The excessive bone loss that can occur in menopause compromises bone strength, resulting in an increased risk of fracture.
BONE is made up of calcium and protein. There are two types of bone: compact and spongy. All the bones in the body contain some of each type.
Compact bone appears hard and solid, and is found on the outside of bones. Spongy bone is found on the inside of bones and is filled with holes.
Bone is constantly undergoing change, with old bone broken down and new bone formed daily.
More bone is formed than is broken down when young, especially in childhood. Our bones stop growing between 16 and 18 years of age, with peak bone mass density attained by 30 years of age.
After that, more bone is broken down than is formed. This gradual and small amount of bone loss continues for the rest of your life.
A little bit of bone loss does not usually cause problems. However, excessive bone loss results in osteoporosis, which is characterised by compromised bone strength, resulting in an increased risk of fracture.
Although the bones are still of the same size, the outer walls of compact bone become thinner and the holes in spongy bone become larger, thereby weakening the bone considerably.
Osteoporotic fractures are increasingly common in Asians. The impact of these fractures is tremendous. It affects the physical, psychosocial and financial aspects of a patient’s life and family, as well as the community. The mortality risk is about 25% in the first year. The quality of life is also substantially affected.
About 10% will be bedridden and 25% wheelchair bound. In addition, chronic disabling pain affects the patient emotionally and mentally.
Women have a higher risk of developing osteoporosis than men as their bones are smaller and lighter. The condition of a woman’s skeleton depends on two factors: the amount of bone attained before menopause and the rate of bone loss thereafter.
Bone loss increases after menopause when the ovaries stop producing oestrogen, which is essential for bone health as it protects against bone loss. Hence, menopause is the biggest culprit in the process of bone loss.
Osteoporosis is more common in Asian and Caucasian women, and those of slender build.
Women’s risks of osteoporosis are increased further if they have an early menopause, ie before 45 years of age and when their uteri are removed (hysterectomy) before 45 years of age, especially when the ovaries are removed at the same time or if they do not have periods for more than six months due to exercise or excessive dieting.
The risk of osteoporosis is also increased in hormone-related conditions, for example, overactive thyroid gland (hyperthyroidism), overactive parathyroid glands (hyperparathyroidism), reduced oestrogen, adrenal gland conditions like Cushing’s syndrome, and conditions affecting the pituitary gland.
The risk is also increased if there is a family history of osteoporosis; a parent had a hip fracture; heavy smoking and alcohol consumption; lack of exercise; rheumatoid arthritis; eating disorders like anorexia nervosa and bulimia; prolonged use of high doses of steroids, eg in treating asthma and arthritis; and by medicines like diuretics, anticonvulsants and some medicines used in the treatment of breast cancer.
The clinical features of osteoporosis do not appear until a lot of bone is lost, thus explaining why it is called a silent disease. There are no warning symptoms or signs in most instances until a bone fractures following a minor fall or sudden impact.
The most common fracture sites are found in bones that have a lot of spongy bone – spine, hip and wrist.
The features include backache, decrease in height and slight back curvature.
There is usually no pain with osteoporosis. However, when there is a fracture, there will be pain, tenderness and even deformity. An obvious sign of osteoporosis is the characteristic bending forward (stooping) of the spine. This occurs because the fractured bones in the spine cannot support the body weight.
Diagnosing bone loss
The diagnosis of osteoporosis is often made after a fracture has occurred.
Individuals who are at increased risk of osteoporosis will be referred by their doctors for a dual energy X-ray absorptiometry (DEXA) scan. The procedure is painless and takes about 15 minutes to be done.
The DEXA scan measures the bone density and compares it with the bone mineral density (BMD) of a healthy young adult. The difference between the BMD measured and that of a healthy young adult is calculated as a standard deviation (SD), which is a measure of the variability based on an average or expected value.
The SD, which is called a T score, is classified as follows:
·Normal (T -1)
·Osteopenia, in which BMD is less than normal but not sufficient to be classified as osteoporosis (T -1 to T -2.5)
·Osteoporosis (T -2.5)
Another term used in bone density measurement is the Z score, which is the individual’s bone density expressed in standard deviation units compared to an age-matched population.
