Vitamin D deficiency in the development of pediatric syncope due to orthostatic hypotension

Abstract

Summary. The existence of a contradictory understanding of the role of vitamin D deficiency in the genesis of orthostatic hypotension, which is based mainly on research in small groups of adults, substantiates the relevance of studying this problem among children. The aim of the study – to investigate the serum vitamin D level in children with syncope due to orthostatic hypotension (OH), as well as its relationship with the indicators of functional cardiovascular system state. Materials and Methods. 24 children with the diagnosis of syncope due to OH and 24 relatively healthy children aged 8–17 years were examined. As an indicator of vitamin D availability, the level of 25(OH)D in serum was determined by enzyme immunoassay method. The calculation of integral indicators of the functional cardiovascular system state was carried out according to the data of the physical examination using empirical formulas. Heart rate variability (HRV) was studied based on the results of Holter monitoring during a 24-hour period of normal functioning. Results. A significantly lower level of vitamin D was recorded in patients with syncope due to OH compared to healthy respondents (19.9±1.4), (30.9±1.2) ng/ml; p=0.000001). A decrease in systolic blood pressure in the supine position and during the 1st, 3rd, 5th, 7th, 10th minutes of active orthostasis was found on the background of a decrease in the serum concentration of vitamin D in the group of syncope due to OH (p0.05). Conclusions. Significantly lower serum 25(OH)D levels were recorded, and the prevalence of vitamin D deficiency was 54.2 % in the group of children with syncope due to OH. The results of this study confirm the close connection of vitamin D deficiency with a decrease in the cardiovascular system adaptive mechanisms. HRV indicators do not depend on the serum level of vitamin D in children with syncope due to OH

Keywords

• vitamin d deficiency
• autonomic nervous system
• syncope due to orthostatic hypotension
• children