Osteoporosis: The Silent Disease

Interview with Theresa Lowry Lehnen (GPN, RNP, PhD) Clinical Nurse Specialist and Associate Lecturer South East Technological University (SETU)

It is estimated that up to 300,000 people in Ireland have osteoporosis. Although more common in females who have gone through the menopause, it can also affect men and even children.

It is commonly known as the “Silent Disease”, and is characterised by low bone mass and structural deterioration of bone tissue, leading to bone fragility and an increased risk of fractures.

Osteoporosis is the most common metabolic bone disease in Ireland and increases the risk of ‘fragility fractures’. These fractures occur mainly at the hip, vertebrae, and distal forearm and are associated with significant morbidity, mortality, and reduced quality of life, attributed not only to the fracture itself but also to the high prevalence of comorbidities in this patient population.

According to the Irish Osteoporosis Society (IOS), 20% of people aged 60 and above who sustain a hip fracture will die within 6 to 12 months, due to secondary complications and 50% of people over the age of 60 who sustain a fractured hip will lose their independence. Only 15% of people in Ireland are diagnosed with bone loss, leaving an estimated 280,000 people undiagnosed.

Causes of Osteoporosis

According to Theresa Lowry Lehnen, Clinical Nurse Specialist and Associate Lecturer South East Technological University, osteoporosis is multifactorial in origin. “It occurs when there is an imbalance between new bone formation and old bone resorption,” she explains.

“Bone turnover is regulated by the interaction between osteoblasts and osteoclasts. Osteoblasts form new bone and osteoclasts are responsible for bone resorption. Both types of cell are under hormonal regulation. Up to 90 percent of peak bone mass is acquired by age 18 in females and age 20 in males. The amount of bone mass in the skeleton can keep increasing until a person reaches their late 20’s, at which point, bones have reached their maximum strength and density, known as peak bone mass. As people age the rate of bone resorption by osteoclast cells exceeds the rate of bone formation, so bone weakens.”

Theresa adds that the greatest cause of osteoporosis is oestrogen deficiency which results in increased bone turnover in which resorption exceeds formation. “Corticosteroids can also induce osteoporosis in which trabecular bone is particularly affected from suppression of osteoblastic activity,” she says.

Modifiable and Non-modifiable Risk Factors for Osteoporosis

Modifiable Risk Factors

• Sex hormones: The reduction of oestrogen levels in women at menopause is a strong risk factors for developing osteoporosis. Men have a gradual reduction in testosterone levels as they age. Treatments for prostate cancer that reduce testosterone levels in men and treatments for breast cancer that reduce oestrogen levels in women accelerate bone loss.
• Endocrine: Too much thyroid hormone can cause bone loss. This can occur in hyperthyroidism or if too much thyroid hormone medication is used to treat an underactive thyroid. Osteoporosis has also been associated with overactive parathyroid and adrenal glands and hypogonadism.
• Medication use: Long-term use of certain medications, such as glucocorticoids and some anticonvulsants can lead to loss of bone density and fractures. Depo-Provera contraceptive has been proven to cause bone loss, particularly high risk if given during adolescence when bone is being laid down.
• Lifestyle factors: An inactive lifestyle can lead to weakened bones and increased risk of osteoporosis.
• Cigarette smoking and excessive consumption of alcohol increases the risk of bone loss and fractures.
• Poor diet increases the risk for osteoporosis. Low calcium and Vitamin D intake contributes to diminished bone density, early bone loss and an increased risk of fractures.
• Eating disorders, severely restricting food intake, low BMI and being underweight weakens bone in both men and women.

Non-modifiable Risk Factors

• Sex: Women are much more likely to develop osteoporosis than men. Women have less bone tissue and lose bone faster than men because of the changes that occur with menopause
• Age: The risk of developing osteoporosis as bones become thinner and weaker increases with age.
• Body size: People who have small body frames tend to have a higher risk of developing osteoporosis because they have less bone mass to draw from as they age
• Ethnicity: White and Asian women are at highest risk. African American and Hispanic women have a lower but significant risk.
• Genetic: A family history of osteoporosis is a very strong risk factor. People whose parents have a history of fractures also seem to have reduced bone mass and may be at greater risk for fractures.

