The Association Between Subcutaneous Fat Density and the Propensity to Store Fat Viscerally

Background: Alterations in the cellular characteristics of subcutaneous adipose tissue (SAT) may reduce its ability to expand in times of caloric excess, increasing the propensity to store excess calories viscerally (visceral adipose tissue [VAT]). We hypothesized (1) that increased SAT density, an indirect marker of fat quality, would be associated with an increased VAT/SAT ratio and increased cardiovascular disease (CVD) risk and (2) that these associations would be independent of the absolute volume of SAT. Methods: We investigated the association of SAT density with the VAT/SAT ratio and CVD risk in 3212 participants (48% women, mean age, 50.7 years) from the Framingham Heart Study. Adipose tissue depot density and volume were quantified by computed tomography; traditional CVD risk factors were quantified. Results: Higher SAT density was correlated with a higher VAT/SAT ratio in men (r = 0.17; P < .0001) but not in women (r = 0.04; P ≥ .05). More adverse levels of CVD risk factors were observed in the high SAT density/high VAT/SAT ratio group than in the referent group (low density/low ratio). For example, women had an increased risk of diabetes (odds ratio [OR], 6.7; 95% confidence interval [CI], 2.6–17.6; P = .0001) and hypertension (OR, 1.6; 95% CI, 1.1–2.4; P = .009). Additional adjustment for SAT volume generally strengthened these associations (diabetes OR, 10.8; 95% CI, 4.1–29.0; hypertension OR, 2.5; 95% CI, 1.7–3.7; all P < .0001). These trends were similar but generally weaker in men. Conclusion: High fat density, an indirect marker of fat quality, is associated with the propensity to store fat viscerally vs subcutaneously and is jointly characterized by an increased burden of CVD risk factors.