A significant barrier to the classification of altered body composition and patterns in patients with lipoatrophy and/or abnormal fat deposition has been the lack of a clear definition of these syndromes and a simple means to diagnose this problem in patients.  With altered body dimensions as the most striking feature, it makes sense to look to currently employed anthropometric measurements to diagnose and classify these changes. 

Anthropometry to Predict Altered Fat Deposition

Anthropometric measures can be used to characterize a person’s body dimensions compared to a “normal” or against a personal baseline.  In addition to height, weight, frame size, and quantification of body compartments, several circumferences and fatfolds will help to determine patterns of body compartment loss and gain. 

At this year’s International Conference on AIDS, three posters discussed efforts to validate currently standardized anthropometry to characterize and identify altered central fat deposition in HIV+ patients.  In one study 73 patients (43 men and 30 women) were measured by anthropometry, bioelectrical impedance analysis (BIA), dual energy x-ray absorptiometry (DEXA), and computed tomography (CT) in addition to a physical examination and patient survey to identify measures with specificity and sensitivity to altered fat deposition.[i]   Waist-to-hip ratio alone was not sensitive or specific to differentiating patients with altered fat versus those without altered fat.  However, the measured difference became statistically significant once the groups were differentiated by other tests. 

The criterion method for determining visceral versus subcutaneous fat volume is magnetic resonance imaging (MRI).  This method was compared to anthropometric pre- and post-trial measures in 48 HIV+ patients and 7 hypocalorically fed controls during their involvement in studies of protein supplementation, exercise therapy, and growth hormone therapy.[ii]  Simple and multiple regression evaluation was performed with changes in visceral (VAT) and subcutaneous (SAT) adipose tissue along with weight change, body mass index, waist circumference, waist-to-hip ratio, sex, and abdominal fatfold.  Waist circumference changes were the best predictors of VAT in simple regression evaluation and sex was the best predictor in multiple regression evaluation.  Sex and waist circumference changes improved the model to predict VAT.  Abdominal fatfold was the best predictor of SAT change with an improvement in the model when body weight change was added.  This study suggested that simple anthropometric measures might help to identify changes in visceral and subcutaneous fat with abdominal fat deposition.

A study of 43 men and 13 women conducted in England suggested that standard measures of arm and thigh circumference, waist-to-hip ratios, and four-site fatfolds (triceps, biceps, subscapular, and suprailiac) were not predictive of altered fat deposition including lipoatrophy.[i]  None of the standard measures were different between the groups with (n=18) or without (n=38) altered fat deposition as diagnosed on physical examination by clinicians.  The authors’ conclusions suggested a need for “alternate standardized clinical anthropometric approaches” to provide a means of “simple monitoring of prevalence, severity and progression” of changes in fat deposition.   

Following are recommended anthropometric measures with additional proposed alternate anthropometric approaches* to characterizing body patterns we have developed for use by dietitians.[ii]  Figure 1 discusses methodology.  These measures have been proposed to clinicians and researchers who have the means to validate such measures with the hope that we will be able to adequately identify and characterize the physical alterations we see in many of our long-term surviving HIV+ patients.

Proposed Complementary Anthropometric Approaches

Dimensions: Back, * ridge, * knob, * midarm circumference, abdominal circumference (at rest, sucked in, * and pushed out*), chest circumference, * breast circumference, * thigh circumference, calf circumference

Upper body fatfolds: triceps, biceps, subscapular, suprailiac, abdominal,* sides at umbilical

level, * back at umbilical level. *

Lower body fatfolds: thigh

Figure 1. Methodology for Complementary Body Measures

Back:  have the person stand or sit up straight with arms relaxed at side.  Take the length measure from edge to edge of the acromion process. àFrom the right and left sides, palpate toward the center of the back at the level measured to determine the existence of a ridge (sometimes firm and sometimes spongy) that should be differentiated from muscle ridges.  Measure width of ridge. àFrom the center of the back about mid-scapula, and from bottom of skull, palpate to detect ridge and measure height.

àFrom edges of ridge, palpate inward to determine the existence of a “knob” region.  If present, squeeze from sides deeply to determine edges and measure width and height.

Abdominal Area Measures: àMeasure abdominal circumference at the umbilical level to the nearest 1/10 cm.  This measure is typically about 2.5-3 cm below the waist. àMeasure abdominal fatfold about 2.5 cm to the person’s right of their belly button. àMeasure side fatfolds (ask the client to raise his/her arm to the side) at the mid-axilary line and at the level of the umbilicus.  Because people are sometimes asymmetrical take both the left and right side fatfold measures to the nearest mm. àMeasure the back fatfold about 2.5 cm to the right of the spinal column at the level of the umbilicus.

Figure 3.  Equations for Evaluation of Altered Fat Deposition Measures

** mm

Summary

            The definition, characterization, and identification of altered fat deposition in our HIV+ patients presents a new challenge to HIV-specialist dietetics professionals.  Standardizing methods will help us to discriminate between normal and abnormal fat gains and losses as well as help us to monitor therapies aimed at normalizing body composition and function in our patients.