I saw the "news" blurb about how a new study says vitamins cause you to die sooner. Here's the bummer problem with media and with junk science. I was going to write something similar, but these folks have done it so well! Don't believe everything you read about health.
Shame on AMA’s Archives of Internal MedicineOctober 11, 2011
Did you hear the breaking news last night—that multivitamins may shorten your life? Here’s how junk science from the AMA set off the media frenzy.
Bloomberg phrased it this way: “Multivitamins and some dietary supplements, used regularly by an estimated 234 million US adults, may do more harm than good, according to a study that tied their use to higher death rates among older women.” The study’s authors outrageously concluded, “We see little justification for the general and widespread use of dietary supplements.”
The study, published in the American Medical Association’s (AMA’s) Archives of Internal Medicine, assessed the use of vitamin and mineral supplements in nearly 39,000 women whose average age was 62. The researchers asked the women to fill out three surveys, the first in 1986, the second in 1997, and the last in 2004, reporting what supplements they took and what foods they ate, and answering a few questions about their health.
That’s right, all the data was self-reported by the study subjects only three times over the course of the 19-year-long study. To say the data is “unreliable” would be a generous description. This kind of “data” has no place in a valid scientific study.
Then the researchers looked at how many of the women had died by 2008. They reported that the number of deaths were somewhat higher for women who took copper, a little bit lower for women who took calcium, but about average for most of the women.
In the study, all of the relative risks were so low as to be statistically insignificant, and none was backed up by any medical investigation or biological plausibility study. No analysis was done on what combinations of vitamins and minerals were actually consumed, and no analysis of the cause of death was done beyond grouping for “cancer,” “cardiovascular disease,” or “other”—there was certainly no causative analysis done. The interactions of potential compounding risk factors is always tremendously complex—and was ignored in this so-called study.
“Multivitamin” can mean many different things, and of course changed tremendously over the 19 years during which this “study” was conducted. Were they high quality? Were the ingredients synthetic or natural? How much of each nutrient was taken? Were they really taken at all? How good is anyone’s memory in describing what took place over many years? One would assume that that the women’s diets fluctuated greatly over the same period; when self-reporting only three times in 19 years, there is a great deal of information one would naturally leave out even if some of it was accurate. No analysis was done of the effect of supplements on the women’s overall health, nor of their effect on women of other ages.
In short, this study is less than useless: it is dangerous, because it is being used by the media and the mainstream medical establishment to blacken the eye of nutritional supplements using poor data, bad analysis, and specious conclusions—otherwise known as junk science.