Vitamin D and its relation to sleep disturbance and depressive symptomatology – Results of the German Health Interview and examination survey for adults

Vitamin D (Vit D) ia a neurosteroid hormone that may be involved in the pathophysiology of sleep disturbance as well as depressive disorders. Data derived from the nationally representative cross-sectional German Health Interview and Examination Survey for Adults (N = 7000) were used to analyze possible relationships between Vit D blood levels and degree of sleep disturbance as well as depressive symptomatology (Patient Health Questionnaire-9. Vit D levels are significantly lower in subjects with frequent problems falling asleep (47.2 ± 24.9 vs. 44.8 ± 21,3 nmol/l; p < 0.03). Additionally, there is a trend for lower Vit D levels in subjects with frequent problems maintaining sleep (47.4 ± 25.9 vs. 46.0 ± 21,8 nmol/l; p < 0.08). Subjects with depressive disorder versus non-depressed subjects also demonstrate a trend towards lower Vit D levels (45.0 ± 25.1 vs. 47.2 ± 24.3 nmol/l; p < 0.07). For correlational analysis only Vit D levels ≤ 50 nmol/l were considered to avoid ceiling effects. The degree of depressive symptomatology correlates significantly with Vit D levels (r = −.035, p ≤ 0.025). Differential analysis of winter and summer months only revealed a significant correlation between low Vit D and depression during the summer (r = −0.104, p ≤ 0.000), but not in winter (r = −.024, p = 0.22). Vit D levels appear to be negatively related to sleep disturbance and depression. This appears to be restricted to months during which dermal Vit D synthesis from sunlight is warranted.