BACKGROUND: Obesity and hypertension represent serious health issues affecting the pediatric population with increasing prevalence. Hypovitaminosis D has been suggested to be associated with arterial hypertension. Serotonin by modulating nitric oxide synthase affect blood pressure regulation. The biological mechanism by which vitamin D specifically regulates serotonin synthesis was recently described. The aim of this paper is to determine the associations between vitamin D, serotonin, and blood pressure in obese children. METHODS: One hundred and seventy-one children were enrolled in the prospective cross-sectional study. Two groups of children divided according to body mass index status to obese (BMI ≥95th percentile; n = 120) and non-obese (n = 51) were set. All children underwent office and ambulatory blood pressure monitoring and biochemical analysis of vitamin D and serotonin. Data on fasting glucose, insulin, HOMA, uric acid, and complete lipid profile were obtained in obese children. RESULTS: Hypertension was found only in the group of obese children. Compared to the control group, obese children had lower vitamin D and serotonin, especially in winter. The vitamin D seasonality and BMI-SDS were shown as the most significant predictors of systolic blood pressure changes, while diastolic blood pressure was predicted mostly by insulin and serotonin. The presence of hypertension and high-normal blood pressure in obese children was most significantly affected by vitamin D deficiency and increased BMI-SDS. CONCLUSIONS: Dysregulation of vitamin D and serotonin can pose a risk of the onset and development of hypertension in obese children; therefore, their optimization together with reducing body weight may improve the long-term cardiovascular health of these children.

• Keywords
• Children, Hypertension, Obesity, Serotonin, Vitamin D,
• MeSH
• Blood Pressure Monitoring, Ambulatory MeSH
• Child MeSH
• Hypertension * epidemiology   MeSH
• Body Mass Index MeSH
• Insulin MeSH
• Insulin Resistance * MeSH
• Humans MeSH
• Vitamin D Deficiency * MeSH
• Pediatric Obesity * complications   epidemiology   MeSH
• Prospective Studies MeSH
• Cross-Sectional Studies MeSH
• Serotonin MeSH
• Vitamin D MeSH
• Vitamins MeSH
• Check Tag
• Child MeSH
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Insulin MeSH
• Serotonin MeSH
• Vitamin D MeSH
• Vitamins MeSH

UNLABELLED: The aim of our study was to investigate whether nocturnal blood pressure (BP) dip is associated with increased left ventricular mass index and hypertrophy in children with hypertension (HT). We retrospectively reviewed data from all children with confirmed ambulatory HT in our center and performed ambulatory blood pressure monitoring (ABPM) and echocardiography at the same time. Left ventricular hypertrophy (LVH) was defined as left ventricular mass index (LVMI) ≥95th centile. Non-dipping phenomenon was defined as nocturnal BP dip <10 %. A total of 114 ABPM studies were included, the median age of children was 15.3 years (3.8-18.9), 80 children had renoparenchymal HT without end-stage renal failure, 34 had primary HT, and 27 studies were done on untreated children and 87 on treated children. Non-dipping phenomenon was present in 63 (55 %) studies (non-dippers). The LVMI adjusted for age was not significantly different between non-dippers and dippers (0.87 ± 0.03 vs. 0.81 ± 0.02, p = 0.13). Left ventricular hypertrophy was not significantly higher in non-dippers than in dippers (20 vs. 9 %, p = 0.12). CONCLUSION: Hypertensive children without end-stage renal failure with non-dipping phenomenon do not have increased prevalence of LVH or higher LVMI adjusted for age than hypertensive children with preserved nocturnal BP dip. WHAT IS KNOWN: • Adult and pediatric hypertensive patients with end-stage renal failure have often nocturnal blood pressure non-dipping phenomenon. • Non-dipping phenomenon is in patients with end-stage renal failure associated with increased prevalence of left ventricular hypertrophy. What is New: • Pediatric hypertensive patients without end-stage renal failure with blood pressure non-dipping phenomenon do not have increased prevalence of left ventricular hypertrophy.

• Keywords
• Children, Hypertension, Left ventricular hypertrophy, Nocturnal blood pressure dip, Non-dipping,
• MeSH
• Blood Pressure Monitoring, Ambulatory MeSH
• Antihypertensive Agents therapeutic use   MeSH
• Kidney Failure, Chronic complications   physiopathology   MeSH
• Circadian Rhythm physiology   MeSH
• Child MeSH
• Echocardiography MeSH
• Hypertension complications   physiopathology   MeSH
• Hypertrophy, Left Ventricular etiology   MeSH
• Blood Pressure physiology   MeSH
• Humans MeSH
• Adolescent MeSH
• Statistics, Nonparametric MeSH
• Child, Preschool MeSH
• Retrospective Studies MeSH
• Sensitivity and Specificity MeSH
• Check Tag
• Child MeSH
• Humans MeSH
• Adolescent MeSH
• Male MeSH
• Child, Preschool MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Antihypertensive Agents MeSH