Skull bone marrow fat changes measurably with age in people
Brain MRI scanners are built for the brain, but the scans also contain information about the bones of the skull. Researchers used existing MRI data to measure fat content in skull bone marrow at scale. That fat content shifts substantially with age, and shows genetic correlations with Parkinson’s disease.
By middle age, bone marrow adipose tissue accounts for 50 to 70 percent of total bone marrow volume in healthy people. As people age, the fat content of that marrow increases. In women, fat content rises more rapidly after menopause. Researchers developed an artificial neural network that automatically measures fat content in skull bone marrow, also called calvarial bone marrow adiposity (BMA), from MRI scans, a standard brain imaging technique.
41 genetic locations identified
The researchers, whose work was published in eLife, identified 41 locations in the genome strongly linked to skull bone marrow fat content. Six of those were found only in one sex. The trait turned out to be strongly inherited, both in twin studies and in studies looking at common genetic differences between people.
Links to Parkinson’s and cognitive ability
Genetic correlation analyses revealed associations between skull bone marrow adiposity and both cognitive ability and Parkinson’s disease. The researchers describe these correlations as intriguing, given the recently discovered direct channels connecting skull bone marrow to the brain’s protective membranes (the meninges), through which substances are exchanged. Whether that biological connection explains the genetic correlations, however, has not been established.
Search terms to explore further: calvarial bone marrow adiposity MRI aging | bone marrow fat genetic architecture | calvarial channels meninges brain