Comparison of the Body Roundness Index and A Body Shape Index With Body Fat and Visceral Fat in People Living With HIV.

A Body Shape Index

The ABSI is a measure of the body shape and the concentration of body volume. The ABSI is defined as the waist circumference (WC) divided by the body mass index (BMI) raised to two-thirds and by the square root of the person's height. WC will be measured just above the uppermost lateral border of the ilium at the end of a normal exhalation as recommended by NHANES guidelines. BMI will be calculated as Weight (kilograms) / Height (meters)2. Height will be measured using a standard stadiometer. With the participants without shoes. The measure will be taken with their back towards the stadiometer, buttocks touching the measurement surface, feet flat and externally rotated 60 degrees. The participants head will be aligned so that the horizontal line from the ear canal to the lower border of the orbit of the eye is parallel to the floor. The measure will be taken at the end of normal exhalation. Weight will be measured with the participant wearing minimal clothing and no shoes.

Body Roundness Index (BRI)

BRI is utilized to quantify the body shape of an individual using WC and height. WC will be measured just above the uppermost lateral border of the ilium at the end of a normal exhalation as recommended by NHANES guidelines. Height will be measured using a standard stadiometer. We will ask the participant to take off their shoes and stand with their back towards the stadiometer, with the buttocks touching the measurement surface at all times, feet flat and externally rotated approximately 60 degrees. Before taking the measurement we will align the participants head so that the horizontal line from the ear canal to the lower border of the orbit of the eye is parallel to the floor. The measure will be taken at the end of normal exhalation. Hip circumference will be measured at the widest part of the hip/buttocks area and will be added to increase the accuracy of the measure.

Visceral Adipose Tissue (VAT)

Visceral adipose tissue. VAT will be evaluated using the GE Logiq V2 ultrasound device. This measure will be used to evaluate the relationship between ABSI and BRI with VAT. The validity of ultrasound for measuring VAT has been established. The measurement will be taken using a 8 MHz abdominal probe transducer with the participant in supine position at the end of normal exhalation. Water based gel will be applied to the participants abdomen before the test. The transducer will be placed vertically against the skin in the saggital plane and pressed as lightly as possible to minimize the compression of the abdominal region. The distance between the posterior linea alba and the peritoneum immediately below, and 1 centimeter to the right of, the xiphoid process will be scanned. The measurement will be reported in centimeters.

Body fat (through bioelctrical impedance analysis; BIA)

Body fat will be measured using a Bioelectrical Impedance Analyzer (In body 770). The subject will stand on electrodes and grab a pair of electrodes. The test takes5 minutes and the analyzer is on for less than 1 minute. Body fat is calculated through the impedance or resistance of a low level electrical current passing through the body. Body fat percentage will be recorded.