Author: Dārta Jakovicka
It would probably be too harsh to call it the “silent killer” but it could definitely be called the “silent thief”, as it has a habit to rob your bones. The 20th of October is World Osteoporosis day and its main aim is to raise awareness about this bone degrading disease. Osteoporosis has a good reason to have its own day – according to International Osteoporosis Foundation, in 2010 there were approximately 22 million women and more than 5 million men aged between 50-84 years in European Union (EU) alone suffering from osteoporosis. Furthermore, the prognosis is not encouraging – these numbers will rise dramatically.  It sounds as an introduction of a horror movie, but let’s get to the point and get to know this thief better.
What is osteoporosis?
First of all, let me explain the process of bone metabolism. Imagine that our bones are like a brick wall where osteoblasts (bone forming cells) replace empty spaces in the wall with new bricks. In turn, osteoclasts (bone resorbing cells) take away the old ones. It is called bone homeostasis or normal bone remodelling process where old tissue is replaced by new bone tissue and is tightly regulated by endogenous and exogenous factors. Endogenous factors result from conditions within the organism (e.g. overproduction or underproduction of specific hormones) and exogenous – caused by external factors (low calcium and vitamin D intake, steroid hormone therapy etc.). When osteoporosis occurs, there is an increased bone turnover between the processes of resorption and formation, resulting in a deficit of each remodelling cycle and an increased risk of fractures. If we get back to the picture of the brick wall, osteoclasts do not use hammer anymore to get rid of the old bone, but has brought in a TNT (Trinitrotoluene), accelerating the bone resorption process and making the bone more fragile. If you are not into construction processes, imagine the bone like a honeycomb, where spaces become much larger as the disease progresses (Figure 1).
Fig. 1. Normal bone vs Osteoporotic bone 
You probably think – I have heard about osteoporosis from my grandparents, that their bones become brittle and sometimes even lead to fractures, thus it is a component of a normal aging process, so there is nothing we can do to prevent it or even be aware of it. Sorry, but this time you are wrong.
The good news is that osteoporosis represents a preventable and treatable disorder, which can be diagnosed in a pretty simple way.
How can osteoporosis be diagnosed?
Bone strength strongly correlates with Bone mineral density (BMD), which is the amount of bone mineral in bone tissue. The golden standard for assessment of BMD is dual energy X-ray absorptiometry (DXA) – an only 20-minutes-long scan of hip and spine. After completion, it shows a specific score, which is compared to the standard score, defined by World Health Organization (WHO) (Figure 2). As BMD score decreases, the risk of fractures increases and in the worst case scenario leads to diagnosis of osteoporosis. It should be on the top of the list for a family doctor if the patient has a history of fractures without significant trauma (e.g. your grandmother fell from the chair and couldn’t stand up because of fractured hip), a history of prolonged glucocorticoid (class of steroid hormones) therapy or if the patient is a postmenopausal woman. 
Fig. 2. DXA scan of the femoral neck (hip) and lumbar spine. The green area of the panel indicates normal T- score values, the yellow one – osteopenia (low BMD) and the red area – osteoporosis 
Key players of osteoporosis
Low BMD does not only correlate with suppressed estrogen levels but also with a history of smoking, frequent alcohol intake, hypercalcemia (too much calcium from the bones is released into the blood), hyperparathyroidism (excess parathyroid hormone production) and low D-vitamin levels. As we know, calcium is the key player in bone structure support – 99% of total body calcium is stored in bones and teeth. So, it would be worth knowing that diet rich in saturated fatty acids results in a decrease in calcium absorption and, in turn, an increase in protein intake has the opposite effect. 
Vitamin D plays an important role in calcium absorption, as well as in the process of osteoblast production and in the maintenance of osteoblast survival, making it crucial in treating bone turnover diseases, like osteoporosis. 
There are several options for slowing down the bone turnover process. Daily reminders by doctors about performing weight bearing exercises has a reasonable cause – these activities increase the BMD index. Sufficient consumption of milk and milk products (in association with calcium levels), fruits and vegetables (for normal potassium levels) and fatty fish (for normal vitamin D levels) can make a huge impact on maintaining normal bone density. For postmenopausal women it is crucial to follow their estrogen levels and to consider a hormone therapy. 
To conclude, osteoporosis can affect anyone, and the risk of developing osteoporosis increases with several risk factors. We ourselves are highly responsible for getting sufficient levels of calcium and vitamin D and incorporating sports activities in our lifestyle. But do not put all the blame on yourself – all you can do is slow this process down. Also, do not hesitate to discuss with your doctor how you could together detain this silent thief, called osteoporosis.
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