Diagnosis Osteoporosis can be diagnosed by:

1. The presence of a fragility fracture
2. Measurement of bone mineral density (BMD)
3. Bone biopsy: Bone biopsy is a diagnostic procedure restricted to untypical, unclear and complicated cases in evidence based guidelines on diagnosis and treatment of osteoporosis. Bone Biopsy is not routinely used and should never be undertaken without consultation with a specialist in osteoporosis and metabolic bone disease.

Theresa continues, “Most fractures occurring after 50 years of age are osteoporotic. All persons presenting with a fragility fracture after 50 years of age or menopause should be considered as possibly osteoporotic. A detailed history of the fracture occurrence, physical examination and evaluation for other fractures is carried out while noting any presence of back pain, kyphosis, and height loss. Baseline laboratory tests include: Full blood count: Serum chemistry levels: Liver function tests: Thyroid-stimulating hormone level: 25-Hydroxyvitamin D level: Serum protein electrophoresis: 24-hour urine calcium/creatinine: Testosterone (total and/or free) and luteinizing hormone/folliclestimulating hormone.

“Additional testing should include measurement of bone mineral density (BMD) and if there is height loss and/or back pain, imaging of the spine. On average BMD is lower in women than in men, because women have smaller bones and smaller trabeculae. Women, as they also go through the menopause lose more bone in their lifetime than men; 50% in females Vs 35-40% in males.”

Osteopenia is the early stage of osteoporosis and places a person at risk of developing osteoporosis. The Irish Osteoporosis Society divides osteopenia into three categories:

1. Mild Osteopenia is a T-score of -1 to -1.49 and usually requires lifestyle changes; however, causes should be investigated and addressed.
2. Moderate Osteopenia is a T-score of -1.5 to -1.9 which usually requires lifestyle changes. Causes should be found and addressed and the person may require medication, depending on the cause, or if they have had a fragility fracture.
3. Marked Osteopenia is a T-score of -2 to -2.49 which requires lifestyle changes. Causes should be found and addressed and the person may require medication, depending on the cause, or if they have had a fragility fracture.

Treatment

Osteoporosis is treatable and fractures are preventable. “The primary goal of osteoporosis therapy is to reduce the risk of fracture,” she says. “A comprehensive osteoporosis treatment program includes a focus on proper nutrition, exercise, and safety issues to prevent falls that may result in fractures. In addition, medication to slow or stop bone loss, increase bone density, and reduce fracture risk may be prescribed.

“The treatment selected for each individual is based on their risk of fracture or re-fracture, causes of osteoporosis, age, DXA scan results and medical history. Assessment of bone markers before and at three and six months after the commencement of treatment will give an earlier indication of the response to treatment.”

Calcium and Vitamin D supplements

Calcium and vitamin D are essential for the prevention and treatment of osteoporosis. “Bone is a major store of calcium and phosphate. Every cell in the body requires calcium. Vitamin D helps to regulate cell growth and the immune system and is essential for the absorption of calcium. It increases the body’s ability to absorb calcium by 30-80%. Vitamin D is the only vitamin required by the body that does not have to be consumed through food or supplements as it is manufactured through the skin, when exposed to sunlight,” adds Theresa. “Supplements are generally only recommended when the daily amounts of calcium and Vitamin D from dietary sources are not being met.

HRT – Hormone Replacement Therapy

Oestrogen replacement for women going through the menopause can help to maintain bone density and reduce fracture rates while they are on the treatment. “There is a direct relationship between the lack of oestrogen after menopause and the development of osteoporosis. Early menopause before age 45 and any long phases in which the woman has low hormone levels and no or infrequent menstrual periods can cause loss of bone mass. Oestrogen therapy and oestrogen with progesterone hormone therapy are approved for the prevention of osteoporosis in postmenopausal women provided there are no contraindications. HRT is not suitable for people who have a history of breast cancer in their family, particularly in early menopausal patients or patients who have had a history of deep vein thrombosis,” she says.

