Autoimmune Thyroiditis and Vitamin D.

Hashimoto's thyroiditis (HT) is marked by self-tissue destruction as a consequence of an alteration in the adaptive immune response that entails the evasion of immune regulation. Vitamin D carries out an immunomodulatory role that appears to promote immune tolerance. The aim of this study is to elaborate a narrative review of the relationship between vitamin D status and HT and the role of vitamin D supplementation in reducing HT risk by modulating the immune system. There is extensive literature confirming that vitamin D levels are significantly lower in HT patients compared to healthy people. On the other hand, after the supplementation with cholecalciferol in patients with HT and vitamin D deficiency, thyroid autoantibody titers decreased significantly. Further knowledge of the beneficial effects of vitamin D in the prevention and treatment of autoimmune thyroid diseases requires the execution of additional randomized, double-blind, placebo-controlled trials and longer follow-up periods.

Pregnancy, Breastfeeding, and Vitamin D.

Exclusive breastfeeding is considered the ideal food in the first six months of life; however, paradoxically, vitamin D content in human breast milk is clearly low and insufficient to obtain the recommended intake of 400 IU daily. This article summarizes the extraordinary metabolism of vitamin D during pregnancy and its content in human breast milk. The prevalence of hypovitaminosis D in pregnant women and/or nursing mothers and its potential maternal-fetal consequences are analyzed. The current guidelines for vitamin D supplementation in pregnant women, nursing mothers, and infants to prevent hypovitaminosis D in breastfed infants are detailed. Low vitamin D content in human breast milk is probably related to active changes in human lifestyle habits (reduced sunlight exposure).

Assessment of vitamin D status and parathyroid hormone during a combined intervention for the treatment of childhood obesity.

BACKGROUND: Obesity is associated with vitamin D deficiency. The aim of this work is to analyze the changes in vitamin D status and PTH levels in a group of children with obesity receiving combined intervention program in order to get BMI status reduction. METHODS: Longitudinal study in 119 children with obesity, aged 9.1-13.9 years, included in a 1-year combined dietary-behavioral-physical activity intervention. Anthropometric measurements (weight, height, BMI and fat mass index) were registered every 3 months and blood testing (calcium, phosphorous, 25(OH)D and PTH) were collected at the beginning and after 12 months of follow-up. A control group was recruited (300 healthy children, aged 8.1-13.9 years). The criteria of the US Endocrine Society were used for the definition of hypovitaminosis D. RESULTS: Vitamin D deficiency was significantly higher in obesity group (31.1 vs. 14%). There was negative correlation between 25(OH)D and fat mass index (r = -0.361, p = 0.001). Patients with BMI reduction throughout combined intervention were 52 (43.7%). There was a significant increase in the prevalence of hypovitaminosis D in patients without BMI reduction at the end of follow-up, but in those patients with BMI reduction there was no changes of vitamin D status. CONCLUSIONS: Obesity increases the prevalence of suboptimal vitamin D status, and a BMI status reduction in children with obesity may be required to at least stabilize vitamin D status.

[Prevalence of hypovitaminosis D and associated factors in Spanish population of school children and adolescents]. / Prevalencia de hipovitaminosis D y factores asociados en la edad infantojuvenil.

OBJECTIVE: To analyse the prevalence of hypovitaminosisD and associated factors in school children and adolescents living in a region of northern Spain. DESIGN: Cross-sectional study (convenience sampling). SETTING: Primary Health Care. PARTICIPANTS: A total of 602 Caucasian individuals (aged 3.1 to 15.4years) were included in the study. MAIN MEASUREMENTS: Prevalence of hypovitaminosisD were calculated (dependent variable). HypovitaminosisD is defined according to the US Endocrine Society criteria: deficiency (calcidiol <20ng/mL), insufficiency (calcidiol: 20-29ng/mL), and sufficiency (calcidiol ≥30ng/mL). Gender, age, body mass index, residence, and season of the year were recorded (independent variables), and their association with hypovitaminosisD was analysed by multiple regression. RESULTS: The prevalence of hypovitaminosisD was 60.4% (insufficiency: 44.6%; deficiency: 15.8%). Multivariate analysis showed that factors associated to hypovitaminosisD were being female (OR: 1.6; 95%CI: 1.1-2.3), pubertal age (OR: 1.8; 95%CI: 1.2-2.6), autumn (OR: 9.5; 95%CI: 4.8-18.7), winter (OR: 8.8; 95%CI: 4.5-17.5) and spring time (OR: 13.2; 95%CI: 6.4-27.5), living in urban areas (OR:1.6; CI95%: 1.1-2.2), and severe obesity (OR: 4.4; 95%CI: 1.9-10.3). CONCLUSIONS: There is a high prevalence of hypovitaminosisD in juvenile populations. being female, pubertal age, autumn, winter and spring seasons, severe obesity, and living in urban areas are factors associated to hypovitaminosisD. Consideration should be given to the administration of vitamin supplements and/or the increase in the ingestion of natural vitaminD dietary sources.

Vitamin D deficiency in children with epilepsy taking valproate and levetiracetam as monotherapy.

