Gluteus Maximus Shape Changes Reflect Aging and Metabolic Health, Study

A new study to be presented at the Radiological Society of North America (RSNA) meeting reveals that the shape of the gluteus maximus muscle in the buttocks changes differently with aging, lifestyle factors, frailty, osteoporosis, and type 2 diabetes, with distinct patterns observed between men and women. Utilizing 3D MRI mapping, the researchers created detailed anatomical models from a series of MRI images, advancing beyond prior studies that primarily focused on muscle size or fat content.

The gluteus maximus, one of the largest muscles in the body, plays a key role in metabolic health. The team, led by researchers at the University of Westminster, analyzed 61,290 MRI exams from the UK Biobank database, combining imaging with data on physical measurements, demographics, disease biomarkers, medical history, and lifestyle questionnaires. This allowed examination of 86 variables and their associations with muscle shape changes over time.

According to co-author Marjola Thanaj, higher physical fitness indicated by vigorous activity and stronger hand grip correlated with larger gluteus maximus shape, while aging, frailty, and prolonged sitting times were linked to muscle thinning. In participants with type 2 diabetes, men exhibited muscle shrinkage, whereas women displayed enlarged muscles, potentially due to fat infiltration within the muscle. Frailty also affected men and women differently, with men showing widespread muscle shrinkage and women experiencing more localized effects.

These findings indicate that men and women respond biologically differently to conditions such as type 2 diabetes. Changes in muscle shape, rather than size, may signal early signs of functional decline and metabolic issues related to insulin resistance, but further research is necessary to explore these sex-specific responses.

The study highlights the importance of assessing muscle morphology, not just size, to understand metabolic health and disease progression. The shape alterations in the gluteus maximus muscle could serve as markers for early metabolic compromise, especially in type 2 diabetes, underscoring the need for personalized approaches in diagnosis and treatment across genders.