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Boning Up: New Guidelines on Low Bone Density

By Jane Harrison-Hohner, RN, RNPFebruary 12, 2010
From the WebMD Archives

Have you ever had a bad fall off your bike, a crash while in-line skating, or an athletic injury while playing sports, and had to be away from normal fun activities for four to six weeks? Now imagine having low bone density, a fall, a hip fracture, and NEVER being able to resume taking care of yourself. Among older women (average age 82) after a hip fracture, about 25% will need long term assistance and 50% will have permanent loss of their prior mobility.

Now you may be thinking “That’s so far away, why should I be thinking about this now?” If you are a younger woman (age 14-30) you are now laying down the bone mass you will have for the rest of your life. Your decisions about birth control, diet, and other lifestyle choices can help determine your future bone density. If you are a woman above the age of 50, you may already have been told that you have lower bone density (“osteopenia“). New guidelines have just been published for the diagnosis and treatment of low bone density (NAMS, 2010). So this is a good time to update the latest recommendations on bone health for women of all ages.

When should I get tested for bone density?

Testing, usually done by a Dual Energy X-ray Absorptiometry (DEXA) scan of hip, spine, and wrist, is rarely done in women under 50. The exception to this rule would be if the woman has medical condition known to interfere with bone density. Health issues with known bone impacts can include: hyperthyroidism, type 1 diabetes, Cushing’s disease, rheumatoid arthritis, excess cortisol, and a greater than three use month use of oral (not inhaled) corticosteroids.

Historically all women were urged to get tested around age 50. Currently only 50 year- olds with one or more of these risk factors should be referred for bone density screening:

  • Bone fracture (excluding toe, finger, ankle, skull) after menopause
  • Body mass index (BMI) less than 21 (e.g., 5’6″ and 128 pounds)
  • Current smoker
  • Daily alcohol intake of more than 8oz. wine, 2 oz. of liquor, or 24 oz. of beer
  • Rheumatoid arthritis

By age 65 and over, all women should have bone mineral density (BMD) testing done. Insurance coverage, including Medicare, will reimburse BMD testing done in woman aged 65 and older.

What are the lifestyle choices for young women that impact bone?

Diet: Calcium and Vitamin D intakes are generally recognized as being very important in younger women. This mineral and vitamin act in concert to increase the amount of bone laid down in young women. Current daily dose recommendations are 1000-1300 mg. of elemental calcium and 800-1000 IU of Vitamin D.

The newer, higher doses of Vitamin D are based in part on studies of young persons living at the 21st latitude (i.e., Honolulu, Hawaii) who averaged 1 ½ hours of sun exposure per week. Among these sun exposed 24 year olds, almost half had less than adequate levels of Vitamin D in their blood (Binkley, 2007). Vitamin D is available in fatty fish and fortified dairy products. Here are some of the highest food sources of Vitamin D:

  • Cod liver oil, 1 tablespoon 1360 IU
  • Cooked salmon, 3.5 ounces 400 IU
  • Sardines in oil, drained 1.75 ounces 250 IU
  • Tuna in oil, drained 3 ounces 200 IU
  • Vit D fortified orange juice, 1 cup 142 IU
  • Vit D fortified milk, 1 cup 98 IU
  • Vit D fortified yogurts, 6 ounces 80 IU
  • Egg yolk, 1 20 IU

As a teenage woman the requirement for calcium is 1300 mg per day; by age 20 the recommended daily intake is 1000 mg per day. Here are some of the highest food sources of calcium:

  • Plain yogurt, 1 cup 435 mg
  • Milk, 1 cup 300 mg
  • Tofu, calcium-set, ½ cup 250 mg
  • Cheese, 1 oz 200 mg
  • Kale, 1 cup cooked 93 mg
  • Sardines, 2 92 mg
  • Almonds, 1 oz 80 mg
  • Dried beans, 1 cup cooked 70 mg
  • Spinach, 1 cup cooked 54 mg
  • Broccoli, 1 cup cooked 75 mg

As you can note, one would have to be a very conscientious eater to get the recommended amounts from food. Many women opt to take a supplement which contains both calcium and vitamin D.

Birth control method: Beginning in the 1990′s the first studies on the effects of birth control on bone density began to appear. One study in a small group of young women found that Depo-Provera seemed to suppress normal increases in bone density. By contrast, Norplant and birth control pills did not (Cromer, 1996).

Later studies were more reassuring. In a group of 433 teenage women, while Depo-Provera users had significant loss in BMD (compared with bone gain in the birth control pill [BCP] and women not using any form of contraception) all women stayed within the range of normal bone density. Moreover, the rate of bone loss slowed down after the initial year of Depo-Provera use (Cromer, 2008). Rahman and colleagues (2010) followed 240 young women for two years with DXA bone scans every six month. They established that the higher bone loss among Depo-Provera users could be blunted if Depo users quit smoking and increased their calcium intake.

