No matter which osteoporosis drug your doctor chooses for you, it's helpful
to know as much as possible about how the disease has affected you. One way to
tell is to ask about your "markers."
When you're being treated for osteoporosis, your doctor orders a blood or
urine test. This reveals several markers -- levels of different enzymes,
proteins, and other substances circulating in the body -- that provide clues
about your disease and the progress of your treatment.
Your bones are alive and constantly growing -- not static, like you see them drawn in books. Bones continually change throughout your life, with some bone cells dissolving and new bone cells growing back in a process called remodeling. With this lifelong turnover of bone cells, you replace most of your skeleton every 10 years.
But for people with osteoporosis -- a thinning of the bones -- bone loss outpaces the growth of new bone. Bones become porous, brittle, and prone to fracture. Look at an...
Bone-specific alkaline phosphatase (Bone ALP or BALP).
This is an estimate of the rate of bone formation over your entire skeleton.
Bone formation may sound like a good thing, but depending on the circumstances,
too much can be bad. People with osteoporosis generally have BALP levels that
are up to three times normal.
Osteocalcin. This is another marker of bone
Urinary N-telopeptide of type I collagen, or uNTX. This is
a marker of bone resorption, or loss of bone.
Vitamin D levels. This measure assesses whether you have a
deficiency of vitamin D, which is essential for your body's absorption of
calcium. You can be taking plenty of calcium, but if you don't have enough
vitamin D, it won't be efficiently absorbed by your body.
SOURCES: Michael Holick, MD, PhD, professor of medicine,
physiology and biophysics, Boston University Medical Center. Robert Recker, MD,
MACP, professor of medicine and director, Osteoporosis Research Center,
Creighton University School of Medicine, Omaha, Neb. National Osteoporosis