Osteoporosis
Risk factors
Incidence/prevalence
Pathogenesis
Fragility fractures, unrelated to trauma are typically the type of fractures manifested in those with osteoporosis.
The biggest risk factors for patients with osteoporosis are not trauma related fractures. It is due to the skeletal fragility due to low bone mineral density that accompanies individuals with osteoporosis.
White and Asian women ages 50 and older are at a higher risk for osteoporosis especially post-menopausal women of these races.
In osteoporosis there is a increase in bone resorption that takes place, not giving enough time for bone production, therefore there is a loss of bone mass. This could result in a complete loss of the bone template used to make new bones in the body.
Estrogen acts through estrogen receptor α (ERα) and ERβ (ESR1 and ESR2). ERα is the primary mediator of estrogen's actions and configuration. Osteoblasts present ERβ, however, these are not as pronounced. Single nucleotide polymorphisms of ERα can affect the fragility of bone.
Skeletal fragility, the common manifestation of osteoporosis according to the National Library of Medicine, can be caused by failure to produce skeleton of optimal mass and strength during growth; excessive bone resorption resulting in decreased bone mass and an inadequate formation response to increased resorption during remodeling of the bone.
Anyone with a past history of fractures increases the risk of its prevalence.
According to the International Osteoporosis Foundation, one in three women and one in five men over the age of 50 worldwide have osteoporosis. Therefore, osteoporosis is greater among older women than men.
Risk for falls in trauma related injuries is less likely to occur with osteoporosis but is still likely. It increases the likelihood of fractures particularly of the hip or wrist.
Men that have low testosterone levels. This is relevant to osteoporosis because testosterone assists in keeping the bones strong.
Smoking decreases the ability of blood supply to the bones and other tissues. The nicotine in cigarettes slows the production of osteoblasts which are a key role in bone production. It also decreases calcium resorption which is essential in keeping the bones strong and healthy.
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Those who have undergone bariatric surgery since, after this procedure is performed, calcium and vitamin D absorption is compromised.
Those with other comorbidities such as kidney failure, inflammatory bowel disease, rheumatoid arthritis, liver disease since autoimmune diseases are associated with increased bone loss.
Those who take oral corticosteroids regularly or other high-risk medications such as thyroid hormone replacement, immunosuppressant drugs, and warfarin can cause a reduction in the body's ability to absorb calcium and can increase how fast bone is broken down. They decrease the function of osteoblasts, essential in bone formation which is impaired due to these medications.
Osteoporosis has a greater incidence in those with low bone mass at either the femur, neck or lumbar spine or both. Those at an increased risk of low bone mass, a precursor to osteoporosis, includes petite and underweight adults as well as older individuals. The CDC states, "In the United States in 2010, an estimated 10.2 million people aged 50 and over had osteoporosis and about 43.3 million more people had low bone mass."
Mutations in the VDR gene cause high metabolism of minerals in the bone, ultimately causing a reduction in bone density levels. The receptor for VDR is dependent on the environment, specifically calcium.
Osteoblasts produce RANKL, a ligand for the receptor activator of NF-κB (RANK) on hematopoietic cells, encourages the stimulation osteoclast activity. Osteoblasts also produce osteoprotegerin which blocks RANKL/RANK cycle, in charge of osteoclast activity and stimulation. Osteoblasts interact with osteoclasts in order to activate RANK. So, it has been determined that excessive expression of osteoprotegerin, which increase with age, are correlated with an increased risk of fractures and a lowering in bone mass density.
Absence or excessive runt-related transcription factor 2 (Runx2) or downstream factor also known as osterix are essential in order to stimulate osteoblast differentiation, otherwise their abnormal levels have been linked to decreasing bone mass.
Postmenopausal women who have a lack of estrogen, since they naturally decline during that time, is a key factor in the pathogenesis of osteoporosis in these individuals. An increase in bone resorption and there is impairment in bone formation, causing bone loss to estrogen deficient individuals.
With age or defects in the production or activity of local and systemic growth factors in the TNF family contribute to impaired osteoblast activity. IGF and TGF-β can alter bone formation. Mutations of BMP2 gene can be linked to low BMD and increased fracture risk.
Diagnostics
Treatments
Clinical Manifestations
Mutations of the first intron of gene coding for the type 1 collagen α1 chain and high homocysteine can contribute to an increase in fractures.
