Bone is a dynamic structure, constantly being remodeled by cells that remove it (osteoclasts) and renew it (osteoblasts). Once adulthood is reached, these two processes should stay in relative balance, but as hormonal status changes over time, the removal process predominates. For some people, hormonal-mediated bone removal may be predated or augmented by other conditions.
Predominance of bone removal results in low bone density (sometimes referred to as osteopenia). When bone density declines, the structure of bone is altered and it loses some of its strength and flexibility. Severe bone loss is referred to as osteoporosis; osteoporotic bone has thinner outer cortex and trabecular supporting structure.
Low bone density and osteoporosis are associated with increased risk of fracture. Other factors, however, are also important in predicting fracture risk: age, smoking status, body size, alcohol use, etc. The FORE Fracture Risk Calculator (https://americanbonehealth.org/bone-health/introducing-the-fore-fracture-risk-calculator/) can be used to calculate fracture risk. Importantly, the radiographic assessment of bone density by DXA scanning, which is the most widely used method of predicting fracture risk, does not take into account all of the factors that are relevant to this prediction. The quality of bone (how it is structured and what its mineral composition is), as well as its density, is also important. Bone quality is not generally assessable through non-invasive testing.
It is common for patients to undergo DXA scanning, be told that their bone density is low, or that it is declining rapidly based on serial scans, and that as a result prescription medications are recommended to reverse the process of bone loss. Although for some patients this may be appropriate – particularly when the risk of fracture is very high – for others it may not be for several reasons:
- DXA scanning is subject to error, particularly if the patient is not properly positioned during the scan
- Factors that are causing the imbalance of bone resorption and bone renewal have not been identified and addressed
- Risks resulting from the use of the medications may be significant, particularly with bisphosphonates, which are associated with osteonecrosis of the jaw, and with spontaneous fractures owing to their effect on bone, which is to block the removal process such that bone formation predominates, which increases bone density but alters its quality (making it structurally more brittle).
When a DXA scan shows low bone density, it is appropriate to do lab testing to assess for conditions that are associated with bone loss (imbalance between removal and renewal). Testing includes the general assessment that we use for most patients in integrative care (for hormonal status, nutrients, gut health/celiac status, and inflammation), as well as assessment of factors that are more specific to bone, including PTH, serum calcium, Vitamin D levels, 24 hour urine calcium, C Telopeptide (CTX) and osteocalcinin. The latter three factors assess balance between bone removal and renewal, and are used in initial assessment of causes of low bone density and to monitor impact of treatment over the short run, with biannual DXA scanning and fracture risk prediction over the long run.
There are multiple causes of low bone density from imbalance between resorption and formation of bone:
- Nutrient deficiency, either dietary or due to poor absorption from the gut
- Hormonal imbalance: hypothyroidism or its overtreatment, hyperthyroidism, hyperparathyroidism, insufficient or excess insulin/diabetes, low growth hormone/IGF-1
- Chronic inflammation and oxidative stress: infection or leaky gut-based
- Heavy metal toxicity: cadmium, lead, mercury, aluminum, iron
The approach to treatment is as follows:
- Healthy diet and weight-bearing exercise
- Nutrient supplementation with magnesium, calcium, Vitamin K2, Vitamin D3, strontium, and trace minerals
- Address issues identified through history and diagnostic testing: nutrient deficiencies, hormonal gut health, inflammation/oxidative stress, heavy metal toxicity
Helpful resources are:
- R Keith McCormick, “The Whole-Body Approach to Osteoporosis,” 2008
- Lani Simpson, “Dr. Lani’s No-Nonsense Bone Health Guide,” 2014
- Genuis SJ and Bouchard TP, “Combination of Micronutrients for Bone Study,” J Environmental and Public Health, 2012: http://downloads.hindawi.com/journals/jeph/2012/354151.pdf
- Sifat M, et al, “Melatonin-micronutrients Osteopenia Treatment Study,” Aging 2017: https://s3-us-west-1.amazonaws.com/paperchase-aging/pdf/vmFJfarchkyMAtwWn.pdf