In this 20-point project I’ll investigate to what extent osteoporosis influences different populations and speculate about, based on various facts and figures, the most effective way to cope with it. To help understand what osteoporosis exactly is and how it develops I’ll describe the main aspects on a cellular level.
The aim of this project is not to discover new medical treatments or cures for osteoporosis but rather to speculate how different methods of treatment could possibly affect the prevalence of the disease.
This paper is made up of three main parts: In the first part I’ll discuss social prevalence and give several examples of how osteoporosis affects different population groups; The second part discusses bones and their metabolism on a biological level; The last part consists of two chapters, methods of treatment and speculation.These last two chapters are more of a speculative nature compared to the first two parts that are more factual.
One of the most interesting aspects of osteoporosis is that even though it affects such a large part of the population and therefore costs society enormous quantities of money vary few people seem to know the potential problems that await us in the future.
The first step in tackling osteoporosis is to gain more knowledge about the subject which I’ll try to offer in this 20-point project.
Osteoporosis is the main underlying cause for most bone fractures and related diseases in the elderly. It is a condition where bone mass decreases and the microscopic architecture in the bone has partly been lost. The bone becomes fragile and is more prone to fractures than a healthy one.Osteoporosis usually only affects the elderly and is due to an acceleration of the natural degeneration of the bone.The disease is, in and of itself painless and is difficult to notice because of the absence of direct symptoms.There are modern techniques for measuring the mass and architecture of the bone so that osteoporosis can be detected early. However, examination is costly and not very effective since only a fraction of the population is tested.Most people notice osteoporosis because of symptoms that are a result of the disease. If, for example, the bones of the spine have become fragile and lost their architecture problems such as back pain and loss of height will be noticeable. Other instances when osteoporosis can be suspected is when bone fractures occur from light impacts (blows) that normally would not cause the bone to fracture. There are also a number of risk factors that increase the likelihood of attaining osteoporosis. The female sex, old age, light skin tone, close relatives with osteoporosis, poor nutritional intake, and physical inactivity are only a few of the main determents.
Before statistical data can be collected and used one must know the exact definition of osteoporosis. In other words, how the statistics were derived at. The World Health Organization, WHO, defines osteoporosis based on bone density measurements and then relating the deviation to normal statistical values. For example if a person has a standard deviation between 1 to 1.25 below standard values in a selected population he suffers a mild form of osteoporosis called osteopenia. Deviations rating less than 1.25 are considered osteoporosis.According to a report by SBU5 (statens beredning för utvärderning av medisinsk teknologi) 22% of the Swedish women in the age group 40-49, and 43% in the age group 70-79 have osteoporosis. The bone density measurements for determining osteoporosis were done in the lower back.
One problem with collecting statistical data on osteoporosis is that only a small proportion of the population has been examined and thus results are inconclusive.Large numbers of people, mainly females, live their lives without ever knowing that they have porous bones caused by osteoporosis. The symptoms can be relatively unnoticeable such as gradual crouching of the spine and fractures caused by light impact. In conclusion, the total number of people with osteoporosis is probably greater than most of the statistics studies done on osteoporosis.
Osteoporosis has gradually increased in most industrial countries, but for unknown reasons it affects some much more than others. For example, Norway and Sweden have the largest increase of osteoporosis in the world. In contrast, their neighboring country Finland has only about half as many cases of osteoporosis.
Today, approximately 70 000 people in Sweden attain fractures caused by osteoporosis and according to Gun Leander1 is three times as many as during the 1950:s. This costs society huge amounts of money with only hip fractures costing over three million crowns annually. In a Swedish newspaper article10, Birgitta Jakobsson claims that every second woman and one out of four men over 50 are fractured because of osteoporosis. Unfortunately the disease has not only increased among the elderly but also juvenile osteoporosis is on the rise. The main reasons are thought to be serious dieting in early ages (as young as seven years) before the skeleton has had time to fully develop.
