Washington: People blame osteoporosis for backbone fractures but the real villian is likely to be the spine or vertebrae, which evolved to absorb the pounding of upright walking.
Compared to apes, humans have larger, more porous vertebrae encased in a much thinner shell of bone. The design works well until men and women age and suffer bone loss, leaving them vulnerable to cracks and breaks, according to the latest study.
Conversely, apes can suffer comparable bone loss as they age, but have much thicker vertebral shells to begin with so that their vertebrae remain intact, the journal Public Library of Science reports.
"In evolution we have great adaptation but there is sometimes a tradeoff," said Meghan Cotter, lecturer in anatomy at Case Western Reserve University School of Medicine, who led the study, according to a varsity statement.
"The structure is great for walking around but not good when you have osteoporosis," Cotter said.
Cotter worked with David Loomis from Musculoskeletal Mechanics and Materials Lab, anatomy professor Scott W. Simpson and anthropology professor Bruce Latimer, both from Case Western.
In his studies of early hominids, Latimer found fractures in the vertebrae of human skeletons but not in ape remains in the Hamann-Todd collection.
The collection of more than 3,000 human and more than 1,200 ape specimens is housed nearby at the Cleveland Museum of Natural History.
"We`re now living about twice as long as when the adaptation evolved and that results in major problems," Cotter said. "It highlights that we are not perfectly evolved specimens."