Osteoporosis: The Silent Disease

Osteoporosis: The Silent Disease

Osteoporosis: The Silent Disease

By Robert A. Jacob, M.D.

Osteoporosis is a disease that has been recognized for generations, but only recently it has received the attention it deserves from medical professionals and the public. It is a disease that gradually weakens bones, making them progressively more fragile and prone to fracture. It can have an enormous impact on one''s health and quality of life.

The strength of our bones is dependent almost solely on the amount of calcium deposited. It is the calcium content which gives our bones their density and, hence, their strength. The consequence of low-bone density is an increased risk of fractures. Like many other diseases, such as hypertension and atherosclerosis, osteoporosis is a silent disease until some dreaded complication occurs.

Osteoporosis does not cause bone or joint pain until a fracture occurs. Worldwide studies have established that women achieve their peak bone mass at age 30. There are no good large-scale studies that have established the age of peak bone mass in men. Not everyone achieves their potential ideal peak bone mass. Because of factors such as inadequate calcium and vitamin D intake during youth, eating disorders, smoking, excessive alcohol, genetics and even nationality, ideal bone density may never be achieved.

Data published from The National Institute on Aging, reports there are 10 million people with osteoporosis and another 34 million people with low-bone mass, osteopenia. Osteoporosis and osteopenia are diagnosed based on bone mineral density (BMD). A numerical score is calculated and the results are reported as a T-score, which compares a person''s BMD to the young referenced population.

Studies have demonstrated racial and geographical predilections for the development of osteoporosis. For example, white women have a greater incidence than black women; Asians have a higher prevalence than Hispanics. White women are especially at risk. Although 80 percent of patients with osteoporosis are women, there are over two million men with the disease. In the U.S. it has been estimated that 20 percent of postmenopausal white women have osteoporosis and 50 percent have osteopenia. The prevalence in males is less at about five percent with osteoporosis and 40 percent having osteopenia.

An alarming statistic is that there are 1.5 million osteoporosis-related fractures in the U.S. annually. It has also been established that the risk of a 50-year-old white woman suffering a vertebral fracture during her lifetime exceeds her risk of developing breast cancer.

The majority of our bone mass accumulates during the first two decades of life. Up to 60 percent of our total bone mass occurs during adolescence and reaches its peak at about age 30 in women. At this point, there is a steady and incremental loss of bone mass of 1-2 percent per year with acceleration to 2-3 percent per year at menopause. This continues for approximately 10 years followed by a tapering again to a 1-2 percent loss per year thereafter.

Men lose bone mass later and at a slower rate than women. These bone loss changes, in both men and women, appear to be linked to both age-related and changes in levels of sex hormones. Men do lose the bone mass more gradually, simply because they generally do not undergo an abrupt period of sex hormone withdraw as women do in menopause. Their mid-life loss is less profound. It has been shown that bone density in men is affected by declining androgens and estrogen levels. Both of these sex hormones are present in men with the androgens being the precursor to the estrogens.

PREVENTION

Our ultimate goal is prevention and this must begin in childhood with the focus on good nutrition and regular exercise. This then becomes the cornerstone of prevention throughout our lives with adequate amounts of calcium and vitamin D intake beginning in childhood and extending life long. Calcium and vitamin D recommendations vary as we age. Children and adolescents need 1,000 mg of calcium and 400 units of vitamin D per day. Patients over 65 need 1,500 mg of calcium and 400-800 units of vitamin D per day. Avoiding excessive alcohol and smoking plus a healthy diet and regular physical activity are all modifiable lifestyle choices.

Physical activity is known to be one of the most important factors in both prevention and treatment. This is especially true of weight-bearing activities. Vigorous exercise and weight training have been shown to have beneficial impact but the exercise need not be strenuous to achieve results. Recently published data from the Nurses Health Study has reported that women who walk four hours per week had a 40 percent reduction in the risk of hip fractures. Postmenopausal women who walked at least eight hours per week had the same benefit of fracture prevention offered by hormone replacement therapy.

New technologies have made the early detection of osteoporosis readily available at a reasonable cost. Plain X-rays are notoriously imprecise in the diagnosis of low-bone mass.

The gold standard for bone density testing is the central DXA scan which measures bone density at two sites, the spine and the hip, and this provides multi-site bone density readings which are reported as T-scores, Z-scores and percent of young reference adult.

With the development of accurate and precise diagnostic tools has come the genesis of several new drugs and refinement of drug strategies in the treatment and prevention of low-bone mass. Hormone replacement therapy, once the mainstay for prevention and treatment, is no longer considered to be a long-term, safe and effective preventive medication. Studies from the Women''s Health Initiative have suggested that estrogen replacement therapy be utilized for the shortest period of time and at the lowest possible dose to achieve control of peri-menopausal symptoms. The newer medications
including the bisphosphonates, such as Risedronate and Alendronate; Calcitonin nasal sprays and a selective estrogen receptor modulator (SERM Raloxifene) have all been shown to increase bone mass and skeletal strength. They decrease the bone resorptive process and increase the uniformity of mineralization. The most recently introduced agent is a synthesized derivative of parathyroid hormone. It is a daily injection that is a treatment option for a select group of patients for a high risk of fracture. Drug choice is a complex issue and requires considerable clinical judgment as to the best treatment for any individual patient.

Robert A. Jacob, M.D., received his B.A. degree from Western Reserve University in Cleveland, Ohio . After that he attended Ohio State University where he earned his M. Sc. and M.D. degrees. His post-graduate training includes a surgical internship at University of Alabama Hospitals , general surgery training at Akron City Hospital in Ohio , and his Orthopaedic Surgery Residency at the University of Alabama . He is board certified in Orthopaedic Surgery and International Society of Clinical Densitometry. He is the senior member of Bluegrass Orthopaedic Group with which he has been affiliated since he began private practice.

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