Osteoporosis literally means ‘porous bone’. However, the term osteoporosis has been clinically defined as "a metabolic bone disease characterized by low bone mass and microarchitectural deterioration of bone tissue leading to enhanced bone fragility and a consequent increase in fracture risk".

In other words, osteoporosis is caused by low bone mass, as well as a weakened structure. Bones that were once strong enough to support our body become fragile and fracture more easily during daily activities such as bending to pick up a newspaper.

In fact most people don’t know that they have osteoporosis until they have had a fracture. Unfortunately, by this stage the disease is quite advanced. For this reason osteoporosis is often called the ‘silent disease’ because you do not feel any symptoms as your bones become weaker. Bone loss usually occurs slowly over time without symptoms, a bone breaking often being the first symptom of osteoporosis.

The consequences of osteoporosis are devastating. Each year in the United States the disease leads to a 1,500,000 fractures mostly of the hip, spine and wrist; in the United Kingdom there are more than 200,000 osteoporotic fractures per annum costing approximately £942m. This picture is much the same the world over.

The remodelling process is under a complex control system involving several hormones including oestrogen, hyperthyroid hormone, calcitonin and Vitamin D.

At the menopause, there is a rapid fall in oestrogen levels which in turn creates a rapid loss of bone, particularly at sites of predominantly cancellous bone such as the spine, hip, wrist and heel. Osteoporosis may be caused by other 'secondary' factors such as rheumatoid arthritis and calcium malabsorption. A difficulty with rheumatoid arthritis is that one of the most popular forms of treatment, cortico-steroids, also tends to cause further osteoporosis. Disuse is also a cause of osteoporosis, which explains why older men may also suffer.

Multiple tiny compression fractures in the spine cause loss of height and the characteristic hunched back. If we stumble and put out our arm to break our fall, this could cause a fracture of the wrist (Colle’s fracture). As we get even older, our balance deteriorates and there is a tendency to fall more frequently, often onto our hips which may have been weakened by osteoporosis.

Osteoporosis is a complex disease and certain factors are linked to the development of osteoporosis. Hence people with these factors (sometimes called risk factors) are more likely to develop osteoporosis.

Gender: Women are more likely to develop osteoporosis than men, because of lower peak bone mass and accelerated bone loss after the menopause.
Age: The longer you live the greater the likelihood of developing osteoporosis, hence as an ageing population the figures for osteoporosis are on the increase.
Genetics: A person with family history of osteoporosis tends to have lower bone mass.
Body Size: Small-boned, thinner women and men are at a greater risk than heavier, big-boned people.
Ethnicity: Caucasians and Asians are at a significantly higher risk of developing osteoporosis than individuals of African heritage. Whilst the risk of fracture is lower for African American and Hispanic women, significant numbers of these women do develop osteoporosis.
Hormone levels: Early menopause, occurring naturally or surgically (via a hysterectomy and oophorectomy) can increase a woman’s likelihood of developing osteoporosis. Young women with abnormal absence of menstrual periods (amenorrhoea) during their childbearing years (e.g. athletes, ballet dancers) have thin bones. Also low testosterone levels in men can contribute to bone loss.
Diet: Inadequate calcium and vitamin D intake is deleterious to bone health while excessive consumption of other nutrients such as proteins, fibre and sodium can decrease calcium absorption.
Exercise: Bone is an active organ and responds to external stimuli, hence it is important to remain physically active throughout life.
Lifestyle options: Lifestyle habits like smoking and alcohol consumption are generally not good for healthy bones.
Medications: Long term use of certain medications can lead to bone loss. The following drugs are known to contribute to the development of osteoporosis: chronic corticosteroid therapy, excessive thyroid therapy, anticoagulants, chemotherapy, gonadotropin-releasing hormone and anti-convulsants.
Medical conditions: There are a variety of medical conditions that might impact the bone health, these include: anorexia nervosa, rheumatoid arthritis, amenorrhoea, hyperthyroidism, primary hyperparathyroidism, multiple myeloma, organ transplantation and chronic conditions such as kidney, lung or gastrointestinal diseases.

Next Section - Clinical Measurement

CLIP

Please contact our Webmaster
with questions or comments.