OBJECTIVE: The aim of this study is to evaluate if valproate (VPA) and levetiracetam (LEV) as monotherapy are associated with vitamin D deficiency among children with epilepsy. MATERIAL & METHODS: A cross-sectional clinical (seizure types, aetiology of epilepsy, dosage, drug levels, and duration of AED treatment) and blood testing (calcium, phosphorus, 25-OHD and PTH) study was accomplished in 90 epileptic children (AED group: 59 receiving VPA, and 31 receiving LEV) and a control group (244 healthy subjects). 25-OHD levels were categorized as low (<20ng/ml), borderline (20-29ng/ml), or normal (>30ng/ml) RESULTS: The average dosage of VPA and LEV was 20.7±4.7mg/kg/d and 24.1±7.9mg/kg/d, respectively. The mean duration of VPA therapy was 2.5±1.4years, and with LEV was 2.3±1.6years. Mean calcium and 25-OHD levels were significantly higher (p <0.05) in the control group. There was a negative correlation (p <0.01) between 25-OHD and VPA levels (r=-0.442). Vitamin D deficiency (%) was significantly higher (p <0.05) in VPA (24.1%) and LEV (35.5%) groups than in control group (14%). The multiple logistic regression analysis showed that VPA monotherapy (OR: 1.9, CI 95%: 1.1-3.8) and LEV monotherapy (OR: 3.3, CI 95%: 1.5-7.5) were associated with an increased risk of vitamin D deficiency. CONCLUSIONS: The prevalence of vitamin D deficiency is common in children with epilepsy taking VPA or LEV. Hence vitamin D status of children treated with VPA and LEV should be regularly monitored and vitamin D supplements should be considered on an individual basis.

Seasonal variations in calcidiol and parathyroid hormone levels in healthy children and adolescents in Navarre, Spain: a cross-sectional study.

OBJECTIVE: To analyze the seasonal variations in calcidiol and parathyroid hormone serum levels along a natural year in a paediatric population living in a region of the north of Spain considering a normal nutrition status. DESIGN: A cross-sectional study. SETTING: Navarra Hospital Complex, Pamplona, Spain. PARTICIPANTS: A total of 413 Caucasian individuals (aged 3.1 to 15.4 years): 227 school children (96 males and 131 females) and 186 adolescents (94 males and 92 females), with normal nutritional status. MAIN OUTCOME MEASURES: Clinical examination (sex, age, weight, height and body mass index) and blood testing (calcium, phosphate, alkaline phosphatase, calcidiol and parathyroid hormone) during the year 2014. RESULTS: Calcidiol levels were lower during spring (25.96 ± 6.64 ng/mL) and reached its maximum level in summer (35.33 ± 7.51 ng/mL); parathyroid hormone levels were lower in summer (27.13 ± 7.89 pg/mL) and reached maximum level in autumn (34.73 ± 15.38 pg/mL). Hypovitaminosis D prevalence was 14.3% in summer and 75.3% in spring. Parathyroid hormone levels were compatible with secondary hyperparathyroidism in eight individuals (1.9%). There is a correlation (p < 0.01) between calcidiol and parathyroid hormone (r = -0.336). Logistic regression showed significant increased risk of hypovitaminosis in females (OR:1.63) and adolescents (OR:1.77), and when blood samples taken in autumn (OR:12.22), winter (OR:8.54) and spring (OR:19.72). CONCLUSIONS: There is a high prevalence of hypovitaminosis D in the paediatric population with a healthy nutrition situation in Navarre, mainly during the months of autumn and winter, and, especially, in spring time. Given the difficulties in maintaining a sufficient amount of body vitamin D content along the year, it should be considered to give vitamin supplements and/or increase the intake of its natural dietary sources or vitamin D fortified foods.

Deficiencia de vitamina D en escolares y adolescentes con un estado nutricional normal / Vitamin D deficiency among children and adolescents with normal nutritional status

Objetivo: analizar la prevalencia de la deficiencia de vitamina D a lo largo de un año natural en una población pediátrica con un estado nutricional normal. Material y métodos: estudio transversal clínico y analítico (calcio, fósforo, fosfatasa alcalina, calcidiol y hormona paratiroidea) en 413 sujetos (entre 3,1 y 15,4 años): 227 escolares (96 varones y 131 mujeres) y 186 adolescentes (94 varones y 92 mujeres), de raza caucásica y estado nutricional normal, durante el año 2014. Para definir la deficiencia de vitamina D se han aplicado los criterios de la Sociedad Americana de Endocrinología. Resultados: los niveles de calcidiol eran más bajos en primavera (25,96 ± 6,64 ng/ml) y alcanzaban su máximo nivel en verano (35,33 ± 7,51 ng/ml); mientras que los de PTH eran más bajos en verano (27,13 ± 7,89 pg/ml) y alcanzaban su máximo nivel en otoño (34,73 ± 15,38 pg/ml). La prevalencia de deficiencia de vitamina D era del 14,3% en verano y del 75,3% en primavera. En 8 casos (1,9%) existían cifras de PTH compatibles con hiperparatiroidismo secundario. Existía una correlación negativa entre calcidiol y PTH (p < 0,01). No existía correlación entre IMC y calcidiol. Conclusión: en la población pediátrica con una situacion nutricional normal existe una alta prevalencia de deficiencia de vitamina D en los meses de otoño e invierno y, especialmente, en primavera, y habría que considerar la necesidad de administrar suplementos vitamínicos y/o ingerir mayores cantidades de sus fuentes dietéticas naturales (AU)

