**EP329: Bloods For Bone Health**
**Dr. Auric Bishop:** Welcome, my name's Dr. Auric Bishop. I'm a cardiologist, an author, and a keynote speaker. I'm the CEO of the Healthy Heart Network. I'm all about trying to help people live as well as possible for as long as possible. Heart disease is huge in Australia. Every 20 minutes, someone suffers a heart attack. Most of these could probably have been avoided if only we knew what to do. This podcast is all about helping you understand blood pressure, weight, and cholesterol for better health. If you enjoy this podcast, I would be honoured for a five-star review. You can share it with your family and friends. It may well save someone you love.
Hi, my name is Dr. Ulrich Bishop, and welcome to my podcast and videocast station. As always, I'm really very grateful that you've taken the time to tune in and have a listen, and I hope I can share with you something that's valuable for you or for someone you care for.
Today, I'd like to talk about the blood tests you might get done if you've got a concern or a problem with your bones, thinking osteopenia or osteoporosis. Well, just a quick recap. If you're wondering about osteopenia and osteoporosis and thinking, "Oh, look, I feel fine. Probably won't happen to me," all I can encourage you to do is think again. The stats are compelling: about 40% of all women and 30% of all men will, in a lifetime, have an osteopenic or osteoporotic fracture. That makes it pretty hard to duck, regardless of who you are.
Now, on a previous podcast, I talked about the very things that could put you at risk and the sort of things that, if they're going on in your life, I think it'd be really valuable for you to have a conversation with your general practitioner about whether you should be having a bone mineral density check. Now, we spoke about that. It's a machine, a piece of equipment that we call a DEXA scan—DEXA stands for dual x-ray absorption scan. Now, I'm not going to go into the physics of it, mainly because I don't understand it, but it is a test that we've used for many years. It's broadly available; it's where all the researchers sit, and to a large degree, it's a great starting point. It will give you a measure of your bone mineral density compared to what it would have been for an average 30-year-old of the same sex as you. So you get a really good idea of where you are.
Now, today I'm going to talk about blood tests that you'd get checked if there was a query about your bone health. So let's kick that off. Imagine you've had your DEXA scan, and I'd add in there that there are Medicare rebates for DEXA scanning in certain situations. However, it may be something that you want to invest in sooner than a rebate comes around because you want to be ahead of the game and ahead of the curve. Through our own center here in Hobart, which I've touched on before—a centre called OsteoStrong, a wellness centre, and there are franchises scattered around Australia—we're able to help people build their bone mineral density naturally through a structured programme that we offer on a weekly basis. It's very convenient and very effective. But the sooner you know you've got a problem with the bones, the sooner you can interact and really put something in place to change your outcome. So my own feeling is it may be worth getting a bone mineral density scan sooner rather than later.
In that previous podcast, I covered a lot of the flags that might trigger that conversation with your GP. To let you know, a bone mineral density scan might cost you about $150 to $200 out of pocket if you're not covered by a Medicare rebate. Given so many people are impacted by bone health, it may be something that you choose or discuss with your GP, and together you choose that it's a good option for you.
All right, so we've done our bone mineral density scan. Our bone density is on the low side. If it's on the low side, we call that osteopenia, so reduced bone mineral density. If it's really lower than that, we call it osteoporosis. So osteopenia is the first stage of thin bones, and osteoporosis is the significant sort of second stage, if you like, of thin bones. What do we do next? Well, I'm going to put out there that it's certainly worth a conversation with the GP, and I'm sure most GPs will have done this. You may want to write some of these down, but these will also be available on a blog. So you can go to my blog and check it out.
Well, of course, you'll want to check what we call ECU, which is standard electrolytes, creatinine, and urea. Now, this just gives us a great feel for how the kidneys are working. Super important, super easy, done all the time, and pretty cheap. You want to just make sure you don't have renal impairment because if that sneaks up on you, that's important. ECU: electrolytes, creatinine, and urea.
Next, you want to make sure the liver's working okay, including things like alkaline phosphatase, which ties into bone health. Liver function, we know, is central to good bone health, so get that checked—LFTs, liver function tests. I generally include magnesium, calcium, and phosphate—CMP—because they're all interplaying when it comes to bone health. Things like calcium may be elevated if there's a renal problem or a parathyroid problem. So we may well follow on with other tests subsequently.
So let's start with the calcium. If the calcium is normal, it's pretty unlikely you're going to have hyperparathyroidism. If your renal function is normal and your calcium is normal, then obviously that interplay is not occurring. So calcium, magnesium, phosphate—CMP. A full blood examination is certainly worth doing. And if you're doing these sorts of tests, there are also general screens for one of the better terms. So why not throw them in there?
I would add to that list a test called an ESR. ESR stands for erythrocyte sedimentation rate. Your erythrocytes— you've probably heard that word before, but if you've forgotten what they are, your erythrocytes are your red blood cells. So your red blood cell sedimentation—sedimentation means how something settles. The rate over time: what we do is we take a tube of blood, shake it up, look at all the red blood cells inside, and see how long it takes for those red blood cells to settle in that tube, which is held vertically.
