the histologic mechanisms that lie underneath the associations between concomitant changes of abdominal fat volume and attenuation with incident CVD risk factor profiles,” they concluded.
Study Limitations
- One limitation includes the study design; observational studies limit causal inferences within findings.
- The sample included primarily white individuals, making it difficult to generalize results to individuals of other races or ethnic backgrounds.
Disclosures: Drs Pedley and Fox are employees of Merck & Company, Inc.
