Friday, January 20, 2012

Bone Mineral Density Tests

The recommendations for when and how often women should be tested for osteoporosis with bone density testing (DXA Scan) has been vague.   Many women are tested in their early 50s when they go through menopause with follow up tests as frequently as every year.  Others break a hip without ever being tested.

 A new study published in The New England Journal of Medicine states that bone loss develops slowly and women who have a  normal test when they are 65 do not need to be retested for 15 years!  Even women who show some bone loss can wait many years before they are tested again, according the the study authors.

The study followed 5,000 women over age 67 for over 10 years.  These women did not have osteoporosis at the beginning and they found fewer than 1% of women with normal beginning bone density developed osteoporosis over the next 15 years.  Only 5% of women who started with mild bone loss developed osteoporosis.

This study points to the fact that we have been over testing normal women who would not develop significant bone loss.  But there are a few aspects of the study that are important to note.  They only studied women with normal or slightly low Bone Mineral Density (BMD).  Women who have had prior broken bones, or who have significant bone loss at the time of screening should be followed more closely...perhaps every 3-5 years.

Not everyone agrees with the 15 year recommendation either.  "An interval of 15 years is too long", says Felicia Cosman, MD, senior clinical director for the National Osteoporosis Foundation.  She cites flaws in the study design.

Here is what I recommend for patients.  Get a screening BMD test at age 60-65.  If you are a smoker, take corticosteroid drugs,  are thin and fair, or have a mother or sister with osteoporosis or a broken hip, have the first screening test within 5 years of your last menopause period.  If that first DXA test is in the normal range,  there is no reason to repeat the test for at least 10 more years.  If the first test shows mild to moderate bone loss, repeat in 3 years to assess stability.  The most important test is the first one to establish a baseline and further testing should be tailored toward each individual woman.

There is an easy online tool that can help women and men calculate their risk of having a fracture in the nest 10 years.  It can help guide us to when we need to get a Bone Mineral Density (BMD) test by taking account of certain known risk factors.


Raymond Bouchayer said...

Good article Dr. Toni , but I do not see any mentions of Men and Osteoporosis .
A absolute fantastic Dr......who's name shall not be mentioned diagnosed me when I was in my early 50's with a very serious case of Osteoporosis .
I think at the age of 40 the first test should be done as a base line followed 5 years later...what say you ?

Toni Brayer, MD said...

Raymond: You make a good point that we should not ignore men. Men are not targeted for screening because they have higher bone mass due to testosterone. As testosterone declines with age, they lose bone also but not at the rate of women and they generally retain enough bone mass to live healthy older lives.

There are certain metabolic bone disorders that occur in both women and men and, as you pointed out, osteoporosis can occur in both.

It is not recommended that either men or women be screened in their 40's for what is a rare occurrence. The key word here is general population "screening" rather than targeted scans for symptoms or diagnosis.

Anonymous said...

Dr. Toni,

I am a 53 year old female, and my 86 year old mom has osteoporosis. My GYN suggested I get a baseline BMD when my periods are completely over. My primary care doc said I should do one now as a baseline. What do you suggest I do?



Toni Brayer, MD said...

I would suggest waiting until your periods are over (which should be pretty soon). Bone loss begins to accelerate when Estrogen falls. If you have menopausal symptoms that require estrogen replacement, that will also help preserve bone. If you do not need Estrogen for symptoms you will have plenty of time to decide on the need for treatment for bone loss alone if the DXA scan shows osteoporosis.

There is a genetic link to bone loss but exercise, no smoking,and calcium replacement are equally important for healthy bones.

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