July 10, 2011

MALAYSIA: These old bones of mine

PENANG, Malaysia / The Star / Health / July 10, 2011


By Dr Pauline Lai Siew Mei

Taking care of bone health in the elderly – a focus on osteoporosis

MRS WLL, a 60-year-old Chinese woman, sees her general practitioner for her annual check up. She has been in good general health for the past several years. She experienced menopause in her early 50s and was given hormone replacement therapy (HRT) for her menopausal symptoms; and for the prevention of osteoporosis. She is currently not on any chronic medications.

Although the patient has no personal history of fractures, her older sister experienced a hip fracture.

Elderly people are more adversely affected by the secondary consequences of fractures than younger persons. Fractures of the hip often lead to devastating consequences, like persistent pain and limited physical mobility. – Reuters

She is 1.58m and weighs 46kg. She smokes cigarettes, drinks several cups of coffee a day, and rarely exercises. Her height has remained stable over the past four years.

Given the publicity surrounding the results of the Women’s Health Initiative study on HRT, she expresses her concern about the risk/benefit of her continued use of HRT.

What is osteoporosis?

Osteoporosis is a major public health concern worldwide. Although osteoporosis is more prevalent in women, it can also affect men. This disease can occur at any age and in any racial or ethnic group. However, it is more common in postmenopausal women, especially Asians and Caucasians.

In the United States, 13% to 18% of women above the age of 50 years have osteoporosis. Although there is limited data on the prevalence of osteoporosis in Asia, it has been estimated that by the year 2050, 50% of hip fractures will occur in Asia due to an increase in the elderly population.

In 1994, the World Health Organization (WHO) defined osteoporosis as a “disease characterised by low bone mass and micro-architectural deterioration of bone tissue, enhanced bone fragility and an increase in fracture risk.”

Typically, osteoporosis is a “silent disease”. There are usually no symptoms until the first fracture occurs. As the disease progresses, symptoms may include back pain, fractures, loss of height, skeletal deformity, neck strain, mid abdominal pain, alterations in bowel functions, such as constipation and rarely, lung disease.

Clinical considerations
The most common fractures associated with osteoporosis occur at the hip, spine and wrist. Worldwide, the incidence of hip fractures is increasing dramatically. It has been estimated that by the year 2050, the incidence of hip fractures will reach 3.25 million in Asia due to an increase in the elderly population. In the United States, approximately 1.5 million fractures are attributed to osteoporosis.

In Malaysia, it is estimated that by year 2020, about 3.3 million Malaysians will be above 65 years of age. Urbanisation and extended life expectancy contribute to the increased incidence of osteoporosis. Hip fractures due to osteoporosis affected 88 men and 218 women per 100,000 in Malaysia. Of these patients, 63% were Chinese, 20% were Malays and 13% were Indians. No Malaysian data was available on the incidence of other types of fracture due to osteoporosis.

Elderly people are more adversely affected by the secondary consequences of fractures than younger persons. Fractures of the hip often lead to devastating consequences, like persistent pain and limited physical mobility.

The prognosis for women who have suffered a hip fracture is poor. Approximately 28% of patients die within six months and 33% within one year of fracture. Enforced bed rest predisposes patients to lung complications, blood clots, disorientation, and muscle weakness.

Fractures of the spine are associated with back pain and significant performance impairments. Even minor fractures of the wrist or shoulder may disable formerly independent elderly persons, who may then require personal assistance in daily living activities for many months. This leads to the loss of independence and reduced quality of life.

Risk factors for osteoporosis
The risk factors for osteoporosis can be divided into two main categories: non-modifiable and potentially modifiable risk factors.

● Non-modifiable risk factors for osteoporosis include:

Advanced age: Ageing is the most important risk factor for osteoporosis fractures due to reduced bone mineral density (BMD). Gradual loss of bone starts to occur between the age of 30 and 40. Elderly women with poor health, dementia and poor uncorrected eyesight have an increased likelihood of falling and sustaining a fracture.

Being female: Postmenopausal women are most vulnerable and about four times more likely to develop osteoporosis than men. Menopause naturally results in a decreased production of oestradiol, which is vital for the regulation of the female bone remodelling cycle.

In postmenopausal women, the lifetime risk for osteoporotic fractures is between 40% and 50%. Men usually have bigger bones and do not suffer the rapid decline in BMD as experienced in women.

Early menopause: Premature menopause (<45 years of age) including surgical menopause, results in decreased levels of oestrogen and accelerated bone loss at an earlier age.

