Bone Density

Original Editor - Lucinda hampton

Top Contributors - Lucinda hampton, Angeliki Chorti and Kim Jackson  

Introduction[edit | edit source]

BMD Peaks around 30 Women lose BMD more rapidly than Men

Bone density is a measure of the amount of minerals (mainly calcium and phosphorous) contained in a certain volume of bone, accounting for approximately 60% of bone strength. [1] Bone density changes throughout life. [2] Bone mineral density (BMD) is set by the amount of bone present in the skeletal structure; the higher the BMD, the stronger the bones, and vice-versa. [3] BMD is greatly influenced by genetic factors (60% to 80% of variance in peak bone mass is attributed to genetic factors) [4] which can be modified by environmental factors and medications (see epigenetics). In normal conditions, BMD increases during childhood and peaks at roughly age 25, which is maintained for about 10 years. [5] After age 35, both men and women usually lose 0.3–0.5% of their BMD per year as part of the aging process.[3]

Bones provide the scaffolding that allows our bodies upright to remain upright. Healthy bones are not solid, their interiors being made of a honeycomb structure with tiny holes to keep them light and springy. When bones reduce their mineral density they have much larger holes as well as thin cortical walls, which can increase their risk of fracturing. This is why bone density is important.

Bone density measurements are useful in the diagnosis of osteoporosis, to see how well osteoporosis treatments are working, and to predict how likely the bones are to break.[6][7]

Risk factors for low BMD[edit | edit source]

Bone structure changes in osteoporosis
Insufficiency fracture L4

Bone mineral density can decrease in a wide variety of conditions and increase the risk for osteoporosis and osteopenia. Low bone density is a global problem, worldwide, osteoporosis causes more than 8.9 million fractures annually, resulting in an osteoporosis fracture every 3 seconds.[8]

Increased risk factors for lower bone density may include:

Estrogen and BMD[edit | edit source]

BMD (especially the vertebrae) decreases with menopause

Estrogen is important in maintaining BMD in women. After menopause, when estrogen levels start falling, loss of BMD accelerates. During the first 5–10 years after menopause, women can experience up to 2–4% loss of BMD yearly, resulting in the loss of up to 25–30% of their BMD in these 10 years. The accelerated bone loss after menopause is a major cause of osteoporosis in women, referred to as postmenopausal osteoporosis. [3]

Prevention of BMD loss[edit | edit source]

Prevention of bone loss can not be other than multifactorial due to the multiple influences on bone health. To date, although there are suggestions for ways to prevent bone loss and osteoporosis, mainly based on reported risk factors, there is no definite answer to this question. Increasing peak bone mass (PBM) in adolescence has been supported as an effective factor for preventing osteoporosis and fractures in older age. [10] One means for achieving this in adolescents are exercise programmes as part of vigorous physical activity (VPA) for at least 5 to 6 months. [10] Although vitamin D deficiency in children and adolescents is widely managed with supplementation to prevent future bone issues, it is now suggested to provide an unlikely clinically important benefit for BMD, regardless of baseline vitamin D status. [11] Further investigation is warranted to explore the interactions between important factors and provide solid guidance on this topic.

Measuring BMD[edit | edit source]

DEXA scanner in use
R.E.M.S. technology applied to lumbar spine

Bone mineral density can be measured by various methods, with DEXA being the most prevalent in modern clinical practice. Other ways to measure BMD include:

  • Single energy x-ray absorptiometry: a single x-ray beam is used to measure bone density at peripheral sites for example the forearm and heel. The area to be tested is wrapped in a tissue-like substance or immersed in water to improve the quality of the results.
  • Ultrasound: measurements taken during an ultrasound may provide data on the structural integrity of bone. New ultrasound devices such as quantitative ultrasound (QUS) can estimate bone density of the heel within minutes, providing an automatic print-out of results.[12] An example of this the new device is the Radiofrequency Echographic Multi-Spectrometry (REMS) is a relatively recent technology that performs the analysis of bone quantity and quality through a non-ionizing approach. The ultrasound device known as Echolight was approved by the FDA and doctors in the US are beginning to give it a try. REMS technology ultrasound signals appears to be able to overcome the most common artifacts, for example OA and vertebral fracture of the lumbar spine, which affect the value of BMD by DXA. Will the New Ultrasound Device Replace DEXA Bone Density Testing? [13][14][15]

Management of low BMD[edit | edit source]

Weight exercises are good for BMD

Osteoporosis medicines aim to improve bone density and while the increases may appear small, this can have a very positive effect on reducing fracture rates. For example, medication can increase bone density in the hip by approximately 1-3% and in the spine by 4-8%, over the first 3-4years of treatment. Medication can reduce spinal fractures by around 30-70% and hip fractures by 30-50% (a positive effect can be seen as early as 6 – 12 months after starting treatment).

