It is normal to think of our bones as solid, rigid structures and indeed they are to a certain extent.
In reality, however, they are constantly changing, being broken down and reforming throughout our lives. As children our bones grow and strengthen, and this process actually continues well into adulthood with peak bone density occurring in our late 20s.
After that there is a long, steady decline in the strength of our bones which for women is accelerated after the loss of estrogen that occurs with menopause.
When this deterioration in our bone strength is excessive it leads to a condition called osteoporosis. This can affect both men and women, however, women are especially at risk because they have less bone mass to begin with compared to men, they use calcium from their bones to grow babies, and they have the aforementioned accelerated bone loss after menopause.
Osteoporosis causes bones to be unable to bear the normal stresses our bodies place upon them and can collapse or fracture.
The most common places for this to happen are in the weight bearing bones, especially the bones in the thigh and in the spine. Sometimes these fractures are not immediately noticed such as collapse of the vertebrate in the spine which can be gradual and not cause symptoms until well advanced.
This is one of the reasons we can become shorter as we get older. Unfortunately, in the spine once these fractures occur there’s not much that can done to restore the vertebrate to normal. Sadly, as well, when older men and women suffer a break in the hip their ability to recover and resume normal activity is often limited. In some studies, up to 50% of older individuals who suffer a hip fracture die within a year.
Fortunately, there are effective treatments available to slow and sometimes reverse bone loss associated with aging.
Because there are often no signs or symptoms of osteoporosis until it is too late, screening tests are necessary to identify those individuals who are at high-risk for suffering a fracture.
There have been many tests developed for this purpose, some more accurate than others. These include plain X-rays, CAT scans to measure bone quantity, ultrasounds of the bones in places like the arm or heel, blood tests looking for bone breakdown products in the bloodstream, and a unique type of X-ray called dual-energy x-ray absorptiometry or DEXA for short.
While there are advantages and disadvantages to all of these, DEXA has been shown to most accurately predict who will benefit from treatment and is therefore the most widely recommended screening test.
A DEXA scan is painless and very safe. The radiation dose is extremely small, the same as 1/10th of a chest X-ray or about a day’s worth of exposure to natural background radiation. Standard measurements are made at the hips and spine and a score given that compares the bone density to that of a healthy 30-year-old.
This score, along with other clinical information, is used to guide whether treatment is needed to avoid fractures. Current recommendations are for all women 65 and older to have a DEXA scan.
Women younger than age 65 can also be considered for screening if they have one or more of the following risk factors: previous non-traumatic fracture, long-term steroid usage, parental history of hip fracture, low body weight, current cigarette smoking, excessive alcohol consumption, rheumatoid arthritis, and other conditions that interfere with calcium absorption. Screening is not recommended however for premenopausal women.
As always, the best recommendation is to discuss your risks and screening options with your primary care provider.
- This series is brought to you by Brian Bell, M.D., Lincoln County’s only board-certified OB/GYN and Chief of Staff at Cabinet Peaks Medical Center