The health risks associated with obesity are no secret—heart disease, cancer, and diabetes, to name a few. But did you know that obesity can also weaken your bones?
Research has shown that obesity increases the risk of osteoporosis, a disease of the bones that is characterized by reduced bone mass and bone quality.
What does obesity have to do with osteoporosis? It all comes down to fat—bone marrow fat.
Researchers measured fat levels in more than 100 men and women between the ages of 19 and 45 who were obese, but otherwise healthy. They found that participants with more fat in the blood, muscle, and liver had higher levels of fat in their bone marrow—and higher levels of bone marrow fat equates to weaker bones. Put simply, fat bones are weak bones—and weak bones are more likely to fracture.
The research lends new insight into the process of bone formation. Throughout an individual’s lifetime, bone undergoes a continuous process of removal of old bone (called resorption) and addition of new bone (called formation). This process makes bones larger, heavier, and denser. In this particular study, the researchers focused on bone marrow fat because that is where cells either develop into osteoblasts (the cells responsible for bone formation) or fat cells. It appears that obesity has an effect on this process—either by triggering cells to break down bone too quickly or to overpopulate it with fat cells.
Research will likely be ongoing to explore the relationship between obesity and osteoporosis. For now, the facts are clear: obese people tend to have more bone marrow fat, which results in weaker bones and a higher risk of fracture. Add this to the long list of reasons to maintain a healthy weight.
Bredella MA, Gill CM, Gerweck AV, et al. Ectopic and serum lipid levels are positively associated with bone marrow fat in obesity. Radiology. Published early online July 16, 2013. doi: 10.1148/radiol.13130375