Skeleton Pirate
Artist: LindaB
Tuesday, April 24, 2012
Interpretation of BMD Scans in Patients Stopping Strontium Ranelate Treatment
“The oral administration of strontium ranelate causes a clinically significant overestimation of BMD because of the high attenuation of X-rays by strontium atoms in bone." GM Blake and I. Fogelman “performed a theoretical study to calculate the long-term effect of strontium treatment on BMD and establish the duration of past treatment for which the remaining bone strontium content (BSC) has a negligible effect on BMD.” “Estimates of the strontium BMD artefact after treatment has stopped were performed on the assumption that the BSC effect accounts for 75% of the total measured BMD change at 3 years.”
“If 75% of the BMD changes are explained by BSC, in the average patient, 3-year treatment leads to a spine BMD artefact of 11.2%, decreasing to 3.8% 10 years after stopping treatment. The BMD artefacts at the total hip and femoral neck sites are smaller by factors of 0.65 and 0.53, respectively.” “On average, 6-month treatment is required for the spine BMD artefact to exceed 3%, the figure adopted as the maximum BMD change caused by bone strontium that has a negligible effect on scan interpretation.”
The researchers concluded that “strontium ranelate treatment lasting for > 6 months can affect BMD measurements for many years afterward.”
http://www.ncbi.nlm.nih.gov/pubmed/16939400
J Bone Miner Res. 2006 Sep;21(9):1417-24.
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Wandering Skeleton
Artist: Joel Hoekstra
Osteoporotic Bone
Source: www.mayoclinic.com
11 comments:
Bone Lady, Some (or most) of this went over my head. Sorry, but would like to understand it. Did I get this much right - Dexa shows 6% increase while on strontium, but that actually means l.5% increase?????
To: Anonymous of 06/28/12
No, that is not correct. Let me give you two examples.
A patient has taken strontium ranelate for three years and has a spine BMD of 0.749 g/cm2 (uncorrected). Reducing that score by 11.2% gives the patient a corrected BMD of 0.665 g/cm2.
Another patient has stopped taking strontium ranelate for 10 years and has a spine BMD of 0.749 g/cm2 (uncorrected). Reducing that score by 3.8% gives the patient a corrected BMD of 0.721 g/cm2.
The correction factor depends on how long a patient has been taking strontium ranelate or how long since she stopped taking it. The correction factor is greatest at the spine and less at other sites on the body.
Does not seem as intimidating after your explain it. Thank you.
Is there any significance in where the strontium comes from. I believe Doctor's Best is mined in the US, but some brands use India instead. That kinda worries me, am I being overly cautious?
To: Anonymous of 07/12/2012,
You’re welcome. I’m glad I was able to help with your previous question.
Strontium occurs in nature as mineral deposits of celestine, also called celestite (strontium sulfate) and strontianite (strontium carbonate). Citric acid and citrate also occur in nature. Strontium citrate is manufactured from strontium minerals and citrate.
I think where the strontium comes from is significant because the quality and quantity of the mineral deposits vary by country. However, it may be difficult to find out where a company is getting its strontium because the source is seen as proprietary information. I think after you read the following references, you will see that the original source of strontium minerals is not the U.S.
http://www.ehow.com/facts_6961323_strontium-mined_.html
“Strontium sulfate is the most common strontium mineral. Strontium sulfate is also known as celestite. China, Spain and Mexico produce approximately 98 percent of celestite. While there are celestite deposits in the United States, none has been mined since 1959.’
“Strontium is generally converted from the celestite form by chemical means. One form of the processed strontium is strontium carbonate (strontianite). Some strontium carbonate is naturally occurring. Deposits of it have been found in Malawi and China, but China is the only producer from this source.”
“While China is the largest producer of strontium carbonate, the quality and quantity of China's celestite reserves are below those of Spain and Mexico. This has made China dependent on imports of celestite to meet the supply needs for strontium carbonate processing.”
“Due to demand for celestite by China for production of strontium carbonate, Iran has increased its production of the material. It's a viable export for Iran thanks to lower shipping costs and government subsidies. Decrease in other consumption of the material has led to reduced production by Spain.”
See: http://minerals.usgs.gov/minerals/pubs/commodity/strontium/mcs-2010-stron.pdf
According to the U.S. Geological Survey, “U.S. production of strontium minerals ceased in 1959. The United States is 100% import reliant on celestite, the most common strontium mineral consisting primarily of strontium sulfate.”
“Import Sources (2005-08): Strontium minerals: Mexico, 100%. Strontium compounds: Mexico, 85%; Germany, 9%; and other, 6%. Total imports: Mexico, 93%; Germany, 4%; and other, 3%.”