A diagnosis of osteopenia or osteoporosis does not mean that the risk of fracture is increased. The doctor will consider other factors like age, other medical conditions, use of medicines and previous injuries, before providing the appropriate advice.
The World Health Organization has developed a fracture prediction tool (FRAX). FRAX uses the clinical risk factors and BMD at the hip to provide a 10-year probability of hip fracture and the 10-year probability of a major osteoporotic fracture of the spine, forearm, hip or shoulder.
Preventing bone loss
There are several lifestyle measures that influence bone health.
The benefits of exercise are well documented, with beneficial effects on bone, heart and lung health. There are three types of exercises: aerobic, weight-bearing, and flexibility. An example of a moderate aerobic exercise of at least 30 minutes each day is a two-mile walk.
Weight-bearing exercise, ie those in which the legs and feet support the body’s weight, can delay or prevent bone loss. They include aerobics, dancing, walking, running, skipping and jumping on the spot, all of which also strengthens the muscles, ligaments and joints.
It is essential to wear footwear that supports the ankles and feet. Flexibility exercises, like yoga and stretching, help maintain muscle function and joint flexibility, and may also improve balance, which can decrease the risk of fractures due to falls.
Each exercise session should start with a 10 minute warm-up, and at the end, a cool-down session for five to 10 minutes.
In a good workout, a person will need to exercise towards the target heart rate for at least 30 minutes three times a week. A doctor will be able to provide advice on the target heart rate, which is dependent on a person’s age.
If a person has been diagnosed with osteoporosis or is not used to strenuous activity, it would be prudent to check with the doctor before commencing an exercise programme, especially if you’re above 40 years old or overweight.
A healthy diet is vital as it prevents cardiovascular disease, osteoporosis, diabetes and some cancers.
A balanced diet is high in grains, fruits and vegetables, with adequate water, vitamins and minerals, but low in fat.
The intake of sweets and fatty food should be limited. Fat intake should be less than 30% of daily calories.
Calcium is essential to maintain strong bones. The recommended daily consumption of elemental calcium in premenopausal and postmenopausal women is 1,000mg and 1,500mg respectively.
This can come from leafy green vegetables, calcium-rich dairy products (low fat or non-fat), and calcium-fortified foods and juices.
If this is not sufficient, calcium supplements may be used.
The body’s absorption of calcium is increased by vitamin D, which can be attained with about 15 minutes of daily exposure to the sun without any sunscreen, eating certain foods like milk, eggs, oily fish and liver, or vitamin D supplements.
It is advisable to eat plenty of fresh fruits and vegetables, nuts and seeds, legumes, complex carbohydrates like oats, wholegrain bread, brown rice, and essential fatty acids (good fats) from oily fish, like sardines and pilchards.
You should limit or reduce the intake of salt, saturated fat, stimulants like alcohol, coffee and tea, sugary food and junk food.
Supplemental vitamins and minerals may or may not be required, depending on whether the diet is balanced or otherwise. A discussion with the doctor or nutritionist would be helpful.
Other lifestyle factors that can help prevent osteoporosis include:
·Limiting alcohol consumption – the recommended daily limit is three to four units of alcohol for men and two to three units for women. Avoidance of binge drinking is essential.
It is important to eliminate environmental factors that can result in falls, thereby reducing the risk of fractures.
Some measures to avoid falls indoors include keeping rooms free of clutter, keeping floors smooth but not slippery, installing grab bars and using a rubber bath mat in the tub or shower, avoiding obstacles that you might trip over, and switching on the lights if getting up at night.
Some measures to avoid falls outdoors include wearing rubber-soled shoes, avoid walking on slippery surfaces, and using a cane if it is needed for added stability.
>Dr Milton Lum is a member of the board of Medical Defence Malaysia. This article is not intended to replace, dictate or define evaluation by a qualified doctor. The views expressed do not represent that of any organisation the writer is associated with. For further information, e-mail firstname.lastname@example.org. The information contained in this column is for general educational purposes only. Neither The Star nor the author gives any warranty on accuracy, completeness, functionality, usefulness or other assurances as to such information. The Star and the author disclaim all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.