Osteoporosis means “porous bone” and is a progressive bone-thinning disease characterized by losing too much bone or not making enough new bone. This decreased bone mass leads to fragile bones susceptible to fractures.
The National Osteoporosis Foundation (NOF) estimates that 9 million Americans have osteoporosis and 48 million have low bone density. Density measures the amount of calcium and minerals in the bone and is a measure of bone strength. The NOF suggests from a study that approximately one in two women and up to one in four men at or over 50 years old will break a bone due to osteoporosis. Spinal fractures are the most common type of osteoporotic fractures. Other common broken bones are in the hips and wrist. In fact, 40% of all women will have at least one spinal fracture by 80 years old. These vertebral fractures can permanently alter the shape and strength of the spine.
Bone is a living and essential growing tissue. Bone is vital to our survival; it forms red blood cells, stores essential minerals and supports our muscular system allowing us to move. Living bone is made of three major components: collagen, calcium-phosphate mineral complexes, and bone cells. Collagen is a protein that gives bones a flexible framework. Collagen and minerals allow bone to be both flexible and strong to withstand compressive stress. More than 99% of the body’s calcium is stored within bones and teeth, the remaining 1% is found in the blood and is tightly regulated. As living tissue, bone is constantly being renewed by specialized cells. Old bone is removed by osteoclast cells and new bone is formed by osteoblast cells.
Up until young adulthood the rate of new bone formation exceeds bone removal. This allows bones to grow larger and stronger with increased bone mineral density until peak bone mass is reached by age 30, this is maintained for several years. Then, bone resorption gradually begins to exceed bone formation. Each year bone loss naturally declines at a rate of 0.5% -1.0% per year. Women experience an accelerated loss of 1.0%-2.0% per year 5-10 years after menopause.
Osteoporosis may occur when there is a dysfunction in either bone growth or bone turnover. The rate of bone turnover is also directly affected by hormones. Bone loss accelerates in women after menopause because of a natural decline in estrogen.
Osteoporosis can occur from an imbalance in hormones.
- Hyperthyroidism is an excessive secretion of the thyroid glands.
- Hyperparathyroidism is increased activity of the parathyroid glands.
- Testosterone deficiency is a decrease in the sex hormone testosterone.
- Diabetes is a disease where the body does not produce or use insulin correctly. This leads to hyperglycemia, an increase in blood sugar. This increases susceptibility to infection and to glucose in the urine.
Other Causes of Secondary Osteoporosis
- Thalassemia is a hereditary form of anemia, a disorder of too few red blood cells.
- Multiple myeloma is a condition where there are multiple tumors within the bone and bone marrow.
- Leukemia is a serious cancer characterized by unrestrained growth of white blood cells in the tissues.
- Metastatic bone disease occurs when malignant tumor cells spread from one part of the body to the bones.
Osteoporosis is more likely to develop if optimal bone mass was not reached during the bone building years. It is very important that young children and adolescents receive a balanced diet with calcium and Vitamin D as well as a high level of physical activity for bone strength.
Osteoporosis does not affect everyone. There are factors that increase the risk of developing osteoporosis. Some risk factors are genetic, or inherited from biological parents. Other risk factors are due to medical conditions or particular medication usage. Risk factors that are considered "lifestyle-related" are ones that are modifiable and can be changed.
Non-modifiable risk factors:
- Female gender – women tend to have less bone mass and lose bone faster than men
- Older age - bones become thinner and weaker with age
- Menopause – decreased estrogen levels
- Family History of fractures or osteoporosis
- Small frame or low body weight
- Caucasian and Asian Ethnicity – these individuals are at a higher risk compared to African American and Hispanic ethnicities
- History of a fracture
Modifiable “lifestyle related” risk factors:
- Increased alcohol consumption – limit alcohol to 2-3 ounces per day
- Sedentary lifestyle
- Increased intake of caffeine, sodium, or protein -special high protein diets, eating excess salt, or increased caffeine intake can cause the body to lose calcium and lead to bone loss
- Reduced intake of vegetables and fruit
- Low levels of calcium and Vitamin D - A diet low in calcium and vitamin D promotes bone loss
- Medications - long-term use of certain medications, such as steroids and some anti-seizure medications can lead to bone density loss
- Anorexia nervosa- this restrictive eating disorder increases the risk for osteoporosis
Osteoporosis is often referred to as a ‘silent disease’, because it often progresses with little to no symptoms. The first sign of osteoporosis may be a fracture from a traumatic fall or benign event. More commonly bones actually become so weak they break after a benign event. Compression spinal fractures are caused by weakened vertebrae that can cause mid back pain.
In severe cases of osteoporosis, simply bending forward can cause a vertebral "crush fracture.” This type of vertebral fracture causes the front height of the vertebra to decrease, creating a wedged shaped vertebral body. This wedged shape allows for a forward curve in the mid back, called kyphosis. Kyphosis causes the shoulders to slump forward and the top of the back to look enlarged and humped.
Lab tests may be used to rule out any secondary disorders that might cause osteoporosis. An X-ray may detect problems with bone density if bones have lost 40% or more of normal density. An X-ray may also be used to evaluate a suspected fracture.
Above is a pelvic x-ray demonstrating poor bone penetration suspicious for osteoporosis.
The best diagnostic test to assess bone density is a bone mineral density (BMD) test. The most widely recognized bone mineral density test is a DEXA scan. A DEXA scan stands for Dual-Energy X-ray Absorptiometry. This low level x-ray measures the density of three important bone sites and is a completely painless, non-invasive test that takes minutes to complete.
In a DEXA scan, the amount of mineralized tissue within a section of spine or hip is measured. The value is compared to others of the same age and gender, measured as a Z score, and to healthy 30-year olds of the same gender at peak bone mass, measured as a T score. These scores are expressed as a deviation from the average. This indicates how far above or below normal one’s bone quality lies. A decrease in BMD clearly presents great risk of fracture. For each 1-point T-score decrease, the risk of fracture doubles.
The World Health Organization criterion defines osteopenia and osteoporosis as:
- Normal bone density is within one standard deviation of peak bone mass, T score 0 to -1.0
- Osteopenia is when the bone mass is between 1 and 2.5 standard deviations below peak bone mass, T score -1.1 to -2.5
- Osteoporosis is when the bone mass is 2.5 standard deviations below peak bone mass, T score less than -2.5
There is still no cure for osteoporosis, prevention is key. It is essential to focus on proper nutrition, exercise, and safety issues to prevent falls that may result in fractures. There are medications that can be prescribed to slow or stop bone loss, increase bone density, and reduce fracture risk. Please talk with your provider to learn if medications are an appropriate treatment option.
The Physical Therapists at Virginia Fitness & Therapy Center offer an Osteoporosis Program. Through the Osteoporosis Program your therapist will work one-on-one with you in designing the supervising an exercise program to manage and increase bone mass. The program is tailored to each persons specific needs based on the diagnosis given by the medical provider and your bone density exams. The program entails a blend of postural assessment and education, balance training, strengthening exercises, and breathing and relaxations techniques.
The Genetics of Bone DensityViews 5858