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Amid all the confusion about taking drugs like Actonel and Boniva to fight bone loss (there is evidence that these drugs can make bones brittle), we decided to rerun Mary Carpenter’s story from last fall about diagnosing and treating osteopenia and osteoporosis.
SARAH S. WAS diagnosed with osteopenia based on a comparison of bone density measurements a few years apart, with a “big jump” down in the more recent measurement. Although her bone density had not been terrific for several years, she was taking steps inconsistently. Since the latest test, Sarah has made an effort to consume 1,200-1,500 mg/calcium per day in a combination of supplements along with “trying to up my milk and yogurt and cheese.” She also focuses more on weight-bearing exercises, including walking, biking and dancing, along with weight training. For Sarah, knowing the risk has been upped is “scary,” but the knowledge that she could forestall osteoporosis gives her hope. Her next step is a 24-hour urine test to see if there’s any improvement.
Osteopenia–decreased bone density which has not decreased sufficiently to be deemed osteoporosis–is considered an early warning sign for osteoporosis and the need for immediate action. Women who receive this diagnosis are generally grateful for the heads-up.
Osteopenia is defined by taking the “normal young” score–that of an average 30-year-old white woman–and measuring how much her bone density deviates from that norm, which is called a T-score. Bone density is most accurately measured by DXA (for dual-energy X-ray absorptiometry), or DEXA, which can detect as little as 2 percent bone loss per year, and the radiation dose is much lower than with standard X-rays.
“Normal” includes bone density within one standard deviation (SD) of the “young normal.” Osteopenia, also called low bone mass, begins at 1 to 2.5 SDs away from the norm; and osteoporosis is diagnosed with 2.5 SDs or more. One estimate has the risk for broken bones increasing by 50 to 100 percent for every standard deviation below the young-normal standard; with osteoporosis, even simple movements can break bones, especially in the hips. A problem with this system, however, is that some people naturally have a lower bone density–so it can help to have a baseline measurement from when you were closer to “normal young.”
Also, osteopenia–defined only recently in 1992–is considered by some physicians to be not only arbitrary and irrelevant but creating unnecessary worry along with unnecessary medical responses. Steven R. Cummings of the University of California, San Francisco, said, “There is no basis, no biological, social, economic or treatment basis whatsoever” for using one standard deviation. “As a consequence, more than half the population is told arbitrarily that they have a condition they need to worry about.” According to the National Osteoporosis Foundation, osteoporosis affects 10 million Americans, mostly women, while an additional 34 million have osteopenia.
Low bone mass is most often the result of aging. Beginning after age 30, existing bone cells are reabsorbed by the body faster than new bone is made; during the same period, bones begin to lose minerals, especially calcium, which makes them weaker. The number-one risk factor for decreased bone density is being female, and in particular being small-boned, because women start off with less bone mass than men. And hormonal changes at the time of menopause can speed loss of bone mass. Other top risk factors include being Caucasian or Asian, and having a family history of low bone mass.
Then there are the usual suspects: lack of exercise, smoking, drinking excessive amounts of alcohol. And one more unusual suspect: regularly drinking cola drinks –a Tufts University study found that women who drank three or more cola-based sodas a day had 4 percent lower bone mineral density in the hip, with caffeinated sodas doing the most damage. While caffeine is known to interfere with calcium absorption, the main culprit would be phosphoric acid, a major ingredient in most sodas–although the amount is minimal compared to that in chicken or cheese. Alternatively, the problem may simply be that people drinking so much soda are drinking less milk, or consuming less overall nutritional food and drink.
Treating osteopenia with medication has been shown to have marginal benefits. The more common recommendation is to increase calcium and weight-bearing exercise. However, there is the daunting statistic that almost 80 percent of bone density is determined by heredity and only 20 percent by lifestyle.
The nay-sayers feel that the added worry is unnecessary, and that additional testing and treatment is both unnecessary and costly. But they may not personally be up against the small bones and heredity shared by people like Sarah S.
–Mary Carpenter
