As women age, osteoporosis becomes a growing concern – especially with all the attention it’s received since 2002 as part of the United States Bone and Joint Decade.

We’ve heard about the impact it can have on our quality of life, the necessity of preventative care, and the importance of being screened for this condition via a Bone Mineral Density (BMD) test.

Current recommendations call for postmenopausal women or women aged 65 and up to be screened for osteoporosis. But, testing intervals can range anywhere from one to five years, depending on age and other factors, creating confusion.

A new study published this month in The New England Journal of Medicine provides guidelines regarding testing intervals for osteoporosis screening.

Almost 5,000 women, aged 67 and older, with normal bone mineral density were studied for 15 years to help identify a BMD testing interval. Researchers identified this interval as the estimated time for 10% of women to “make the transition to osteoporosis” before experiencing a major fracture.

Adjustments were made for estrogen use and other risk factors such as body-mass index, smoking, usage of oral glucocorticoids and rheumatoid arthritis.

Based on the study results, the authors recommend that older women who have already taken a BMD test and have been identified as having advanced osteopenia (low bone mineral density) should be tested annually while women with moderate osteopenia may be retested every five years. Those with mild osteopenia or normal bone density may be rescreened after 15 years.

What are T-scores?

The T-score compares your bone density to that of a healthy 30 year old adult of the same sex. A T-score above -1 indicates normal bone density. A T-score between -1 and -2.5 indicates signs of osteopenia, or low bone density. A T-score below -2.5 indicates osteoporosis.

For women who began the study with a normal T-score of -1.00 or higher, only 10% developed osteoporosis, during an average period of 16.8 years.

Women with mild osteopenia (scores between -1.01 to -1.49), saw 10% developing osteoporosis after an average of 17.3 years.

For those with moderate osteopenia (scores between -1.5 to -1.99), it took an average of 4.7 years for 10% to develop osteoporosis.

Among the women who started with advanced osteopenia (lowest starting scores of -2.00 to -2.49), the time it took for osteoporosis to develop was just 1.1 years.

Age Matters

The longitudinal study also showed that the transition from osteopenia to osteoporosis was longer with younger age. For example, among participants with moderate osteopenia, the estimated BMD testing interval was approximately 5 years for women who were 70 years old and approximately 3 years for those who were 85 years old.

Dr. Margaret Gourlay of the University of North Carolina School of Medicine, lead author of the study, conceded that while researchers expected women with thinner bones to transition to osteoporosis faster, they “were not expecting this kind of separation between the low-risk and high-risk group. For those women with a T-score above -1.5 to have just a 10 percent chance of making the transition to osteoporosis after 17 years was a great surprise…good news.”

The Bottom Line

While this study helps to clarify the screening and rescreening procedure and allows doctors and clinicians to make better recommendations regarding BMD testing, it is important to be aware that these are merely guidelines and each of us has different needs based on our lifestyles and family history.

Women at higher risk for developing osteoporosis – smokers, daily alcohol consumers, those who weigh less than 127 pounds, who have rheumatoid arthritis, and/or who have had fractures or a history of fractures in their family – should consider speaking to their physician about being tested at a younger age – 50 to 64 – to establish their T-score and better monitor their Bone Mineral Density over time. Older women, too, may elect to be rescreened sooner than their T-score indicates, based on their physician’s recommendation.

But most importantly, all women should take care to maintain their bone and joint health through preventative healthcare, exercise, proper nutrition and supplementation, and positive lifestyle choices, and make every effort stay well-informed and in-tune with their body’s needs.

In my case, I had a Bone Mineral Density test done when I was about 40 years old. According to this study, it would not be recommended that I even have a BMD test until I'm well into my 60s. But, like so many other health measures (blood pressure, BMI, total cholesterol, LDL cholesterol, HDL cholesterol), I think it is helpful to benchmark these numbers at an early age. That way, 10, 15 or 20 years down the line, I know if I these numbers are "normal" for me. In the case of the BMD test, I found that I was a bit on the low side of normal.