Osteoporosis Overview
Osteoporosis literally means porous bone and is a skeletal disorder characterized by compromised bone strength predisposing an increased risk of fracture (See Figure 1).
Figure 1: Bone Comparison*
* permission to use image granted by Turner Biomechanics Laboratory.
Osteoporosis is a general term for a skeletal condition characterized by a reduction in the mass of the bone affected and an increase in the risk of fractures. There are several forms of the disease, and osteoporosis should be differentiated from osteopenia.
Osteopenia is a bone condition in which the concentration of mineral is diminished and the total bone mass is reduced. In osteoporosis, whatever bone is left is normally mineralized. In osteopenia bone is demineralized.
In normal bone development, old bone is removed and new bone is generated in a balanced system of coupled actions. For unknown reasons, as people age, the coupled actions get out of balance; old bone is removed at a faster rate than it is replaced. This leads to osteoporosis. In osteoporosis, the bone composition remains normal, but both bone mineral and bone matrix are reduced. Figure 1 shows a cross-section of a normal and an osteoporotic bone. If bone strength is compromised, but not yet severe, a diagnosis of osteopenia is made. Patients with osteopenia are at risk of developing osteoporosis.
Osteoporosis is the most common type of bone disease impacting 20 million Americans and leads to approximately 1.5 million fractures in the US each year. The disease is typically asymptomatic until a fracture occurs. Preventing these fractures means recognizing who is at risk and identifying an appropriate screening protocol for them.
Osteoporosis is classified as either primary or secondary. Primary osteoporosis is the deterioration of bone mass that is not associated with a chronic illness. Secondary osteoporosis results from chronic conditions or their treatment that contribute significantly to accelerated bone loss.
Patient history and physical examination are not sensitive enough to diagnose primary osteoporosis. Nonetheless, the physical examination is important for the diagnosis of secondary osteoporosis as well as the direction of further evaluation. The medical history provides valuable information regarding the presence of chronic conditions, behaviors, and level of physical fitness, all of which can increase or decrease the risk of osteoporosis.
It is currently not possible to reverse established osteoporosis. The goal of therapy is to prevent osteoporosis or possibly to halt its progression. Ultimately, one third of all women and one sixth of all men will have a hip fracture. Vertebral compression fractures are even more problematic with osteoporosis causing approximately 700,000 to 750,000 vertebral fractures a year. These fractures result in increased hospitalization, increased economic burden and decreased quality of life. Typical osteoporotic fractures include fractures of the vertebra, distal forearm and hip. Of the approximately 25 million American women who have osteoporosis, one third will have a documented fracture. Vertebral compression fractures account for 150,000 hospital admissions each year in the US with an average length of stay of 9 days.
Osteoporosis is a public health problem. There are 125 million people at risk for osteoporosis-related fractures worldwide including 35 million people in the US. Moreover, the fracture rate is increasing faster than the population is aging. During the course of their lifetime, 30% of all postmenopausal white women will develop osteoporotic fractures.
Risk Factors
While osteoporosis is more common in women than in men, both sexes become vulnerable as they age. Additional risk factors for osteoporosis can be classified as genetic, nutritional and behavioral. These risk factors include:
Genetic:
- thin and/or small frame
- family history of osteoporosis
- race (white or Asian)
Behavioral:
- certain medications
- inactive lifestyle
- cigarette smoking
- excessive use of alcohol
- high caffeine intake
Nutritional:
- low body weight
- low calcium diet
Other:
- postmenopausal state
- advanced age
- certain diseases
- low testosterone levels in men
Patients suffering from osteoporosis may experience loss of height, changes in the way their clothing fits, and /or spinal deformity. However, osteoporosis is typically asymptomatic until a fracture occurs and therefore it is critical to recognize individuals who are at risk and identify an appropriate screening protocol for them.
Links to additional information about Osteoporosis (and sources for data on this page):
