Human abdominal organ volumes peak in midlife then decline

In a retrospective study of 15,408 adult patients aged 18 to 100 years, researchers mapped life-course changes in abdominal organ volumes and tissue density using automated CT segmentation. The team analyzed 25,161 abdominal CT scans, evaluating organ attenuation in 9,548 unenhanced examinations. Men had larger organ volumes than women across nearly all organs and age groups. Liver, pancreas, and kidney volumes followed an inverted U-shaped trajectory, rising into midlife and declining thereafter. For example, median pancreatic volume peaked at age 40 to 49 years at 67.7 milliliters in women and 86.2 milliliters in men, before dropping to 35.5 and 46.4 milliliters in the oldest group. Spleen volume decreased across age groups, whereas adrenal volume rose into later adulthood. Attenuation declined with age across most organs, falling most sharply in the pancreas and adrenals.