Vitamin D is associated with visual memory in young northern adolescents

Abstract

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.