As mentioned earlier, light skin tone is a risk factor contributing to osteoporosis.One can speculate that countries with a majority of white people would have a higher frequency of the disease.In the United States for example the white population has a much higher rate of osteoporosis than the colored.Totally 10-15 million people have osteoporosis in the USA and an additional 20 million have low bone mass or osteopenia. Compared to Sweden, only one out of eight of the white male population over 50 is fractured because of osteoporosis. More than 1.5 million fractures are acquired annually costing $14 billion (» 112 billion Kr.).
Although Asians are not as prone as whites there has been a considerable increase in the Asian countries. It has been estimated that one third of all the world’s hip fractures will take place in Asia approximately in the year 2025.
There are other risk factors besides light skin tone. In several countries, such as France where the frequency of the disease is less than in Sweden, the average population is also shorter in height.This is a statistical indication that tall people would be more prone to osteoporosis than shorter ones.
Ones lifestyle seems to play an important role in determining the likeliness of attaining bones that become prematurely porous. As a statistical indication one could compare the frequency between city dwellers and people who live on the countryside (Yrkesmedisinska enheten, Karolinska sjukhus). In several countries where this comparison has been made the results are conclusive.People in cities have a higher rate of osteoporosis than the people who live out on the countryside. Since the physical activity level is generally higher among people on the countryside, the comparisons would serve as an indication that physical activity decreases the frequency of fractures.
Exercise during ones early years (10 - 30) is a very potent factor for minimizing the probability of getting osteoporosis later on in life. A study called LIV 9012 has shown that physical exercise among children (under the age of 24) has greatly decreased during the last few years. Where as young adults between 24 - 27 exercise slightly more during the last decade. The study also shows that children from middle-class homes exercise more than lower-class children. Students who have completed their gymnasium studies exercise more than they who haven’t.
The functions of the skeletal system can be categorized into two groups: a mechanical and a chemical. Protection of inner organs and stability for muscles and other tissue are the main mechanical functions. The chemical functions are mainly the production of red and white blood cells and the regulation of calcium ions.
A healthy bone of an adult is both hard and elastic. This "double feature" maximizes the protection of internal organs and at the same time minimizes the risk for fractures that would easily accompany bones that are inelastic.
The bone is comprised of a mixture of various inorganic salts and minerals and organic material. As a base for the hard qualities of the bone are the inorganic substances and the elasticity is formed mostly by organic material in connection with mineral crystals. But the durability of each individual bone is not only determined by its chemical makeup. Other factors such as the microscopic architecture, bone density, bone mass and surrounding muscles play an important part in bone durability.
To get an improved understanding of what the bone is comprised of I’ll, step-by-step describe the development of bone from a fetus to adulthood.
When the development is complete the bone has a hollow marrow in the shaft (diaphysis) and spongy bone in the ends (epiphyisis) which are both surrounded by hard compact bone. Further, the bone marrow can be categorized into a red and yellow part. The red marrow produces mainly red and white blood cells and the yellow is comprised of mostly fat.
In addition to bone marrow, spongy bone, and hard compact bone, joint cartilage can be found surrounding the periphery of the epiphysis. The cartilage is to minimize the natural occurring process of wear and tear.
An adult bone consists of about 45% mineral substances (calcium salts), 25% water and the remainder of the total weight is comprised of organic material, mainly collagen (protein fibers).
The metabolism of bones is generally considerably slower than other body tissue. As an example, an adult skeleton is totally replaced every ten years. The total turnover rate is maximum in infants (one year) and decreases with age. There are variations in metabolism even inside the bone. The spongy part is for example replaced 5-10 times quicker than the diaphysis.
Because of the chemical mixture of the bone there are, not only cells that build new bone tissue, but also cells that breakdown bone tissue so that proper maintenance and healing can be achieved. The cells that build new tissue are called osteoblasts and the ones that degenerate bone osteoclasts. During bone development the activity of the osteblasts are higher than the osteoclasts. When the bone is fully developed, breakdown of bone is followed by a similar buildup.In other words, the bone is continuously degenerated and built-up and is in a state of equilibrium. With age, the activity of the osteoclasts increases and the bone slowly degenerates. The speed of breakdown is accelerated after the age of about 50 to the ratio of5-10% per decade.
