BONE
HEALTH

OVERVIEW: BONE DENSITY

Bones keep us upright and serve as attachment points for ligaments and tendons. They are also living tissue with blood, nerves, and are constantly changing. Throughout our lifetime, our bones are being broken down on a micro level (called resorption) and then being built back (called formation). Bone mineral density (BMD) is how much formation is happening in relation to how much resorption and reflects how sturdy the bone is. The higher your bone mineral density is, the better off you are (1,2).

Many things impact overall bone health including genetics, age, diet, exercise, kidney disease, infection, hormones, smoking, and alcohol intake (1). 

Having healthy bones is important as low bone density increases the risks of osteopenia (lower BMD) , osteoporosis (very low BMD with greater changes to bone structure), and fractures (2). At any age, fractures can cause major setbacks in general health, pain, joint injury, and risk of arthritis.

CHANGES

Peak bone mass occurs around 28–30 years old but may also happen at a younger age (2). One study stated that lumbar (low back) spine peak bone density occurred at age 20 for women, while another stated it happened at age 28 (4,5). A large study of over 9,000 females leaned toward younger ages 19–20 years old to reach peak BMD, no matter a person’s race or BMI (5). 

Bone density decreases with age but the rate of loss varies with underlying muscle mass, nutrition, age, and activity levels. Weightlifting can slow the rate of decline (but may not help increase it above baseline) whereas pure aerobic, low impact activity does not seem to influence bone density at an older age (2).

Hormones play a part in bone health as estrogen helps increase bone formation. Once estrogen decreases after menopause, there is a faster decrease in bone density as more bone is resorbed and less is being formed (1,6). There is a clear decrease in BMD in post-menopausal people even when compared to those just a few years younger who are in the perimenopausal state (6). It's possible to see a loss of 2.5% per year of BMD starting around the time of perimenopause (3).

WHAT TO DO

Muscle and bone are directly connected (the technical term is the biomechanical coupling theory). To get strong bones, you need strong and active muscles (6). Regular exercise across the lifespan helps with this. 

Things to do now (1):

  • Get regular exercise that puts stress on the bones like weightlifting 

  • Don’t smoke or drink excessively

  • Have a healthy, balanced diet with an appropriate amount of calcium 

Things to do later (1):

  • Know your risk of fractures including bone mineral density, lifestyle, age, fall risk, and previous history of fractures. This can be used to tailor treatment. 

  • Ask your doctor about when you need a DXA (duel energy x ray absorptiometry) scan that looks at your BMD

  • Consider menopausal hormone therapy to be started within 10 years after menopause or before reaching 60. 

Exercise to fit your goals, but if your goal is bone health, a 2022 review recommended: 

  • Four to five exercises for upper and lower limbs as well as the trunk

  • 2–3 sets at 8–12 reps, 3 times a week

  • 60 to 120 seconds rests between sets

  • Weights at 70–90% of the person’s one rep max (2)

A WORD ON ARTHRITIS

Osteoarthritis (which will be referred to as just “arthritis” here) is the degradative change seen in joints with time. It is the cartilage, ligaments, and bone changes in a joint that causes pain and loss of motion (7).

There is no cure for arthritis. Joint replacement is widespread and can be helpful but comes with its own complications and issues, including failure and potential need for repeat surgery. As of right now, the best way to fix arthritis is through knowing the risk factors and prevention. 

Some risk factors can’t be changed, like being born female, your genetics, getting older, structural development, and joint changes that occur with time (7).

The biggest things you can do to help prevent arthritis are:

  • Keep a healthy weight, especially as perimenopause and menopause causes changes and after age 50. 

  • Prevent injury. Take preventative measures for your joints to help prevent sports injuries (including movement mechanics & prehab). 

  • If you already have an injury, keep doing things to prevent repeated injuries and stay active.

  • Think about your job. Jobs with high physical loads will increase risk of arthritis (7).

  • Think about your sport. High-impact sports may increase risk, but that may be due to injury rather than playing (evidence unclear).  

  • Stay strong. Continue to exercise and keep your muscles strong to prevent loss with age. 

REFERENCES

  1. de Villiers, T. J. d. (2024). Bone health and menopause: Osteoporosis prevention and treatment. Best Practice & Research Clinical Endocrinology & Metabolism, 38. https://doi.org/10.1016/j.beem.2023.101782 

  2. Massini, D. A., Nedog, F. H., Oliveira, T. P. d., Santana, C. A. A., Neiva, C. M., Almeida, T. A. F., Macedo, A. G., Castro, E. A., Espada, M. C., Santos, F. J., & Filho, D. M. P. (2022). The Effect of Resistance Training on Bone Mineral Density in Older Adults: A Systematic Review and Meta-Analysis. Healthcare, 10. https://doi.org/10.3390/healthcare10061129 

  3. Lobo, R. A., & Gompel, A. (2022). Management of menopause: a view towards prevention. The Lancet Diabetes & Endocrinology, 10, 457-470. https://doi.org/10.1016/ S2213-8587(21)00269-2 

  4. Löfman, O., Larsson, L., & Toss, G. (2000). Bone Mineral Density in Diagnosis of Osteoporosis. Journal of Clinical Densitometry, 3(2), 177–186. https://doi.org/0169-4194/99/2:177–186/$12.50 

  5. Xue, S., Kemal, O., Lu, M., Lix, L. M., Leslie, W. D., & Yang, S. (2020). Age at attainment of peak bone mineral density and its associated factors: The National Health and Nutrition Examination Survey 2005–2014. Bone, 131. https://doi.org/10.1016/j.bone.2019.115163 

  6. Sipilä, S., Törmäkangas, T., Kovanen, V., & Laakkonen, E. K. (2020). Muscle and bone mass in middle-aged women: role of menopausal status and physical activity. Journal of Cachexia, Sarcopenia and Muscle, 11, 698–709. https://doi.org/10.1002/jcsm.12547 

  7. Whittaker, J. L., Runhaar, J., Bierma-Zeinstra, S., & Roos, E. M. (2021). A lifespan approach to osteoarthritis prevention. Osteoarthritis and Cartilage, 29(12), 1638-1653. https://doi.org/10.1016/j.joca.2021.06.015