Screening and Vitamin D

[doxycycline]

Hi Dr. Feigenbaum and Dr. Baraki,

I am new to barbell medicine and I have recently watched a bunch of your guys content. It’s been very interesting, especially as someone who has a background in healthcare, so thank you.

Late in the screening podcast Jordan mentioned how he does not recommend healthy people get screened for Vitamin D except for those with chronic disease. The USPSTF concluded that there is insufficient evidence to provide a recommendation for healthy adults, so their recommendation is “no recommendation” since they are uncertain of any benefits (see https://www.acpjournals.org/doi/10.7326/M14-2450). I think this is an important distinction. By providing the recommendation that one shouldn’t get screened, you are actually providing a recommendation when USPSTF’s true conclusion was “no recommendation” or “we don’t really know”.

Moreover, I think it’s interesting that you mention most of the of medical literature supporting Vitamin D screening is in the context of those with a serious disease like liver failure or kidney failure. You then mention that, because of this, if you do not have a serious disease, one doesn’t need to get screened for Vitamin D. I think this could be an error in thinking due to availability bias in the current nutrition literature. As mentioned in the Nutrition Science series of articles by Alan Flanagan, much of the early research on nutrition was this “single-nutrient focus” model and work on specific deficiencies in certain vitamins and minerals manifesting to symptoms that had short latency periods. As the biomedical research progressed and evolved to hold RCT as the gold-standard, they were incorporated into nutrition science into what we’ve now been recognizing as an “awkward fit” due to the complex, multi-factorial nature of nutrients. My point being that if much of the medical literature has historically focused on reductionist nutrition science that deals with severe deficiencies and diseases with short latent periods that illustrates the “one nutrient – one disease" kind of model, you will find less information in the medical literature on things outside of that, specifically diseases that we deal with nowadays that have a long latent period (i.e. cvd). And perhaps this may be what is happening. Heany, in Nutrients, Endpoints, and the Problem of Proof (2008), noted the following:

The original nutrient deficiency diseases were all of short latency and involved discrete body systems and dysfunctions. Rickets, pellagra, and beriberi are good cases in point. And, while the working science has progressed far beyond these beginnings, these short latency diseases have remained the implicit model for much of our thinking about nutritional deficiency and, to a substantial extent, our determination of nutrient intake requirements.

With that said, the current evidence is insufficient with regards to vitamin D deficiency and long latent disease. However, making the recommendation that one should not get vitamin D screening indicates that we do know what’s best, when in reality, we simply don’t know.
​​

[Jordan_Feigenbaum]

@doxycycline

Hi Dr. Feigenbaum and Dr. Baraki,

I am new to barbell medicine and I have recently watched a bunch of your guys content. It’s been very interesting, especially as someone who has a background in healthcare, so thank you.

Late in the screening podcast Jordan mentioned how he does not recommend healthy people get screened for Vitamin D except for those with chronic disease. The USPSTF concluded that there is insufficient evidence to provide a recommendation for healthy adults, so their recommendation is “no recommendation” since they are uncertain of any benefits (see https://www.acpjournals.org/doi/10.7326/M14-2450). I think this is an important distinction. By providing the recommendation that one shouldn’t get screened, you are actually providing a recommendation when USPSTF’s true conclusion was “no recommendation” or “we don’t really know”.

I am recommending against routing screening for Vitamin D, which I feel like is supported by the current evidence base. The USPSTF does not go this far directly, but without any clinical indication to investigate Vitamin D status, I feel comfortable recommending against routine screening. This is consistent with both the UK NICE Guidelines and Choosing Wisely campaign as well.

@doxycycline

Moreover, I think it’s interesting that you mention most of the of medical literature supporting Vitamin D screening is in the context of those with a serious disease like liver failure or kidney failure. You then mention that, because of this, if you do not have a serious disease, one doesn’t need to get screened for Vitamin D. I think this could be an error in thinking due to availability bias in the current nutrition literature. As mentioned in the Nutrition Science series of articles by Alan Flanagan, much of the early research on nutrition was this “single-nutrient focus” model and work on specific deficiencies in certain vitamins and minerals manifesting to symptoms that had short latency periods. As the biomedical research progressed and evolved to hold RCT as the gold-standard, they were incorporated into nutrition science into what we’ve now been recognizing as an “awkward fit” due to the complex, multi-factorial nature of nutrients. My point being that if much of the medical literature has historically focused on reductionist nutrition science that deals with severe deficiencies and diseases with short latent periods that illustrates the “one nutrient – one disease" kind of model, you will find less information in the medical literature on things outside of that, specifically diseases that we deal with nowadays that have a long latent period (i.e. cvd). And perhaps this may be what is happening. Heany, in Nutrients, Endpoints, and the Problem of Proof (2008), noted the following:

With that said, the current evidence is insufficient with regards to vitamin D deficiency and long latent disease. However, making the recommendation that one should not get vitamin D screening indicates that we do know what’s best, when in reality, we simply don’t know.
​​

I think that is also a reasonable take, however choices need to be made when ordering tests. I am comfortable with my recommendations based on the present evidence, which includes not having a specific cut-off for deficiency, in addition to the risks, costs, and potential benefits. Should the evidence change, I am happy to update my position.

[Austin_Baraki]

@doxycycline

The USPSTF concluded that there is insufficient evidence to provide a recommendation for healthy adults, so their recommendation is “no recommendation” since they are uncertain of any benefits (see https://www.acpjournals.org/doi/10.7326/M14-2450). I think this is an important distinction. By providing the recommendation that one shouldn’t get screened, you are actually providing a recommendation when USPSTF’s true conclusion was “no recommendation” or “we don’t really know”.