The osteoblast cells create new bone tissue in two steps: First they create a so-called bone matrix consisting of soft bone tissue. They then mineralize the matrix, which causes it to become hard. New hard bone tissue has been created. Some of the cells are captured in the mineralized bone and are called osteocytes. These are equipped with "antennas" which enables them to communicate with each other and also with the osteoblasts that sorround the bone tissue.
Osteoclasts are formed in the red bone marrow. They are large in size and consist of multiple cell nucleous. The breakdown process is initiated by their attaching to the mineralized bone. With a so-called proton pump the osteoclast gives off acid and specific enzymes enclosed in small "shells". The acid desolves the hard-mineralized bone, which allows the enzymes to react with the remaining soft tissue. The result of the chemical reactions is that a hole is created. One could say that the osteoclasts work in the opposite sequence compared with the osteoblasts. In other words, first they demineralize the bone and then breakdown the soft tissue.
Certain types of white blood cells are transformed into "killer cells" that "eat" organic material. They are produced in the same place as the osteoclasts and have similar properties.Osteoclasts are said to be a type of white blood cells that are specialists in destroying bone tissue.
The hard-mineralized bone tissue is surrounded only by one layer of osteoblast cells.Between the mineralized bone and the osteoblast cells lies a thin sheet of soft bone tissue (bone matrix) which the osteoblasts have created.
Osteoclasts can only attach themselves to mineralized bone. So if the hard bone tissue is surrounded by bone matrix and osteoblasts how can the bone "eating" osteoclasts penetrate through this barrier and attach onto the mineralized bone? According to Den tysta epidemin1 today’s researchers claim that the osteoblasts actually help the breakdown process and yield for the large osteoclasts cells.
There are different hormones that stimulate osteoclast activity. Some of these hormones can attach themselves to the osteoblast cells due to special receptors. It is believed that the hormones cause the osteoblast cells to breakdown the soft bone tissue instead of mineralizing it. After the soft tissue has been degenerated the osteoblast cells send signals to the osteoclasts in order to activate them.The osteoblasts then move aside giving the bone "eating" osteoclasts room to affix onto the hard bone tissue.The breakdown process of the osteoclasts is ready to begin.
For normal function the bones need a series of different materials. Amino acids for collagen production, calcium and phosphate for mineralisation and a number of different inorganic and organic substances such as hormones, vitamins and enzymes.
The activity of the osteoblasts and osteoclasts is either directly or indirectly related to the above mentioned substances. This leads to a delicate system that is dependent on a large number of variables (substances) that all have to be within certain limits in order for the system to function properly as a whole.
The disease, osteoporosis, is a result of an imbalance in one or several of the variables that affect the buildup or breakdown process. An imbalance doesn’t necessarily have to mean that the bone degenerates. The bone can for example become overly elastic and soft, or hard and relatively brittle.
To get a better understanding of the different processes that control osteoblast and osteoclast activity I’ll give a few examples of important influential factors.
The fat-soluble vitamin-D is a key coenzyme that has several functions. It is needed for the absorption of calcium. A long term shortage of vitamin-D may lead to a decreased mineralisation of the bone and it becomes soft and is easily deformed. Small children are especially prone to the disease (rachitis) that may develop from a lack of vitamin-D.Some good nutritional sources of the vitamin are milk, eggs, butter, and liver. Another source is sunlight (UV-rays), which initiates a reaction in skin cells that form vitamin-D.
Calcium is another key component in bone health. But calcium is also needed for other reactions in the body and can therefore be found in different body fluids mainly the blood. The concentration of calcium in the blood is very important and must constantly be kept between certain levels. Special glands have developed to ensure correct concentrations and work by a feedback system. If the levels become too low the glands secrete hormones that allow calcium to be taken from the bones deposits to raise the concentration in the blood. Since the bones consist of approximately 45% calcium salts a continuos transport of calcium to the blood will seriously deteriorate them.
Even though the mechanisms of bone function are fairly well understood treating bone related diseases is still mostly qualified guesswork. As an example it is believed that one of the mechanisms that control the activity of the osteoblasts and osteoclasts are weak electrical currents sent to bone tissue. But as this method was used artificially in order to accelerate the healing process of fractured or deteriorated bones it gave no satisfying results.
