Bone Disease and HIV/AIDS: More Common Than You Think -- This Month in HIV
An Interview With Todd Brown, M.D., Ph.D., and Ben Young, M.D., Ph.D.
Bonnie Goldman: Let's turn to supplementation, since you both mentioned it just now. What is the role for vitamins? Which vitamins would you recommend? Dr. Brown, I know you have done some studies on vitamin D, and the importance of vitamin D.
Todd Brown: Vitamin D deficiency is very common in the general population, and in HIV-positive patients, as well. It's associated with all kinds of medical problems. Bone density and fractures is one of them.
The current recommendations are that everyone should be getting at least 800 international units of vitamin D daily. That's probably not enough, given the high prevalence of vitamin D deficiency. There is some work being done in the general population to change those guidelines. I think 1,000 or 1,500 international units would be more appropriate to get to adequate vitamin D levels.
Bonnie Goldman: Some people take prescription vitamin D weekly, or monthly. Is there a difference between taking it daily or weekly or monthly? Or taking prescription versus non-prescription vitamin D?
Todd Brown: Not really. They are different formulations of a similar compound: vitamin D. You could either get it by prescription (something called ergocalciferol) or over-the-counter (generally something called cholecalciferol). Either of them can be used.
The problem with big dose supplementation of vitamin D is that there is a risk of overdoing it, and becoming toxic on vitamin D. So if you are giving yourself large doses of vitamin D -- more than about 2,000 international units a day -- you probably want to talk to your doctor or provider about that.
"The problem with big dose supplementation of vitamin D is that there is a risk of overdoing it, and becoming toxic on vitamin D."
-- Todd Brown, M.D., Ph.D.
Bonnie Goldman: What are the risks?
Todd Brown: If you have very high levels of vitamin D, you can get too much calcium absorption. We should back up a little bit to say what vitamin D does.
Vitamin D's main job is to allow calcium and phosphate to be brought in from the gut. If you have too much vitamin D on board, your calcium levels can go too high. That's the real problem.
Bonnie Goldman: Do you recommend most people take calcium pills with their vitamin D?
Todd Brown: Most people do require calcium. The current recommendation is to take between 1,000 and 1,200 milligrams of calcium. Depending on people's diets, they may get close to that; if they are a big milk drinker, they could be able to get that in their diet alone. But most people need somewhere between 600 and 1,000 milligrams of calcium supplementation a day.
Bonnie Goldman: Is there any way to monitor your vitamin D levels and your calcium levels?
Todd Brown: There is a relatively easy blood test to measure vitamin D called the 25-hydroxy vitamin D level. It's a test that can easily be done. This is what really tells you whether or not someone has an adequate amount of vitamin D.
Bonnie Goldman: I was looking at different recommendations, and some said vitamin D levels should be over 30, and some said over 25 was enough. Which one is it?
Todd Brown: There's a lot of controversy as to what constitutes adequate vitamin D. Right now, above 30 is considered vitamin D sufficient. Between 20 and 30 is considered insufficiency, and less than 20 is considered deficiency.
Some people bring the lower number down, saying that there's a severe deficiency state of less than 10. Some people think -- from looking at big studies in large populations -- that the optimal level of vitamin D is somewhere around 40 to 50. But generally, people whose levels are less than 30 probably should get their vitamin D levels up.
Bonnie Goldman: What would be the best way to do that?
Todd Brown: With vitamin D replacement, as you had mentioned, either by prescription or by over-the-counter vitamin D.
Bonnie Goldman: I understand that that doesn't work for everybody. There was a small study where it worked for only 49 percent of the participants. Although, of course, we don't know if they were taking it; we don't know a lot of things.
"If you take vitamin D, generally, you'll be able to see a response. Some people are more resistant to supplementation, meaning they need more vitamin D to get their vitamin D levels up. Some antiretroviral medications may chew up vitamin D. Efavirenz [Sustiva or Stocrin, which is one of the drugs in Atripla], ... has been associated with lower vitamin D levels."
-- Todd Brown, M.D., Ph.D.
Todd Brown: The biggest issue is compliance. I think there was a study -- and this may be the one that you're speaking about -- that was presented at the retrovirus meeting last year, where they looked at various doses of vitamin D, and how much they change your vitamin D level. The main issue that I saw with that study is that the compliance was not very good.
So, if you take vitamin D, generally, you'll be able to see a response. Some people are more resistant to supplementation, meaning they need more vitamin D to get their vitamin D levels up. Some antiretroviral medications may chew up vitamin D.
Efavirenz [Sustiva or Stocrin, which is one of the drugs in Atripla], in a study that we were working on, has been associated with lower vitamin D levels. Why that is, isn't entirely clear. But people on efavirenz may need more vitamin D.
Bonnie Goldman: Does this mean that people taking efavirenz or Atripla should be taking a greater supplementation of vitamin D, above the recommendation?
Todd Brown: We don't know that exactly, now. But it looks like people who are on those medications are more likely to be vitamin D deficient. So, extending that, they may need more vitamin D to reach the same vitamin D level as someone who is not on those drugs.
Ben Young: We have been talking about vitamin D, but I'd like to get your thoughts as to whether checking a vitamin D level should be something that should be part of baseline, or annual, laboratory assessment for people living with HIV.
