Investigation of total 25-hydroxy vitamin D concentrations and postoperative delirium after major cardiac surgery

Editor—Delirium is a serious and common complication after major surgery. Low vitamin D concentrations have been proposed as a risk factor for incident delirium, 1 Fu N. Miao M. Li N. Zeng S. Zhu R. Zhang J. Association between vitamin D concentration and delirium in hospitalized patients: a meta-analysis. PLoS One. 2023; 18e0281313 Google Scholar progressive cognitive decline, 2 Toffanello E.D. Coin A. Perissinotto E. et al. Vitamin D deficiency predicts cognitive decline in older men and women: the Pro.V.A. study. Neurology. 2014; 83: 2292-2298 Google Scholar dementia, and Alzheimer's disease. 3 Littlejohns T.J. Henley W.E. Lang I.A. et al. Vitamin D and the risk of dementia and Alzheimer disease. Neurology. 2014; 83: 920-928 Google Scholar In a noncardiac surgical population, vitamin D concentrations <30 ng ml−1 reported within 1 yr before surgery were associated with the development of postoperative delirium. 4 Qiu Y. Sessler D.I. Chen L. et al. Preoperative vitamin D deficiency is associated with postoperative delirium in critically ill patients. J Intensive Care Med. 2022; 37: 655-662 Google Scholar However, there are conflicting reports showing no association between vitamin D deficiency and delirium. 5 Dauny V. Thietart S. Cohen-Bittan J. et al. Association between vitamin D deficiency and prognosis after hip fracture surgery in older patients in a dedicated orthogeriatric care pathway. J Nutr Health Aging. 2022; 26: 324-331 Google Scholar ,6 Morandi A. Barnett N. Miller RR 3rd et al. Vitamin D and delirium in critically ill patients: a preliminary investigation. J Crit Care. 2013; 28: 230-235 Google Scholar Vitamin D concentrations are influenced by geographical and seasonal components, which are of notable importance in the northeast region of the USA where direct ultraviolet B light exposure is limited during winter and cutaneous synthesis of vitamin D is very low. 7 Webb A.R. Kline L. Holick M.F. Influence of season and latitude on the cutaneous synthesis of vitamin D3: exposure to winter sunlight in Boston and Edmonton will not promote vitamin D3 synthesis in human skin. J Clin Endocrinol Metab. 1988; 67: 373-378 Google Scholar