Bone Thinning

All of these comments are routinely heard each and every day in physician offices.  Disturbingly, these comments portray a potentially significant problem in this country.  By not understanding the importance of developing their bone structure, many young women are not optimizing their 'bone health' when they are able.  An increase in bone thinning around the time of menopause will occur. It will be much worse in women who have not developed peak bone mass and strength in their 20's and 30's.  This, in turn, can lead to osteoporosis and a higher risk of fractures later in life.  The purpose of this review is to help educate women about achieving optimal bone health and to address many of the myths heard in physician offices everyday.

Contents:

Consequence of Poor Bone Development

Risk Factors for Bone Thinning

Bone Density Testing Criteria

What does it all mean?

The Role of Calcium

Bone development occurs very early in life and peak bone density occurs by 25-30 years of age.  The development of bone requires adequate 'building blocks' to form a firm foundation for the skeletal system.  In a very simplistic way, bone is constantly undergoing change or remodeling.  Bone building, by cells called osteoblasts, and bone breakdown, by cells called osteoclasts, commonly occur within major bones.  When bone is being built, more bone is added for strength, while less bone is broken down.  In general, bone building predominates until approximately age 30.  Gradual bone loss begins to occur between age 40 and 50, and progresses rapidly after menopause.  One of the building blocks used by osteoblasts for bone development is calcium.  Calcium is so important during development that a fetus extracts calcium from the mother through the placenta to aid in development.   Each and every living cell in the body requires calcium to function properly and your body cannot make calcium. 

Therefore, achieving adequate nutrition, including calcium, during childhood and beyond is vital for skeletal development and overall health and well-being.  Bone strength and density remain relatively constant until one approaches menopause, when bone loss will begin to occur.  After menopause, bone loss accelerates during the first 3-5 years.  This bone loss leads to more fragile bones and places a woman at greater risk for fracture. 

Genetics seems to play a big role in bone development and bone thinning.  A number of studies have shown a relationship between family members and bone thinning.  For instance, a pre-menopausal woman whose mother had osteoporosis is at increased risk for low bone density¹ . These findings suggest that women with a family history of osteoporosis should be educated about bone health and optimizing their bone density at an early age.

A number of conditions can alter calcium stores within the body, which may indirectly affect bone health.  For instance, calcium requirements during pregnancy are increased in order to allow development of the fetus.  In addition, breast milk production requires significant amounts of calcium.  Therefore, if adequate calcium intake is not achieved during pregnancy or breastfeeding, total calcium stores will decrease and can lead to bone deterioration.  Also, certain gynecologic conditions that predispose women to low estrogen levels before menopause can lead to an increased risk for bone thinning.

Inadequate bone development during adolescence and/or bone loss that subsequently occurs, especially around menopause, can lead to osteopenia and osteoporosis.  Approximately 10 million U.S. women meet criteria for osteoporosis, while another 15 - 22 million have osteopenia ^2,3 . While many people have heard of osteoporosis, osteopenia is still a relatively new term. Here's the difference:

Osteoporosis is a skeletal disease of low bone mass that results in a compromise of bone strength and increase risk of fracture, particularly of the hip, wrist and spine. This bone loss can occur without symptoms.  In fact, osteoporosis is thought of as a silent disease until the thinning has resulted in a fracture, which can lead to pain and long recovery periods.  It is a large problem in the U.S. with over 1.5 million fractures related to osteoporosis each year, including 700,000 spinal fractures and 250,000 hip fractures.  The national direct expenditures for osteoporosis fractures are estimated to be $14-17 billion annually ⁴ .

Osteopenia is a recent term that describes bone thinning that has not reached osteoporosis proportions.  It is considered a precursor to osteoporosis and defined as a decrease in bone mineral content.  In general, the lower the bone density, the higher risk of fracture. When there is a diminished quantity of bone found during a bone density test, but not to levels consistent with osteoporosis, a person may be told they have osteopenia.  In essence, the term should be thought of as a 'warning sign' that bone health should be addressed and optimized.

Many people are being tested for osteoporosis with devices in their physician offices or at health fairs.  Commonly called bone density tests, they attempt to measure the strength of bones.  Importantly, these tests are non-invasive.  No needles are involved and they do not hurt.  The test takes 10-15 minutes to perform and the amount of radiation is 1/10 the amount used in a chest x-ray.  The bone density test allows for an estimate of fracture risk for that patient. 

There are many ways of attempting to measure bone density.  The gold standard test is called a DEXA (dual energy x-ray absorptiometry).  Most of the significant studies on osteoporosis have used the DEXA scan.  The best area to perform the DEXA scan is on the hip and lower (lumbar) spine.  An evaluation of bone strength in these areas can help predict who is at risk for fracture at these sites.  DEXA results are given by a T-score, which is used to determine if a patient has bones that are normal, or in the osteopenia or osteoporosis range. 

Less useful, though very common, types of bone density testing include ultrasound or DEXA of the wrist, ankle or forearm.  Since these areas often do not correlate to the central skeletal areas (hips and spine), they are not as accurate for diagnosing osteopenia or osteoporosis.  If one of these tests is done and bone thinning is diagnosed, a confirmatory hip and lumbar spine DEXA should be done. 

Bone density testing should be done on patients at risk for bone loss.  In general, bone density testing is done around menopause or with significant height loss.  The best way to determine if a bone density test is needed is to determine if significant risk is present (see chart above) and discuss with your physician.  The most recent National Osteoporosis Foundation recommendations state that bone mineral density testing should be performed for:

•All woman aged 65 and older regardless of risk factors.

•Postmenopausal women under age 65 with one or more risk factors in addition to being white, postmenopausal and female.