In Malaysia, the median age for menopause is 50.7 years old versus 51.4 years for women of European origin. In addition, with the extended lifespan, women are currently living an average of 30 years after commencement of menopause. Therefore, it is expected that the number of women who would suffer from osteoporosis due to menopause would increase.

Ethnicity: Being Caucasian or Asian increases the risk of osteoporosis. In the US, hip fracture rates for Caucasian women were 1.5 to four times higher than Afro-American women. This difference may be attributed to structural differences, such as greater peak bone mass, a slower rate of bone loss after menopause and better quality of bone micro architecture in Afro-American women. It is still not clear whether these are purely due to genetic differences or predispositions.

A family history of osteoporosis or previous fracture(s): Both men and women with a maternal family history of hip fractures have a greater risk for developing osteoporosis. The reason is not clear, but may be related to an increased propensity to falls, poor ability to protect oneself from injury or a genetic predisposition.

In addition, women who have suffered five or more fractures are 10 times more likely to experience another.

Personal medical history: Certain medical conditions can predispose an individual to accelerated loss of bone mass. Hormonal abnormalities such as hyperparathyroidism, hyperthyroidism and Cushing’s syndrome can impair the bone forming process.

● Potentially modifiable risk factors for osteoporosis include:
- Thin and/or small frame
- Thin, petite women are at a greater risk for developing osteoporosis because they have a lower body mass index (BMI) compared to women with large builds as they have less bone to lose than those with more body weight and larger frames.
- A BMI of 20 to 25 is ideal. A BMI below 19 is considered underweight and is a risk factor for osteoporosis.

Poor nutrition: A low BMI is often associated with poor nutrition. Nutritional deficiencies, such as inadequate calcium or vitamin D intake, anorexia or bulimia are risk factors for osteoporosis. Adequate calcium and vitamin D intake is important for optimal bone health as well as the prevention of falls.

Drug-induced osteoporosis: The most common medicine that can cause osteoporosis is steroids, especially when used in the long-term. It has been estimated that 30% to 50% of patients taking long-term systemic steroids will eventually experience a fracture.

Other medications that can cause osteoporosis are anticonvulsant drugs (such as phenytoin, phenobarbitone, carbamazepine and primidone), heparin (a blood thinner) and medroxyprogesterone (the main ingredient of an injectable depot form for birth control).

Cigarette smoking: Smoking increases the risk of osteoporotic fractures by up to 1.5 times. Smoking lowers BMD due to decreased calcium absorption. Cigarette smoking also increases the risk for osteoporosis by decreasing blood circulation to the bone.

Excessive alcohol intake: Excessive alcohol intake (more than two units a day) increases the risk for osteoporosis.

Sedentary lifestyle: A sedentary lifestyle places an individual at greater risk for osteoporosis because exercise and activities place weight on bones and help to prevent its deterioration. Women who sit for more than nine hours a day are 50% more likely to have a hip fracture than those who sit for less than six hours a day.

Falls and poor eyesight: Although bone loss is an important factor associated with hip fracture, there are other demographic and clinical factors that increase the risk of falling.

- Approximately 33.3% of persons over 65 years of age are at an increased risk of falling annually.
- Elderly women with poor health, dementia and poor uncorrected eyesight have a higher risk for falls and thereby fractures.
- Other factors include environmental hazards such as slippery or uneven walkways, medications with sedative properties or those that worsen muscle weakness.

What is this patient’s risk of a future fracture? Mrs WLL has several risk factors. She is an elderly, Asian woman, who experienced menopause in her early 50s. She also has an older sister who has experienced a hip fracture, indicating a strong family history of osteoporosis.

In addition, she is petite with a small frame, smokes cigarettes, drinks several cups of coffee a day, and rarely exercises.

How should this patient be evaluated? Osteoporosis can only be diagnosed through the measurement of BMD. The gold standard for the measurement of BMD is the dual energy x-ray absorptiometry (DXA) scan.

Measurement of the hip is the most useful for predicting fractures while measurement of the spine is useful for monitoring therapy.

BMD results are usually presented as a T-score. As the T-score falls below -2.5, the fracture risk increases exponentially.

Are there any preventive strategies for this patient? Lifestyle modification should be the foremost aim of prevention for all women. Lifestyle habits such as cigarette smoking and excessive use of alcohol or coffee can have a negative impact on bone health.

