Vitamin D status among Thai school children and the association with 1,25-Dihydroxyvitamin D and parathyroid hormone levels

Vitamin D status and parathyroid hormone assessment in girls with central precocious puberty

PURPOSE

The objective of this study was to analyze vitamin D status and PTH concentrations in 6- to 8-year-old girls with central precocious puberty.

METHODS

A cross-sectional clinical and blood testing study (calcium, phosphorus, 25(OH)D and PTH) was carried out in 78 girls with central precocious puberty (CPP group), aged 6.1-7.9 years. A control group was recruited (137 prepubertal girls, aged 6.1-8.2 years). The criteria of the US Endocrine Society were used for the definition of hypovitaminosis D.

RESULTS

There were no significant differences in vitamin D status between both groups. There were no significant differences in 25(OH)D concentrations between CPP (25.4 ± 8.6 ng/mL) and control groups (28.2 ± 7.4 ng/mL). In contrast, PHT concentrations in CPP group (44.8 ± 16.3 pg/mL) were higher (p < 0.05) with respect to control group (31.0 ± 11.9 ng/mL). In CPP group, there was a positive correlation (p < 0.05) between PTH concentrations and growth rate, bone age, and basal estradiol, basal FSH, basal LH and LH peak concentrations.

CONCLUSION

Vitamin D status in 6- to 8-year-old girls with CPP is similar to that in prepubertal girls. PTH concentrations were significantly higher in girls with CPP, and this could be considered as a physiological characteristic of puberty and, in this case, of pubertal precocity.

Vitamin D deficiency in South-East Asian children: a systematic review

OBJECTIVE

To describe the prevalence and determinants of vitamin D deficiency (VDD) among healthy children aged between 0 and 18 years living in South-East Asia (SEA).

DESIGN

We systematically searched Ovid MEDLINE and Ovid EMBASE for observational studies assessing VDD among healthy children in the SEA region as the primary or secondary outcome from database inception to 6 April 2021. PubMed was used for e-pubs and publications not indexed in Medline. Publications that included abstracts in English were included. We performed a systematic review to describe the prevalence of VDD in SEA children.

RESULTS

Our initial search identified 550 publications with an additional 2 publications from manual screening. Of those, 21 studies from 5 different countries (Thailand, Indonesia, Vietnam, Malaysia and Cambodia) were summarised and included in forest plots. The prevalence of VDD (<50 nmol/L) ranged from 0.9% to 96.4%, with >50% of newborns having VDD, and severe VDD (<30 nmol/L) ranged from 0% to 55.8%. Female sex and urban living were the most common determinants of VDD.

CONCLUSIONS

VDD among healthy children living in the SEA region is common. Efforts to detect VDD and the implementation of preventive measures, including education on safe sun exposure and oral vitamin D supplementation or food fortification, should be considered for key target groups, including adolescent females and pregnant and lactating women to improve the vitamin D status of newborns.

PROTOCOL REGISTRATION NUMBER

This study is registered with PROSPERO (CRD42020181600).

Associations Between Body Composition, Leptin, and Vitamin D Varied by the Body Fat Percentage in Adolescents

BACKGROUND

Serum leptin levels reflects one's degree of obesity and can affect vitamin D levels. The relationship between body fat, leptin, and 25-hydroxyvitamin D (25(OH)D) has not been extensively studied in adolescents. This study aimed to investigate the correlations between body composition and leptin and 25(OH)D levels in boys and girls.

METHODS

Participants aged 12-14 years (n = 205) were grouped according to sex. After body composition was recorded using bioelectrical impedance analysis, they were classified into three groups according to body fat percentage (%BF) (< 30, ≥ 30 and < 40, and ≥ 40). Serum leptin and 25(OH)D levels were measured using the enzyme-linked immunosorbent assay (ELISA). Correlations between all variables were analyzed according to sex and the percentage of BF groups.

RESULTS

Boys and girls with %BF ≥ 30 showed no difference in body mass index (BMI), %BF, and leptin and 25(OH)D, while other variables of body composition were more common in boys than in girls. The %BF, body fat mass (BFM), and 25(OH)D of both sexes with %BF ≥ 30, and leptin levels of boys with %BF ≥ 40 increased with an increase in %BF. A negative correlation between leptin and 25(OH)D levels was found in boys with %BF < 40 and girls with %BF < 30. In the %BF ≥ 30 and < 40 groups, there were negative correlations between leptin, BFM, free fat mass, and muscle mass (MM); between leptin, 25(OH)D, and height in boys; and between 25(OH)D, body weight, BMI, and MM in girls.

