Recent Results

Physical Performance, Muscle Mass and Quality of Life

At their baseline clinic visit, participants completed several physical performance exams, along with questionnaires about pain levels and quality of life. Participants also took a deuterated creatine pill and provided urine samples from which we are able to determine an accurate measure of skeletal muscle mass (See “Muscle Mass: section below for a description of the D3Cr measure). SOMMA scientists used this data to better understand how different quality of life factors are related to physical performance. SOMMA scientists found:

• Participants who reported having some difficulties walking around had lower muscle mass and worse performance on various physical function tests, such as chair stands and the 400-meter walk.

• Participants who reported greater pain and discomfort performed worse on physical function tests, such as grip strength and walking tests.

• Participants who reported higher levels of depression and anxiety had worse performance on the stair climb and chair stands tests.

Muscle Mass

One novel method for measuring muscle mass is d3-creatine (D3Cr) dilution. Participants took a natural, non-toxic pill called deuterated creatine and provided a urine sample. Using this, we can determine an accurate measure of skeletal muscle mass. With SOMMA data, scientists have found:

• Higher muscle mass = stronger grip strength

• Higher muscle mass = faster walking speed (taking into account body size)

• Measuring muscle mass by D3Cr is comparable to measuring with Magnetic Resonance Imaging (MRI).

Mitochondrial Function

During the initial visit, participants had muscle tissue sampled from their thigh. Using data from the muscle tissue sampling, the treadmill test, and Magnetic Resonance, scientists have explored the relationship between mitochondrial function and physical fitness. Mitochondria are the parts of cells that produce energy molecules. Our goal is to understand what factors explain the variability in mitochondrial function and VO2 peak (fitness measured by treadmill test).

• The scientists found that better mitochondrial function = stronger leg power and higher VO2 peak.

Physical & Cognitive Function

Participants completed a number of physical function tests, such as walking a certain distance or doing the four-square step test. They also completed multiple cognitive tests, including a test in which they replaced certain digits (numbers) with symbols, also known as the Digit Symbol Substitution Test. From a study of the relationship between cognitive and physical function, researchers found:

• Physical function measured by the four-square step test is a better predictor of cognitive function than other physical function tests.

• Cognitive function measured by the Digit Symbol Substitution Test is a better predictor of physical function than other cognitive tests.

• These data suggests there is an underlying factor that determines how quickly people naturally do a number of physical and thinking tasks.

Other Interesting SOMMA Findings:

• The relationship between visual function and physical performance in the Study of Muscle, Mobility and Aging (SOMMA)

• The association between chrononutrition behaviors and muscle health among older adults: The study of muscle, mobility and aging

• Childhood adverse life events and skeletal muscle mitochondrial function