by Marcelle Pick, OB/GYN NP
Osteoporosis is a progressive condition where more bone is lost than is formed, resulting in decreased bone mass, or a bone mineral density (BMD) that deviates two or more points from the norm. Over time whatever bone is left is thin and porous and fractures easily doing everyday things—like walking and coughing.
Women with osteopinea experience a weakening of the bone matrix and a loss of flexibility, but bone mineral density deviates only 1-1.5 points from the norm. It is considered a precursor condition to osteoporosis.
Osteoporosis occurs earlier and more severely in white women from Northern European descent who are small-boned and thin. Asian women also have a slightly higher risk. Other risk factors include:
- Post-menopause, either natural or surgical
- Delayed puberty, persistent amenorrhea, low hormone levels
- Poor diet, including vitamin D, calcium, and/or magnesium deficiency
- Advanced age
- Heavy alcohol consumption
- Under or overexercising
- Less than 15% body fat
- Elevated blood acid levels
- Use of corticosteroids or other medical drugs
- Thyroid or kidney disorders
- Bone cancers or other malignancies
- GI conditions that interfere with natural mineral absorption
When diagnosing osteopinea and osteoporosis, most doctors rely on a bone density scan, usually dual-energy X-ray absorptiometry, or DEXA. There are other tests, including CT scans, dual photon asroptiometry (DPA) and ultrasound, but DEXA is by far the most prevalent.
In this test an X-ray is focused on a body site (usually the wrist, hip or lumbar spine). Particles that don’t hit a mineral will pass through tissue and can be measured—the more roadblocks along the path the greater the loss of energy in the beam of light. In this way, bone mineral density can be measured. But no two women are the same, even though the test holds them to the same norm. A larger boned woman may have more bone tissue, thus more minerals and may score a higher density then a smaller boned woman.
A bone scan that deviates 2 or more points from the baseline indicates osteoporosis by traditional standards. A score above 1.5 indicates osteopenia, although I have seen women put on Fosamax who deviated only 1.3 points. Different machines will give different readings, so look at your bone scan results with a healthy dose of skepticism.
And realize that while it is one of the best tools we have right now, measuring BMD is more important as a point of comparison over time than your number. Despite what you may have been told, low-density bone is not necessarily weak.