A new study published in Diabetes Care finds that bone loss alone does not explain the increased fracture risk observed in some older adults with type 2 diabetes.

The article, "Type 2 Diabetes and Longitudinal Changes in Cortical and Trabecular Bone Density, Microarchitecture, and Strength: The Framingham Study," sought to better understand why people with type 2 diabetes are at greater risk of fractures.

Researchers from Trinity College Dublin and St. James’s Hospital have shown that dexamethasone, a commonly prescribed anti-inflammatory steroid, can reduce harmful inflammation triggered by Mycobacterium avium without weakening the ability of human immune cells to control the infection. The findings suggest dexamethasone may thus offer a new adjuvant approach for better managing nontuberculous mycobacterial (NTM) disease. 

NTM infections present a growing global health challenge, particularly among people with chronic lung disease. Treatment often requires prolonged courses of multiple antibiotics, yet many patients continue to experience symptoms driven by persistent inflammation. Steroids are not routinely used in NTM disease because clinicians have traditionally been cautious about suppressing T cell immune responses during infection.

Here, the research team, based in the Trinity Translational Medicine Institute, investigated how human macrophages, specialised immune cells that act as a first line of defence against infection, respond to Mycobacterium avium. 

They found that treatment with dexamethasone significantly reduced infection-driven macrophage metabolic activity while also lowering the production of inflammatory signals. Importantly, the steroid reduced the inflammatory response but did not increase bacterial growth within these key immune cells.