USPSTF Gives D Grade to Vitamin D

Clever title, huh?  Kinda made you want to read this post, right?  We're living in such a fast-paced world that we learn via sound bites and 140 characters at a time.  We want & need every morsel of information summarized neatly into easily digestible bits.  Unfortunately, truth & science aren't always so malleable to this way of learning.

Case in point is the United States Preventive Services Task Force's Clinical Guideline regarding vitamin D & calcium supplementation to prevent fractures in adults as published early online yesterday in the Annals of Internal Medicine.  Up until recently, we lumped everything & everyone together stating that calcium 500-1,000mg daily + vitamin D 400-800 units was good, regardless of age, gender, and risk factors.

Well, as the USPSTF attempted to explain in their guidelines, the evidence for primary fracture prevention in both men and premenopausal women is woefully scant.  Thus, they weren't able to analyze risks vs benefits.  And when it comes to noninstitionalized postmenopausal women, the data for benefit in primary fracture reduction using calcium doses greater than 1,000mg daily and vitamin D greater than 400 units daily, was inadequate to analyze risks vs benefits.

Before I get to the USPSTF's D grade, let's be clear as to how finely they're dividing the population & parsing their words, almost as if in legalese.  For instance, this Recommendation Statement only addresses primary fracture prevention, that is in those men & women who've never had an osteoporotic fracture before.  In this statement getting all the press, there's no attempt to address secondary prevention in those who've already sustained a hip or vertebral or wrist fracture.  Furthermore, there's no mention of institutionalized postmenopausal women, just noninstitutionalized postmenopausal women & premenopausal women (along w/men).  

So it's for those non-institutionalized postmenopausal women who take less than 1,000mg daily of calcium and/or less than 400 units daily of vitamin D for whom the USPSTF was unable to find any benefit.  Worse there was some concern over an increase risk for kidney stones.  Thus they recommended against this dose in this group since they can't recommend something that offers no benefit while putting that person at risk, no matter how small.  Check out the editorial for more info.

If this appears to be an about-face from their December 2011 meta-analysis & June 2012 draft, both published in the Annals of Internal Medicine, read the conclusion carefully: Combined vitamin D and calcium supplementation can reduce fracture risk, but the effects may be smaller among community-dwelling older adults than among institutionalized elderly persons. Appropriate dose and dosing regimens, however, require further study (italics mine).

Bottom line: as much as I want to be able to make a blanket statement about vitamin D & calcium, the evidence doesn't allow for it.  So if you're a community-dwelling postmenopausal female, don't take small doses of calcium (less than 1,000mg daily) or vitamin D (less than 400 units daily).  But what about larger doses? What about men, institutionalized postmenopausal women, and premenopausal women?  What do they do?  Either wait for studies to be published (if they're more concerned about potential side effects) or "Go Big or Go Home".

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