Vitamin D and Memory Decline: Two Population-Based Prospective Studies

J Alzheimers Dis. 2016;50(4):1099-108. doi: 10.3233/JAD-150811.

Kuźma E1, Soni M1, Littlejohns TJ1,2, Ranson JM1, van Schoor NM3, Deeg DJ3,4, Comijs H4, Chaves PH5, Kestenbaum BR6, Kuller LH7, Lopez OL8, Becker JT8, Langa KM9, Henley WE1, Lang IA1, Ukoumunne OC1, Llewellyn DJ1.

Author information

• 1University of Exeter Medical School, Exeter, UK.
• 2Clinical Trial Service Unit and Epidemiological Studies Unit, University of Oxford, Oxford, UK.
• 3Department of Epidemiology and Biostatistics, EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands.
• 4Department of Psychiatry, EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands.
• 5Benjamin Leon Center for Geriatric Research and Education, Florida International University, Miami, USA.
• 6Kidney Research Institute, Division of Nephrology, University of Washington, Seattle, USA.
• 7Department of Epidemiology, University of Pittsburgh, Pittsburgh, USA.
• 8Department of Neurology and Psychiatry, University of Pittsburgh, Pittsburgh, USA.
• 9Division of General Medicine, Veterans Affairs Ann Arbor Center for Clinical Management Research, Institute for Social Research, and Institute for Healthcare Policy and Innovation, University of Michigan, all in Ann Arbor, USA.

Abstract

BACKGROUND:

Vitamin D deficiency has been linked with dementia risk, cognitive decline, and executive dysfunction. However, the association with memory remains largely unknown.

OBJECTIVE:

To investigate whether low serum 25-hydroxyvitamin D (25(OH)D) concentrations are associated with memory decline.

METHODS:

We used data on 1,291 participants from the US Cardiovascular Health Study (CHS) and 915 participants from the Dutch Longitudinal Aging Study Amsterdam (LASA) who were dementia-free at baseline, had valid vitamin D measurements, and follow-up memory assessments. The Benton Visual Retention Test (in the CHS) and Rey's Auditory Verbal Learning Test (in the LASA) were used to assess visual and verbal memory, respectively.

RESULTS:

In the CHS, those moderately and severely deficient in serum 25(OH)D changed -0.03 SD (95% CI: -0.06 to 0.01) and -0.10 SD (95% CI: -0.19 to -0.02) per year respectively in visual memory compared to those sufficient (p = 0.02). In the LASA, moderate and severe deficiency in serum 25(OH)D was associated with a mean change of 0.01 SD (95% CI: -0.01 to 0.02) and -0.01 SD (95% CI: -0.04 to 0.02) per year respectively in verbal memory compared to sufficiency (p = 0.34).

CONCLUSIONS:

Our findings suggest an association between severe vitamin D deficiency and visual memory decline but no association with verbal memory decline. They warrant further investigation in prospective studies assessing different memory subtypes.

KEYWORDS:

Cognition; memory; prospective studies; vitamin D