CONCLUSION

A negative correlation between leptin and 25(OH)D levels varied according to sex, while for body composition, it was evident at 30 and 40% BF.

Vitamin D deficiency in a population of migrant children: an Italian retrospective cross-sectional multicentric study

BACKGROUND

Vitamin D is a hot topic in the scientific community. Its deficiency and the implications for the children's health became increasingly discussed during the last 20 years. The main aim of this retrospective study was to determinate the prevalence of vitamin D metabolism disorders in a population of adopted children and their risk factors.

METHODS

We gathered data from 2140 children observed in five different National Working Group for the Migrant Children of the Italian Society of Pediatrics centers, variously located in Italy. Serum 25-hydroxy (OH)-D concentration was used to determine every child's vitamin D status, defined as severely deficient (serum 25-OH-D < 10 ng/ml), moderately deficient (serum 25-OH-D {≥10 ng/ml U < 20 ng/ml}), mildly deficient (serum 25-OH-D {≥20 ng/ml U < 30 ng/ml}) and normal (serum 25-OH-D ≥ 30 ng/ml).

RESULTS

Mean value of serum 25-OH-D was 22.7 ng/ml (SD ± 12.1). Vitamin D status was deemed as normal in 483 (22.6%) children, mildly deficient in 718 (33.6%) children, moderately deficient in 730 (34.1%) children and severely deficient in 209 (9.8%) children.

CONCLUSIONS

A very high percentage of migrant children is affected by hypovitaminosis D, with a strong association with age, geographic origin, season of blood sample collection and time spent in Italy after the arrival. This finding highlights the need for corrective measures. However, these measures cannot be applied without increasing the access of migrant populations to healthcare services.

Vitamin D pathway gene polymorphisms, vitamin D level, and cytokines in children with type 1 diabetes

AIMS

The study aimed to examine genetic polymorphism of vitamin D-related genes and association between those genes and vitamin D and cytokines levels in children with type 1 diabetes (T1D).

MATERIALS AND METHODS

This study was conducted among 100 T1D children and 100 controls at Division of Endocrinology and Metabolism, Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand, during 2016 to 2018. Vitamin D metabolite levels were measured by liquid chromatography-tandem mass spectrometry method, serum cytokine levels of IFN- ɣ, IL-10, IL-13, IL-17α, IL-2, IL-4, IL-6, and TNF-α by immunoassay, and genetic variations at VDR, CYP2R1, CYP27B1, GC, DHCR7, and CYP24A1 by polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS

A relationship between studied single nucleotide polymorphisms and T1D was found in CYP2R1 (rs10741657) (GA, OR: 1.83, 95% CI: 1.01-3.31; p = 0.04). VDR haplotypes were also remarkably different between T1D patients and controls. Controls had higher frequency of haplotype TACT than T1D patients (p = 0.02). Vitamin D and all cytokine levels, except for IL-17α, were significantly increased in T1D compared to controls. The polymorphism of DHCR7 (rs12785878) was positively associated with 25OHD₃ and 3epi25OHD₃ levels and was negatively associated with 25OHD₂ level. On the other hand, polymorphism of CYP27B1 (rs4646536) was negatively associated with 3epi25OHD₃ level. Polymorphisms of CYP27B1 (rs4646536) and GC (rs2282679) were positively associated with TNF-α levels. VDR variation of rs1544410, rs731236, and rs7975232 also showed negative association with IL-10 levels. In contrast, the level of IL-10 was positively associated with DHCR7 (rs12785878).

CONCLUSION

Relationships between T1D and CYP2R1 polymorphism and VDR haplotype were found. Vitamin D gene-related variations were associated with vitamin D and circulating cytokine levels in children with T1D.

Serum vitamin D level is inversely associated with liver fibrosis in post Kasai's portoenterostomy biliary atresia patients living with native liver

Objective

This study aims to investigate the association of serum vitamin D (VD) levels with the severity of liver fibrosis (LF) in post Kasai’s portoenterostomy biliary atresia (PKBA) patients living with their native liver.

Methods

In this cross-sectional study, carried out in a tertiary Children’s Hospital in Taipei, Taiwan, PKBA patients living with their native liver were enrolled. Liver biochemistry data, serum 25-hydroxyvitamin D (25-OHVD), acoustic radiation force impulse (ARFI), and scores of Pediatric Quality of Life questionnaire (PedsQL) were collected.

