Osteoporosis literally means porous bones. It is a bone disorder commonly found amongst older people, and occasionally in younger men and women.
The bones in our skeleton are made of a hard outer shell (the cortex) and a light but strong inner mesh. The inside looks like honeycomb, with blood vessels and bone marrow in the spaces between bone. The material that bone is made of is largely collagen (protein) filled with calcium salts and other minerals.
Bone tissue is alive and constantly changing to allow our bones to cope with the loads they carry during life. Old worn out bone is broken down by cells called osteoclasts and replaced by bone building cells called osteoblasts. This process of renewal is called bone turnover or remodelling. In osteoporosis this process is disrupted, so that the osteoclasts work harder than the osteoblasts leading to weaknesses in the bone structure.
When osteoporosis occurs, the outer shell becomes thinner and the spaces or holes in the inner mesh become bigger, making it fragile and liable to break easily. Osteoporosis usually affects the whole skeleton but it most commonly causes fractures (broken bones) in the wrist, spine and hip.
Osteoporosis affects one woman in every two over the age of 50 and one woman in every two over the age of 70. In Sheffield today over 25,000 women are thought to have osteoporosis. Men are less likely to develop osteoporosis. Nevertheless, one in 5 men over the age of 50 will have an osteoporosis-related fracture. A small number of men and women under the age of 60 develop osteoporosis and occasionally osteoporosis occurs in teenagers and children.
Osteoporosis develops slowly over a number of years. Initially there may be no symptoms at all giving rise to the term the “silent epidemic”. As the disease progresses, bone strength is lost and eventually they become so weak that they break easily, usually from an injury that you would not normally expect to cause a fracture e.g. just a simple fall from a standing height. By the time fractures occur 30% to 60% of the skeleton has disappeared.
Fractures of the bones in the spine (the vertebrae) can cause back pain with loss of height as the spine tends to curve forward giving rise to the unkind description "the Dowager's hump". A fracture of the spine is sometimes associated with several weeks of acute pain but it could be pain free (silent). Curvature of the spine is often associated with breathing difficulties, chest infections and digestive problems including indigestion
A number of reasons. Firstly, women have on average a lower amount of bone simply due to the fact that they tend to be smaller and have smaller skeletons than men. They also go through the menopause and this is associated with faster loss of bone strength over a few years. Finally, women live longer on average than men, and as fractures occur more commonly in later life, we see more women with osteoporosis.
Oestrogen, which is produced by a woman's ovaries before her menopause, helps maintain bone structure. After the menopause oestrogen levels fall and the positive effects of oestrogen on bone are lost. Women who go through the menopause early are at greatest risk of developing osteoporosis.
Sheffield has a nationally and internationally renowned specialist centre for osteoporosis at the Northern General Hospital. It is affiliated to the University of Sheffield and has extensive research programmes for the disease. It provides a bone density scanning service and a clinical service for patients with established osteoporosis. If you have one or more of the risk factors listed below, discuss this with your GP and they may consider referring you for a bone density scan.
It is never too early or too late to prevent osteoporosis. A balanced diet with plenty of fruit, vegetables and dairy produce together with lots of fresh air and exercise will help develop strong bones during adolescence. Excessive dieting should be avoided and smoking, and drug abuse discouraged. Strong bones in our twenties will set us up for life.
Lack of exercise is one of the biggest problems in the middle years as busy working lives often mean little time for sport. However, weight-bearing exercise and a balanced diet remain important factors that we can control.
Men and women over the age of 60 who have already had osteoporosis-related fractures should be on treatment to prevent future fractures. It is never too late to begin preventative treatment. In more elderly people, daily calcium and vitamin D supplementation becomes important. The best preparations are available from your family doctor.