Osteoporosis is often called a silent disease because bone loss occurs without symptoms.
People may not know that they have osteoporosis until their bones become
so weak that a sudden stress from a bump or fall causes a hip (femur) to fracture or
a vertebra to collapse. Collapsed vertebrae may initially be felt or seen in the form
of severe back pain, loss of height, or spinal deformities such as stooped posture
(kyphosis).
Osteoporosis is detected by measuring bone mass with a bone mineral density
(BMD) test. The most widely used BMD test is a dual-energy x-ray absorptiometry
or DXA. With a very low exposure to radiation, it can measure bone density at the
hip and spine. BMD tests can identify osteoporosis, help estimate the risk of future
fractures, and measure response to osteoporosis treatment.
The U.S. Preventive Services Task Force (USPSTF) recommends that women should begin screening at age
65 or younger if a risk assessment indicates, (i.e., low body weight, parental history
of hip fracture, smoking), but the evidence is insufficient to assess the balance of
risks and harms of screening for osteoporosis to prevent osteoporotic fractures in
men.60 61 Other expert groups recommend that all postmenopausal women and men
over 50 should be screened with DXA. Still, other expert groups say men at age
70 should begin screening. There are no “official” recommendations about how
frequently DXA screening should be carried out. One recommendation is to screen
every two to five years if osteopenia (mild loss of bone density) is present, and every
two years for people with osteoporosis.
DXA testing is expressed as a T-score that compares an individual’s BMD to a
young woman in her twenties or as a Z-score that uses the average for your age,
gender, and race/ethnicity for comparison. T-scores are expressed as a negative
number that is a measure of standard deviation (variance from an average) below
normal. A T-score of -1 to -2.5 is classified as osteopenia, and a T-score of -2.5 and
below is classified as osteoporosis. About one-third of women ages 50 to 65 and
two-thirds of women over 65 fall into the osteopenia category. By the time women
reach age 75, about half of them will have a BMD that places them in the osteoporosis
category.
There is no discrete cutoff between a finding of disease or no disease in measures
of BMD using DXA technology. T-scores do not measure bone quality, so a low
T-score in a young woman may represent a negligible risk of a fracture compared
to an elderly woman with the same T-score. In general, there is a continuum of
fracture risk, with risk highest among individuals with low BMD values. There is
debate about whether osteopenia should be considered a predictable aspect of aging
and concern about the potential for overtreatment based on the diagnosis. One
reason for this concern is that although they are at increased risk, many people with
osteopenia do not go on to full-blown osteoporosis or have a fracture.
To help guide the decision about taking bone-strengthening drugs, the USPSTF
recommends the use of one of 5 different tools. Four of these (the Osteoporosis Self-Assessment Tool [OST], the Osteoporosis Risk Assessment Instrument [ORAI], the Osteoporosis Index of Risk [OSIRIS], and the Simple Calculated Osteoporosis Risk Estimation [SCORE]) were specifically designed to identify individuals
with a BMD T-score of –2.5 or lower. The FRAX (Fracture Risk Assessment
Tool), a more complex computer-based country-specific fracture risk assessment
tool, was designed to estimate 10-year probabilities of hip and major osteoporotic
fracture.
The FRAX considers your age, health history, T-score, if you have had a previous
fracture and other factors to calculate your risk of a fracture in the next ten years.
Guidelines on the use of the FRAX suggest that treatment be considered if the
10-year risk of a hip fracture is 3% or higher or if the risk of a major osteoporotic
fracture (e.g., hip, vertebra, humerus, or wrist) is 20% or higher. As is the situation
with the use of BMD to assess fracture risk, the FRAX has limitations because
patient-provided data may be inaccurate, presence of other diseases and conditions
may not be accounted for, and some significant variables including physical activity,
balance, calcium and vitamin D intake and use of tobacco and alcohol may not be
fully accounted for in the model. The FRAX is available at https://www.sheffield.
ac.uk/FRAX/tool. A similar risk calculator is available from The Foundation for
Osteoporosis Research and Education at riskcalculator.fore.org.
Because it is simpler and as accurate as the other screening tools, a recent review
of screening strategies for postmenopausal women younger than 65 recommends
using the Osteoporosis Self-Assessment Tool (OST) before BMD testing.
This blog presents opinions and ideas and is intended to provide helpful general information. I am not engaged in rendering advice or services to the individual reader. The ideas, procedures and suggestions in that are presented are not in any way a substitute for the advice and care of the reader’s own physician or other medical professional based on the reader’s own individual conditions, symptoms or concerns. If the reader needs personal medical, health, dietary, exercise or other assistance or advice the reader should consult a physician and/or other qualified health professionals. The author specifically disclaims all responsibility for any injury, damage or loss that the reader may incur as a direct or indirect consequence of following any directions or suggestions given in this blog or participating in any programs described in this blog or in the book, The Building Blocks of Health––How to Optimize Your Health with a Lifestyle Checklist (available in print or downloaded at Amazon, Apple, Barnes and Noble and elsewhere). Copyright 2021 by J. Joseph Speidel.
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