Osteoporosis

Osteoporosis, which occurs in both women and men, is a condition in which bones become fragile and more likely to break. This can be the result of many factors including a decrease in the hormone estrogen occurring during menopause in women, or a decrease in testosterone occurring in men as they age. Because osteoporosis often has no obvious symptoms, it is often left undiagnosed until the person affected suffers a broken or fractured bone during a minor fall.

What role do hormones play bone disease?

Too much or too little of certain hormones in the body can contribute to osteopenia and osteoporosis.

• During and after menopause, the ovaries make much less of the hormone estrogen. Estrogen loss may also occur with surgical removal of the ovaries or because of excessive dieting and exercise. Estrogen helps protect bone.
•  Men produce less testosterone (and estrogen—produced in small amounts in males) as they age.  Reductions in these hormones may also contribute to bone loss.
• Bone loss can result from the damaging effects of excess cortisol, as occurs in Cushing’s syndrome.  Sometimes the adrenal glands produce excess cortisol because of a pituitary gland or other tumor. More commonly, Cushing's syndrome develops as a result of long-term use of corticosteroid medications (steroids) such as prednisone and cortisone, used to treat inflammatory disorders like rheumatoid arthritis or asthma.
• Other hormone imbalances that may increase the risk of osteoporosis include an overactive thyroid gland, diabetes, and hyperprolactinemia, in which the pituitary gland produces too much of the hormone prolactin.
• Thyroid cancer survivors whose treatment includes high doses of thyroid hormone also have a higher risk.
• Eating disorders, especially anorexia nervosa, increase the risk of osteoporosis. Bone loss occurs partly because of poor nutrition and, in women, partly because the ovaries stop functioning normally, producing less estrogen.

Symptoms

Early in the course of the disease, osteoporosis may cause no symptoms.

Later, it may cause:

• Dull pain in the bones or muscles particularly low back pain or neck pain.

Possible Treatments

More detailed intervention depends on individual circumstances, and so only an overview can be presented here.

There are several types of treatment available, and often a combination will be more appropriate than just one.

Hormone replacement therapy (HRT)

Oestrogen seems to protect bone strength. The drop in oestrogen, which occurs following menopause, is mirrored by an increased loss of bone for a few years thereafter. The loss continues, but less steeply, in older women.

Hormone replacement therapy replaces oestrogen and so reduces the rate of bone loss.

The pros and cons of HRT are many, and they are the subject of much debate.

HRT is thought to be of most benefit for preventing osteoporosis if it is started early in menopause and is taken for at least five years. However long-term use increases the risk of side-effects.

Any woman considering HRT should therefore discuss the risks and benefits for her individual circumstances with her doctor before making a decision about treatment.

Briefly, HRT is known to be associated with an increased risk of breast cancer,cancer of the lining of the womb (endometrial cancer), blood clots in the veins (thrombosis), stroke and heart disease.

However, as well as preventing osteoporosis, HRT reduces the symptoms of the menopause, which can be distressing for some women. It's also associated with a reduced risk of bowel cancer.

The length of time that treatment should be continued is also an issue of contention.

Whether or not to use HRT to prevent osteoporosis and how long for will depend on a woman’s individual risk of developing the condition, her personal and family medical history and her individual views on the potential risks and benefits, all of which should be discussed with her doctor.

HRT is not now recommended as a first choice of therapy for long-term prevention of osteoporosis in women who are over 50 years of age because there are other medicines available that do not carry the risks associated with HRT.

There's more information about these medicines below.

HRT remains an option for women over 50 at risk of fractures for whom these other medicines are not suitable.

HRT is also still a suitable option for women who have had an early menopause.

However in this case HRT should only be used for treating menopausal symptoms and preventing osteoporosis until the age of 50, after which time other medicines may be more suitable.

Bisphosphonates

This is a group of medicines that slows the rate at which bone is dissolved, thus favouring a build-up in bone strength over time. Two types are in common use:alendronic acid (Fosamax) and disodium etidronate (Didronel PMO).

Alendronic acid and disodium etidronate can be used in men and women who have, or are at risk of developing, osteoporosis, including where this is secondary to the use of steroid drugs.

Risedronate sodium (Actonel) and ibandronic acid (Bonviva) are other bisphosphonates used only in women after the menopause, but are otherwise similar to the others.

There are slight differences between the bisphosphonates in the available preparations and how frequently they are taken, but they act in the same way.

Alendronic acid and risendronate sodium reduce the occurrence of fractures of the hip and spine, whereas etidronate and ibandronic acid have only been shown to reduce fractures of the spine.

The most common side-effects associated with bisphosphonates are digestive in nature, for example indigestion, diarrhoea, constipation and abdominal pain.

Alendronic acid and ibandronic acid have strict instructions for how they should be taken because they can cause irritation and ulceration of the foodpipe (oesophagus).

Strontium ranelate

Strontium ranelate (Protelos) is used for the treatment of osteoporosis in postmenopausal women. It is usually reserved for women who cannot take bisphosphonates.

It has a dual action of increasing bone formation, as well as decreasing bone breakdown, and it has been shown to reduce the risk of spinal and hip fractures.

Strontium seems to be asociated with an increased risk of blood clots in the veins, but not to the same extent as HRT or raloxifene (see below).

Raloxifene

Raloxifene (Evista) is a type of medicine called a selective oestrogen receptor modulator (SERM). It can be used to both prevent and treat osteoporosis in postmenopausal women.

Raloxifene stimulates bone growth just as oestrogens do, but it has an anti-oestrogen effect on the uterus (womb) and on breast tissue.

The latter effect is seen as desirable because it may reduce the tendency for long-term oestrogen-based HRT to increase the risk of developing breast cancer.

However, raloxifene may increase the risk of developing blood clots in the veins and can't be used by a woman with a past history of deep vein thrombosis (DVT). The risk of thrombosis with raloxifene is similar to the risk with HRT.

It is preferably used only in women who are five years past their menopause. It would be an option for a woman between 55 and 70 years.

It has been shown to reduce the occurrence of spinal fractures, but not hip fractures.

What other treatments are used in osteoporosis?

These treatments are quite specialised and not commonly used.

Calcitonin

Calcitonin (Miacalcic) is a hormone involved in the regulation of bone turnover. It is given by injection or nasal spray and is used for postmenopausal osteoporosis when treatment with bisphosphonates, strontium or raloxifene is unsuitable.

It can relieve pain when used following a collapsed vertebrae. But it has a number of potential side-effects, including allergic reactions.

Calcitriol

Calcitriol (Rocaltrol) is a vitamin D-like compound that can be used in osteoporosis following the menopause or in situations where osteoporosis has been caused by steroid drugs.

Studies of the effect of calcitriol on bone loss and fractures have produced conflicting results, however it has been shown to reduce the risk of spinal fractures but not hip fractures.

Teriparatide

Teriparatide (Forsteo) is used for the treatment of osteoporosis in postmenopausal women and in men with an increased risk of fracture.

It works by increasing the formation of bone and is given by daily injection under the skin, using an injection pen similar to those used by people with diabetes for injecting insulin. It has been shown to reduce the incidence of spinal but not hip fractures.

Hip protectors

Hip protectors are shock-absorbing pads that can be worn to cushion the impact over the hip bone, should a person fall down. They spread the load across a wider area of the upper leg and are useful as an extra measure in an elderly person prone to falls.

Hip protectors come as a sort of girdle with padding at the sides. However, it can be difficult for people to remember to put one on, or even wish to wear one.