Osteo = bone
Porosis = porous. “Normal” bones have small holes in them, but Osteoporotic bones have much larger holes, making them more porous.
More technically, Osteoporosis is known as “a skeletal disorder characterised by compromised bone strength predisposing a person to an increased risk of fracture” (Beck, Daly, Singh & Taaffe, 2017). This is particularly concerning for the elderly population who are at a higher risk of trips and falls due to decreased balance, strength and power as they age. If they were to have a fall, the presence of Osteoporosis increases the risk of a bone fracture significantly. You may have also heard of the term Osteopenia. It is a decrease in Bone Mineral Density (BMD), just like Osteoporosis, but not significant enough for an Osteoporosis diagnosis. Therefore these people are at a lower risk of a fracture, however, intervention is still required to prevent the progression to Osteoporosis.
Osteoporosis is diagnosed through undertaking a dual-energy x-ray absorptiometry scan (DEXA) which measures one’s Bone Mineral Density (BMD). Quite often in the first instance, your GP will recommend this for you and write you a referral if deemed necessary based on your risk factors. Risk factors for the development of Osteoporosis that may prompt your GP/specialist to want a scan include:
- Being over the age of 50
- Female who is estrogen deficient or low estrogen
- Other medical conditions that increase the risk of OP, such as primary hyperparathyroidism.
- Poor diet, particularly lacking in calcium
- Low levels of vitamin D Physical inactivity
- A bone fracture that occurred in a scenario that typically wouldn’t result in a fracture
- Taking prednisone or other steroid type medications that may result in bone loss
Your referring doctor will go through the results of your DEXA scan with you, but how do they interpret the results for diagnosis? One of the primary results they look at is the “T-score”. This measure compares your BMD to that of a healthy 30 year old, of your sex. The actual T-score number refers to how many standard deviations (SD) your BMD is away from that of the average healthy 30 year old’s. The World Health Organisation defines a normal BMD as a T-score greater than -1.0, Osteopenia a T-score of -1.0 to -2.5, and Osteoporosis a T-score of greater than -2.5.
But why does bone loss occur as we age?
At any given time, at a cellular level, we have both osteoblasts and osteoclasts working away on our bones. Osteoblasts build bone tissue and osteoclasts resorb and break down bone tissue. In the below graph, you can see that around age 30, we are at our peak bone mass. Up until this point, our osteoblasts are working faster than our osteoclasts. But then after that point, bone mass starts to decrease. This is because our osteoclasts start to dig deeper into our bones and our osteoblasts don’t build as much bone tissue.
But why is there that sudden decline in bone mass in women around age 50-60? Menopause. Estrogen is protective to our bones (for many reasons) and when going through menopause, we have a decrease in the amount of estrogen on our body. Therefore, there is a net bone loss.
Treatment overview
If there were to be no treatment for someone with OP, BMD would
continue to decline with age. Therefore, with an intervention, even maintaining an individual’s current BMD and preventing further loss is a win! However, it is still possible to increase your bone mineral density to that of someone with Osteopenia or to normal levels!
Depending on your T-scores and other lifestyle factors, will depend on the treatment given. Best treatment involves a multi-disciplinary approach, utilising a variety of modalities. These may include a combination of:
- Pharmacological methods – 6-monthly or annually injections eg. Prolia.
- Non-pharmacological methods;
- 1.) Increase calcium intake eg. seeing a Dietitian for dietary modifications or taking a supplement
- 2.) Increase Vitamin D eg. sun exposure or dietary intake
- 3.) Exercise intervention!!!
So HOW does exercise help to increase BMD?
Wolff’s Law. It states that bones will adapt to changes in load, to be able to withstand these same forces in the future. If the load being placed on a bone increases, the bone tissue will remodel to be able to appropriately withstand this force. Exercise is a vital method of providing a challenging stimulus to bone, to encourage remodeling by utilising Wolff’s Law. Studies have shown that for loading to be effective at placing stress on bone, it must;
- Be dynamic in nature, not static
- Induce high strain and deformation on bone
- Be performed rapidly
The Position Statement for Osteoporosis released by ESSA (Exercise & Sports Science Australia) in 2017, details the 3 primary modalities of exercise for treatment of Osteoporosis, and the frequency, intensity and duration that these should be performed at. These finer details of prescription vary for each individual depending on their T-score and their risk of fracture. Therefore, the individualised exercise prescription should be done by an appropriately trained professional, such as an Accredited Exercise Physiologist.
Below is a general overview of the specifications for each modality of exercise prescription:
**It is strongly recommended to consult an Exercise Physiologist before commencing a new exercise program with Osteoporosis.
Impact Loading
- Frequency: 4-7d/week
- Intensity: Moderate-High (2-4x bodyweight)
- Duration: Working up to 50 jumps per session (3-5 sets of 10-20 repetitions)
- Examples: Vertical and lateral jumping, bounding, skipping rope, step ups.
Progressive Resistance Training (PRT)
- Frequency: 2d/week
- Intensity: High-Very high (80-85%1RM)
- Duration: 2-3 sets of 8-10 repetitions, 8 exercises per session
- Examples: Lunges, deadlifts, chest press.
Balance Training
- Frequency: 4d/week or incorporating into other sessions in week
- Intensity: Challenging
- Duration: Total of 30 minutes, at least 10seconds per exercise
- Examples: Tandem stance/walking, crossover walks, foam walking, dual tasking
As mentioned above, even maintaining BMD with treatment is a success, as we are fighting the downward trend. However with the appropriately prescribed interventions from a multi-disciplinary team, is it possible to increase your BMD and thus decrease your chance of a fracture!
Olivia Marshall-Baird
Accredited Exercise Physiologist
References:
Beck, B., Daly, R., Singh, M., & Taaffe, D. (2017). Exercise and Sports Science Australia (ESSA) position statement on exercise prescription for the prevention and management of osteoporosis. Journal Of Science And Medicine In Sport, 20(5), 438-445. doi: 10.1016/j.jsams.2016.10.001
Medicare. Bone mass measurements. Retrieved on 21st January 2022 from https://www.medicare.gov
Osteoporosis: Peak Bone Mass in Women. (2022). Retrieved 1 March 2022, from https://www.bones.nih.gov
Wikipedia. (2013). File:615 Age and Bone Mass.jpg. Retrieved 1 March 2022, from https://en.wikipedia.org
Wolff’s Law: Physical Therapy, Workouts, and More. (2019). Retrieved 1 March 2022, from https://www.healthline.com
World Health Organization, (2007). WHO scientific group on the assessment of Osteoporosis at primary health care level.
