Osteoporosis, or porous bone, is a disease characterized by low bone mass and structural deterioration of bone tissue, leading to bone fragility and an increased risk of fractures of the hip, spine, and wrist. Osteoporosis has no signs or symptoms until a fracture occurs – it is often called a ‘silent disease’.
To understand osteoporosis, it is important to understand bone and its remodeling process. Bone is living, growing tissue. It is made mostly of collagen, a protein that provides a soft framework, and calcium phosphate, a mineral that adds strength and hardens the framework. Throughout one’s lifetime, old bone is removed and new bone is added to the skeleton. During childhood and teenage years, new bone is added faster than old bone is removed. As a result, bones become larger, heavier, and denser. Bone formation outpaces resorption until peak bone mass (maximum bone density and strength) is reached, typically by the late 20s. After that time, bone resorption slowly begins to exceed bone formation.
For women, bone loss is fastest in the first few years after menopause, and it continues into the post-menopausal years. Osteoporosis – which mainly affects women but may also affect men – will develop when bone loss occurs too quickly or when bone formation occurs too slowly. Osteoporosis is more likely to develop if one did not reach optimal peak bone mass during bone-building years.
Osteoporosis Incidence & Burden
Worldwide, osteoporosis causes more than 8.9 million fractures annually. An osteoporotic fracture occurs every three seconds. Worldwide, over 200 million women are affected. Worldwide, 1 in 3 women over age 50 will experience osteoporotic fractures, as will 1 in 5 men aged over 50.
Nearly 75% of hip, spine and distal forearm fractures occur among patients 65 years old or over. By 2050, the worldwide incidence of hip fracture in men is projected to increase by 310% and 240% in women, compared to rates in 1990. It is projected that more than about 50% of all osteoporotic hip fractures will occur in Asia by the year 2050.
Certain risk factors are linked to the development of osteoporosis and contribute to an individual’s likelihood of developing the disease. Many people with osteoporosis have several risk factors, but others who develop the disease have no known risk factors. Some risk factors cannot be changed, but some risk factors can be modified by changing lifestyle.
Non-modifiable risk factors: • Family history • Older age • History of broken bones and height loss • Underweight • History of taking corticosteroid for more than 3 consecutive month • Diseases: rheumatoid arthritis, overactive thyroid, over-active parathyroid glands, type 1 diabetes or a nutritional/ gastrointestinal disorder such as Crohn’s or celiac disease, periods stopped for 12 consecutive months, ovaries removed before age 50, low testosterone levels • Menopause
Modifiable risk factors:
• Allergic to milk or dairy products, without taking any calcium supplements • Exposed to sunlight without taking vitamin D supplements • Low level of physical exercise • Smoking • Use of alcohol
Osteoporosis is often called a silent disease because bone loss occurs without symptoms. People may not know that they have osteoporosis until their bones become so weak that a sudden strain, bump, or fall causes a hip to fracture or a vertebra to collapse. Collapsed vertebrae may initially be felt or seen in the form of severe back pain, loss of height, or spinal deformities such as kyphosis (severely stooped posture).
Following a comprehensive medical assessment, doctor may recommend to have the bone mass measured. A bone mineral density (BMD) test is an important measure of bone health. BMD tests can identify osteoporosis, determine risk for fractures (broken bones), and measure the response to osteoporosis treatment. The most widely recognized BMD test is a central dual-energy x-ray absorptiometry, or central DXA test. It is painless – a bit like having an x-ray, but with much less exposure to radiation. It can measure bone density at hip and spine. BMD tests can: • Detect low bone density before a fracture occurs. • Confirm a diagnosis of osteoporosis if someone already have one or more fractures. • Predict the chances of fracturing in the future. • Determine the rate of bone loss, and monitor the effects of treatment if the test is conducted at intervals of a year or more.
To reach optimal peak bone mass and continue building new bone tissue as someone ages, one should consider several factors. Calcium: An inadequate supply of calcium over a lifetime can contribute to the development of osteoporosis.
Vitamin D: Vitamin D plays an important role in calcium absorption and bone health.
Exercise: Like muscle, bone is living tissue that responds to exercise by becoming stronger. Smoking: Smoking is bad for bones as well as heart and lungs. Smokers also may absorb less calcium from their diets.
Alcohol: Regular consumption of 2 to 3 ounces a day of alcohol may be damaging to the skeleton, even in young women and men.
Medications that cause bone loss: Several medications can contribute to bone loss. For example, the long-term use of glucocorticoids can lead to a loss of bone density and fracture.
Therapeutic medications: Several medications are available for the prevention and/or treatment of osteoporosis, including: bisphosphonates (zoledronic acid, Neridronate, Alandronate, Ibandronate, Residronate, calcitonin; estrogen (hormone therapy); estrogen agonists/antagonists, parathyroid hormone (PTH) analog; parathyroid hormone-related protein (PTHrp) analog; RANK ligand (RANKL) inhibitor; and tissue-selective estrogen complex (TSEC).