Medical management isn't the only way to improve bone health. It may also be important to include daily exercise, good nutrition (including adequate amounts of calcium and vitamin D), smoking cessation, limiting alcohol intake and to assess fall risk. [16] [17]

Physiotherapy[edit | edit source]

There are many ways to help boost and maintain bone density. For tips on promoting bone health, see the physiotherapy and dietary section in the Osteoporosis, Osteogenic Exercises and Mechanical Loading of Bone pages.

References[edit | edit source]

  1. Schneider R. Imaging of Osteoporosis. Rheum Dis Clin North Am. 2013 August; 39(3): 609-31.
  2. Santos L, Elliott-Sale KJ, Sale C. Exercise and bone health across the lifespan. Biogerontology. 2017 Dec;18(6):931-946. doi: 10.1007/s10522-017-9732-6. Epub 2017 Oct 20.
  3. 3.0 3.1 3.2 Caballero B, Finglas P, Toldrá F. Encyclopedia of food and health. Academic Press, 2015. Available from:https://www.sciencedirect.com/referencework/9780123849533/encyclopedia-of-food-and-health [accessed 12/9/2023]
  4. Shlomo M. Williams Textbook of Endocrinology. Elsevier, 2020. Available from:https://www.clinicalkey.com.au/#!/content/book/3-s2.0-B9780323555968000267 [accessed 12/9/2023]
  5. Davies JH, Evans BAJ, Gregory JW. Bone mass acquisition in healthy children. Arch Dis Child. 2005;90:373-78.
  6. NIH Bone Density Available:https://www.cancer.gov/publications/dictionaries/cancer-terms/def/bone-density (accessed 6.8.2022)
  7. Medical news today 11 ways to increase bone density naturally Available:https://www.medicalnewstoday.com/articles/325903 (accessed 6.8.2022)
  8. Johnell O, Kanis JA. An estimate of the worldwide prevalence and disability associated with osteoporotic fractures. Osteoporosis international. 2006 Dec;17(12):1726-33. Available:https://pubmed.ncbi.nlm.nih.gov/16983459/ (accessed 6.8.2022)
  9. Yale medicine Low bone density Available:https://www.yalemedicine.org/conditions/bone-density-test (accessed 6.8.2022)
  10. 10.0 10.1 Min SK, Oh T, Kim SH, Cho J, Chung HY, Park DH, Kim CS. Position Statement: Exercise Guidelines to Increase Peak Bone Mass in Adolescents. J Bone Metab. 2019 Nov;26(4):225-239.
  11. Wu F, El-Hajj Fuleihan G, Cai G, Lamberg-Allardt C, Viljakainen H, Rahme M, Grønborg I, Andersen R, Khadilkar A, Zulf M, Mølgaard C, Larnkjær A, Zhu K, Riley R, Winzenberg T. Vitamin D supplementation for improving bone density in vitamin D–deficient children and adolescents: systematic review and individual participant data meta-analysis of randomized controlled trials. Am J Clin Nutr 2023; 118(3):498-506.
  12. Better Health Bone density testing Available:https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/bone-density-testing (accessed 6.8.2022)
  13. Caffarelli, C., Tomai Pitinca, M.D., Al Refaie, A., De Vita, M., Catapano, S. and Gonnelli, S., 2022. Could radiofrequency echographic multispectrometry (REMS) overcome the overestimation in BMD by dual-energy X-ray absorptiometry (DXA) at the lumbar spine?. BMC Musculoskeletal Disorders, 23(1), pp.1-8. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9118880/ (accessed 6.8.2022)
  14. Cortet B, Dennison E, Diez-Perez A, Locquet M, Muratore M, Nogués X, Crespo DO, Quarta E, Brandi ML. Radiofrequency Echographic Multi Spectrometry (REMS) for the diagnosis of osteoporosis in a European multicenter clinical context. Bone. 2021 Feb 1;143:115786. Available:https://www.sciencedirect.com/science/article/pii/S8756328220305743?via%3Dihub (accessed 6.8.2022)
  15. Better Bones Will the New Ultrasound Device Replace DEXA Bone Density Testing? Available:https://www.betterbones.com/bone-health-basics/will-the-new-ultrasound-device-replace-dexa-bone-density-testing/ (accessed 6.8.2022)
  16. Kanis JA, Cooper C, Rizzoli R, Reginster J-Y. European guidance for the diagnosis and management of osteoporosis in postmenopausal women. Osteoporos Int. 2019; 30(1): 3–44.
  17. Qaseem A, Hicks LA, Etxeandia-Ikobaltzeta I, Shamliyan T, Cooney TG; Clinical Guidelines Committee of the American College of Physicians; Cross JT Jr, Fitterman N, Lin JS, Maroto M, Obley AJ, Tice JA, Tufte JE. Pharmacologic Treatment of Primary Osteoporosis or Low Bone Mass to Prevent Fractures in Adults: A Living Clinical Guideline From the American College of Physicians. Ann Intern Med. 2023 Feb;176(2):224-38.