Bones are much more complex than they look.
Most people could give a basic description of what osteoporosis is, but a common mistake is believing osteoporosis is just a basic part of aging. Truly understanding what causes osteoporosis and how bone tissue works can help clear up that myth.
Osteoporosis literally translates to “porous bone.” If someone has been diagnosed with osteoporosis, that means the density and quality of bone tissue are reduced. As a result, the bones are thin, brittle, weak, and easily broken or fractured.
Understanding Bone Density
It’s hard to believe that bones are living tissue—given how skeletons are presented in cartoons—but starting from birth, bone tissue is constantly being “remodeled.” That means new bone cells are being deposited, while older cells are absorbed into the bone matrix (a process called resorption).
“The cells that build bones are osteoblasts, and they’re responsible for bone formation,” says Sonal Chaudhry, MD, endocrinologist at NYU Langone Health. “Cells that resorb or break down bone are osteoclasts. In order to maintain healthy bone and remodeling, you do need both of these types of bone cells.”
During adolescence, more bone tissue is deposited than lost. This means the bones are more dense and strong, reaching their peak in your early 20s. After that, bone deposits decrease, and you start to resorb more bone tissue than you deposit. This is normal—but for people with osteoporosis, the bone loss is more extreme and they are more prone to fracture.
“Healthy bone is comprised of a dense matrix. In somebody who has osteoporosis, that matrix is less dense. There are more spaces; there are more holes in the bone,” says Dr. Chaudhry.
Bone density loss occurs on a spectrum, and doctors can use a bone density test score to diagnose someone with osteoporosis. If the bone density is low but not low enough to be osteoporosis, this is known as osteopenia. Without intervention, osteopenia can develop into osteoporosis.
Who’s at Risk for Osteoporosis?
About 54 million Americans have osteopenia or osteoporosis, according to the National Osteoporosis Foundation. Certain factors can put someone more at risk for osteoporosis, including:
Age above 50 years
White or Asian ethnicity
Low body mass index
Excessive alcohol consumption
Poor nutrition, including vitamin D or calcium deficiency
And frequent falls.
Postmenopausal women have the highest risk of osteoporosis. Part of that can be explained by women’s tendency to have lower body weights and smaller frames, which are risk factors for osteoporosis.
But furthermore, the hormone estrogen drops significantly after menopause, and this hormone reduces calcium absorption. Calcium helps with bone remodeling, so if the body isn’t absorbing the available calcium, bone loss is worsened, according to the National Institutes of Health.
Preventing osteoporosis is the best treatment. Following health habits to prevent bone loss, especially during youth and young adulthood, can help make sure bone density is strong for a lifetime to come.
After an osteoporosis diagnosis, doctors will assess fracture risk and bone loss to prescribe the most appropriate therapy. Treatments for osteoporosis focus on slowing the rate of bone loss, increasing bone density, and reducing the risk of falls and fractures, which can worsen the condition and quality of life.
Some of the most important osteoporosis treatments are lifestyle changes, including eating a healthy diet, exercising, and not smoking. Another important part of managing the condition is getting bone density tests regularly. Learn more about how exercise helps treat osteoporosis.
“If osteoporosis is left untreated, your risk of fracture really does increase over time, especially as you get older,” says Dr. Chaudhry.
Dr. Chaudhry is an endocrinologist at NYU Langone Health in New York City.
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So, osteoporosis is defined
by a low bone density,
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micro architectural changes in bone that
increase your risk of having a fracture.
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So the cells that build
bone are osteoblasts, and
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they're responsible for bone formation.
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Cells that resorb or
break down bone are osteoclasts.
00:00:30,870 --> 00:00:34,384
In order to maintain healthy bone and
00:00:34,384 --> 00:00:37,499
you do need both of these
types of bone cells.
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But osteoporosis can occur when
there is more resorption going
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on than bone formation.
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Osteoporosis in and of itself
doesn't cause any symptoms, until or
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unless you unfortunately fracture.
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A healthy bone is comprised
of a dense matrix and
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in somebody who has osteoporosis,
that matrix is less dense.
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There are more spaces,
there are more holes in the bone.
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And there's changes in the architecture of
the bone that increase the weakness and
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fragility of bones increasing
your risk of fracture.
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So tripping over the sidewalk and
maybe fracturing your forearm, or
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hopefully not, but
hip fracture in that setting.
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If osteoporosis is left untreated,
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your risk of fracture really does increase
over time, especially as you get older.
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Calcium: fact sheet for health professionals. Washington, DC: National Institutes of Health, Office of Dietary Supplements. (Accessed on December 21, 2021 at https://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/.)
Clinical manifestations, diagnosis, and evaluation of osteoporosis in postmenopausal women. Waltham, MA: UpToDate, 2019. (Accessed on December 21, 2021 at https://www.uptodate.com/contents/clinical-manifestations-diagnosis-and-evaluation-of-osteoporosis-in-postmenopausal-women.)
Fixed risk factors. Nyon, Switzerland: International Osteoporosis Foundation. (Accessed on February 6, 2019 at https://www.iofbonehealth.org/fixed-risk-factors.)
Osteopenia: when you have weak bones, but not osteoporosis. Cambridge, MA: Harvard Health Publishing, 2018. (Accessed on December 21, 2021 at https://www.health.harvard.edu/womens-health/osteopenia-when-you-have-weak-bones-but-not-osteoporosis.)
What is osteoporosis? Nyon, Switzerland: International Osteoporosis Foundation. (Accessed on December 21, 2021 at https://www.iofbonehealth.org/what-is-osteoporosis.)
What is osteoporosis and what causes it? Arlington, VA: National Osteoporosis Foundation. (Accessed on December 21, 2021 at https://www.nof.org/patients/what-is-osteoporosis/.)Who’s at risk? Nyon, Switzerland: International Osteoporosis Foundation. (Accessed on December 21, 2021 at https://www.iofbonehealth.org/whos-risk.)