Upper body subcutaneous fat tied to adverse cardiometabolic risk factors
A cross-sectional association exists between higher upper body subcutaneous fat and adverse cardiometabolic risk factors, and this association is independent of body mass index (BMI), neck circumference and abdominal fat, a community-based epidemiologic cohort study suggests.
“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,” researchers said.
A total of 2,306 participants (mean age 60 years; 54.4 percent women) were included in the study. Their mean upper body subcutaneous fat was 309.9 cm3 in women and 345.6 cm3 in men.
Higher upper body subcutaneous fat volume correlated with adverse levels of cardiometabolic risk factors. Each additional 50-cm3 increment in upper body subcutaneous fat in men and women 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 (p≤0.008 for all). [Am J Med 2017;130:958–966.e1]
Patterns were comparable with prevalent cardiometabolic risk factors. After additional adjustment for BMI, neck circumference and abdominal visceral adipose tissue, such associations remained significant.
“Although cross-sectional, our findings suggest that upper body subcutaneous fat may have a substantial effect on cardiometabolic risk factors, independent of a number of crucial confounders, anthropometric measures of adiposity and abdominal visceral adipose tissue,” researchers said.
Neck circumferences served as a surrogate anthropometric measure of subcutaneous fat in the upper body in earlier studies, which identified associations between neck circumference and multiple cardiometabolic risk factors such as diabetes, hypertension, insulin resistance and metabolic syndrome. [J Clin Endocrinol Metab 2010;95:3701–3710; Obes Res 2003;11:226–231; Clin Endocrinol 2013;78:874–881; Cardiovasc Diabetol 2013;12:76–82]
“Our prior work has shown that a higher neck circumference is associated with more adverse cardiometabolic risk factors and a higher burden of subclinical atherosclerosis, even after taking into account traditional risk factors and generalized adiposity,” researchers said. [J Clin Endocrinol Metab 2010;95:3701–3710; Diabetes Care 2013;36:e153–e154]
“However, we have shown in this current study that neck circumference correlated only mildly with upper body subcutaneous fat, suggesting that neck circumference is merely a proxy of upper body fat and is not a sufficient measure to explore the pathogenic role of fat in the upper body region,” they added.
In this study, the authors recruited patients from the Framingham Heart Study who underwent multidetector computed tomography (MDCT) between 2008 and 2011, and conducted sex-specific multivariable-adjusted regression analyses. Included covariates were age, ethnicity, smoking status, alcohol intake, physical activity, postmenopausal status and hormone replacement therapy, and additional models adjusted for BMI, neck circumference or abdominal visceral adipose tissue.
“Our study is the first to use upper body subcutaneous fat volume assessed by MDCT; thus, confirmation of our findings is warranted in other population-based studies,” researchers said. “Exploring the relationship between upper body subcutaneous fat and various markers of inflammation, oxidation, fibrosis and hypoxia may help in the understanding of the pathophysiology of upper body subcutaneous fat.” [Best Pract Res Clin Endocrinol Metab 2013;27:163–177]