Vitamin D is associated with visual memory in young northern adolescents

ABSTRACT

Background

Vitamin D status has been linked to visual memory in adults. We hypothesized a similar association in young adolescents.

Methods

Participants were 9–13 years. The Rey-Osterrieth Complex Figure Task (ROCF), Rey Auditory Verbal Learning Task (RAVLT), Digit Span (Forward, Backward), and verbal fluency task assessed visual and verbal learning/memory, attention/working memory, and executive functioning/language, respectively. An at-home, mail-in blood spot test assessed 25(OH)D levels.

Results

Participants (N = 56) were 10.7 ± 1.3 years, 61% females, 25(OH)D levels 84.2 ± 25 nmol/L(39.9 - 167.2 nmol/L) and 41% had insufficient vitamin D status (<75 nmol/L). Only measures of visual memory (ROCF-Recall, -%Recall of Copy) were significantly correlated with 25(OH)D, r = .34, p < .01 and r = .33, p < .01, respectively, and 25(OH)D remained a significant independent predictor on multiple regression analyses, which included age and sex.(ROCF-Recall overall model: Adj R²= .24, p < .001; for 25(OH)D: p = .009; ROCF-%Recall of Copy overall model: Adj R²= .20 p < .002; for 25(OH)D: p = .01). Individuals with sufficient vitamin D performed significantly better only on these measures (t-tests; ROCF-Recall, p = .016, d = 0.68; ROCF-%Recall of Copy, p = .022, d = 0.64). Despite moderate effect sizes (d = 0.4–0.5) in the Younger Age Group (9–10 years), only in the Older Age Group (11–13 years) was 25(OH)D significantly correlated with ROCF-Recall, r = .64, p = .0001 and ROCF-%Recall of Copy, r = .64, p = .0001, as well as working memory (Digit Span-Backward), Spearman’s r = .46, p = .013. Similarly, those in the Older Age Group with sufficient vitamin D performed significantly better on ROCF-Recall, p = .01, d = 1.07; and ROCF-%Recall of Copy, p = .009, d = 1.08.

Conclusions

Vitamin D insufficiency was common in young adolescents. Similar to adults, visual memory was better among participants with higher 25(OH)D and those with sufficient levels. This effect was especially pronounced among older participants, suggesting possible time- and/or age-related implications of vitamin D status on cognition.

KEYWORDS:

• Vitamin D
• cholecalciferol
• cognition
• memory
• adolescents
• northern
• nutrients
• nutrition

Acknowledgements

We wish to thank Professor Emerita, Dr. Lynn Beattie, for her helpful comments and suggestions on the manuscript as well as all participants and caregivers who made this study possible. We would also like to acknowledge Doctors Data Inc. for providing a reduced rate on blood spot testing for our research purposes and School District #57 for assistance with recruitment.

Data availability statement

Due to the nature of this research, participants of this study did not agree for their data to be shared publicly, so supporting data is not available.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Research ethics board approval

Harmonized Review: University of Northern British Columbia and University of British Columbia. H20-03081; Date approved: 2020-12-17.

Additional information

Funding

This study was supported by a Seed Grant from the Division of Neurology, University of British Columbia, and startup funding from the Division of Medical Sciences, University of Northern British Columbia.

Notes on contributors

Katherine R. F. Bailey

Katherine R. F. Bailey received her Bachelor of Health Sciences Honours Degree from the School of Health Sciences, University of Northern British Columbia. She is currently a medical student in the University of British Columbia’s Northern Medical Program.

Jacqueline A. Pettersen

Jacqueline A. Pettersen is a Cognitive Neurologist and Associate Professor in the Division of Neurology, Department of Medicine, University of British Columbia and affiliate Associate Professor with the Division of Medical Sciences at the University of Northern British Columbia. Nutrition and its role in cognition has been one focus of her research, particularly the importance of vitamin D and other micronutrients.