Medicine For People!

May 2010

Currently on the Clinic Facebook Page

Osteoporosis and Osteopenia: Evaluate Your Risk

This is the fourth in a series of articles on bone health. In the first article we showed that bones are living tissue, much more complex than a hunk of calcium. Then we examined the major test for osteoporosis, the DEXA scan. While I have previously held this up as a valuable test, further consideration shows that it has unpublicized limitations.

The DEXA scan unnecessarily frightens women about their risk of fracture. Because it has a powerful economic constituency, doctors continue to use it and people continue to believe in it.

Now that I've made the case that the DEXA scan does a poor job predicting who is at risk, where do we go from here? The risk of bone fracture is real and can lead to serious complications. If we can't trust the DEXA, what can we trust? How can we keep our bones strong? In this newsletter I give you a better way to evaluate your risk. In the final installment, I will cover the best strategies for preventing fractures.

The First Step – Consider Your Age

First, realize that we cannot prevent every fracture. That's impossible. But we can take steps to identify men and women at risk and to give them tools and information to reduce that risk. We don't always need DEXA to do this. Here's how.

Look at Your Age

As I showed in our April 2010 newsletter, the major risk factor is age1 .

Hip Fracture Chart

Figure: At age 70, about one woman in 200 (0.5%) will break a hip each year; at age 80, about 1 in 50 (2%); at age 90, should they survive that long, about 1 in 25 (4%).2

Major Factors – Health, Eye-sight, and Mental Sharpness

After age, the most important risk factors are the state of your health, the acuity of your eyesight, and your mental capacity. If you are strong, your vision is good, and you don't live in a mental fog, you have a better chance of not falling down and breaking something. This is not rocket science, but it is science.3 The chart below shows the degree to which various factors increase your risk.

Factor Increased risk of fracture
Rating one's own health as "poor" 240%
Taking an anticonvulsant medication 180%
Inability to rise from a chair without using one's arms 110%
Mother had a hip fracture 100%
History of hyperthyroidism in the past 80%
Resting pulse rate over 80 per minute 80%
Rating one's own health as "fair" 70%
On your feet less than four hours per day 70%
Currently using tranquilizers 60%
Depth perception poor 50%

What do these percents actually mean? The percents are the increase over the baseline. For example, of 200 women 70 years old, one has a fracture each year just because of her age. If that woman rates her own health as poor, then we would estimate the rate of fracture in her category to be 240 percent of 1 per 200, or 2.4 times 1 per 200, or 2.4 chances per 200.

Other Risk Factors

Listed below are major risk factors4 for which I do not have a percent increase. Again these factors have to do with general health and health habits, vision, and mental sharpness. This list of factors also includes your family history, because genetics always stacks the deck. Here is the list of risk factors:

  • You have had any fracture as an adult5
  • A member of your birth family has had a low-impact fracture

  • You weigh less than 127 pounds
  • You smoke
  • You have used at least 5 mg of prednisone (or similar potent corticosteroid) for at least 5 months
  • Estrogen deficiency at any time of life, but especially before the age of 456
  • You have poor vision
  • You have dementia
  • You've had recent falls
  • You've not consumed an average amount of calcium during your life
  • You have a low level of physical activity
  • You drink more than two drinks of alcohol most days

These factors are why we need to look beyond a score on a DEXA scan. Agility, equilibrium, muscle strength, nutrition7, and alertness prevent falls and strengthen bones. The DEXA can't tell you a thing about these key factors.

Online tools for Personal Assessment

If you'd like a custom estimate as to your risk of fracture, you can check out http://www.qfracture.org/ (doesn't ask for a DEXA score) and http://www.shef.ac.uk/FRAX/tool.jsp?locationValue=9 (for Caucasians, DEXA score optional, brand of scanner helpful). Remember, these websites only produce estimates. Our ability to predict fractures, just as our ability to predict heart attack, stroke, cancer and many other serious illnesses, is limited.

Bone Strength in Perspective

Articles about osteoporosis and osteopenia are often sensationalized. Bad news sells newspapers. Certainly we are living longer, so instead of dying of tuberculosis at age 47, we live until we're in our seventies and up. At those ages, some people break bones. The good news is that some people do not break bones and the strong-bone contingent is growing. In Finland, for example, the rate of hip fracture rose constantly between 1970 and 2004, but has fallen since then. Researchers wonder if increased awareness, better fitness, etc, has made the difference, but they really don't know.8

One reason for the recent improvement in Finland may be prevention. We've discussed this before and we will review both pharmaceutical and nutritional prevention next month. Of course, the third leg of prevention is vigorous activity! So, when you finish up this newsletter, get up from your computer and go outside!

Factoid: Adolescent females gain more bone per pound of lean body weight than do young men, and young women actually have denser bones than young men. This is reversed as we age.

