Osteopenia vs. Osteoporosis

Q:  Should I be on a medication for my bone health?

I am 50 years old, 5'3½" and I weigh 105 pounds. My only exercise is routine housecleaning and running the kids around. I don't smoke and I've been taking calcium supplements (500mg with vitamin D) twice a day. I take HCTZ and lisinopril for my blood pressure. Last year, my bone density t-score was -0.5 at the spine and -1.1 at the hip. My repeat bone density this year is -0.6 at the spine and -1.3 at the hip.

My primary care doctor told me whether or not to take a prescription medication was my decision. I know Fosamax is a popular medication, but I don't want to take something unnecessarily, or take something and then find out in a few years that it causes something else bad, like we learned about some kinds of hormone replacement therapy.

A:  I'm impressed with your knowledge of osteoporosis. You have outlined important points to consider in the development and management of osteoporosis. Your thin frame does put you at risk. On the other hand, your exercise (housecleaning and running after kids are exercise), calcium and vitamin D intake, young age, and even the HCTZ (hydrochlorothiazide) medication protect you from osteoporosis.

In osteoporosis, bones have become so thin and weak that they break easily - especially bones in the hip, backbone (spine) and wrist. In the US, 8 million women and 2 million men already have osteoporosis, and 34 million more people have osteopenia. This means they don't have osteoporosis yet, but have lost enough bone to make them more likely to get it. White and Asian women are most likely to get osteoporosis.

Bone density describes how solid your bones are. Ordinary x-rays do not show bone loss until a lot of bone is gone. The best way to measure bone density is with a DEXA scan (dual energy x-ray absorptiometry/densitometry), which uses low energy x-rays to scan the spine, hip, and wrist.

The results of your scan are measured against standard scores to determine your risk of fracture. The t-score compares your bone density to a standard score based on young, healthy adults. A t-score of -2.5 or more usually means some degree of osteoporosis is present.

I interpret your bone density tests as osteopenia (a t-score less than -1.0 but not as low as -2.5, which would be osteoporosis). While most doctors would recommend medication for women with osteoporosis to prevent breaking a hip or spine, doctors argue about whether medications are necessary for women with osteopenia.

I follow the recommendations of the National Osteoporosis Foundation. It advises starting medication based on the t-score and the presence of major risk factors, such as smoking, low body weight, personal history of fracture as an adult, family history of non-traumatic fracture, and long-term use of prescriptions like prednisone. Minor risk factors are low calcium intake, low physical activity, overuse of alcohol, and circumstances where an accidental fall is likely.

The foundation suggests all women with a t-score less than -2 should start medication and women with additional risk factors should start medications with a t-score less than -1.5. Using these guides, you should simply continue with your calcium, vitamin D and exercise.

By the way, I'm not convinced that your bone density is truly declining, since your tests were only a year apart. These tests are not perfect, and the difference in your t-scores may be within the error of the test. To reliably diagnose a decline in bone density, tests should be at least two years apart.

Julie L. Mitchell, MD, MS, is an Assistant Professor of Medicine at the Medical College of Wisconsin. She practices internal medicine at the Froedtert & Medical College General Internal Medicine Clinic - East. Her column appears in the Milwaukee Journal-Sentinel.