Understanding osteoporosis

After menopause, bone breakdown outpaces bone build-up because oestrogen deficiency triggers the activity of the osteoclasts, the cells responsible for bone breakdown. Bone is continuously broken down and re-formed and thus has an on-going requirement for calcium, but also for energy and for other nutrients.

The diagnosis of osteoporosis is made by measuring the difference between the density of your bones and that of a healthy young adult. A score is calculated as a standard deviation and is called a T score. If your T score is -2.5 or less this signifies significant bone thinning, or osteoporosis. Osteoporosis is a silent disease, meaning it doesn’t cause any symptoms until it manifests with, for example, a low impact fracture.   Osteoporotic fractures are really common with substantial morbidity and mortality: it is thought that 1 in 3 women and 1 in 5 men experience a fragility fracture after age 50. Currently in the UK we don’t have a national screening programme for osteoporosis so you may have to be proactive in asking your doctor for a DEXA scan.

What are the treatments for osteoporosis?

Bisphosphonates are the group of medicines prescribed for osteoporosis, and 3-4 year studies confirm that they work well in decreasing the risk of vertebral (40-70%), hip (20-50%) and non-vertebral (15-39%) fracture. In women with osteoporosis who have had a fracture, bisphosphonates decrease the risk of a second fracture by an impressive 50%. If you haven’t had a fracture but have osteoporosis, bisphosphonates are likely to have benefits. It is important to actually have a DEXA scan to measure bone density rather than simply start a bisphosphonate preventatively because in postmenopausal women who have never had a fracture, bisphosphonates have not been shown to be more effective than adequate calcium and vitamin D to prevent fractures. [1]

However,  approximately half of the people who are treated with osteoporosis drugs will stop taking the medicine within a year. This problem has been reported whether the medicine is taken once a week or once a month and it is due to common side effects such as heartburn. Avoid taking another medication to treat the side effects – bisphosphonates can cause reflux type symptoms, but not only will proton pump inhibitor medication (like omeprazole) for this not help, they can actually cause harm.[2]

Serious complications of bisphosphonates are rare but include osteonecrosis of the jaw, where the bone in the jaw has poor circulation. Ironically,  atypical femoral fractures  are another possible side effect, particularly with increased length of bisphosphonate use (this is thought to be because bisphosphonates may change the quality of bone, making the bones more brittle).

Bearing this in mind, if you are taking bisphosphonates this is my advice :

  • Have a review with your prescribing doctor every 5 years to see if you need to stay on the bisphosphonate or if it is worth considering a drug holiday and reassessing bone density in 2 years.
  • After 5 years, discuss with your Dr the idea of using a lower dose of medication. For example the FLEX study found that the equivalent of 35mg/week of alendronate had the same results 5 years later as the 70mg/week dose. [3]

I am a big advocate of hormones for osteoporosis prevention. It is the loss of hormones in the first place that increases our risk of osteoporosis. Oestrogen has been proven to prevent fractures in a mixed risk population. The benefits on bone density are dose dependant.  Oestrogen protects not only the skeleton but also the intervertebral discs which make up one quarter of the length of the spinal column, preventing loss of height.  Did you know that this latter benefit is not produced by osteoporosis  drugs like bisphosphonates?

In addition, I’m sure you’ll agree that prevention is better than cure! So what can you do to prevent osteoporosis?

A systematic review and meta-analysis documented the benefit of vitamin D, finding that in 26 studies vitamin D was associated with 14% decreased risk of falls (47% in those vitamin D deficient, 10% in those not deficient, and both statistically significant).[4]

Sufficient vitamin D is difficult to derive from diet alone and if you live in a country where the latitude makes sunlight scarce, you will need to check your levels and supplement with vitamin D to normalise levels if low. Some vitamin D supplements also contain vitamin K2 (as do fermented foods), which may help to bind calcium to the bones and prevent deposits of calcium in the arteries.

Unlike vitamin D, calcium is best obtained from the diet and taking unnecessary calcium supplements, particularly without vitamin D, has actually been linked to an increased cardiovascular risk[5], as has an excessive total calcium intake[6] so calcium supplementation should only be given to those who have confirmed inadequate calcium in the diet. Use this calculator to check that you are consuming 700mg of calcium per day (www.rheum.med.ed.ac.uk/calcium-calculator.php).

Zinc is also necessary for bone formation because it is an enzyme co-factor for bone mineralisation. Zinc is found in seafood, beef, lamb and spinach. Boron is a trace element found in fruits, nuts and vegetables that reduces urinary calcium loss, and 2 mg of boron per day should easily be met with a diet rich in fruits, nuts and vegetables.

Exercise – ideally an hour of moderate activity per day.

Quit smoking, quit soft drinks that contain phosphates which can leach calcium out of bones and reduce alcohol and caffeine. Eat at least five servings of fruits and vegetables for every one serving of red meat, chicken or fish.

[1] Use of Oral Bisphosphonates in Primary Prevention of Fractures in Postmenopausal Women: A Population-Based Cohort Study

[2] Proton pump inhibitor use and the antifracture efficacy of alendronate.

[3] Effects of continuing or stopping alendronate after 5 years of treatment: the Fracture Intervention Trial Long-term Extension (FLEX): a randomized trial.

[4] Clinical review: The effect of vitamin D on falls: a systematic review and meta-analysis.

[5] Associations of dietary calcium intake and calcium supplementation with myocardial infarction and stroke risk and overall cardiovascular mortality in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition study (EPIC-Heidelberg).

[6] Long term calcium intake and rates of all cause and cardiovascular mortality: community based prospective longitudinal cohort study