Body Composition Testing

Ways to Monitor Wasting Syndrome and Lipodystrophy

HIV and the medications used to treat the virus affect the body in many ways. As people live longer, we are beginning to see some of the effects of long-term HIV medication use. The problem of lipodystrophy, the loss of fat from the arms and legs and subsequent gain in the abdomen and back of the neck has significantly impacted the body image of many HIV-infected people. Wasting syndrome, the excessive weight loss seen in advanced cases of HIV, is not only a threat to physical health but to body image and emotional health as well. In order to manage these two problems, their progress must be closely monitored. This can be done using Body Composition Testing. Let's look at what types of testing are used to monitor these problems and how these results can be beneficial to the patient.

What is Wasting Syndrome?

What is Lipodystrophy?

What is Body Composition?

The human body is made of water, fat, proteins, sugars, and various vitamins and minerals. Maintaining these substances in the proper ratios is essential for a healthy life. One component of particular importance is body fat. Too much fat places you at risk for diseases such diabetes, heart disease, and high blood pressure. Too little fat can indicate a serious health problem that needs to be addressed. Body composition testing can be used to monitor lipodystrophy and wasting. Two such tests are Body Mass Index (BMI) and Anthropometry.

What is Body Mass Index (BMI)?

Body mass index (BMI) is an indirect measurement of body composition. Specifically, BMI is a measure of comparison between your body's fat composition and that of established standards seen in the average healthy person. By knowing how your amount of body fat compares to the average healthy person, doctors can assess your risk for diabetes, heart disease, or hypertension. In the case of wasting syndrome, BMI allows your doctor to monitor body fat composition, providing additional information valuable in the assessment of excessive weight loss. If the BMI indicates body fat is below the established standards, the doctor can intervene in an effort to slow or reverse the loss.

Important Fact:
Under certain circumstances, BMI can be an inaccurate measurement of body fat. For instance, if a weight lifter and obese man have the same body weight and height, they will have the same BMI but their body composition will be different. Also, keep in mind that using BMI alone to diagnose wasting may result in missed diagnosis.

How is BMI Calculated?

BMI is a mathematical calculation that compares weight to height. BMI calculator programs are online but if you can't find one a pencil, paper, and calculator will do fine. To find your BMI, do the following calculations:

The BMI is equal to the body weight in kilograms divided by body height in meters squared (kg/m x m)

To find your weight in kilograms you divide your weight in pounds by 2.2 (lbs/2.2)

To find your height in meters divided your height in inches by 39.4 (inches/39.4)

Let's do a sample calculation:

A man 5 feet 6 inches tall weighs 185 pounds. His BMI is calculated in this manner:

His height equals 66 inches. Divide that by 39.4 and the result is 1.68 meters

His weight equals 185 pounds. Divide that by 2.2 and the result is 84.1 kilograms

His BMI equals 84.1kg divided by 1.68 squared (1.68 x 1.68) or a BMI of 29.8

But now that we have the BMI, in the case of our example a BMI of 29.8, what does that number mean?

What Does the BMI Result Mean?

The National Center for Health Statistics has conducted studies regarding BMI and has formulated these BMI levels and what they mean.

• BMI values less than 18.5 - considered underweight (as is the case in wasting syndrome).

• BMI of 18.5 to 24.9 - considered healthy and normal.

• A BMI of 25.0 to 29.9 - considered overweight. This range corresponds to about 10 percent over ideal body weight, meaning there is an increased risk of heart and blood vessel disease.

• A BMI of 30.0 to 40.0 - considered obese or approximately 30 pounds over ideal body weight. At this level, the risk of heart disease rises.

• A BMI of greater than 40 - considered extremely obese with a very high risk of heart disease, diabetes, and high blood pressure.

Nutrition Resources To Keep You Healthy

About.com's Nutrition Site

What is Anthropometry?

While it is the simplest body composition test, Anthropometry provides important information about those living with lipodystrophy. Anthropometry simply means "measuring the body". Simply put, anthropometry involves the measurement of arms, legs, and other body parts in an effort to detect body fat loss. Anthropometry is useful in the monitoring of lipodystrophy. There are three types:

• Extremity Measurement - By measuring the circumference of the arms and legs, the physician can monitor and measure the degree of fat redistribution seen in lipodystrophy.

• Skinfold Measurements - By using calipers (a specialized measuring tool) measurements can be taken from various skinfolds on the body. These measurements are compared to standards to gauge the degree of fat composition of the body. Depending where the skifold measurement is taken, people with lipodystrophy will have an alterred skin fold measurement.

• Waist to Hip Ratio - This ratio is calculated by dividing the hip circumference by your waist circumference at its narrowest point. A waist to hip ratio of less than 0.9 in men and less than 0.8 in women is considered normal and healthy. People with lipodystrophy will have increased waist circumference and therefore will have an alterred waist to hip ratio.

Body Composition Testing is useful in the monitoring and management of wasting and lipodystrophy in the HIV infected person. Maintaining a healthy weight and minimizing the effects of lipodystrophy are two steps in maintaining your health.

_Sources:

"Body Composition Testing - Fact Sheet No. 128"; New Mexico AIDS Infonet; 25 Jun 2007.

American Heart Association; "Body Composition Tests"; 2007.