Will One A Day® make grandma have fewer days?
A new study in the Archives of Internal Medicine reports that dietary supplements — including multivitamins, folic acid, iron and copper, among others — “appears associated with an increased risk of death in older women.”
But before anyone throws away their vitamins consider the following.
All the study’s reported statistical associations of concern are weak, barely (suspiciously?) statistically significant and none are backed up by an medical investigation or biological plausibility. Food and vitamin intake was self-reported by the study subjects only three times by the women over the course of the 22-year long study — so “unreliable” would be a generous description of it.
Although a number of confounding risk factors for mortality were supposedly considered (at least statistically) by the researchers, multivariate analysis is simply not designed to handle such poor and inadequate data collection, and the complex interactions of potential confounding risk factors.
The bottom line is that the researchers have no idea how much vitamins and minerals, and in what combinations, these women actually consumed or why they died. To condemn multivitamins with such shoddy statistical inference is absurd.
This study proves nothing other than shocking and shockingly junky results can get published in otherwise reputable journal.
None of this is to say that some (many?) people aren’t wasting their money and obtaining false comfort overdosing on vitamin, mineral and other dietary supplements — but that’s a different question from safety that we’ll leave for another day.