Abstract Background Subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) are associated with adverse cardiometabolic risk profiles. Objectives This study explored the degree to which ...changes in abdominal fat quantity and quality are associated with changes in cardiovascular disease (CVD) risk factors. Methods Study participants (n = 1,106; 44.1% women; mean baseline age 45.1 years) were drawn from the Framingham Heart Study Third Generation cohort who participated in the computed tomography (CT) substudy Exams 1 and 2. Participants were followed for 6.1 years on average. Abdominal adipose tissue volume in cm3 and attenuation in Hounsfield units (HU) were determined by CT-acquired abdominal scans. Results The mean fat volume change was an increase of 602 cm3 for SAT and an increase of 703 cm3 for VAT; the mean fat attenuation change was a decrease of 5.5 HU for SAT and an increase of 0.07 HU for VAT. An increase in fat volume and decrease in fat attenuation were associated with adverse changes in CVD risk factors. An additional 500 cm3 increase in fat volume was associated with incident hypertension (odds ratio OR: 1.21 for SAT; OR: 1.30 for VAT), hypertriglyceridemia (OR: 1.15 for SAT; OR: 1.56 for VAT), and metabolic syndrome (OR: 1.43 for SAT; OR: 1.82 for VAT; all p < 0.05). Similar trends were observed for each additional 5 HU decrease in abdominal adipose tissue attenuation. Most associations remained significant even after further accounting for body mass index change, waist circumference change, or respective abdominal adipose tissue volumes. Conclusions Increasing accumulation of fat quantity and decreasing fat attenuation are associated with worsening of CVD risk factors beyond the associations with generalized adiposity, central adiposity, or respective adipose tissue volumes.
Objectives The aim of this study was to evaluate whether computed tomography (CT) attenuation, as a measure of fat quality, is associated with cardiometabolic risk factors above and beyond fat ...quantity. Background Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) are pathogenic fat depots associated with cardiometabolic risk. Adipose tissue attenuation in CT images is variable, similar to adipose tissue volume. However, whether the quality of abdominal fat attenuation is associated with cardiometabolic risk independent of the quantity is uncertain. Methods Participants were drawn from the Framingham Heart Study CT substudy. The VAT and SAT volumes were acquired by semiquantitative assessment. Fat quality was measured by CT attenuation and recorded as mean Hounsfield unit (HU) within each fat depot. Sex-specific linear and logistic multivariable regression models were used to assess the association between standard deviation (SD) decrease in HU and each risk factor. Results Lower CT attenuation of VAT and SAT was correlated with higher body mass index levels in both sexes. Risk factors were generally more adverse with decreasing HU values. For example, in women, per 1 SD decrease in VAT HU, the odds ratio (OR) was increased for hypertension (OR: 1.80), impaired fasting glucose (OR: 2.10), metabolic syndrome (OR: 3.65), and insulin resistance (OR: 3.36; all p < 0.0001). In models that further adjusted for VAT volume, impaired fasting glucose, metabolic syndrome, and insulin resistance remained significant. Trends were similar but less pronounced for SAT and for men. There was evidence of an interaction between HU and fat volume among both women and men. Conclusions Lower CT attenuation of VAT and SAT is associated with adverse cardiometabolic risk above and beyond total adipose tissue volume. Qualitative indices of abdominal fat depots may provide insight regarding cardiometabolic risk independent of fat quantity.
Abstract Background Upper body subcutaneous fat is a distinct fat depot that may confer increased cardiometabolic risk. We examined the cross-sectional associations between upper body subcutaneous ...fat volume and cardiometabolic risk factors. Methods Participants were patients from the Framingham Heart Study who underwent multi-detector computed tomography between 2008 and 2011. Sex-specific multivariable-adjusted regression analyses were conducted. Covariates included age, ethnicity, smoking status, alcohol intake, physical activity, postmenopausal status, and hormone replacement therapy. Additional models included adjustment for body mass index (BMI), neck circumference, or abdominal visceral adipose tissue. Results There were 2306 participants (mean age 60 years, 54.4% women) included. Mean upper body subcutaneous fat was 309.9 cm3 in women and 345.6 cm3 in men. Higher upper body subcutaneous fat volume was associated with adverse cardiometabolic risk factors. In women and men, each additional 50-cm3 increment in upper body subcutaneous fat was associated with a 3.23 and 2.65 kg/m2 increase in BMI; 2.16 and 0.88 mm Hg increase in systolic blood pressure; 2.53 and 1.66 mg/dL increase in fasting plasma glucose; 0.12 and 0.11 mg/dL increase in log triglycerides; and 4.17 and 3.68 mg/dL decrease in high-density lipoprotein cholesterol, respectively (all P ≤.008). Similar patterns were observed with prevalent cardiometabolic risk factors. These associations remained significant after additional adjustment for BMI, neck circumference, or abdominal visceral adipose tissue. Conclusions Higher upper body subcutaneous fat is cross-sectionally associated with adverse cardiometabolic risk factors. Our findings underscore the importance of subcutaneous adiposity in the upper body region that may provide a better understanding of the pathogenic properties of obesity in the development of cardiometabolic sequelae.
Arterial calcification is associated with cardiovascular morbidity and mortality. To improve the understanding of the pathogenesis involved with iliac artery calcium (IAC), we sought to examine the ...associations between the burden of IAC with adiposity measures and peripheral artery disease (PAD). Participants (n = 1,236, 52% women, mean age 60 years) were drawn from the Framingham Heart Study Offspring cohort who underwent multidetector computed tomography. The extent of IAC was quantified based on calcified atherosclerotic plaques detected in the iliac arteries. High IAC was defined based on gender-specific 90th percentile cut-off points from a healthy referent subsample. PAD is defined as an ankle-brachial index < 0.9, intermittent claudication, and/or history of lower extremity revascularization. The association between PAD and IAC was assessed using multivariable-adjusted logistic regression models. The burden of high IAC was 20.5% in women and 25.5% in men. High IAC was not associated with generalized (body mass index) or area-specific (waist circumference, and volumes of thoracic periaortic, abdominal subcutaneous, and visceral adipose tissue) adiposity measures (all p ≥0.22). High IAC was associated with increased odds of PAD (odds ratio 10.36, 95% confidence interval 4.28 to 25.09). This association persisted even after additionally adjusting for coronary artery calcium (odds ratio 11.25, 95% confidence interval 4.29 to 29.53). Burden of IAC was associated with an increased risk of PAD.
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