gms | German Medical Science

Objective: Assessed data about the relationships between seasonal determinants and the occurrence of aneurysmal subarachnoid hemorrhage (aSAH) are conflicting. Because hypovitaminosis D has been identified as a risk factor for other vascular diseases, according to seasonal difference of vitaminD level, we examined its association with aSAH.

Methods: We randomized vitaminD (VitD) levels (25-(OH)-vitaminD3) in patients admitted to our department 2007-2015. Mean values of VitD levels were demonstrated to detect 2 months with a peak (summer) versus decrease of VitD level (winter), annually. Therefore, we stratified clinical course and outcome analysis in SAH patients admitted between 2007 to 2015, seasonally.

Results: VitD levels of all registered patients during 2007-2015 (n=95036) were retrospectively analyzed. We stratified 2 patient groups, admitted in summer versus winter, annually. A total of 278 SAH patients were included in this cohort. Concerning aneurysm rupture, there is a significant higher rate of hemorrhage during winter (p<0,01;OR1,7) associated with a higher risk for aneurysm size >5mm (p<0,01;OR1,9). We could detect a significant lower rate of neurological deficits indicated as Hunt&Hess grades (p<0,0001;OR7,9) and high blood volume described as Fisher3-blood-pattern (p<0,05;OR1,7) in patients admitted in summer. In addition, SAH patients in summer had a statistically significant lower rate of early hydrocephalus (p<0,05;OR1,8), cerebral vasospasm (p<0,05;OR1,7) and followed delayed ischemic neurological deficits (p<0,01;OR2). Delayed cerebral infarction and shunt implantation 6 months post SAH showed a higher rate in SAH patients admitted in winter without reaching a statistical significance. Concerning clinical outcome 6 months after SAH, patients with hemorrhage onset in summer had a higher chance for favorable outcome (modified Rankin Scale 0-2) (p<0,05;OR1,7).

Conclusion: We demonstrated a higher risk for aneurysm rupture, SAH-dependent complications and unfavorable outcome in patients admitted during winter season with the highest rate of VitD deficiency. However, further research is needed to develop a therapeutic scheme for VitD in aneurysm patients.