Now, here's an interesting thing: if there are inflammatory proteins within the blood, those inflammatory proteins, if you like, act like a thickened viscous fluid and slow down that erythrocyte sedimentation rate. If you've got beautiful, healthy blood and none of those extra inflammatory proteins are kicking around, then that beautiful, healthy blood doesn't offer proteins as a resistance to the falling, if you like, through this column of red blood cells. So if you've got beautiful, healthy blood, your red cells will just fall to the bottom of the tube very quickly, resulting in a low erythrocyte sedimentation rate. If you've got these proteins kicking around in there—abnormal proteins that shouldn't be there—your erythrocyte sedimentation rate will be elevated.
Now, it doesn't tell you what the problem is; it just tells you there's something wrong, and it could be, therefore, a flag for further testing. One of the really important abnormalities of a very high erythrocyte sedimentation rate is that we can see it in myeloma. Myeloma is a bone marrow tumour, but it can lead to features of osteoporosis throughout the skeleton without looking like a focal or localized abnormality.
Next blood test: thyroid function. We use a simple test called TSH—thyroid stimulating hormone. So we measure that thyroid stimulating hormone. If that's high, thyroid stimulating hormone is produced by the brain; it's in the pituitary gland, the little brain, the little gland that sits sort of just behind your eyeballs, actually. The gland, the pituitary gland, sort of hangs off the bottom of the front lobes of the brain in a special little pouch or pocket, really literally behind the eyeballs and behind the nose. That gland, the pituitary gland, releases thyroid stimulating hormone (TSH) based on how active the thyroid gland is.
So if the thyroid gland is underactive, then the pituitary gland will increase the thyroid stimulating hormone to bring up that thyroxin level and vice versa. If, for example, the thyroid is overactive, then the feedback loop would mean that that TSH is low because the body doesn't want to drive the thyroid gland any harder; it wants it to reduce how much thyroxin it's producing.
It is important because thyroid hormone, certainly at high levels, increases turnover of bone and can drive osteoporosis over time. So TSH—get it checked.
Next one: vitamin D. Who would have thought? Of course, vitamin D is important. And for us souls who live down here in Hobart in those cooler climes during winter, there's a high percentage of the population that can run into the risk of vitamin D deficiency. Of course, the slip-slop-slap campaigns of years gone by have encouraged us to cover up during the warm seasons anyway, so that we may be out in the sun, but we may not be getting the sunlight trigger to convert the cholesterol-based precursors in our skin to the active vitamin D, which our body needs.
Vitamin D is super important for bone health, for reabsorption, for keeping calcium in the body and in the bones. Check that vitamin D. If you need to, you need to supplement with it. Very simple to do. Vitamin D supplementation is probably being covered on another podcast, but it is a little bit tricky, and you might even think about how you best do that; you talk to your GP about that.
You probably also want to know how the adrenal glands are working, and a very simple marker for that is a blood test called DHEAS—dihydroepiandrosterone sulfate. DHEAS is a marker of adrenal function and a precursor to the sex hormones as well. So check it out. You might talk to your GP about getting that checked.
At the same time, check dihydrotestosterone. Checking again because we know these sex hormones are closely linked to bone mineral density and bone health. Testosterone, which you need to measure as a number within the bloodstream, but you also need to measure sex hormone binding globulin, which holds the testosterone. You need a measure of sex hormone binding globulin plus the total testosterone to get an idea of free testosterone that's available to help with bone metabolism.
You may wish to check insulin-like growth factor number one. Insulin-like growth factor number one is a marker of growth hormone function. You may wish to check estradiol, particularly for ladies, and progesterone. Both estradiol and progesterone will give us some insight into that sort of hormonal, female hormonal status. Low levels of both those hormones could be implicated with bone mineral density loss.
FSH and LH—these are the gonadotropins, and they will speak to whether someone's premenopausal, postmenopausal, or perimenopausal and give us some interaction there. For men, I think one final blood test that could be really important, and I recommend this being considered every year—again, you want to talk to your GP about this—is PSA, which stands for prostate-specific antigen. That PSA is important because it gives us a marker of what's going on with the prostate. If there is something going on with the prostate, that marker will be up. If you're tracking it year on year, then if, for example, there is some change in the prostate, it should be flagged with that.
Well, what else can I say? I'm pretty happy that we've covered most of the blood tests that are worth a conversation with your GP should you be confronted with a situation that your bone mineral density is lower than you would have expected. So checking kidney function, checking liver function, checking calcium, phosphate, and magnesium, checking for blood examination, looking at how those little erythrocytes or the red cells settle in a tube of blood, checking the thyroid, checking the vitamin D, checking DHEAS, dihydroepiandrosterone, checking all those other sex hormones—dihydrotestosterone, testosterone, estradiol, progesterone, LH, and FSH if appropriate. You might also want to check growth hormone and prostate.
Well, what a lot to get through! I hope you found that valuable. If you are on a bone health journey, follow us on our Facebook page, Hobart OsteoStrong Facebook page. We put lots of information up there. If you know someone who's got bone-related issues, please share this information with them because it really, really has a major impact on morbidity, and morbidity is the thing that makes life miserable. Mortality is what ends life. So bone health is super important if we're trying to look after people's health span and quality of life.
For now, I'm going to wrap up. I am going to wish you the very best. As always, thank you so much for tuning in. Wishing you the very best and your family the very best. Hope you live as well as possible for as long as possible. Take care, and bye for now.
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