Association of Vitamin D and B12 Levels with Actigraphic Sleep in Cognitively Unimpaired Middle-Aged and Older Adults

BACKGROUND Low vitamin D and B12 levels are linked to low self-reported sleep quality and conditions comorbid with sleep disturbances in older adults. We examined the associations between serum vitamin D and B12 levels with actigraphic sleep indices in middle-aged and older adults. METHODS We studied 460 participants aged 40 and older [70.9±12.0(sd)years; 52.8% female; 22.2% Black] in the Baltimore Longitudinal Study of Aging. Predictors included total serum vitamin D and B12,sleep outcomes included total sleep time (minutes), sleep efficiency (%), sleep onset latency (minutes), wake after sleep onset (minutes), and average wake bout length (minutes). We examined race and sex as effect modifiers of associations between vitaminsand sleep. RESULTS Higher vitamin D concentration was associated with longer total sleep time (B = 23.63 minutes, 95% CI: 9.62, 37.64) and shorter wake bout length (B = -0.29 minutes, 95% CI: -0.50, -0.09). Vitamin D deficiency was associated with shorter total sleep time (B=-23.03 minutes, 95% CI: -42.05 -4.01). The associations between vitamin D and sleep were stronger among Black participants. Higher B12 was associated with shorter wake after sleep onset in women but longer wake after sleep onset in men. B12 insufficiency/deficiency was associated with longer total sleep time in men but shorter total sleep time in women. CONCLUSIONS Higher vitamin D levels are associated with longer and less disturbed sleep in middle-aged and older adults. Future studies are needed to understand if maintaining optimal vitamin D levels improve sleep quality and promote better sleep-associated health outcomes.