Having low bone mass means the bones are weaker than expected. Bones become weak because bone tissue is being lost faster than it is being gained. When the low bone mass is severe or if a fracture occurs because of low bone mass, it is called Osteoporosis.
There are a number of different causes of low bone mass. Most commonly, low bone mass is related to menopause, but it can also be related to medical conditions, genetic conditions, lifestyle, and medications.
When bones are weak, they are more likely to fracture. When a bone is fractured as a result of low bone mass, it is called a fragility fracture. Fragility fractures take time to heal and often require surgery.