Summary: UT Southwestern researchers used MRI to uncover sex-specific fat distribution patterns in muscle and bone influenced by age and BMI, offering insights for personalized strategies to prevent age-related diseases.

Key Takeaways

  • Sex-Specific Fat Accumulation Trends: The study found that muscle fat infiltration (MFI) increases significantly with age in women but is more strongly tied to body weight in men, with women also having nearly double the subcutaneous fat thickness compared to men.
  • Link Between Muscle Fat and Bone Marrow: Researchers discovered a relationship between MFI and bone marrow area, suggesting that weakened bones may facilitate fat infiltration into muscles, increasing risks for musculoskeletal and metabolic disorders.
  • Potential for Dual-Targeted Therapies: The findings highlight opportunities to develop interventions addressing both muscle and bone health, offering personalized strategies to prevent and manage age-related conditions.

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Researchers at UT Southwestern Medical Center have identified sex-specific patterns of fat accumulation in muscle and bone, providing insights that could inform strategies for preventing and treating age-related diseases. Their study, published in Diagnostics, utilized advanced MRI to examine how fat infiltrates skeletal muscle, subcutaneous tissue, and bone marrow, uncovering key differences influenced by age and body mass index (BMI).

“Musculoskeletal disorders are the leading cause of disability in the U.S., with enormous impacts on quality of life and longevity,” says Jimin Ren, PhD, associate professor in the Advanced Imaging Research Center and of radiology at UT Southwestern. “This study identifies key contributors to muscle fat infiltration (MFI), a harmful process that can lead to muscle atrophy and dystrophy.”

The study analyzed MRI scans from 107 UT Southwestern patients, ranging in age from 11 to 79, and revealed distinct sex-specific trends. Among women, MFI increased significantly with age, while in men, it was more closely tied to body weight. Subcutaneous fat thickness was found to be nearly double in women compared to men (8.9 mm vs. 4.3 mm), increasing with age in women but decreasing in men, especially among nonobese individuals.

The research also highlighted a relationship between MFI and bone marrow area, suggesting that weakened bone structures may allow fat infiltration into surrounding muscles. These findings underline the importance of maintaining musculoskeletal strength to mitigate risks for falls, fractures, and metabolic disorders in aging populations.

“By linking fat infiltration within muscle to fat in the bone marrow, the study highlights a potential avenue for dual-targeted therapies that support both muscle and bone,” said lead author Talon Johnson, PhD.