Another example of how theory and practice not always coincide is the debate on calcium intake. As I’ve described earlier, the blood-calcium levels must be within certain boundaries. If the levels are too low, calcium will be subtracted from the bones resulting in a diminished bone mass. Logically, an increased calcium intake would slow down or inhibit this process. But statistical evidence shows that countries, such as Sweden, where calcium intake is high suffer from more cases of osteoporosis than countries with a lower intake. On the other hand, individual population studies indicate that a calcium supplementation decreases the risk for fractures.
Of all the medical treatments available, hormonal treatments are by far the most effective. Especially estrogen treatment is very well documented and supposedly reduces the risk for fractures with about 50 percent. Scientific studies1 show that three years of estrogen treatment increases bone density by 10%. Estrogen works by hooking onto special "estrogen-receptors" in the bone, forcing a series of (anabolic) reactions to take place.These reactions "/. reduce bone resorption and retards or halts postmenopausal bone loss."3
Several studies show that during at least 10 years of treatment after menopause bone mass is preserved. But soon after estrogen treatment has stopped the bones start to degenerate at a faster rate.
There is a distinct difference between studies that compare fractures and studies that compare bone mass or density. Even though rapid loss of bone tissue might, to some extent, be prevented with estrogen, it doesn’t mean that the overall number of fractures will decrease noticeably. Especially when most of the studies were done only a few years after women’s menopause and most fractures don’t appear until the age of 60 - 70. Therefore statistical data on fractures among postmenopausal women should be regarded as highly inconclusive.
Physical activity or exercise is another way of preventing osteoporosis. But exactly what types of exercises reduce the risks for osteoporosis?
First of all the concept, "peak bone mass" must be clarified. Peak bone mass is the highest bone mass relative to total body weight that a person reaches during ones lifetime. This usually happens between the ages 20 - 30. Men have a higher peak bone mass than women resulting in a reduced risk for osteoporosis. In other words, the more bone mass one has as a young adult the more can be subtracted from the bones later on in life before they become brittle and porous.
Studies indicate that during the years of growing up the bone building process is dependent on physical activity6, 7, 8. Low activity results in a relatively low peak bone mass and vice versa. But all types of physical activity don’t have beneficial effects. For example swimmers have a lower bone mass than expected. This is most likely due to the fact that swimming doesn’t stress the bones significantly. Other activities, such as weightlifting that apply more stress to bones, have noted a higher bone mass. Conclusions from several studies6, 7, 8 are that exercises that stress the skeletal system are the ones that will promote significant bone growth resulting in a higher peak bone mass.
Statistical data clearly shows that osteoporosis is on the rise in virtually all countries around the world. Is this an indication that the quality of our bones is becoming worse?
Osteoporosis mostly affects the elderly and since the average human lifespan has greatly increased especially during the last century one could suspect a natural rise in the disease. Predictions can also be made that the increase of osteoporosis will become even faster in the future because of the aforementioned increase in longevity.
An increase in osteoporosis costs society huge amounts of money which is probably the main reason why it is favorable to try to find methods of decreasing the disease.But osteoporosis doesn’t, in and of itself, cost society very much money. It is the fractures caused by the disease that cost. So any decrease in bone fractures is going to decrease the costs for society.
There are several ways of decreasing the likelihood of getting osteoporosis.
One way is physical exercise. Even though it has not been proven (mostly because some of the mechanisms are still unknown) that exercise promotes the growth of bone tissue individual studies indicate that exercise has a positive affect on bone composition. According to, Ulf Lerner1 the bone building process seems to be influenced by the physical activity levels of the individual. If physical activity is low, for example in astronauts, or people who are forced to stay in bed for longer periods of time due to an illness the bone degenerates at a faster rate. It has also been shown that bone mass can be increased in individual bones if they are stressed more than others are. Tennis players have a higher bone mass in their "racquet arm" than their other arm.
Exercise doesn’t only promote bone growth it has also other beneficial factors such as increased muscle mass, better balance and hormone stimulation.
