Today I would like to expand on the last discussion and discuss a more comprehensive testing strategy beyond DEXA scan to look for root causes of osteoporosis.
The first additional testing that I would consider when someone comes in with questions about recent DEXA score would be a D-pyrilink urinary test. The D-pyrilink is a protein that is part of the bone matrix. During the process of bone break down and recapture for new bone formation, the D-pyrilink protein is briefly circulating in free-form and can be excreted through the urine, and the amount can be measured. If the bone is reabsorbing and being rebuilt at a normal rate without excessive loss, the amount of D-pyrilink in the urine will be relatively modest. If the body is breaking down bone faster than recapturing and rebuilding, the amount will be elevated. So measuring urinary D-pyrilink excretion can be a useful addition to a DEXA scan to see if the active state of bone loss.
Additional tests that can be helpful in circling in on the causes of a person's osteoporosis and bone loss includes:
– A hormone panel to assess the adequacy of estrogen, progesterone, testosterone, cortisol, and DHEA (basic anabolic adrenal marker). Incidentally most of the commercially available D-Pyrilink tests are lumped together with the above hormones in a single bone health panel.
– A vitamin D metabolite panel. This would include not only the commonly tested D3, but a metabolite called calcitriol, which is directly converted from vitamin D3 in response to the body's needs to improve calcium absorption in the gastrointestinal tract. This can be a useful indicator of the body’s perceived lack of available calcium, either from inadequate dietary intake or difficult absorption for a variety of reasons. In which case the ratio of calcitriol to vitamin D3 will be elevated. In addition, we will often get a basic parathyroid hormone level. The parathyroid hormone is the master control of calcium blood level regulation. Under normal circumstances with adequate vitamin D/calcium economy, the parathyroid levels will be in the lower end of the range. Even slight elevations of parathyroid hormone still considered normal but suboptimal can indicate the body's perception of inadequate calcium/vitamin D economy.
– A gastrointestinal functional markers profile. This can be very useful when we suspect that the patient has adequate dietary intake of nutrients necessary for bone formation such as protein and calcium, however the body is unable to properly absorb those nutrients for variety of reasons (prior abdominal surgeries, chronic infections, hypochlorhydria, mild digestion, inflammatory bowel disease etc.) the panel can measure stool residues of various digestive enzymes and nutrients, telling us if absorption is the problem causing osteoporosis.
– Last but not least, and probably first and foremost in most cases, a good diet history to see if the patient has a reasonable amount of nutrients available for normal bone formation.