Locally produced cytokines such as IL-1 and prostaglandins can stimulate or inhibit bone resorption and formation. PGE2 are produced by bone cells by COX2 activity stimulates bone resorption.
Dexa scan: Measures bone density levels. Doctors recommend bone density tests if you have lost height as this can can compression fractures in the spine. Have a history of a fractured a bone as this can increase your risk for a broken bone. Frequent steroid usage such as prednisone which interferes with the bone rebuilding process, and a drop in estrogen levels typically after menopause which can lead to weakening of bones. Bone density tests are performed on the bones most likely to break including the lower spine bones, the narrow neck of your femur and bones in your forearm. The test typically tests 10-30 minutes. Results are represented by your T-score and Z-score. A T-score of -1 and above indicates a normal level. Between -1 and -2.5 indicates osteopenia, and -2.5 and below (down to 4.0) indicates you have osteoporosis. The Z-score is representative of how many standard deviations you are greater or lower away from your respective range and further tests are needed to identify the cause of this severity.
CT scan: a special contrast dye is given in the area of the body being examined to assess bone mineral density. On routine Cts, L1 vertebral body trabeculation measuring less than 90-135 HU indicates possible osteoporosis. A radiologist is in charge of this text and assessing the results.
Bone density numbers: Normal bones is 833 mg/cm2, osteopenic bone: 833 to 648 mg/cm2 and Osteoporosis: < 648 mg/cm2
Ultrasound: On the cancellous heel bone. BUA and SOS are the two parameters in the ultrasound test. BUA represents the ultrasound variation from normal range and the frequency of sound wave production relating to the absorption in the cortical bone and scattering wave detection in the cancellous bone being observed. BUA is measured in a range from 0.1-1 MHz. SOS measures the distance a sound wave travels and taking into account the unites of time.
Pain and bone deformity caused by a broken or a collapsed spine, cervical and dorsal kyphosis indicating decreased bone density.
Loss of height over time causes a risk of compression fractures in the spine.
Post-menopausal women that have decreased estrogen levels leading to a decreased bone density and increased fracture and broken bone rate
Individuals with a stooped posture. Excessive curvature of the spine.
A bone that breaks much easier than what is expected. Experience of pathological fractures.
Calcium and Vitamin D deficient individuals. These are needed to maintain bone density levels
Bisphosphonates: Alendronate, Risedronate, Ibandronate, and Zoledronic acid. Work by slowing down bone resorption, osteoclast activity. They also help to strengthen your bones by reversing bone loss and preventing future bone fractures
Selective estrogen receptor modifiers (SERMs): Raloxifene and Tamoxifen. This is a hormone therapy used for postmenopausal women to increase estrogen levels by slowing bone less and decreasing fracture risk
Calcitonin (Calcimar): acts as the hormone calcitonin in preventing osteoclastic bone loss and containing bone minerals
Teriparatide (Forteo): This is the only medication that helps to build bone. It is similar to the natural hormone in your body, the parathyroid hormone so, it is the only one that encourages osteoclast activity. It increases bone mass and strength.
Denosumab (Prolia): prevents osteoclast activation and activity in the body. Given a shot once every 6 months subcutaneously and is given alongside calcium and vitamin D since this medication lowers the levels of these in your body
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Personal experience
Social Determinants of Health
Nancy Macklin- She had grown up on a dairy farm. She always had lots of calcium in her diet so, she was shocked when she got diagnosed with osteoporosis. Nancy was diagnosed through a routine bone density scan, never having any family history of osteoporosis.
Stage 1: occurs when bone loss and bone formation occur at the same rate. There are no symptoms at this stage and your bone density scores are above -1
Stage 2: Bone loss is happening faster than your new bone can form. At this stage there will still not be any symptoms and bone density scores are between -1 and -2.5 respectively. This indicates likely osteopenia
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Stage 3: You are considered to have osteoporosis. Your bone loss is way above your bone growth and puts you at a high risk for pathological fractures. Fractures tend to be the main symptom. You will likely have a bone density of -2.5 or lower
Stage 4: The highest stage. Osteoporosis likelihood of fractures is higher than stage 3. Other symptoms include, changes in your spine by creating a stooped posture and loss of height. You will have one or more fractures at this point.
