Professor Cedric Annweiler of the Angers University Hospital in France recently wrote a review paper on vitamin D and dementia to see if the current evidence meets Hill’s criteria for causation.
A remarkable JAMA-Neurology paper found those with the lowest vitamin D levels were three times more likely to develop dementia.
This paper along with others led Dr. Annweiller to investigate whether the evidence to date is strong enough to satisfy Hill’s criteria, which is a collection of findings seen when causation is likely. Here is what he found:
He concluded: "The correction of hypovitaminosis D in older adults is justified from a cognitive perspective in preclinical studies and by a number of cross-sectional and longitudinal observational studies reporting direct associations between decreased 25OHD concentrations and cognitive disorders.”
It is important to remember that you can get dementia with a high 25(OH)D status as well. Maintaining a healthy D level simply reduces the risk of developing the disease.
About: John Cannell, MD