Osteoporosis is a disease of bone and is a serious threat among elderly men and women. This is actually related to wear and tear of bone and there is increase in risk of spontaneous fracture due to decrease in bone quantity. It is widely prevalent in our country and osteoporotid fracture is a common cause of morbidity and mortality in adult men and women.
In early days it was not focused or noticed due to absence of suitable diagnostic facility or clear-cut method for its diagnosis. WHO defined osteoporosis as a common skeletal disease where bone resorption exceeds bone formation with increased destruction of anatomic structure denoting presence of one or more fragility fracture.
As per data about prevalence of disease world-wide, 25% of women over the age of 50 have been found to succumb to breakage of bone due to having low bone mass and half of them (12.5%) are having risk of osteoporosis. In case of men only 8% of them have been found to suffer from osteoporosis. In our country the data was scarce till 1990 through there were several cases of bone fracture and low bone mass, now as per estimation there are about 12 million cases of osteoporosis and also there are chances of increase in many fold due to poor calcium and vitamin D intake, nutritional fads and poor acceptable to Hormone Replacement Therapy.
In other words the major causes of osteoporosis are inadequate calcium intake, immobility, alcoholism, smoking and drug effect. (The longterm use of some drugs such as steroid, heparin and warfarin etc, propagate the causes of bone loss).
It is revealed from a study on 4,895 patients in various cities of India that 80% of women and 50% of men (out of them}, suffer from low bone mass. Also 73.9% of women and 26.2% of men of above 60 years of age among them have been suffering from osteoporosis. So it is concluded that the situation is alarming.
Diagnosis
In the past X-ray has been used or otherwise there was no safe method for diagnosis of this disease. Also no simple blood or urine test was available for detection of osteoporosis, though the experiment is being done to develop for this disease and is likely to become available within coming months. Now Radiographic absorptiometry, Ultrasound densitometers, single photon Absorptiometry (SPA), Dual photon Absorptiometry (DPA) Dual X-ray Absorptiometry (DEXA) and Quantitative tiometry etc are available. They measure bone density of the lumber spine, hip and distal radios or ulna and play an important role in diagnosis and in fallow-up treatment response. Cost of DEXA investigation is much more high compared to ultrasound & QCT investigation. Though the facilities are available only in big cities of India.
Bone Mineral Density (BMD) is an important determinent of fracture risk in patients with osteoporosis and forms the basis of WHO classification.
Treatment
The treatment of established case of osteoporosis is difficult and is much more time consuming affairs. In this context clinical work is being done on war footing. Since the prevention is better than cure. Hence it is suggested for intake of adequate quantity of calcium, Vitamin D3, execrcise, HRT etc. However the followings drugs/methods are usually prescribed for treatment of osteoporosis.
(1) Calcium supplements
(2) Intake of Vitamin D3, Calcitriol, Sodium fluride
(3) Hormone Replacement Therapy (HRT)
(4) Bisphosphonates
(5) Exercise
1. Calcium Supplements
The intake of calcium as calcium salt or by nutritive products (diary items) is the best way for calcium supplementation. Calcium carbonate or calcium citrate salt are generally used. Calcium citrate is better absorbed than carbonate salt. It has shown reduction rate of bone loss and propensity to fractures. Women are required to take 1 gm of elemental calcium in their diet daily and increase up to 1.5 gm / day in case of history of osteoporosis in their family. In men 1-1'5 gm per day is also required. However in case of high dose of calcium, the patient is to be monitored to avoid hyper-calcermia, hyper calciuria and renal failure. Alfacalcidol 0.25 mcg (twice) with calcium 500mg prevents bone loss in women suffering from postmenopausal osteoporosis.
2. Vitamin D. Calcitriol & Sodium fluoride
Vitamin D in a dose of 0.5mcg per day is useful in corticosteriod induced osteoporosis, renalbone dystheophy and menopausal osteoporosis, Calcitriol has also been shown to reduce the incidence of verteberal compression fracture in women with mild to moderate established post menopausal osteoporosis. Its action is actually to promote calcium absorption from intestine and to reduce calcium resorption from the distal renal tubule and also calcium mobilisation from bone in the presence of para thyroid hormone.
It is clinically observed that Calcitriol increases bone mineral density by decreasing bone resorption but not by increasing bone formation. Its mean dose 0.8 mcg/day. Sodium fluoride is also observed as helping in bone formation as bone remodelling stimulants and bone formation stimulating regimens.
3. Hormone Replacement Therapy
Sex hormone Estrogen helps to maintain bone density in women. It can be prescribed for women with post menopausal osteoporosis within 20 years of menopause. Estrogen replacement therapy is most effective when started within 4-6 years of menopause. It SLOWS the bone loss and also reduces the risk of fractures, if started even after 6 years of menopause. HRT is considered as the first line of treatment of osteoporosis. Today it is the most economical treatment. The normal effective dose is 0.625 mg/day.
In case of women with intact uterus, cyclical progestragen is also used as medroxy progesterone acetate 5 to 10mg/day for 14 days. Generally estrogen is taken with progestogen. In osteoporotic women with an intact uterus, a combination of estrogen and progestogen or synthetic molecule that combine both estrogen & progestogen like properties has been found to be very effective in preventing bone loss. The side effect of breast cancer and menstruation has been observed sometime. In such cases HRT is to be discontinued. There is also risk of endometrial cancer with HRT. Now-days transdermal estrogen patch is also available for patient who cannot tolerate oral oestrogens.
On seeing the anti-estrogen effect of some HRT agent, new drug working as selective estrogen receptor modulators are developed. Clomifene and Tamoxifene are the drugs for induction of ovulation and prevention of secondary breast cancer. Now Raloxifene has been developed for prevention of breast cancer having action to prevent bone loss. It increases the BMD in spine, hip and total body. It decreases the risk of verte-beral fracture also.
5. Bisphosphonates
The Bisphosphonates bind tightly to the internal surfaces of trabecular bone and inhibit its breakdown. It also modifies the behaviour of bone resorption cells causing slow resorption of trabecular bone. Ultimately it prevents bone loss and increases bone mass over a period of 2-3 years. Alendronate and Etindronate are the drugs of this group generally used.
Chemically Alendronate is 4 amino-1 -hydroxy-butylidenebi- phosphonates and has been found to reduce the rate of bone resorption in post menopausal women, increasing bone mass in the spine and hips and reducing the incidence of fractures. Alendronate 5mg tablet is used for prevention and 10mg tablet is for treatment of osteoporosis. It is poorly absorbed from GI and is reduced if taken with food, beverage and calcium. Also 50% of absorbed drug binds to bone surfaces within 12 to 24 hrs and remains buried in bone and is retained inactively for months or years. Hence it is better to take this drug with water in the early morning in standing or sitting posture only.
6. Exercise
Lack of exercise and immobilization are the major cause of bone disease. In case of osteoporosis regular exercise is the best method of recovery from bone loss. In other way exercise is the best for bone remodeling cycle. It stimulates bone cell to grow. Bone mineral maintenance or hypertrophy depends on the types of exercise, frequency of exercise and use of gravity during exercise The exercise should be done on regular basis.
In a nutshell it is concluded that osteoporosis is a disease of silent nature and is effecting Indian population. Its diagnosis and regular treatment are very limited, costly and time taking and is yet to be regularised/ established. Hence prevention is better than cure. The adequate calcium and vitamin D intake, exercise, tissue selective estrogens HRT for post menopausal women, calcitonin & fluorides, are useful to prevent osteoporosis.
-- The author is based in Kolkata and writes on industry issues