DXA Screening for Osteoporosis

What is Osteoporosis?

Who has not known someone who had always been active and healthy, and then had a fall and never recovered from a hip fracture?  Or an otherwise healthy 75 year old woman with severely limiting spine deformity caused by multiple spontaneous fractures of the spinal bones leaving her with a “humped” back such that she can never see the sky? These are the result of osteoporosis. Our interest in osteoporosis should be a personal interest in our own health and that of aging family members, along with a concern for the enormous health-care cost of this common malady of advancing age. According to the North American Menopause Society, about 40% of American women will suffer an osteoporosis-related fracture during her lifetime. The good news is that this disease is—for the most part—preventable and treatable if diagnosed in its earlier stages.

Osteoporosis is a bone disorder. Women with osteoporosis lose bone strength, leading to an increase in the risk of bone fracture.  With enough stress or trauma, the strongest bone will break. But bones weakened by osteoporosis may break with very little force, such as a fall from the standing position.  A weakened bone may even break spontaneously from minor stress. Fractures are painful, limit mobility, and can cause temporary or permanent disability or deformity.  The common areas of fracture are the hip, spine and wrist.  While there are many causes of osteoporosis, the most common form of this disorder is post-menopausal osteoporosis, resulting from the dramatic decrease in estrogen levels at menopause.

Bone strength is related to the density of the bone, the structure of the bone, and bone quality. Bone is living tissue that is constantly changing, renewing, and healing.  Old bone is continually being resorbed allowing for other cells to lay down new bone.  This is how a broken bone heals. It is also how bone gets stronger (just like muscle) in response to exercise or stress.  Similar to muscle strength, bone strength is affected by genetics, nutrition, and exercise.  Our bones reach their peak mass and strength at age 20 to 30, after which we lose bone mass and bone strength as we age.  If we understand how to build stronger bones while we are young and slow the normal decline, we can reduce our risk for fractures that might limit our mobility, quality of life and life span as we age.  Genetics and family history may help or hinder the process for each individual and these are not within our control. But lifestyle and nutrition are also important factors in how bones age.  As physicians caring for women throughout their adult lives, we want to consider individual risk factors and monitor changes in your bone health along this path. Our goal is to identify those with osteoporosis and those at risk for osteoporosis, in order to intervene with medical therapy before fractures occur.

A healthy lifestyle, including good nutrition with adequate calcium intake, is vital for building and maintaining bone strength.  While dairy products are the richest source of calcium, other foods (dark green leafy vegetables like broccoli, collard and turnip greens, and kale) provide good amounts. Still other foods are fortified with calcium (ex. orange juice with added calcium). Calcium supplements are necessary after menopause or earlier if the calcium in your diet is not adequate.  Adequate Vitamin D from food sources (Vit. D fortified milk) and sun exposure is important in helping the body absorb the calcium in your diet.  Exercise throughout one’s life is critical in maintaining bone strength. Smoking and excessive alcohol intake increase osteoporosis risk.  These lifestyle factors that we can control become even more important for women who have a family history of osteoporosis, low body weight, medical problems that limit activity, or medical problems that require long term steroid treatment.

Screening for Osteoporosis:

We are fortunate that we now have a tool to screen for osteoporosis. It also detects low bone density that is not yet at the level of osteoporosis but is moving in that direction.  This tool is called DXA which stands for dual x-ray absorbsiometry.  DXA provides a computerized analysis of a low energy x-ray of the hip and spine using less energy than a mammogram.  It has become the primary tool to identify those with osteoporosis and those at risk for developing osteoporosis.  This allows those identified to be offered effective medical treatment for maintaining and improving done density to reduce the long term risk of fracture.

Our recommendation:

Our ability to identify those at risk for osteoporosis and the availability of medical intervention is, in my view, an extraordinary advance in women’s healthcare.  All women age 65 or older should have a DXA scan to assess their bone density and their risk for developing osteoporosis.  Women younger than age 65 who are menopausal and have other risk factors such as a family history of osteoporosis, low body mass, history of smoking, steroid use, poor calcium intake, decreased activity, early menopause should also be screened. Every post-menopausal woman should discuss with her doctor whether she is a candidate for DXA screening. Finally, women with low bone density on DXA should be screened for Vitamin D deficiency.

While diagnosing and treating osteoporosis is an important element of complete women’s healthcare, prevention of osteoporosis should still be every woman’s first goal.