As women age, they find themselves at greater risk of developing a variety of health problems. Should osteopenia be one of them?
The condition was recognized nearly 20 years ago by the World Health Organization as a potential precursor to osteoporosis, a severe thinning of the bones that can lead to increased risk of bone fracture. The idea was that women whose bones had started to thin could take action to reverse the trend before it was too late.
Osteopenia is identified by comparing a woman's bone density with that of a "young healthy adult" at peak bone density, around age 30.
The problem is, all women — and, to a lesser extent, men — begin to lose bone mass in midlife after the natural renewal process plateaus. In women, this accelerates after menopause because the loss of estrogen translates into less collagen for the bone matrix.
"Osteopenia is normal — it's like gray hair," says Dr. Nortin Hadler, a rheumatologist at the University of North Carolina and author of "Worried Sick: A Prescription for Health in an Overtreated America."
Hadler is one of many experts who say that the definition of osteopenia is overly broad and misleading. The way they see it, all women experience bone loss, but only a minority of those diagnosed with osteopenia are really on their way to developing osteoporosis.
"If you look at the way we define osteopenia, it's defined very crudely with very low sensitivity," Hadler says. "So almost everyone who is osteopenic is not in the group who's going to get fragility fractures. They're just in a greater risk group."
Bone-mineral density is assessed with a so-called T-score. A person with a bone density equal to the norm of that "young healthy adult" would have a T-score of zero, but a person with extremely thin bones might earn a score of minus 3. (The most common test for measuring bone density is the dual-energy X-ray absorption test, better known as a DEXA scan. It measures how many X-rays pass through a bone; the denser the bone, the fewer X-rays pass through.)
To qualify as osteopenic, a patient's T-score must be lower than minus 1. That means her bone density is one standard deviation below that of the typical 30-year-old. Statistically speaking, her bone density falls just outside the normal range.
Where to draw the line between osteopenia and osteoporosis is a matter of considerable debate. The World Health Organization says the threshold is minus 2.5. But in 2003, the National Osteoporosis Foundation and the American College of Obstetrics and Gynecology broke with the WHO and recommended that women be treated for osteoporosis if their T-score fell below minus 2.
Under the new definition, 6.7 million American women were instantly "diagnosed" with osteoporosis and would be recommended for treatment — with costs of at least $28 billion, according to a 2007 study published in Health Affairs. Using the minus-2 threshold, more than half of Americans ages 65 and up are labeled as having osteoporosis.
Whether one chooses to treat osteopenia comes down to a judgment call and a weighing of the risks of treatment against the risks of waiting and seeing.
The drugs used to treat osteopenia and osteoporosis, called bisphosphonates, aim to increase mineralization of the bone. They include the brand-name medications Fosamax, Boniva, Actonel and Aclasta.
But the treatments can cause problems. In some women, bisphosphonates can cause ulcers in the esophagus or lead to bone necrosis, or bone death.
Dr. Alexander Fishberg, medical director at the Center for Family Medicine at Florida Hospital, acknowledges that some physicians have fallen into the trap of treating osteopenia like a disease rather than an increased risk. "I think some women may get treated where the risk of fracture is very low," Fishberg says.
But he says that patients shouldn't shrug off concerns about osteopenia, and he points to evidence that many women in the osteopenia category will get fractures.
Fishberg takes T-scores into consideration but says that the decision about whether to treat osteopenia shouldn't be based on the score alone. Fishberg relies on the WHO calculator called FRAX, which takes into account a woman's age, ethnicity, family health history, lifestyle decisions like smoking and drinking and other risk factors. With all of that information, the FRAX algorithm makes two predictions: the chance that a woman will fracture a hip in the next 10 years, and the chance that she will fracture either her hip, spine, forearm or shoulder in the next 10 years. (Anyone can try FRAX online at http://www.sheffield.ac.uk/FRAX.)
The discussion between a patient and her doctor should involve factors such as lifestyle, exercise, calcium and vitamin D, he says.
"That's how I make my decisions," Fishberg says. "A good old-fashioned discussion with your patient to help form a plan so that both parties agree that the treatment is right for them."
Ultimately, the decision about whether to be treated for osteopenia must be made by the patient and doctor, he says: "In this day and age, our treatment should be individualized. An individual score does not define the woman."