Activity Levels, Myosteatosis and Insulin Resistance/Diabetes Mellitus

ABSTRACT
Myosteatosis is a measure of body composition, which measures the presence and degree of fatty infiltration
into the muscle compartment to include deposition around the muscle fibers/bundles, as well as into the
muscle tissue itself. Our work on this measure of ectopic fat has shown myosteatosis to be strongly and
significantly associated with measures of glucose regulation, independent of visceral and hepatic adiposity.
Given the strong links between the glucose dysregulation (i.e. metabolic syndrome and/or diabetes mellitus)
and arterial stiffness, as well as left ventricular structure and function, we believe the study of myosteatosis
may be particularly relevant as a determinant of heart failure. Compared to non-Hispanic Whites,
Hispanic/Latino Americans have significantly higher rates of obesity, cardiometabolic risk factors and type 2
diabetes mellitus (T2DM), resulting in an increased risk for heart failure. To assess the risk factors for different
chronic diseases in this burgeoning population, the NIH commissioned the Hispanic Communities Health
Study – Study of Latinos (HCHS-SOL). In 2007, this study began recruitment at four different field centers
and enrolled over 16,000 Hispanic/Latino Americans from diverse background heritage groups. The HCHS-
SOL has now completed two clinic visits and is scheduled to begin enrollment for visit 3 in December 2019. At
this visit, the study will update the medical history, obtain fasting blood samples that will be used to measure
glucose, insulin and hemoglobin A1C, and will acquire a 2-hour glucose tolerance test. Additionally, the study
will conduct the following assessments on the returning participants: 1) objectively measured physical activity
and sedentary behavior; 2) peripheral arterial disease by the ankle and toe brachial indices, as well as Doppler
waveforms and pulse volume recordings; 3) arterial stiffness by carotid femoral pulse wave velocity and 4)
cardiac structure and function by magnetic resonance imaging. This ensemble of measurements can be utilized
to assess the pathway from physical activity/sedentary behavior to body composition to cardiometabolic risk to
arterial stiffness to cardiac structure and function. Given this, we propose to leverage the existing HCHS-SOL
infrastructure and add the acquisition of new computed tomography scans of the abdomen and mid-thigh to
obtain measurements of myosteatosis and skeletal muscle mass, as well as subcutaneous, visceral and hepatic
adiposity. The goal of this project is to determine the applicability of myosteatosis to the aforementioned
pathway among Hispanic/Latino Americans from diverse background heritages, independent of other
measures of body composition.

Grant Number: 5R01HL152790-04
NIH Institute/Center: NIH
Principal Investigator: Matthew Allison