Todd Brown: Probably. The real problem with the vitamin D question is that we know that a lot of people are deficient, even in the general population. What we don't have a great sense of is whether or not replacing vitamin D can really improve your health. We think that that's true. I think that that's true. But we don't know that for sure. I think that's why people are reluctant to recommend universal testing of vitamin D levels.
Personally, I have a very low threshold for testing vitamin D levels in my patients. It's relatively inexpensive. You get information that you can't get from other sources and the treatment, although we did mention the potential problems of vitamin D replacement, it's relatively well tolerated and relatively inexpensive. I think that for those reasons, the threshold to test vitamin D levels in patients should be pretty low.
Bonnie Goldman: Isn't it true that certain people are at greater risk for low vitamin D, such as people who live in the North and people with dark skin?
Todd Brown: That's absolutely true. There's a big seasonal variation with vitamin D. Vitamin D levels go down by about 10 points in the winter, compared to the summer.
There's a big variation depending on the color of your skin. Patients with darker skin will invariably have lower vitamin D -- again, about 10 to 15 points lower than patients who have lighter skin. Those are very important factors, as well.
Bonnie Goldman: I guess one easy way to increase your vitamin D levels, besides supplementation, is to just find 15 minutes a day to be in the sun.
Todd Brown: That is a good one. We probably do not spend enough time in the sun and when we do, oftentimes, especially in the summer, we put sunscreen on. We're trying to protect our skin, but it is important [to get some sun exposure]. And winter sun, up in the North, may not be enough to really increase your body's ability to make the vitamin D.
Bonnie Goldman: Let's just remind people what's the bad thing about having low vitamin D.
Todd Brown: The biggest issue, and that's why we're talking today, is the effect on your bone health. If vitamin D levels are low, your body won't be able to absorb the building blocks of bone -- that is, calcium and phosphate. And your body doesn't like this very much.
"Patients with low vitamin D levels -- and this is particularly older patients -- are more likely to fall than those who have normal vitamin D levels. That's probably due to vitamin D that's working on the muscle."
-- Todd Brown, M.D., Ph.D.
If it doesn't have enough calcium and phosphate, your body goes to the bones to try to maintain the calcium and phosphate levels, because the bones are the biggest store of calcium and phosphate that we have. As a result, the calcium and phosphate get leached out of the bones, and the bone density decreases. That's the biggest concern.
There are some other issues that are related to vitamin D. Patients with low vitamin D levels -- and this is particularly older patients -- are more likely to fall than those who have normal vitamin D levels. That's probably due to vitamin D that's working on the muscle.
Bonnie Goldman: Is that a balance problem then?
Todd Brown: It's probably a muscular strength problem, rather than balance. We know from many studies -- this is outside of the HIV realm -- that supplementation with vitamin D can decrease the risk of falling.
Bonnie Goldman: I understand there are also heart disease risks in people with low vitamin D levels.
Todd Brown: There have been a lot of studies that have shown that the risk of cardiovascular disease is higher in people who have low vitamin D.
The risk of diabetes is higher with people who have low vitamin D levels. The risk of some infections is higher in people with low vitamin D levels.
So there is a whole host of bad outcomes that have been associated with low vitamin D levels. What's missing -- with the exception of bone health and falls -- are good studies to say that, if you replace vitamin D, you're going to decrease those outcomes.
We've been fooled in the past by trying to use information gathered by the observational studies to make recommendations about treatment. Hormone replacement therapy is a common example.
Bonnie Goldman: So, we should wait before ...
Todd Brown: Specifically, in that population. For example, there's not any great evidence that someone who has a heart attack should be tested for vitamin D.
Having said that, the risks of treatment with vitamin D are relatively low, and it's relatively inexpensive. So I think the threshold to treat is somewhat lower.
Bonnie Goldman: What's the role of exercise, and weight-bearing exercise? Does that help build bones?
Todd Brown: Absolutely. Your muscles pulling on the bone will cause bone to grow. Anytime you exercise your muscles and your muscles pull on the bone, it's going to be good for the bone. Weight-bearing exercise -- weight training or even just walking or jogging, or any time your muscles flex against the bone -- would be helpful.
Bonnie Goldman: Would walking around with a five-pound weight be a nice first step?
Todd Brown: I think any level of activity would be nice; maintaining your level of activity is really important. What you don't want to do is be sedentary. It doesn't necessarily need to be something that you would consider exercise. For example, there have been some studies showing that gardening, an activity that's relatively physical, is actually quite good for the bones. It doesn't necessarily need to be dedicated exercise.
Bonnie Goldman: How often should this be done during one week?
Todd Brown: Probably three or four times a week for at least a half hour.
Bonnie Goldman: Does exercise help build bone by a certain amount? Is there some measurable effect?
Todd Brown: There is. It depends on what exercise you're talking about. You get this information (i.e., trying to see what the effect is) by looking at studies. Oftentimes, the studies really aren't long enough to see a big effect, or the types of exercises are quite different. I wouldn't be able to put a number on exactly how much bone you can build. But there's no question that maintaining your level of physical activity is a really important part of bone health.
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This article was provided by TheBody.com. It is a part of the publication This Month in HIV.
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