Adults with more preserved thymic tissue on CT had lower cardiovascular mortality in two cohorts, giving thymic-rejuvenation research a sharper outcome to test.
The thymus trains developing T cells, then typically shrinks and becomes fatty with age, a process called thymic involution. Its appearance in adulthood may preserve information about aging in both the immune system and the body more broadly.
Researchers trained an imaging model to estimate preserved, non-fatty thymic tissue from chest CT scans, then tested whether the score tracked health outcomes in a lung-screening cohort and the Framingham Heart Study.
- Adults with the most preserved thymic tissue had lower cardiovascular mortality in both cohorts. In the lung-screening cohort, 12-year cardiovascular mortality was 2.9% in the highest score quartile versus 7.5% in the lowest; in Framingham, it was 0.3% versus 3.9%.
- Higher scores also tracked lower all-cause mortality and lung cancer incidence in the lung-screening cohort, but the all-cause association was no longer significant after full adjustment in Framingham.
The score measured thymic appearance—not T-cell output or immune function—and its quartiles were relative to each cohort rather than universal clinical cutoffs. The analysis cannot show whether preserving thymic tissue improves health or whether healthier people simply retain more of it. Smoking, body weight, physical activity, and inflammation tracked with the score, but the study did not test whether changing those factors restores the thymus.
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That immune-aging context is discussed in Rhonda's episode on exercise and immune aging. Here, the replicated cardiovascular signal suggests that thymic appearance may be a visible marker of systemic aging, giving thymic-rejuvenation research a sharper outcome to test.
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