The health of the thymus gland, long considered to have limited function in adults, appears to play a significant role in long-term health, influencing the risk of cardiovascular disease, cancer, and even the effectiveness of cancer immunotherapy. This discovery challenges previous assumptions about the organ’s role beyond childhood and offers new avenues for understanding and potentially improving health outcomes.
Thymus Health Varies and Impacts Disease Risk
Researchers have found that the size, shape, and composition of the thymus gland vary considerably among adults, and these differences are linked to health outcomes. Using CT scans, they developed a “thymus health index” to assess the organ’s condition, revealing that the rate of thymus decline is individual and influenced by factors like age, weight, and smoking status. Women, on average, experience a slower degeneration of the thymus compared to men.
A study analyzing data from over 27,500 participants over a period of more than twelve years demonstrated a clear connection between thymus health and disease risk. Individuals with a healthier thymus had a 63 percent lower risk of cardiovascular disease and a 35 percent reduced risk of lung cancer. Overall mortality from these and other diseases was as well lower in those with better thymus health – 13.4 percent compared to 25.5 percent in those with poorer thymus function.
“These associations were consistent across all analyses and remained significant even when accounting for age and other potential influencing factors,” the research team reported.
Thymus Health May Predict Immunotherapy Response
The condition of the thymus may also influence how well patients respond to cancer treatment. A second study, involving nearly 3,500 cancer patients – including 1,200 with lung cancer – suggests a link between thymus health and the effectiveness of immunotherapy using checkpoint inhibitors.
Patients with a healthier thymus experienced a 37 percent lower risk of tumor progression and a 44 percent reduced risk of death from cancer when undergoing immunotherapy. This effect was particularly pronounced in certain types of lung cancer and melanoma, where the CT scans of the thymus could potentially predict the success of immunotherapy.
“These findings identify thymus health as a previously unrecognized factor influencing immunotherapy,” researchers stated. Further analysis of T-cells and immune signaling pathways revealed that patients with a healthier thymus had greater receptor diversity on their T-cells and more active signaling pathways.
How the thymus influences our health.© Mass General Brigham
Lifestyle Factors and Thymus Function
These results collectively emphasize the importance of the thymus for overall health, even in adulthood. The organ appears to continue functioning and influencing the immune system well into later life. “The thymus could explain why some people are more susceptible to certain diseases, why this increases with age, and why cancer therapies don’t work for some patients,” said Hugo Aerts, co-author from Mass General Brigham.
Notably, the rate of thymus decline appears to be linked to lifestyle. CT scans showed that the thymus shrank more rapidly in smokers, individuals with obesity, and those with elevated cholesterol levels, suggesting that lifestyle choices can influence how long the thymus remains active. The findings, published on March 20, 2026, in Nature and Nature, could have implications for preventative health strategies.
Source: Nature, Mass General Brigham
20. März 2026 – Nadja Podbregar
