What is the treatment?
The most common medication is bisphosphonates, drugs that slow down the activity of the osteoclasts, allowing the bone-building osteoblasts to do their work. For severe osteoporosis, parathyroid hormone treatment can trick the bones into gaining bone mass.
But the good news is that calcium and vitamin D supplements and the right weight-bearing exercise can actually reverse osteoporosis.
But by far the most common disorder is osteoporosis, which affects more than 3 million people in the UK. It's caused by an imbalance in the bone renewal cycle. Bone becomes less dense and more fragile, and more likely to break. It's not necessarily painful in itself, but the broken bones that occur as a result are.
It's more common in older people and is often called a silent disease, as the first sign is usually a broken bone. In fact, osteoporosis causes broken bones in one in two women and one in five men over the age of 50.
Causes include an inherited tendency, smoking and excess alcohol (both toxic to bones), anorexia, yo-yo dieting, pour calcium and vitamin D intake and lack of regular exercise.
Some medical conditions can also increase the risk. These include overactive parathyroid glands (which control the body's calcium levels) rheumatoid arthritis, Crohn's disease and coeliac disease.
Source: Simon Moyes - Consultant orthopaedic surgeon at London Bridge Hospital and Wellington Hospital in London.
When you think about staying healthy, you probably don't spare much thought for your bones - but they are key to your wellness and longevity. There are more than 200 different bones that make up our skeleton, and they also protect our internal organs.
Bone is living tissue and it takes 7 to 10 years to 'turn over' or replenish our skeleton. Like muscles, the more you use your bones, the stronger they become. So regular, weight-bearing exercise, and getting the right nutrients - in particular calcium, magnesium, protein and vitamins D and K - throughout your life are important.
The silent disease
Our bones contain collagen (a protein), calcium and other minerals. Each bone is made up of a thicker outer shell called cortical bone, and an inner honeycomb mesh of tiny struts of bone called trabecula. The process of 'remodelling' or renewal involves cells called osteoclasts, which remove old bone cells, and others called osteoblasts, which lay down new bone cells.
Although our bones stop growing in length when we're about 18, they do continue to strengthen until they peak at around age 25. That is why it's vital to ensure you have enough 'money' in your bone bank in these early years, before the process starts to reverse and bone mass begins to decline gradually from the age of 30.
Osteomalacia, where bones are soft (called Rickets in children), can cause pain and is on the increase due to lack of vitamin D.
The best source of vitamin D is sunlight and it's now thought that the safe sun message has contributed to up to a quarter of UK adults being deficient in vitamin D in spring. This is because the sun we get in the UK isn't strong enough between October and April to protect vitamin D stores built up over the summer months.
Some experts maintain that anything less than optimal levels of this vital vitamin impact on bone health and that we should aim for a circulating vitamin D level in the blood of 75 nmol/L - this is considerably higher than the 25 nmol/L currently advised by the Department of Health.
Osteopenia is a grey area between good bone density and osteoporosis, the bone thinning disease. This is on the increase, too. A study found that nearly 20 per cent of UK women aged between 20 and 29 are experiencing premature bone loss.
When to invest?
You might take them for granted, but your bones need investment through life to ensure they - and you- stay healthy.
Hop, Skip, Run and Jump
Exercise throughout life is vital for good bone health. Try dancing, football, Tennis or running, anything that pulls on the muscles, which in turn pulls on bones, makes bones stronger. Studies have shown hopping on one leg or skipping can increase bone density. Rowing gives a good pull on the spine. For older people, it's also about balance, so that could be tai chi, golf, or even standing on one leg while brushing your teeth!
How is osteoporosis diagnosed?
A DEXA scan which measures bone density is taken, usually of the hips and spine (the main areas affected by osteoporotic fractures). The results are given as T-scores and a result of -2.5 or less is classed as osteoporosis.
Have you checked your bone bank balance?