Thank you Bone Lady, but am still a little confused. In the old posts on NOF (2008, I think) you posted that Dr's Best got their strontium (they said) from USA. I may have remembered that incorrectly, will try to recheck. I had noticed that there are different amounts of strontium listed by different mfgs., but the elemental amount was always 680. Maybe that has to do with the different levels of quality in the strontium that was mentioned. It was the "chemical means" that are generally used to convert the celestite that is very upsetting. Geez, no way I am comfortable with China chemically doing anything to what I am going to take. They can't even handle making safe milk.
You are super knowledgeable about this stuff, thank you.
To: Anonymous of 07/13/2012,
As I recall, it was April995 who posted at NOF that she had called Doctor's Best and been told their strontium citrate is from USA. I think the company spokesperson answered truthfully in saying the strontium citrate is made in the USA. However, I doubt the strontium mineral, one of the raw materials used to make strontium citrate, comes from the USA. According to the U.S. Geologic Survey I quoted earlier,"U.S. production of strontium minerals ceased in 1959." Also according to the Survey, from 2005-08, all the strontium minerals imported into the USA came from Mexico.
I do not have more recent data, and I do not know where Doctor's Best is getting its strontium minerals from. Maybe, instead of buying the mineral and making strontium citrate, the company purchases strontium citrate, does quality checks on it, packages and distributes it. For more information, you can call the company or leave a message on their website.
Here is Doctor’s Best statement about raw materials:
www.drbvitamins.com
“Doctor’s Best directly purchases only the highest grade raw materials from proven and reputable suppliers to be put into product formulations. All raw material suppliers go through our stringent vendor qualification process, which includes a multi-step investigation including all aspects of the production and handling procedures, to ensure the highest level of quality is reached.”
Second Reply to Anonymous of 07/12/12:
I just left the following message on Doctor's Best website and will let you know their response:
Where does the strontium mineral used to make strontium citrate come from? I am a consumer of Doctor's Best Strontium BoneMaker.
Thank you, I had also left a message, nothing so far. You are very kind to go the extra mile to help people!
Strontium Bone Maker is sourced from and manufactured in the US, although I do not think the label has ever stated this. It has not been changed. Sincerely, Julie AndersonCustomer Care
I had also sent an email and they answered today.
Wow, that just goes to show that no matter how official the source looks, it may not be correct. Thanks Bone Lady for showing me how to get this information.
BoneLady,
can you tell me which the value of the correction factor after one year of treatment with strontium ranelate?
Thank you
To: Anonymous 09/17/2012
There are various opinions on what factor to use to correct BMD results for strontium or even whether or not a correction is necessary when comparing year-to-year BMD results for the same patient. Servier, the manufacturer of strontium ranelate has written the following:
http://www.medicines.org.uk/emc/medicine/15410
“The combined effects of strontium distribution in bone and increased X-ray absorption of strontium as compared to calcium, leads to an amplification of bone mineral density (BMD) measurement by dual-photon X-ray absorptiometry (DXA). Available data indicate that these factors account for approximately 50% of the measured change in BMD over 3 years of treatment with PROTELOS 2 g/day. This should be taken into account when interpreting BMD changes during treatment with PROTELOS.”
Servier has also told physicians that it is not necessary to correct a patient’s BMD results each year. If the uncorrected BMD is increasing, then the patient is believed to be in compliance, and her fracture risk should decrease accordingly.
According to a paper published in Bone. 1997 Jan;20(1):47-54 Effects of strontium ions on growth and dissolution of hydroxyapatite and on bone mineral detection:
“The effect of partial substitution of Ca2+ in hydroxyapatite (HA) by Sr2+ on bone mineral content (BMC) and bone mineral density (BMD) measured by dual energy X-ray absorptiometry has been studied using three commercial densitometers. Extrapolating the absorption data for up to 10% replacement of Ca2+ by Sr2+ to 100% substitution of Ca2+ by Sr2+ in HA leads to an apparent increase in BMC or BMD of about a factor of 10.”
According to a paper published in the Journal Clinical Densitom. 1999 Winter;2(4):371-9. Influence of strontium on bone mineral density and bone mineral content measurements by dual X-ray absorptiometry:
“The same adjustment factor (10% overestimation for 1 mol/mol% Sr) can be used for all presently available types of instrument and acquisition modes.”
Both of these research papers came to the same conclusion. That means you would subtract 10% off the BMD in g/cm2 to get the correction for strontium ranelate.
Here is a link with abstracts of both papers:
http://www.osteopenia3.com/Strontium-dexa-scan.html
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