You Can't Win A Fight With Your Wife - Part 2

As I mentioned yesterday, some people are going to believe what they want to believe, no matter the proof.  Just like the fact that I'll never win an argument or battle w/my wife.  But having said that, I must now turn the other cheek, at least with regards to vitamin D.  Little did I realize while working in a vitamin D research lab as a pre-med student many moons ago that I would find vitamin D so fascinating and important (sorry! the truth comes out) almost 3 decades later.  While I am not an expert, I am quite the proponent of getting enough vitamin D and checking/reaching optimal levels.

So I was quite disappointed in the Institute of Medicine's recommendations released last November.  In an editorial published in the New England Journal of Medicine last week, it turns out that for non-bone related indications, members of the IOM considered the existing evidence as inconsistent & inconclusive.  Remember that all the current evidence linking vitamin D levels to cancer, cognitive function, heart disease, and infections is observational in nature.  This data is only able to demonstrate an association.

On the other hand, the data linking vitamin D to falls & osteoporotic fractures is consistent & defnitive, having been derived from cause & effect studies, typically randomized, double-blind, placebo-controlled studies.  Which is why the authors agreed upon 20ng/mL as adequate for bone health looking at PTH response.  But when 20-30ng/mL is considered insufficient by Quest Diagnostics, 30-100ng/mL is considered the normal reference range by Quest, and toxicity is manifest only at levels significantly above 100ng/mL, I can't rationally explain why I want to push vitamin D levels closer to 100ng/mL and farther from 30ng/mL (but, of course, without exceeding 100ng/mL) except to think of a grading system.  So yes, I'm one of those who speak with a forked tongue.

But I can think that I can make a reasonable justification in that some vitamin D is necessary for bone health as long as I don't push beyond the upper limit of normal.  On the other hand, when it comes to vaccinations, I find it impossible to come up with a reasonable justification not to get vaccinated (unless one is allergic), especially since those who go unvaccinated expose not only themselves but others to risk of some infectious disease.

Maybe a better analogy is to consider hormone therapy for menopausal women.  Current randomized, double-blind, placebo-controlled evidence warrants giving estrogen + progesterone for symptomatic vasomotor instability at the lowest dose for the shortest period of time, but not for prevention of heart disease or cognitive decline, while observational & laboratory data suggest other potential indications.

I guess what I'm trying to say is that if you want to do something based upon observational data, try to have some cause & effect data supporting your decision, too.