Selective Estrogen Receptor Modulators (SERMs)

Theresa continues, “SERMs, brand name Evista ® work in a similar manner to oestrogen on bone, by preventing bone loss in postmenopausal women who do not have hot flushes and provided there are no other contraindications. It is used for the prevention and treatment of osteoporosis in postmenopausal women and to reduce risk of invasive breast cancer in postmenopausal women at high risk or with osteoporosis. Evista helps to maintain bone density and reduce fracture rates, specifically at the spine. It is administered as a 60mg tablet once daily. Evista can be taken with or without food or drink and at the same time as calcium and vitamin D supplements. Appropriate weight bearing exercise is also necessary.”

Monoclonal Antibody

Denosumab, brand name Prolia, is a monoclonal antibody which binds to RANK Ligand, inhibiting the maturation of osteoclasts, therefore protecting the bone from degradation. “Prolia is indicated for the treatment of osteoporosis in postmenopausal women and in men at increased risk of fractures. In postmenopausal women Prolia reduces the risk of vertebral, non-vertebral and hip fractures. Prolia is also indicated for the treatment of bone loss associated with hormone ablation in men with prostate cancer at increased risk of fractures. It is the first choice of drug for those at high risk of hip fracture or who have had a hip fracture over the age of 75 with T scores < −2.5 at femoral neck or with a humeral fracture. The recommended dose of Prolia is 60 mg administered as a single subcutaneous injection once every 6 months into the thigh, abdomen or upper arm. Patients must be adequately supplemented with calcium and vitamin D.”

Bisphosphonates

“Parathyroid Hormone – (PTH) brand name preotac is a bone forming agent that stimulates the formation of new bone administered as a daily 100mcg dose, subcutaneous injection in the thigh or abdomen for 24 months. It can only be prescribed by a Consultant, as it is a ‘high tech’ drug for severe osteoporosis. It is contraindicated in patients with cancer. Patients need to have follow up tests done at 1, 3 and 6 months, for elevated serum or urinary calcium. The patient should then have a repeat DXA scan and a new treatment plan should be implemented at the end of the course of treatment.

“Parathyroid hormone – (PTH) teriparatide, brand name Forsteo is a recombinant human parathyroid hormone 1-34 and a bone forming agent that stimulates the formation of new bone. Foresto is a ‘high tech’ medication that can only be prescribed by a Consultant. It is given as a daily 20mcg, subcutaneous injection in the thigh or abdomen for 24 months. The patient should then have a repeat DXA scan and a new treatment plan should be implemented at the end of the course of treatment. PTH is usually recommended for those with severe osteoporosis or fractures and those who cannot tolerate other medications. Forsteo can help with the pain of vertebral fractures and the reduction of vertebral and nonvertebral fractures in women.”

Theresa reflects that other treatments for osteoporosis can include Kyphoplasty and Vertebroplasty:

“Kyphoplasty is a surgical treatment involving a balloon being placed into the fractured vertebrae, followed by “bone cement” being injected into the balloon. Vertebroplasty is a non-surgical treatment involving a needle with “bone cement” inserted into the fractured body of the vertebrae under imaging guidance. The decision to perform these techniques is made by a multi-disciplinary team to ensure that this is the correct approach to managing the collapse.

“Many of the consequences of osteoporosis, particularly vertebral fractures, are associated with severe pain. Patients with established osteoporosis should be treated for pain relief and physiotherapy offered for the secondary effects of osteoporosis. Pharmaceutical and non- pharmaceutical measures can be used to alleviate pain. Patients should be advised of all the options, and encouraged to try different approaches until they find what works best for them.

“Prevention of osteoporosis should ideally start in utero. Childhood and teenage years, are critical periods for developing a strong healthy bone, especially before puberty, between the ages of 8 and 12 years. If good peak bone strength is achieved in early childhood, the risk of osteoporosis in later life is reduced.”

References available on request

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