Thymic involution and rising disease incidence with age.
Level 5 - mechanism / opinion, no new human data
Mechanism-based mathematical modeling using aggregate epidemiological data without new human clinical data
PubMed 29432166 · doi:10.1073/pnas.1714478115
What was done
Researchers developed a minimal mathematical model linking age-related disease incidence to thymic involution and declining T cell production, which declines exponentially in humans with an estimated half-life of approximately 16 years. Combining immunological and epidemiological datasets, they evaluated the model's ability to describe incidence data for infectious diseases and multiple cancer types compared to traditional somatic mutation power-law models with an equal number of fitting parameters.
What was found
The immune decline model outperformed the power-law mutation model in fitting cancer incidence across a wide spectrum of malignancies and provided fits for infectious disease incidence. Aside from the reported ~16-year half-life of T cell production, the abstract provides no specific numerical values, fit metrics, or error estimates.
Why it matters
The findings offer a mathematical framework suggesting that age-related decline in T cell production driven by thymic involution is a major factor in rising cancer and infectious disease incidence, challenging the assumption that cancer incidence curves reflect only somatic mutation accumulation.
Limits
The abstract reports no specific numerical fit statistics, sample sizes, or dataset sources. The study relies on mathematical modeling of aggregate population data and mechanistic reasoning rather than direct experimental or clinical measurement in individual patients.
Cited by
- supports Immune function declines significantly with aging, particularly in people in their 60s.