You are correct that this is the USPSTF position. However, the USPSTF does not see patients. As a clinician, when a patient presents to the clinic or asks about this, you can’t just tell them “the evidence is insufficient to make a recommendation” and leave it there.

So, despite the lack of a clear recommendation from the USPSTF, we need to have a position on the matter for real-world practice. And at present, if an apparently healthy (i.e., normal blood pressure, waist circumference, etc. etc.) and asymptomatic individual presents to the clinic, we do not see a compelling reason to screen them for vitamin D deficiency. There is room for professional disagreement here, as others argue differently - although such arguments are generally not supported by quality evidence. There are certainly clinical sub-populations in whom checking these levels is better supported, of course, but that is a different matter than population-wide general screening.

One other complicating factor here is the issue of vitamin D as a negative acute phase reactant, whereby levels decrease in the setting of acute illness and chronic disease, and can rise / normalize with the resolution of the underlying disease process. This is a situation where, if we are going to recommend vitamin D supplementation/replacement was a pharmacologic intervention for a particular clinical population, RCTs are indeed an appropriate method of investigation (as opposed to the nutritional science side of things, since relatively few foods naturally contain vitamin D).

[doxycycline]

@Austin_Baraki

You are correct that this is the USPSTF position. However, the USPSTF does not see patients. As a clinician, when a patient presents to the clinic or asks about this, you can’t just tell them “the evidence is insufficient to make a recommendation” and leave it there.

So, despite the lack of a clear recommendation from the USPSTF, we need to have a position on the matter for real-world practice. And at present, if an apparently healthy (i.e., normal blood pressure, waist circumference, etc. etc.) and asymptomatic individual presents to the clinic, we do not see a compelling reason to screen them for vitamin D deficiency. There is room for professional disagreement here, as others argue differently - although such arguments are generally not supported by quality evidence. There are certainly clinical sub-populations in whom checking these levels is better supported, of course, but that is a different matter than population-wide general screening.

One other complicating factor here is the issue of vitamin D as a negative acute phase reactant, whereby levels decrease in the setting of acute illness and chronic disease, and can rise / normalize with the resolution of the underlying disease process. This is a situation where, if we are going to recommend vitamin D supplementation/replacement was a pharmacologic intervention for a particular clinical population, RCTs are indeed an appropriate method of investigation (as opposed to the nutritional science side of things, since relatively few foods naturally contain vitamin D).

That makes sense, I appreciate the explanation @Austin_Baraki

A followup question: suppose a healthy patient sees his doctor for his annual physical and wants to take a vitamin D test. Would you discourage him from doing so or remain neutral? I see two possible scenarios:

Scenario 1: Because there’s little proven benefit shown, the clinician reasons that there is no point in doing it. So, the clinician would discourage him from doing so and explain why.
Scenario 2: Although there’s little proven benefit, there’s also little proven evidence of significant risks–i.e. the relative risk/benefit seems to be around 0. So, the clinician reasons that if it would make the patient feel better then the patient should take the test.

What would you do and why?

[Jordan_Feigenbaum]

@doxycycline

That makes sense, I appreciate the explanation @Austin_Baraki

A followup question: suppose a healthy patient sees his doctor for his annual physical and wants to take a vitamin D test. Would you discourage him from doing so or remain neutral? I see two possible scenarios:

Scenario 1: Because there’s little proven benefit shown, the clinician reasons that there is no point in doing it. So, the clinician would discourage him from doing so and explain why.
Scenario 2: Although there’s little proven benefit, there’s also little proven evidence of significant risks–i.e. the relative risk/benefit seems to be around 0. So, the clinician reasons that if it would make the patient feel better then the patient should take the test.

What would you do and why?

If the patient is healthy and has no clinical indications or risks for a disease where replacing vitamin D improves outcomes, I wouldn’t test for it. In isolation, the test does not cost a lot, but it’s part of a larger problem with unnecessary tests- to the tune 337 million dollars in 2015 for vitamin D alone. Rather, I’d encourage the person to make the appropriate lifestyle changes regarding diet and physical activity.

[Austin_Baraki]

@doxycycline

That makes sense, I appreciate the explanation @Austin_Baraki

A followup question: suppose a healthy patient sees his doctor for his annual physical and wants to take a vitamin D test. Would you discourage him from doing so or remain neutral? I see two possible scenarios:

Scenario 1: Because there’s little proven benefit shown, the clinician reasons that there is no point in doing it. So, the clinician would discourage him from doing so and explain why.
Scenario 2: Although there’s little proven benefit, there’s also little proven evidence of significant risks–i.e. the relative risk/benefit seems to be around 0. So, the clinician reasons that if it would make the patient feel better then the patient should take the test.

What would you do and why?

I’d probably ask why they’re interested in checking it, to get a better sense of their reasoning. There may be something about their past medical history or family medical history that I’m unaware of, or they may be asking based on misinformation/misunderstanding - either way, it’s worth knowing their reasoning so it can be addressed appropriately and we can develop a shared plan. It’s also worth noting and discussing with patients that many insurers do not cover routine vitamin D testing in such populations without some other medical indication.

Of course, patients are simply seeing a clinician for recommendations on their health, and they are ultimately in charge of their decisions – so if they choose to go out and pursue testing on their own, they are certainly free to do that as well.