Currently on the Clinic Facebook Page

Our Clinic Facebook Page updates you on health news and opportunities and points you to thoughtful commentary. Here's a recent example.

"Head Case," Depression and Anti-Depressants

If you've any interest in depression, you'll find no more worthwhile way to learn more about it than to read Louis Menand's wise analysis in The New Yorker. Menand, delightfully, answers critics of anti-depressants by pointing out that our ability to separate real diseases from unexplainable symptoms goes way back. We learned about malaria, for instance, by noting that some fevers, but not all, responded to quinine. Should we have withheld quinine for the hundred years or so it took us to discover why it worked?

Menand doesn't push the pills here. He carefully presents the arguments on each side of the question, including the fallabilityof research on anti-depressants and psychotherapy. See more on the clinic Facebook page or jump to Menand's article here.

Other Topics We've Covered on Facebook

  • An inside look at the horse-trading methods used for the Health Care Reform bill
  • When the patient knows best, and the doctor should listen.
  • Primary care: from "corner grocery" to "big box" medical services
  • Big Pharma swings its weight
  • Senate bill threatens access to vitamins and other supplements
  • Should I worry about my blood pressure?
  • Good germs, Bad germs

Soon to Come

  • Colon Cancer Screening
  • Multiple Vitamins

About Medicine for People!

We've been bringing you Medicine for People! for eight years now. Many of our views conflict with the received wisdom, hence the endnotes. If you wish to bring up DEXA scanning or any of our topics with your own physician, the references we give and the footnotes will help your doctor understand the reasons for your questions.

1 N Engl J Med 1995; 332:767-73.

2 Bone. 1996 Jan;18(1 Suppl):65S-75S

3 Science is knowledge based on observation, and tested to be sure the observation is correct.

4 Risk factors for vertebral and nonvertebral fracture over 10 years: a population-based study in women.

Finigan J, Greenfield DM, Blumsohn A, Hannon RA, Peel NF, Jiang G, Eastell R.

J Bone Miner Res. 2008 Jan;23(1):75-85.

University of Sheffield, Sheffield, United Kingdom. j.finigan@sheffield.ac.uk

Risk factors may vary for different types of fracture, in particular for vertebral fractures. We followed 367 women >50 yr of age from a population-based cohort for up to 10 yr. Factors that predicted vertebral rather than nonvertebral fractures related to physical weakness, poor health, and weight loss. Similar factors were also associated with greater bone loss at the hip. INTRODUCTION: Many risk factors predict fractures overall, but it is less clear whether certain factors relate to vertebral fractures in particular. The aim of this study was to compare the risk factors for vertebral and nonvertebral fractures. MATERIALS AND METHODS: We carried out a 10-yr prospective population-based study of 375 women who were 50-85 yr of age initially. At baseline, we measured BMD, blood and urine biochemistry, and anthropometric measurements. Medical and lifestyle data were obtained by questionnaire. Incident vertebral fractures were determined for 311 subjects from spinal radiographs at 0, 2, 5, 7, and 10 yr using an algorithm-based qualitative method, and nonvertebral fractures were confirmed radiographically. Relative risks were calculated by Cox regression analysis. RESulTS: During follow-up, 70 subjects sustained one or more nonvertebral fractures and 29 sustained one or more vertebral fractures. Risk factors that predicted both types of fracture included increasing age, decreasing BMD at all sites, prevalent vertebral fracture, and shorter estrogen exposure. For nonvertebral fractures only, the risk factors included low urinary creatinine and less frequent use of stairs. The factors for vertebral fractures included lighter weight, reduced body fat, heavy smoking, lower serum calcium, albumin, and thyroid T(3), weak grip strength, and poor physical capability. In a multivariate model, weight, fat mass, serum calcium and T(3), prevalent vertebral fracture, and physical capability remained significant. Furthermore, grip strength, serum albumin, weight loss, and physical capability were associated with rate of bone loss at the femoral neck, and a fast rate of bone loss was also associated with vertebral fractures. CONCLUSIONS: We conclude that overall frailty, which may consist of general poor health, small or thin body size, and lack of strength and physical capability, predicts vertebral fractures but is not a significant predictor of nonvertebral fractures. Bone loss rates are associated with similar risk factors and also with the incidence of vertebral fractures.

5 Clinical practice. Osteopenia.

Khosla S, Melton LJ 3rd.

N Engl J Med. 2007 May 31;356(22):2293-300.

Endocrine Research Unit, Division of Endocrinology and Metabolism, Department of Internal Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905, USA. khosla.sundeep@mayo.edu

6 Endogenous hormones and the risk of hip and vertebral fractures among older women. Study of Osteoporotic Fractures Research Group.

Cummings SR, Browner WS, Bauer D, Stone K, Ensrud K, Jamal S, Ettinger B.

N Engl J Med. 1998 Sep 10;339(11):733-8.

