Causes: Age and bone strength
Bone tissue is alive and constantly changes through life to make sure it remains as healthy as possible.
Your overall bone strength is a combination of:
- the amount of bone tissue you have - your bone density
- how healthy or strong that bone tissue is
- and both are affected as you age.
Bone density and age
Right now, inside your bones, older, worn-out bone tissue is being broken down by specialist cells called osteoclasts, and rebuilt by bone-building cells called osteoblasts.
This process of renewal is called bone remodelling, or bone turnover.
Childhood and your teenage years
As we grow, osteoblasts work faster. This allows the skeleton to increase in size, density and strength.
During this period of rapid bone growth, it takes the skeleton just two years to completely renew itself. In adults, this process takes seven to ten years.
Bones stop growing in length between the ages of 16 and 18. But the total amount of bone tissue you have - your bone density - continues to increase slowly, until your late twenties.
Up until about the age of 35, there is usually a balance between the amount of bone that is removed, and the amount of bone that is laid down. The total amount of bone tissue stays the same.
Late thirties onward
The amount of bone that is removed and the amount of bone that is laid down starts to get slightly out of balance as you age. This means more bone tissue is removed, and the total amount of bone tissue starts to decrease.
During this process, your bones don't look any different from the outside. But inside, the outside shell of the bone things. And the struts that make up the structure inside your bones become thinner, and sometimes break down.
The older you get, the more bone tissue you lose. This is why osteoporosis and broken bones become more likely with age.
Bone strength and age
As you get older, the strength of the bone tissue you do have also starts to naturally decrease.
This increases your risk of osteoporosis and broken bones.