Osteoporosis is a disease that makes bones weak and brittle, so they break much more easily than healthy bones. A person with severe osteoporosis might break a bone from something as minor as bumping into furniture or sneezing hard.

Bones might seem solid and unchanging, but they're actually alive and constantly rebuilding themselves. Throughout your life, your body breaks down old bone and creates new bone to replace it. In osteoporosis, this balance tips: the body breaks down old bone faster than it creates new bone, leaving bones thin and fragile.

This disease usually develops slowly over many years and most commonly affects older adults, especially women after menopause. That's why doctors encourage young people to build strong bones through calcium-rich foods, vitamin D, and exercise. The stronger your bones are when you're young, the better protected you are against osteoporosis later in life. Think of it like saving money: the more you save when you're young, the more you have to draw on when you're older.