A study published in *Nature* used artificial intelligence to analyse CT scans and assess thymic health across 27,612 adults, finding that the condition of the thymus, a small organ long thought to lose importance after childhood, could help predict lifespan. Data came from the National Lung Screening Trial (25,031 participants) and the Framingham Heart Study (2,581 participants). Adults with higher thymic health had better survival rates than those with lower thymic health. In the National Lung Screening Trial, people with high thymic health had an estimated 13.4 percent mortality rate at 12 years, compared with 25.5 percent among those with low thymic health. Participants with high thymic health had a 3.4 percent estimated lung cancer incidence at six years, compared with 5.3 percent in the low group. Cardiovascular-specific mortality at 12 years was 2.9 percent in the high thymic health group compared with 7.5 percent in the low group. Researchers stress the findings are 'observational'.