Today, while skimming stories from Google News via RSS feed, I came across a headline from the magazine Time that made me laugh:
Study: Vitamin D Lowers Risk of Death
This was followed by this paragraph:
Doctors have long known that vitamin D is essential to good health. Get enough of it and it ensures strong bones and teeth. But a new study this week suggests an even more extraordinary benefit: a lower risk of death.
That is an extraordinary benefit indeed. Last time I checked, the risk of death was 100%. That is, everyone will die eventually. So reduced risk of death would mean that some people who are consuming vitamin D have become immortal. At least that’s the impression that the headline and lede have you believe would have you believe. The rest of the story goes on to straighten that out:
The new paper, published in the Sept. 10 issue of the Archives of Internal Medicine, is a meta-analysis of 18 previously published studies on the vitamin. None of the original experiments was specifically designed to study how vitamin D affects mortality — the trials involved conditions such as bone fractures, bone mineral density, congestive heart failure and colorectal cancer — but all of them tracked participants’ death data. Overall, researchers found, people who took daily vitamin D supplements were 7% less likely to die during the study — from any cause — than people who didn’t.
Ah, so it is death over the period of time that a study takes. Well, lowering the risk of that is quite a bit different than lowering the risk of death. I would have hoped that the writers and editors at Time would have known that, but I guess not.