Variation in Human Bone Collagen Turnover Among Skeletal Elements

OBJECTIVE: Understanding tissue turnover rate is crucial for isotopic analysis. The stable isotope composition of collagen is often studied in archeology and paleontology, yet bone collagen turnover rates across various skeletal elements remain underexplored. The turnover rate of various skeletal elements in humans was explored to improve the accuracy and reliability of stable isotopic studies. MATERIALS AND METHODS: Bone collagen turnover rates were quantified in multiple human skeletal elements using the bomb carbon dating method. Fifty-three skeletal elements from seven donors, aged 54-78, from a human decomposition facility in Québec, Canada, were sampled. RESULTS: Turnover rates varied significantly among skeletal elements, ranked from slowest to fastest as follows: ulna, humerus, femur, rib, pelvis, and vertebra. Turnover rates must markedly decline through life, and the isotopic composition of bone collagen samples therefore represents a generally long term (years to decade) but uneven (heavily weighted toward earlier life for elements with slow turnover rates) picture of the life history. DISCUSSION: There can be significant variation in turnover rates within skeletal elements, which researchers should account for in isotopic studies. For stable isotope studies aiming to reconstruct temporal variation in life history, the rib and femur may be among the least suitable paired elements for sampling. Such studies should instead select vertebrae and ulnae due to their highly distinct turnover rates.