Comment in:

  • N Engl J Med. 1998 Sep 10;339(11):767-8. PMID: 9731095.

Department of Medicine, University of California, San Francisco, USA.

BACKGROUND AND METHODS: In postmenopausal women, the serum concentrations of endogenous sex hormones and vitamin D might influence the risk of hip and vertebral fractures. In a study of a cohort of women 65 years of age or older, we compared the serum hormone concentrations at base line in 133 women who subsequently had hip fractures and 138 women who subsequently had vertebral fractures with those in randomly selected control women from the same cohort. Women who were taking estrogen were excluded. The results were adjusted for age and weight. RESulTS: The women with undetectable serum estradiol concentrations (<5 pg per milliliter [18 pmol per liter]) had a relative risk of 2.5 for subsequent hip fracture (95 percent confidence interval, 1.4 to 4.6) and subsequent vertebral fracture (95 percent confidence interval, 1.4 to 4.2), as compared with the women with detectable serum estradiol concentrations. Serum concentrations of sex hormone-binding globulin that were 1.0 microg per deciliter (34.7 nmol per liter) or higher were associated with a relative risk of 2.0 for hip fracture (95 percent confidence interval, 1.1 to 3.9) and 2.3 for vertebral fracture (95 percent confidence interval, 1.2 to 4.4). Women with both undetectable serum estradiol concentrations and serum sex hormone-binding globulin concentrations of 1 microg per deciliter or more had a relative risk of 6.9 for hip fracture (95 percent confidence interval, 1.5 to 32.0) and 7.9 for vertebral fracture (95 percent confidence interval, 2.2 to 28.0). For those with low serum 1,25-dihydroxyvitamin D concentrations (< or =23 pg per milliliter [55 pmol per liter]), the risk of hip fracture increased by a factor of 2.1 (95 percent confidence interval, 1.2 to 3.5). CONCLUSIONS: Postmenopausal women with undetectable serum estradiol concentrations and high serum concentrations of sex hormone-binding globulin have an increased risk of hip and vertebral fracture.

7 The National Osteoporosis Foundation has a more comprehensive list of risk factors (it includes vitamin D deficiency, for example) at http://www.nof.org/prevention/risk.htm. (I do not endorse every recommendation made by the NOF.)

8 Nationwide decline in incidence of hip fracture.

Kannus P, Niemi S, Parkkari J, Palvanen M, Vuori I, Järvinen M.

J Bone Miner Res. 2006 Dec;21(12):1836-8.

Comment in:

  • J Bone Miner Res. 2007 Jul;22(7):1098; author reply 1099. PMID: 17371167.
  • J Bone Miner Res. 2007 Jul;22(7):1096; author reply 1097. PMID: 17371166.

Injury and Osteoporosis Research Center, UKK Institute for Health Promotion Research, Finland. pekka.kannus@uta.fi

This epidemiologic study determined the trend in the number and incidence (per 100,000 persons) of hip fracture among older adults in Finland, an EU country with a well-defined white population of 5.2 million, between 1970 and 2004. The results show that the alarming rise in the fracture incidence from early 1970s until late 1990s has been now followed by declining fracture rates. Reasons for this are largely unknown, but a cohort effect toward a healthier aging population and increased average body weight and improved functional ability among elderly Finns could partly explain the phenomenon. INTRODUCTION: Although osteoporotic fractures of older adults are said to be a major public health concern in modern societies with aging populations, fresh nationwide information on their secular trends is limited. MATERIALS AND METHODS: This epidemiologic study determined the current trend in the number and incidence (per 100,000 persons) of hip fracture among older adults in Finland, an EU country with a well-defined white population of 5.2 million, by taking into account all persons >or= 50 years of age who were admitted to our hospitals for primary treatment of such fracture in 1970-2004. RESulTS: The number of hip fractures among >or= 50-year-old Finns rose very constantly between 1970 (1857 fractures) and 1997 (7122 fractures), but since then, the rise has leveled off (7083 fractures in 2004). After this and because of a continuous rise in population at risk, the crude incidence of hip fracture (showing a clear rise in 1970-1997) decreased between 1997 and 2004, from 438 (per 100,000 persons) in 1997 to 374 in 2004. Concerning the age-adjusted fracture incidence, findings were similar. Until 1997, the age-adjusted incidence of hip fracture clearly increased in both women and men, but thereafter, this incidence declined in both sexes: in women, from 494 in 1997 to 412 in 2004, and in men, from 238 in 1997 to 223 in 2004. CONCLUSIONS: The rise in the incidence of hip fracture in Finland from the early 1970s until the late 1990s has been followed by declining fracture rates. Exact reasons for this are unknown, but a cohort effect toward a healthier aging population and increased average body weight and improved functional ability among elderly Finns cannot be ruled out.

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Medicine for People! is published by Douwe Rienstra, MD at Port Townsend, Washington.