Genetics of osteoporosis.

Is osteoporosis hereditary?

Osteoporosis is the most common bone disease, especially in the western world. It affects women more often after menopause but, in recent years, it is much more commonly recognized in men. It is a “silent epidemic”, a disease that lasts for many years of our lives without causing particular symptoms.

Sometimes it can only cause back pain, especially after long hours of standing or “feeling of instability” of the skeleton, especially if there are degenerative problems in the spine (the so-called “salts”). The most important problem that osteoporosis can cause is a fracture.

A percentage of 30-50% of women and 15-30% of men will suffer a fracture during their lifetime. These fractures can occur after minimal injury (e.g. after falling from a standing position on the hip) or after any injury (e.g. weight lifting and vertebral fracture).

The most important problem, however, is that fractures can increase mortality. Overall mortality is around 20% in the first year after a fracture. However, it can reach up to 50% in the elderly (mainly men) after a hip fracture. Of those who survive, half will never return to their previous state of health. Only about 25% will be able to work again almost as before.

But definitely everyone has a limited quality of life. The most important factors are due to the reduction of bone density and occur clinically with skeletal fractures. It is a disease that after a fracture can become disabling and definitely significantly reduces the quality of life.

The causes of osteoporosis

There has been a lot of progress in the last 30 years in trying to understand the cause of osteoporosis. There are many factors that have been found to be responsible. The most important are the genetic, the hormonal, the environmental, the nutritional, the diseases, the medicines, etc.

Age and menopause seem to be the most powerful. However, the occurrence of fractures in younger women as well as the frequency of their occurrence in members of the same family cannot be explained only by them. Studies show that the most important factor is the genetic, heredity, which is considered responsible for up to 85% of the occurrence of the disease.

Studies have been performed on twins who have shown strong genetic activity in the occurrence of osteoporosis with percentages up to 100% in monozygotic siblings (identical siblings). It has also been found that women, relatives of patients with osteoporosis and fractures, have lower bone mass than women relatives of patients without fractures.

Related factors are the geometric construction of the bones (i.e. the size of the bones) and their microarchitecture (i.e. the spongy mesh inside the bone). Another very important parameter is the non-acquisition of maximum bone density in the years of adulthood before menopause. It seems that it is mainly determined genetically, it is not considered a disease but it is a very important aggravating factor for osteoporosis after menopause. This is relatively common in women of the same family.

It has been known for many years that the daughters (or granddaughters) of women with osteoporosis have an increased risk of developing the same problem. It has been observed that if the mother has osteoporosis, the daughter has a 50% chance of developing osteoporosis while if the grandmother had it, this chance rises to 75%. This risk is greater when there are bone fractures.

Also, very thin and relatively short women, especially blue-eyed women, have an increased risk. A lot of research has been done in recent years to find the gene that causes osteoporosis. However, it seems that there is no single gene, but a combination of genes is likely to be responsible for the disease.

Studies have found variations in the genes for vitamin D, collagen, estrogen and many other factors that appear to interfere with bone pathology. In addition, studies show that gene expression is highly influenced by environmental and hormonal factors.

Premature menopause, amenorrhea longer than 6 months in a woman’s lifetime and drugs such as cortisone for a long time significantly increase the risk of osteoporosis. A diet low in calcium and protein as well as a lack of exercise in our daily lives aggravate the condition.

What I must not forget to do systematically:

Every postmenopausal woman should have a bone mass measurement to determine to which category she belongs to. However, women with a hereditary history of fractures from their mother, grandmother or father should be especially careful and not rest on a single measurement.

The progressive revelation of the genetic code will bring to the surface more genes responsible for this serious problem that affects a large part of the population. Therefore, we must understand that osteoporosis is not just a disease of the postmenopausal woman.

Care for its prevention should begin long before it occurs, from childhood and adolescence. Continuous exercise for all ages as well as a diet rich in calcium and dairy promises a healthy skeleton without osteoporosis for most of life.

Advises Ms. Katerina Katsalira, Rheumatologist

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