What You Don’t Know About Bone Health May Hurt You

Poor bones.

They don’t have the flashiness of a beating heart or the curious appearance of a brain. Sure, they help you sit up straight and walk up a flight of stairs, but there are even more reasons to take note of just how important your bones are.

Your skeleton is the armor for your organs, constantly protecting them from everyday damage. Bones are also a repository for calcium and phosphorus, which all your organs’ cells need to survive. When in short supply elsewhere in the body, your bones selflessly give up these minerals—but their altruism comes at a cost. Without calcium and phosphorus, bones become weaker and more susceptible to injury. Nevertheless, they continue their campaign to help keep your body running, literally and figuratively. Simply put, bones may be the unsung heroes of the human body.

According to the U.S. Department of Health and Human Services, bone diseases are sorely underrecognized by medical professionals, leaving many people unaware of their risk for diseases such as osteoporosis, Paget’s disease, and osteomalacia.1 Fractures are the most common consequence of unhealthy bones, and they can exact significant physical, mental, and economic tolls.

Other issues that figure into the bone story? The critical role that prevention plays in bone health, of course, the important link between cancer treatment and bone loss, and the exciting news in drug development in recent years, which is allowing patients and their doctors to have new treatment options for both osteoporosis and cancer-related bone loss. So who needs to pay attention to this issue? Although older and White women are frequent targets of bone-related education, and women who are facing a cancer diagnosis should also pay close attention, all women should heed the message: good health is more than just skin-deep—it’s bone-deep.

Bone Basics

Bones are composed of proteins, minerals, and vitamins. Throughout your life your bones are in a constant process of remodeling, whereby old or injured bone is removed (called resorption) and new bone is formed. As an adult, about 5 to 10 percent of your skeleton is replaced each year.2 When bone loss begins to exceed bone formation, overall bone mass decreases. Bone mass, also termed bone density, refers to the amount of bone in our bodies. Women achieve peak bone mass around age 20 to 25, and after age 30 bones slowly decrease in density. Estrogen is a major component of maintaining bone mass, which is why women face the largest decline in bone mass around menopause, when estrogen begins to wane.

Although some bone loss is inevitable throughout the aging process, the good news is that by building healthy bones in your younger years, you can prevent significant bone loss later in life. Bone strength comes primarily from calcium intake and weight-bearing physical activities. In addition to low calcium intake and a sedentary lifestyle, other modifiable factors associated with weakened bones include excessive alcohol consumption, which decreases the absorption of calcium and vitamin D, and smoking, which reduces calcium. Certain medications can lower estrogen levels and weaken bones, such as aromatase inhibitors used to treat breast and ovarian cancer. When a woman experiences a reduction in estrogen at any point in her life, whether due to menopause, estrogen-blocking contraceptives such as Depo-Provera® (medroxyprogesterone acetate), late onset of puberty, or abnormal loss of her menstrual period, she is at greater risk of bone loss.1

Teresa Vazquez, a former nurse in Clearwater, Florida, notes that although she exercises daily and maintains an adequate intake of calcium, her background in medicine has heightened her awareness of potential problems down the road. “I am concerned about my bones and their health,” she says. “I want to stay active as I age, enjoy outdoor sports, and not rely on others for basic functioning. Without healthy bones, this becomes less probable.”

Building Better Bones

Nutrition and physical activity are the two primary ways to strengthen your bones and reduce your chances of significant bone loss. The body does not produce calcium naturally, so you must consume enough calcium through diet and supplements (see sidebar “Calci-yum!”). The amount needed varies somewhat by age, but most adult women need 1,000 to 1,200 milligrams per day.1–4 For calcium to be absorbed into the bones, however, you must also consume adequate amounts of vitamin D. One of the simplest sources of vitamin D is the sun. Approximately 15 minutes of sunshine on your face or arms three to four times per week is sufficient.1

Strengthening your bones through weight-bearing physical activities is as important as strengthening them from the inside. Such exercise is vital to keeping bones healthy because they cause the muscles and the bones to work harder, increasing their overall strength and performance. Effective weight-bearing activities include the following:

  • Lifting weights
  • Walking, jogging, or running
  • Tennis or racquetball
  • Stair climbing
  • Jumping rope
  • Basketball
  • Dancing
  • Hiking

Engaging in these activities for as little as 30 minutes a day, most days of the week, can make a big difference in your bone health. After leaving the nursing field, Teresa worked for several years as a personal fitness trainer, and many of her clients were women over the age of 40. She says that although weight loss was usually their primary concern, she tried to give them a comprehensive approach to addressing health.

“I always shared information about diet and exercise and the role it played in the health and the function of bones as well as joints, skin, and other areas,” Teresa explains. “I can only hope that by the time they finished training with me, they had a better picture of how everything works in unison.”