Objective: to analyze the prevalence of vitamin D deficiency throughout a natural year in a pediatric population with normal nutrition status. Material and methods: cross sectional clinical and analytical study (calcium, phosphorus, alkaline phosphatase, calcidiol and parathyroid hormone) in 413 caucasian individuals (aged 3.1 to 15.4 years): 227 school children (96 males and 131 females) and 186 adolescents (94 males and 92 females), all of them in a normal nutrition status, during the year 2014. Vitamin D deficiency was defined according to the United States Endocrine Society guidelines. Results: calcidiol levels were lower during spring (25.96 ± 6.64 ng/ml) and reached its maximum level in summer (35.33 ± 7.51 ng/ml); PTH levels were lower in summer (27.13 ± 7.89 pg/ml) and reached maximum level in autumn (34.73 ± 15.38 pg/ml). Vitamin D deficiency prevalence was 14.3% in summer and 75.3% in spring. PTH levels were compatible with secondary hyperparathyroidism in 8 individuals (1.9%). There was a negative correlation between calcidol and PTH levels (p < 0.01). There was not a correlation between body mass index (BMI) and calcidiol. Conclusion: the pediatric population in normal nutrition status shows a high prevalence of vitamin D deficiency during the months of autumn and winter and, especially, in spring; the addition of vitamin supplements and/ or an increase in the ingestion of their natural dietary sources should be considered (AU)

[VITAMIN D DEFICIENCY AMONG CHILDREN AND ADOLESCENTS WITH NORMAL NUTRITIONAL STATUS]. / DEFICIENCIA DE VITAMINA D EN ESCOLARES Y ADOLESCENTES CON UN ESTADO NUTRICIONAL NORMAL.

OBJECTIVE: to analyze the prevalence of vitamin D deficiency throughout a natural year in a pediatric population with normal nutrition status. MATERIAL AND METHODS: cross sectional clinical and analytical study (calcium, phosphorus, alkaline phosphatase, calcidiol and parathyroid hormone) in 413 caucasian individuals (aged 3.1 to 15.4 years): 227 school children (96 males and 131 females) and 186 adolescents (94 males and 92 females), all of them in a normal nutrition status, during the year 2014. Vitamin D deficiency was defined according to the United States Endocrine Society guidelines. RESULTS: calcidiol levels were lower during spring (25.96 ± 6.64 ng/ml) and reached its maximum level in summer (35.33 ± 7.51 ng/ml); PTH levels were lower in summer (27.13 ± 7.89 pg/ml) and reached maximum level in autumn (34.73 ± 15.38 pg/ml). Vitamin D deficiency prevalence was 14.3% in summer and 75.3% in spring. PTH levels were compatible with secondary hyperparathyroidism in 8 individuals (1.9%). There was a negative correlation between calcidol and PTH levels (p < 0.01). There was not a correlation between body mass index (BMI) and calcidiol. CONCLUSION: the pediatric population in normal nutrition status shows a high prevalence of vitamin D deficiency during the months of autumn and winter and, especially, in spring; the addition of vitamin supplements and/ or an increase in the ingestion of their natural dietary sources should be considered.

Objetivo: analizar la prevalencia de la deficiencia de vitamina D a lo largo de un año natural en una población pediátrica con un estado nutricional normal. Material y métodos: estudio transversal clínico y analítico (calcio, fósforo, fosfatasa alcalina, calcidiol y hormona paratiroidea) en 413 sujetos (entre 3,1 y 15,4 años): 227 escolares (96 varones y 131 mujeres) y 186 adolescentes (94 varones y 92 mujeres), de raza caucásica y estado nutricional normal, durante el año 2014. Para definir la deficiencia de vitamina D se han aplicado los criterios de la Sociedad Americana de Endocrinología. Resultados: los niveles de calcidiol eran más bajos en primavera (25,96 ± 6,64 ng/ml) y alcanzaban su máximo nivel en verano (35,33 ± 7,51 ng/ml); mientras que los de PTH eran más bajos en verano (27,13 ± 7,89 pg/ml) y alcanzaban su máximo nivel en otoño (34,73 ± 15,38 pg/ml). La prevalencia de deficiencia de vitamina D era del 14,3% en verano y del 75,3% en primavera. En 8 casos (1,9%) existían cifras de PTH compatibles con hiperparatiroidismo secundario. Existía una correlación negativa entre calcidiol y PTH (p < 0,01). No existía correlación entre IMC y calcidiol. Conclusión: en la población pediátrica con una situacion nutricional normal existe una alta prevalencia de deficiencia de vitamina D en los meses de otoño e invierno y, especialmente, en primavera, y habría que considerar la necesidad de administrar suplementos vitamínicos y/o ingerir mayores cantidades de sus fuentes dietéticas naturales.