How many women experience an osteoporotic fracture?

A few months ago one of our readers asked me to estimate just how many people in the U.S. actually experience an osteoporotic fracture. Sometimes it is difficult to tell fact from fiction and to sort out a pharmaceutical-induced “osteoporosis scare” perception from real fracture data.

Taking this reader’s question to heart, I asked myself , “How do we really know how many people actually have an osteoporotic fracture?”  It became quickly obvious that this is not an easy question to answer, largely because many people suffer “silent”spinal fractures that are never reported to physicians. In fact, it is estimated that two-thirds of all spinal fractures are undiagnosed; thus, they never enter into the official statistics. For example, my father at age 85 was in a car accident and it was incidentally discovered on x-ray that he had had two previous spinal fractures in his upper back. He had never noticed any pain, nor had any reason to think there might be a spinal deformity. Even now at age 98 he has no back pain, but has lost several inches of height.

Equally, many rib fractures are never reported. What we do know about, however, are most of the hip fractures that occur. The total number of hip fractures in the US is held to be somewhat over 300,000 a year. Some hip fractures, however, do slip by the statistics, such as the one experienced by my grandmother. At the age of 101, she fell in the bathtub and fractured her hip. She refused to go to the doctor and said that she “had taken care” of her two sons for a hundred years and they should now take care of her. She went to bed and remained there for one year to the day, at which point she died in her sleep.

So groups like the National Osteoporosis Foundation have made it their business to estimate how many osteoporotic fractures do occur. Their statistic is that one half of women age 50 and older will experience one or another osteoporotic fracture during their lifetime. They also report that one in four men over the age of 50 will also have an osteoporotic fracture in their remaining lifetime.

Granted it is in the best interest of the National Osteoporosis Foundation to seek out the highest possible fracture statistic estimates, and they likely include a great many inconsequential spinal vertebral fractures that were never noticed by the people experiencing them.

In my estimation of fracture incidence, I tend to include only fractures of significance and do not pay much attention to the undiagnosed spinal vertebral fractures. In this sense it is probably fair to say that 30% of US Caucasian women will experience one or another meaningful osteoporotic fractures in their lifetime. For example, looking at spinal fractures alone, I would mention a recent 15-year study looking at 2,700 US Caucasian women. At the onset of the study the average age was 69. Over the next 15 years, 18% of these women suffered a spinal fracture. Finally, the longer you live, the more likely you are to fracture. By the age of 90 about 32% of all females and 17% of all males in the US have experienced a hip fracture (See Susan Ott’s website: http://courses.washington.edu/bonephys/).
References:

Cooper, C. and Melton, L.J. 1992. Vertebral fracture: How large the silent epidemic? BMJ, 304, 793-794.
Cauley, J. et al. 2007. Long-term risk of incident vertebral fractures. JAMA, 298(23), 2761-2767.