Microplastics are now so ubiquitous we're drinking, eating, and inhaling them. As a result, they're showing up in our poop, placentas, reproductive organs, and brains.

Now these fossil-fuel-derived particles, less than 5 mm in size, have been found deep within our bones.

A new review of 62 studies suggests microplastics and smaller nanoplastics are impacting our skeletal health in multiple ways.

"A significant body of research suggests that microplastics can reach deep into bone tissue, such as bone marrow, and potentially cause disturbances in its metabolism," says medical scientist Rodrigo Bueno de Oliveira at the State University of Campinas in Brazil.

Some of the studies in humans found these plastic leftovers accumulating in bone tissues via the blood, following ingestion. There, animal studies show they can reduce bone growth.

What's more, disruptions in osteoclasts – cells that support bone growth and repair – can lead to weakened bone structures, making these compromised bones more susceptible to deformities and fractures.

"In vitro studies with bone tissue cells have shown that microplastics impair cell viability, accelerate cell aging, and alter cell differentiation, in addition to promoting inflammation," explains Bueno de Oliveira.

"The adverse effects observed culminated, worryingly, in the interruption of the animals' skeletal growth."