Weight-bearing exercises and walking programmes (20 to 30 minutes three times a week) can help build stronger bones and muscles and can be used to increase strength, flexibility and balance.

Mrs WLL should also be encouraged to examine her living environment and eliminate the risks of falls or fractures.

Casual exposure of the face, hands and arms to the sun for as little as 10 to 15 minutes a day during peak sunlight hours is usually sufficient for the absorption of adequate amount of vitamin D.

In addition, a healthy, well balanced diet, high in calcium (high calcium skimmed milk, yoghurt, cheese, sardines, tofu, green leafy vegetables) and vitamin D (oily fish, cod liver oil, eggs, fortified dairy products) should be encouraged as elderly patients absorb less calcium through their intestines.

What are her treatment options? Effective therapies for osteoporosis are available to reduce fracture risk by slowing down the rate of bone turnover, preventing further bone loss (beyond that which has already occurred) and increasing bone mass.

● Bisphosphonates - Bisphosphonates (such as alendronate, risedronate, ibandronate or zoledronate) are currently the first choice of treatment for osteoporosis. Bisphosphonates need to be taken in a specific manner and for at least a year to be effective in maintaining and improving bone mineral density (BMD) and to protect the patient against fracture.

Bisphosphonates increase bone mass and decrease fracture incidence in osteoporosis. There are various types of bisphosphonates which differ widely in their efficacy, side effects and routes of administration, thus offering a flexible range of therapeutic options. It needs to be taken first thing in the morning (an empty stomach), swallowed whole with a full glass of plain water, remain upright for at least 30 minutes, and to wait at least 30 minutes before taking any food, drinks or other medicines.

The most common side effects experienced are due to the “first dose effect”, which usually disappears within a month. These symptoms include severe bone, joint, and/or muscle pain and fever.

Patients may take paracetamol or a suitable analgesic to alleviate these symptoms. The other side effect commonly experienced is gastrointestinal side effects.

● Hormone Replacement Therapy (HRT) - As a result of the Women’s Health Initiative study, the role of HRT has recently been re-evaluated. Although HRT has been shown to have a beneficial effect on bone and is still an option for the treatment of menopausal symptoms, other more effective and non-hormonal therapies are available for the treatment of osteoporosis.

● Selective Oestrogen Receptor Modulators (SERMs) - Raloxifene is the only SERM indicated for the treatment of osteoporosis in postmenopausal women.

Raloxifene does not seem to stimulate uterine or breast tissues; therefore it is the drug of choice for women with a history of breast or uterine cancer or for women who have concerns about taking oestrogen, and for those who are unable to tolerate bisphosphonates.

● Anabolic therapy - An example of an anabolic therapy is teriparatide. It is indicated in high-risk postmenopausal women and in men not responding to other treatment.

Examples of such patients are those who are on bisphosphonates but are still losing BMD, still have a fracture and whose T-score is still very low, as well as those intolerant to bisphosphonates.

However teriparatide is not available as oral therapy. It needs to be injected subcutaneously into the thigh or the abdomen, and treatment is limited to 18 months.

● Strontium ranelate - Strontium generates new bones and protects against bone loss. It is available as a 2g sachet which should be diluted in a glass of water and taken at bedtime.

It should be taken on an empty stomach, at least two hours after food, milk or calcium preparations to ensure better absorption from the intestine.

● Calcitonin - Calcitonin is a naturally occurring hormone involved in calcium regulation and bone metabolism. It is only available as an injection or as an intranasal spray. Calcitonin is not widely used to treat osteoporosis. It is mainly used to relieve bone pain, and is therefore used for short periods.

● Vitamin and mineral supplementation - Vitamin D and calcium are not effective in fracture prevention. Therefore, vitamin D or calcium should not be used as a single agent to treat osteoporosis. Instead, vitamin D and calcium should be used as supplements in patients with osteoporosis.

The recommended dose of vitamin D3 is 400-800 IU daily, whilst the recommended dose of calcium in postmenopausal women is 1500 mg daily in divided doses.

When calcium and vitamin D are taken together, the amount of calcium needed may be reduced since intestinal calcium absorption is enhanced by the vitamin D. Excessive intake of calcium and/or vitamin D supplementation may encourage the formation of renal stones. Therefore, individuals should be advised to drink more water.

Dr Pauline Lai Siew Mei is senior lecturer at the Medical Education Research and Development Unit, Faculty of Medicine, University of Malaya. This article is contributed by The Star Health & Ageing Panel.

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