Investigating Factors of Decline in Cognitive Function or Dementia

Regarding the article “Vitamin D and Risk of Cognitive Decline in Elderly Persons,” published in the Archives, July 12, 2010, the authors make a statement in the “Comment” section that

To our knowledge, this is the first prospective study to show that low levels of 25(OH)D are associated with elevated risk of cognitive decline.

Furthermore, they state^1(p1139)