Osteoporosis: Not Your Grandmother’s Bone Disease

When the breakdown of bone exceeds the formation of new bone, overall bone mass and tissue decrease. The result is a disease called osteoporosis, which affects 10 million Americans.1 Osteoporosis causes bones to become excessively thin and weak, leaving them susceptible to breaks and fractures. People with osteoporosis are especially prone to fractures and breaks in the hips and the spine. According to the National Osteoporosis Foundation,5 the disease affects almost half of all women and about 16 percent of men over the age of 50. Although there are numerous bone diseases, osteoporosis is the most common.1

“For a long time, it was considered an esoteric disease,” says Edward Leib, MD, professor at the University of Vermont College of Medicine and director of the university’s Osteoporosis Center at Fletcher Allen Health Care. “People didn’t study it. They didn’t pay attention to it. It was part of aging and a natural consequence of getting older. Then we realized, number one, it’s not a benign diagnosis and, number two, we can do something about it.”

As Dr. Leib points out, osteoporosis is still often thought of as “an old woman’s disease,” but anyone can develop it. Individuals considered at greater risk are women, Whites, people with kidney disease, and older adults. Women who have cancer, are postmenopausal, have smaller body frames, consume less calcium, are forgoing hormone replacement therapy, or lead sedentary lifestyles are considered especially vulnerable.

People with osteoporosis may not know they have the disease until they suffer a fracture or a bone break, which is why it is frequently considered a “silent disease.” Women can undergo a simple and painless procedure called a bone mineral density test—currently the only way to diagnose osteoporosis before fractures occur. Dr. Leib emphasizes the seriousness of osteoporosis-related fractures, especially of the hips, which can increase mortality by nearly 25 percent in the first year postinjury. He notes, however, that a diagnosis of low bone mass is no reason for women to limit their activity.

“What sometimes happens when women discover that they have low bone density is that they don’t understand their actual risk of breaking a bone,” says Dr. Leib. “If we’re talking about younger women—women in their fifties and early sixties—even though they have low bone mass, their risk of fractures is something like 1 to 2 percent per year. They’ve developed this fear that I can’t go skiing anymore or If I go running, I might fall, so I can’t run anymore. That’s sad to see—that women might change their lifestyle or be afraid. It’s very important that not only the patient but the provider understand, when they get these reports, what it implies as far as fracture risk goes.”

The Cancer Connection

One group who should be particularly aware of osteoporosis and fracture risk is women and men diagnosed with or being treated for cancer. Some cancers may require the use of estrogen-blocking medications, such as tamoxifen (Nolvadex®) and aromatase inhibitors. Women diagnosed with cancer often take medications for longer lengths of time than previously, which can mean serious side effects on bone development. Allan Lipton, MD, professor at Pennsylvania State University School of Medicine, notes that the efficacy of aromatase inhibitors over tamoxifen in treating cancer comes with a trade-off: greater risk of bone weakening.

“We know that five years of aromatase inhibitors is better than five years of tamoxifen,” says Dr. Lipton. “In a high-risk woman with positive lymph nodes, many of us are continuing aromatase inhibitors even after five years, which puts her at risk of bone loss and possible osteoporosis.”

Tamoxifen, on the other hand, may actually protect against bone loss in postmenopausal women.6–8 In addition, chemotherapies can act directly on bone formation as well as inhibit ovarian functioning, which depletes estrogen and increases bone thinning.8,9 Dr. Lipton adds that cancer-related bone loss is most common in breast cancer patients who receive chemotherapy or hormonal therapy and in men with prostate cancer who receive androgen depletive treatments. Women who undergo ovarian-ablative therapies are also vulnerable to bone density reduction.9

Breaking the Bone-loss Cycle

As with most diseases, the best cure for osteoporosis is prevention. The National Osteoporosis Foundation reports that consuming adequate amounts of calcium and vitamin D, being physically active, avoiding tobacco and excessive alcohol, and, when necessary, undergoing a bone scan and taking medication to stop bone loss—all can help prevent osteoporosis.5

Recent progress in the development of novel drugs may also help stop bone loss. Hormonal therapies, including estrogen and calcitonin, may help block resorption; and antiresorptive medications called bisphosphonates, which include the well-known drugs Fosamax® (alendronate) and Boniva® (ibandronate), are designed specifically to prevent bone loss and reduce fractures by slowing the breakdown of bone. Dr. Leib says the potential for positive outcomes is great, with most medications reducing the risk of fracture anywhere from 35 to 80 percent, especially in high-risk patients. He and Dr. Lipton both note that the U.S. Food and Drug Administration (FDA) is evaluating the results of a new drug, denosumab, which has completed clinical studies in both women with osteoporosis and those with cancer treatment–related bone loss. Denosumab is specific, targeted, and convenient, requiring administration once every six months. It is designed to act on a protein in the body that promotes bone removal. Researchers think this drug may be particularly helpful in both women with osteoporosis and those with treatment-induced bone loss. Dr. Lipton adds that a bisphosphonate called Reclast® (zoledronic acid) was recently approved by the FDA for the treatment of osteoporosis in postmenopausal women. These two drugs are considered among the most cutting-edge treatments available for bone loss, which is welcome news for all women.