Larger muscles protect bones more efficiently than smaller and also when coordinated properly improve the overall balance. Muscles grow due to an alteration in hormones in the body.With exercise, more growth inducing (anabolic) hormones are released and at the same time less catabolic hormones such as cortisol circulate in the blood. If one exercises on a regular basis as an adult till one is relatively old (say 80 - 90) the natural drop in anabolic hormones will greatly be slowed down.As one of the results one could expect to have healthier bones. One statistical study that strengthens the theory is described in the chapter social prevalence. Comparisons were made on osteoporosis between city dwellers and people who lived out on the countryside.
Virtually all reactions that occur in our body are initiated or in some way controlled by different hormones. Exercise is one way to alternate the activity of these hormones. Another way is to induce chemicals into the body that will stimulate or inhibit certain hormones or reactions. One of the biggest problems with chemical (or hormonal) treatment is that only one or a few different chemicals are imbibed (injected).
The body can be said to be a large factory of chemicals that interact with one another according to certain patterns and principles. When we induce a hormone or other chemicals into this factory it might alternate some reactions in a predicted way but other reactions will also be influenced. This could lead to unwanted side effects or even worsen the condition at hand.
Different types of chronic treatments (for example estrogen) also costs and consumes large amounts of time (visiting the doctor for checkups). Not only does the treatment itself cost, all the research hours that are required before efficient treatment can be applied add up to huge sums.
As already mentioned, osteoporosis is increasing at exponential rates all around the world, costing societies abundance’s with money. Because there isn’t a quick cure available, the above mentioned methods (physical exercise or hormonal treatment) are the main and most potential choices for curing osteoporosis. The main problem before hormonal treatment can be applied is detecting who has the disease. According to SBU5 it is not even profitable to examine those at high risk (women after menopause). In other words there are huge additional costs in examining people who could possibly have osteoporosis.
There are several advantages in physical exercise over hormonal treatment. Here are a few examples:
These examples are meant as an alternative to hormonal treatment for older people who already have slightly porous bones. As mentioned earlier, exercise at younger age decreases the odds of developing osteoporosis later on in life because of a higher peak bone mass. This is however not an argument against hormonal treatment since the problem discussed is not how to prevent osteoporosis but how to cure it.
Something that goes hand-in-hand with exercise is ones diet. If the nutritional intake isn’t sufficient enough then no matter how much one exercises the body will suffer and the bones will degenerate.What is a sufficient diet varies from individual to individual but there are some general guidelines that one should follow. A growing body requires lots of energy for development and if the calorie intake isn’t higher than what the body uses it will suffer. Our diet controls to a large degree the hormonal ratios in the body. If for example one suddenly consumes twice the regular amount of calories a significant increase in anabolic hormones can be detected for a period of time. The composition of ones diet is also of key-importance but this topic area reaches beyond the scope of this paper so I won’t elaborate further.
As explained in the previous chapters osteoporosis is on the rise in most countries and is costing societies vast sums of money. Large amounts of money also go to research in order to find ways to cure the disease. In the future difficulties will arise in curing everybody who gets fractured since there may not be enough money for treatment, operations and providing general care facilities.
Today there are numerous different types of medical treatments available but all of them are more or less ineffective. They are expensive and usually have side effects.Treatments may help some individuals but are very ineffective statistically on the total population.Consequently, more research time should be concentrated on ways to prevent the disease rather than curing it.
One of the cheapest and probably most effective ways of preventing the disease is regular exercise. If the majority of all children were forced to exercise regularly until the age of 20 or 30 (until peak bone mass had developed) their generation would experience a drastic drop in the number of fractures related to porous bones (i.e. osteoporosis).
As mentioned in the introduction, one way to possibly decrease the prevalence of osteoporosis is to gain more knowledge about the subject.In contrast to some other diseases, the general population is unfamiliar with the disease, which contrasts to today’s huge prevalence of the disease. Most of the tall, white, slight women are unaware of the high risks for developing osteoporosis later on in life. If more money was used for education and advertisement the public would have a better understanding of what osteoporosis is and what the potential problems are. They could then take initiatives themselves in order to minimize the risks for developing the disease.
Article written by:
Jason McMillion
Printed: May 7, 1998
