These Italian and UK authors determined whether low levels of serum 25-hydroxyvitamin D {25(OH)D} were associated with an increased risk of substantial cognitive decline in the InCHIANTI population-based study conducted in Italy between 1998 and 2006 with follow-up assessments every 3 years. A total of 858 adults 65 years or older completed interviews, cognitive assessments, and medical examinations and provided blood samples. Cognitive decline was assessed using the Mini-Mental State Examination (MMSE), and substantial decline was defined as 3 or more points. The Trail-Making Tests A and B were also used, and substantial decline was defined as the worst 10% of the distribution of decline or as discontinued testing.
They found: "The multivariate adjusted relative risk of substantial cognitive decline on the MMSE in participants who were severely serum 25(OH)D deficient (levels less than 25 nmol/L) in comparison with those with sufficient levels of 25(OH)D (75 nmol/L) was 1.60. Multivariate adjusted random-effects models demonstrated that the scores of participants who were severely 25(OH)D deficient declined by an additional 0.3 MMSE points per year more than those with sufficient levels of 25(OH)D. The relative risk for substantial decline on Trail-Making Test B was 1.31 among those who were severely 25(OH)D deficient compared with those with sufficient levels of 25(OH)D. No significant association was observed for Trail-Making Test A."
The authors concluded: "Low levels of vitamin D were associated with substantial cognitive decline in the elderly population studied over a 6- year period, which raises important new possibilities for treatment and prevention."
Next step is to test whether treating vitamin D deficiency makes a difference.
For the full abstract, click here.
Arch Intern Med 170(13):1135-1141, 12 July 2010 © 2010 to the American Medical Association
Vitamin D and Risk of Cognitive Decline in Elderly Persons. David J. Llewellyn, Iain A. Lang, Kenneth M. Langa, et al. Correspondence to Dr. Llewellyn: david.llewellyn@pms.ac.uk
Category: N. Neurological, T. Endocrine/Metabolic/Nutritional. Keywords: vitamin D, elderly, cognitive decline, cohort study, journal watch.
Synopsis edited by Dr Linda French, Toledo, Ohio. Posted on Global Family Doctor 3 August 2010