Poor dietary habits- lack of a calcium and vitamin D rich diet can affect bone density levels and contribute to an individual's likelihood of developing osteoporosis
Lack of opportunity to engage in physical activity- With lack of public parks, supportive groups that promote physical activity, etc. individuals, especially those who are older are at a greater risk for developing osteoporosis. With regular physical activity, the body adapts by building more bone and increased bone density.
Social care staff education- If individuals lack this resource, they may not be aware of opportunities and resources that can assist them in supporting good bone health
Frequent health care screenings- This decreases the diagnostic time of osteoporosis and can prevent the number of fracture occurrences. This can also prevent stage progression of osteoporosis and therefore limit the detrimental effects.
Lack of health insurance coverage- affects accessibility to BMD scans. Private insurance coverage was associated with lower probability of diagnosis
Smoking activity- There is an increased frequency of smoking activity among lower income individuals. Smoking decreases the blood supply to the bones, therefore slowing osteoblast activity. Smoking also, decreases the absorption of calcium form the diet.
Nancy had little knowledge about what treatment would look like and the results and effectiveness of these treatments. Her first ordered treatment was Aclasta which is an IV drug. She fountately had a background in the medical field and was familiar with what treatment with IV drug therapy would look like.
She has noticed dietary changes in her diet have helped by ensuring she is eating calcium rich food naturally, instead of just relying on calcium tablets. She also keeps up with her Vitamin D shots
She lives in Canada so she decided to seek out a pair of shoes that makes walking in icy conditions safe, reducing her fall and fracture risk. She bought a pair of spiky shoes to walk in the snow with when she has to leave her house.
She found a resource online to assist in supporting her education surrounding osteoporosis. She stumbled across Osteoporosis Canada. She decided to volunteer through them and supports the company in their finances and works on the database of donors.
Her goal is to have individuals both women and men to request frequent BMD scans from their doctors to reduce detrimental effects of osteoporosis and decrease diagnostic time. She wants to minimize the number of individuals that get diagnosed after sustaining a fracture.
She also wants to help individuals recognize the importance of calcium rich foods in the diet at both a young and older age.
Lastly, she educates people of the importance of getting a baseline bone densitometry test done early.
Nancy wants to make these resources accessible to all areas in Canada so individuals can benefit from these advancements and help improve clinical outcomes.
Works Cited
Godde, K., Gough Courtney, M., & Roberts, J. (2023, February). Health insurance coverage as a social determinant of osteoporosis diagnosis in a population-based cohort study of older american adults. Journal of applied gerontology : the official journal of the Southern Gerontological Society. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9841821/
Mayo Foundation for Medical Education and Research. (2024, February 24). Osteoporosis. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/osteoporosis/symptoms-causes/syc-20351968
Epidemiology: International osteoporosis foundation. IOF International Osteoporosis Foundation. (n.d.-a). https://www.osteoporosis.foundation/health-professionals/about-osteoporosis/epidemiology#:~:text=Osteoporosis%20is%20a%20major%20non,age%20of%2050%20worldwide%20%5B1%5D
Health inequalities: Osteoporosis. (n.d.). https://fingertips.phe.org.uk/documents/Health_inequalities_osteoporosis.pdf
Centers for Disease Control and Prevention. (2021, March 31). Products - data briefs - number 405 - March 2021. Centers for Disease Control and Prevention. https://www.cdc.gov/nchs/products/databriefs/db405.htm
Osteoporosis risk factors. UC San Diego Health. (n.d.). https://health.ucsd.edu/care/endocrinology-diabetes/osteoporosis/risk-factors/
Patient story - nancy macklin: International Osteoporosis Foundation. IOF International Osteoporosis Foundation. (n.d.-b). https://www.osteoporosis.foundation/patients/patient-stories/story-nancy-macklin
Raisz, L. G. (2005, December). Pathogenesis of osteoporosis: Concepts, conflicts, and prospects. The Journal of clinical investigation. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1297264/
Rosen, C. J. (2020, June 21). The epidemiology and pathogenesis of osteoporosis. Endotext [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK279134/#:~:text=In%20contrast%20to%20normal%20remodeling,have%20impaired%20peak%20bone%20acquisition.
Smoking and musculoskeletal health - orthoinfo - aaos. OrthoInfo. (n.d.). https://orthoinfo.aaos.org/en/staying-healthy/smoking-and-musculoskeletal-health/#:~:text=Studies%20have%20shown%20that%20smoking,of%20calcium%20from%20the%20diet.