Medications may not be appropriate for all women. Typical candidates include women who have already been diagnosed with osteoporosis, have had an osteoporosis-related fracture, or are at increased risk for osteoporosis as indicated by a low score on a bone mineral density test. Hormonal medications are more appropriate for postmenopausal women, but women with a history of cancer should speak with their doctor about the use of estrogen-based drugs. Dr. Lipton points out that bisphosphonates can reduce renal function, which is important for women with cancer who may already be at risk for renal dysfunction, such as those with multiple myeloma. In rare cases, long-term use of bisphosphonates can increase the risk of osteonecrosis (loss of blood supply to the bone) of the jaw, and this risk is heightened among women receiving chemotherapy or radiotherapy. Alternatively, most women who have a normal score on their bone mineral density test do not need to consider medications, but, again, talk to your healthcare provider if you have any questions or concerns about whether medications are right for you.

“This is great step in the direction of finding effective therapy for osteoporosis. It’s not for everyone…but it’s a window into the future of finding other ways of stimulating osteoblasts and reducing fracture risk,” says Dr. Leib. “There are a lot of exciting things coming along.”

Calci-yum! Healthy Nutrition Leads to Healthier Bones3–4,10

  • Don’t let your fork stand in the way of better bone health. There is a wide variety of healthy foods that are rich in calcium:
    • Dairy products, like low-fat cheese and yogurt
    • Green leafy vegetables, such as broccoli and collards
    • Calcium-fortified foods, including orange juice, cereal, and tofu
    • Nuts, especially almonds
    • Most dairy products are fortified with vitamin D, but it can also be found in these foods:
      • Cod liver oil
      • Fatty fish, like salmon, mackerel, and tuna
      • Eggs (including the yolk)
      • Fortified cereals
      • Skip the salt. Foods that are heavy in nitrates, such as salami, bacon, and processed foods, can increase the amount of calcium excreted in urine.
      • Colas may also increase loss of calcium through the kidneys.
      • Women between the ages of 19 and 50 are recommended to consume 1,000 milligrams (mg) of calcium per day.
      • Women who are pregnant and lactating also need 1,000 mg per day.
      • Women ages 51 and older need 1,200 mg of calcium per day.
      • Most young adult and pregnant women need 5 micrograms (mcg; 200 international units [IU]) of vitamin D daily.
      • Most women between the ages of 50 and 70 need 10 mcg (400 IU) of vitamin D daily.
      • Women over the age of 70 need 15 mcg (600 IU).

References
1.Bone Health and Osteoporosis: A Report from the Surgeon General. US Department of Health and Human Services Web site. Available at: http://www.surgeongeneral.gov/library/bonehealth. Accessed April 7, 2009.

2.Bartl R, Frisch B, von Tresckow E, Bartl C. Bisphosphonates in Medical Practice: Actions, Side Effects, Indications, Strategies. New York: Springer Berlin Heidelberg; 2007.

3.Dietary Supplement Fact Sheet: Vitamin D. Office of Dietary Supplements. National Institutes of Health Web site. Available at: http://ods.od.nih.gov/factsheets/vitamind.asp. Accessed April 7, 2009.

4.Dietary Supplement Fact Sheet: Calcium. Office of Dietary Supplements. National Institutes of Health Web site. Available at: http://ods.od.nih.gov/factsheets/calcium.asp. Accessed April 7, 2009.

5.NOF Osteoporosis Prevention. National Osteoporosis Foundation Web site. Available at: http://www.nof.org/prevention/index.htm. Accessed April 7, 2009.

6.Denosumab May Help Prevent Bone Loss Related to Use of Aromatase Inhibitors. National Cancer Institute Web site. Available at: http://www.cancer.gov/clinicaltrials/results/denosumab0908. Accessed April 7, 2009.

7.Saad F, Adachi JD, Brown JP, et al. Cancer treatment-induced bone loss in breast and prostate cancer. Journal of Clinical Oncology. 2008;26(33):5465-76.

8.Michaud LB, Goodin S. Cancer-treatment-induced bone loss, part 1. American Journal of Health-System Pharmacy. 2006;63(5):419-30.

9.Shapiro CL, Manola J, Leboff M. Ovarian failure after adjuvant chemotherapy is associated with rapid bone loss in women with early-stage breast cancer. Journal of Clinical Oncology.2001;19(14):3306-11.

10.Eating Right: Giving Your Body a Nutritional Advantage. Foundation for Osteoporosis Research and Education Web site. Available at: http://www.fore.org/patients/eating_right.html. Accessed April 7, 2009.

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