Vitamin D report misleading to the public

A study was just published in JAMA (The Journal of the American Medical Association) that reports an increased risk for falls and fractures in older women who took vitamin D. The majority of studies reporting benefits for vitamins go unmentioned in the lay press, but this one was sensationalized. Headlines reading "Vitamin D increases falls and fractures", which is contrary to a huge body of scientific evidence, are likely to mislead the lay reader. Here's what the authors intended to do:

"To determine whether a single annual dose of 500 000 IU of cholecalciferol (D3) administered orally to older women in autumn or winter would improve adherence and reduce the risk of falls and fracture."

That's right, the dosage was 500,000 IU of vitamin D3 administered in one dose (the RDA has been 400 IU)! The study subjects were followed for 3 to 5 years, and their data generated this conclusion:

"Among older community-dwelling women, annual oral administration of high-dose cholecalciferol resulted in an increased risk of falls and fractures."

Is this unexpected? No; vitamin D is a hormone, and any hormone at supraphysiologic (higher than natural) levels suppresses the function of its receptors and can eventually produce the same symptoms as its deficiency. I appreciate that the authors were attempting to see if a simplified dosage schedule could be used to promote compliance, but it makes about as much physiological sense as trying to eat all your food for one year in a single day. Unfortunately, many people reading only the lay publications will see only "Vitamin D causes fractures" when the opposite is true if supplemented properly: a daily dose based on individual need as determined by the correct blood test.