Other lifestyle choices: Smoking cigarettes has adverse effects on bone density. Nicotine decreases blood estrogen levels (estrogen acts to decrease loss of established bone) and can decrease the body’s ability to absorb calcium (Krall, 1999).

What are the newest updates for women over age 50?

Screening:There has been a move away from universal, early DEXA screening for all newly menopausal women. This has arisen from a newly appreciated fact. Two women, one aged 50 and the other 70, even though they may have the same bone density score may have very different risks of hip fracture. If these two women had no additional risk factors other then lower bone density (“osteopenia”) with a T-score (comparison of a patient’s bone density to a healthy twenty something) of -1.5, the 50 year old would have a ten year risk of hip fracture of 0.4%. Her 70 year old counterpart would have a ten year risk of hip fracture of 1.4%. Now this may not sound so revolutionary, but the FDA suggests that pharmaceutical treatments are most appropriate when the hip fracture risk is 3% or greater.

There is an online tool called “FRAX” from the World Health Organization, designed for clinicians’ use, where a woman’s risk for a hip fracture or overt osteoporosis can be calculated. It is not intended for use if a woman is already on medications for osteoporosis.

For postmenopausal women who are not receiving bone targeted medications, the time between DEXA screenings is suggested to be at least two years. More generally a five year interval between screenings is adequate. If a woman is receiving medications to improve bone density it can take one to two years for a clinically important response to appear on DXA. Just like blood work done in a lab, there are small variations in measurement. Thus it is important to identify only those changes which are outside the variations in measurement.

You can learn more about bone density measurements from the National Osteoporosis Foundation (NOF). Included is an explanation of the types and results of bone density testing.

Treatment: There has been a big shift from ten years ago when medications were started in women with bone densities in the lower normal range. According to the North American Menopause Society��s position paper (2010): “A management strategy focused on lifestyle approaches may be all that is needed for postmenopausal women who are at a low risk for osteoporotic fracture.” Our imaginary 50 and 70 year old women mentioned above would certainly fit in that category.

The lifestyle approaches discussed at length in the NAMS position paper can be summarized as follows:

  • Eat a healthy diet-fruits, vegetables, adequate protein
  • Consume adequate calcium- 1200-1500 mg/day
  • Get adequate Vitamin D-800-1000 IU/day
  • Weight bearing & strength training exercise
  • Avoiding falls
  • Avoid cigarette smoke
  • Consume no more than 7 alcohol drinks/week (1 oz. liquor, 4 oz. wine, 12 oz. beer is considered a drink)

Women who have overt osteoporosis, an osteoporotic fracture, or an elevated risk for fracture by the FRAX tool are the candidates for pharmaceutical treatment. There are now many medications approved for the prevention or treatment of osteoporosis. A short list by class of drugs would include:

  • Bisphosphonates act only on the bone. Alendronate (“Fosamax”), risedronate (“Actonel”), ibandronate (“Boniva”), and zoledronic acid( “Reclast”) are all approved for use in the USA. They given as pills or an IV infusion. Studies have found that up to five years after stopping Fosamax, some bone benefit persists (Wasnich, 2004).
  • Selective estrogen receptor modulators such as raloxifene (“Evista”) act to maintain bone density and have an effect on other body tissues. For example, Evista was developed as an osteoporosis treatment but has now been approved as a way to prevent invasive breast cancer.
  • Estrogen (“Premarin”, “Estrace”), “Vivelle patch”, etc.) as used for hot flash relief, can be used for bone density protection in a subset of women. It does have effects on other tissues (e.g., increases the lining of the uterus, decreases vaginal dryness, and may stimulate breast tissues).
  • Calcitonin (“Miacalcin”) is available as a nasal spray or injection for treatment of already established osteoporosis.
  • Parathyroid hormone (“Forteo”) is one of the few treatments to actually rebuild bone as opposed to maintaining what is present. It is given as an injection, but may not be the first line treatment choice.

The specific medication, appropriate for a particular woman, is best determined by her health care provider. There will likely be several new medications, now in clinical trails, available over the next decade to treat aging baby boomers entering the age of increased fracture risk.

Alas, the 2010 NAMS position statement is not easily available to the public (unless you want to pay for it). I would expect it to filter out into the public domain within several months as it represents the most current thinking on management of osteoporosis. Meanwhile, go for a brisk walk, grab some hand weights (or a tennis racquet)- but be careful not to fall!

If you would like to know more about bone density screening, visit Bone Mass Measurement: What the Numbers Mean.

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