•Postmenopausal women who present with fractures.

Many patients and their physicians are unsure what the term "osteopenia" means and how to manage the problem.  Part of the confusion about osteopenia and osteoporosis involves the different criteria that leading organizations have regarding treatment.  The World Health Organization diagnoses osteoporosis and osteopenia based upon bone density testing. 

World Health Organization Classification:

The National Osteoporosis Foundation states that treatment should begin in low risk patients with a T-score more negative than -2.0.  Patients with risk factors should initiate treatment with T-score more negative than -1.5. 

An important trial (the National Osteoporosis Risk Assessment trial (NORA)) has shed light on the treatment of osteopenia.   This study included over 200,000 postmenopausal women over age 50 with no prior history of osteoporosis who were followed for one year.  Surprisingly, over 39% of the women studied had osteopenia and these women were 1.8 times more likely to have a bone fracture compared to women with a normal bone density⁵.   These findings support the view that osteopenia is a condition of bone thinning that may lead to further bone loss, fragility and osteoporosis. 

Depending on the patient's history and her physician's preferences, osteopenia may come with a variety of recommendations.   In general, recommendations should center on bone health and prevention strategies.  John Sunyecz, M.D., Ob/Gyn and President MenopauseRx , Inc. states, "I review calcium requirements with all of my patients, providing information about adequate dietary intake and the liberal use of calcium supplements if needed.  I also review the importance of weight bearing exercise on the skeletal system."  When deciding how early to discuss bone health with a patient, Dr. Sunyecz routinely places a strong emphasis on building the best bone possible.  He reminds younger patients that between 20 and 30 years of age they will have "developed the bones they will have for the rest of their life" and emphasizes optimal calcium intake. 

Click here to read about a new study regarding Calcium, Vitamin D and the risk of fracture

Another important time for counseling patients about bone health is during pregnancy and lactation.  Since the developing baby needs calcium, the mother should consume at least 1200 milligrams per day.  As one would expect, breast milk production requires significant calcium.  If the mother does not replace this calcium, she may be at risk for bone thinning and osteopenia.  The calcium intake requirement during breastfeeding is also 1200 milligrams per day.   The best opportunity for bone loss prevention starts early in life with proper nutrition ad exercise to maximize bone mass. 

"If a bone density test has determined that a patient fits into the category of osteopenia, a careful review of the patients' history is in order," says Dr. Sunyecz.  "Depending on the situation, I may recommend increasing calcium intake and prescribe weight bearing exercise, with a follow-up bone density test in approximately 24 months."  In some patients with a significant risk of eventually developing osteoporosis, treatment may also include using a medication, in addition to calcium, specifically for the prevention of osteoporosis.  "Calcium is really the 'foundation' of managing patients with osteopenia at risk for further bone thinning," says Sunyecz.  Other lifestyle factors that help to maintain bone mineral density include limiting alcohol and smoking cessation.  In addition, weight bearing exercise, including walking and weight lifting, help stimulate osteoblasts for bone formation.

Recommendations from the National Osteoporosis Foundation and National Academy of Sciences are listed below:

                                        *Source: National Academy of Sciences (NAS)

                                        Recommendations for Vitamin D intake are 400 - 800 units per day. 

Dietary sources of calcium include skim milk, yogurt, cheese, broccoli and kale, and fortified orange juice.  A large amount of food must be consumed to obtain optimal calcium intake.  Since many women are monitoring calorie intake for weight loss, it is often desired to utilize a supplement to avoid a large number of calories from dietary sources of calcium.   Calcium carbonate and calcium citrate exhibit equivalent absorption when taken with meals and are the two most commonly used supplements ⁶ . Calcium carbonate is an excellent choice because it is well tolerated, economical and has more calcium per tablet than any other available product.  Click here for an explanation of the differences.

In general, calcium supplements should be taken in divided doses throughout the day and with meals to obtain optimal absorption.  Lastly, while a multivitamin may contain adequate daily vitamin D, it does not contain enough calcium to supply the recommended amounts.  Therefore, increasing dietary intake or additional use of supplements is recommended. 

"I cannot emphasize how important it is for patients to recognize bone development in their health.  The keys to 'bone health' include optimizing bone qualtiy with adequate calcium intake, identifying risks for bone loss and proper recognition and diagnosis of bone thinning," says Dr. Sunyecz.  "I encourage women of all ages to learn about their bone development and discuss any concerns with their health care provider."

References:

[1] Seeman E, et al Reduced bone mass in daughters of women with osteoporosis.  N Engl J Med 1989;320:554-558.

[2] National Institutes of Health.  NIH Consensus Development Panel on Osteoporosis Prevention, Diagnosis, and Therapy.  Osteoporosis prevention, diagnosis, and therapy. JAMA 2001;285:785-795

[3] National Osteoporosis Foundation.  Physician's Guide to Prevention and Treatment of Osteoporosis.  Belle Mead, NJ: Excerpta Medica, Inc.;2003.

[4] National Institutes of Health.  The National Institute on Aging.  AgePage. Osteoporosis: The bone thief.  Available at: www.nia.nih.gov/health/agepages.osteo.htm

 [5] Siris ES, Miller PD, Barrett-Connor E. Identification and fracture outcomes of undiagnosed low bone mineral density in postmenopausal women. Results from the National Osteoporosis Risk Assessment. JAMA, 2001;286(22):2815-2822.

 [6] Osteoporosis: Pathophysiology and Clinical Management.  Humana Press, Inc.  pp:286-287, 2003

The information provided by MenopauseRx, Inc. is not intended to replace the medical advice of your doctor or health-care provider. Please consult your health-care provider for advice about a specific medical condition. All rights reserved