Results

All the enrolled 33 PKBA patients (36.4% males), aged 1–23 years, possessed 25-OHVD less than 30ng/ml. An inverse correlation was detected between serum 25-OHVD and ARFI (r² = 0.175; p = 0.024). We selected a cutoff value of 23ng/mL to divide PKBA patients into two groups, as the p-value was the most significant at this point when comparing the median ARFI of two groups (p = 0.003). Ten (30.3%) had 25-OHVD≥23ng/ml (HVD group), whereas 23(69.7%) had 25-OHVD<23ng/ml (LVD group). HVD group had lower ARFI (1.13m/s vs. 1.52m/s, p = 0.003), lower aspartate transaminase (AST) (29U/L vs. 64U/L, p = 0.033), and higher scores of self-reported health-related quality of life in psychosocial functioning (86.7 vs. 77.1, p = 0.047) than LVD group.

Conclusion

VD levels are inversely associated with severity of LF in PKBA patients with native liver.

Parathyroid Hormone Levels in Healthy Children and Adolescents

BACKGROUND

Parathyroid hormone (PTH) is important in the assessment of calcium metabolism disorders. However, there are few data regarding PTH levels in childhood and adolescence.

AIM

The aim of this study was to determine PTH levels in a large group of healthy children and adolescents.

PATIENTS AND METHODS

We retrospectively evaluated PTH levels in 1,580 healthy Caucasian children and adolescents (849 females, 731 males, aged 2.0-17.2 years) with 25-hydroxyvitamin D [25(OH)D] levels ≥ 30 ng/ml. All subjects with genetic, endocrine, hepatic, renal, or other known diseases were excluded.

RESULTS

The serum intact PTH concentration (median and inter-quartile range) was 23.00 (15.00-31.60) pg/ml. In our population, the mean 25(OH)D value was 34.27 ± 4.12 ng/ml. The median PTH concentration in boys was 23.00 (15.00-32.00) pg/ml, whereas in girls it was 23.10 (15.00-31.10) pg/ml. However, in girls, PTH levels significantly increased in the age group of 8.1-10.0 years compared to the age group of 2.1-4.0 years (p < 0.0001), whereas in boys it significantly increased in the age groups of 10.1-12.0 years (p < 0.0001) and 12.1-14.0 years (p < 0.0001), leading to the hypothesis of a relationship between PTH level and pubertal and bone growth spurts.

CONCLUSIONS

PTH levels in healthy children and adolescents covered a narrower range than the adult values. Obtaining reference values of PTH in childhood and adolescence could aid in the estimation of appropriate values of bone metabolites.

Predictors of Serum 25-Hydroxyvitamin D Concentrations among a Sample of Egyptian Schoolchildren

Objective. To assess the level of 25-hydroxyvitamin D status among a sample of Egyptian schoolchildren and to evaluate predictors of deficiency and insufficiency. Subjects and Methods. A cross-sectional study comprising 200 prepubescent schoolchildren aged from 9 to 11 years was performed. A questionnaire including frequency of midday sun exposure, milk intake, physical activity, and level of maternal education was taken. Body mass index (BMI) was calculated; serum 25-hydroxyvitamin D [25(OH)D], serum calcium, phosphorus, and parathyroid hormone were measured. Results. Vitamin D deficiency [serum 25(OH)D < 20 ng/mL] was detected in 11.5% of subjects while its insufficiency (serum 25(OH)D is between 20 and 29.9 ng/mL) was detected in 15%. Results revealed that obesity, low physical activity, low sun exposure, and low maternal education level are significant predictors of insufficiency, though female gender, low maternal education level, and low milk intake are significant predictors of deficiency. Lower serum phosphorus and higher serum parathyroid hormone were significantly associated with both deficiency and insufficiency (p < 0.05). Conclusion. Vitamin D deficiency and insufficiency are common among schoolchildren in Egypt. Food fortification, vitamin D supplementation, and increasing maternal awareness about the importance of physical activity and exposure of their children to ultraviolet light may help to overcome this problem.

Hypovitaminosis D in healthy children in Central Thailand: prevalence and risk factors

Background

There are limited data regarding the prevalence and risk factors relating to hypovitaminosis D in children of Thailand, a tropical country with abundant sunlight. The objective of this study was to assess the prevalence of hypovitaminosis D and examine factors associated with hypovitaminosis D in school-aged children in Bangkok, Thailand – a centrally located capital city.

Methods

This cross-sectional study evaluated 159 healthy children (33.3% boys and 66.7% girls), aged 6 to 12 years, in Bangkok, Thailand (located at 13.45°N). Fasting plasma samples were examined for total 25-hydroxyvitamin D [25(OH)D] using electrochemiluminescence immunoassay. Demographic characteristics (age, sex, household income), past medical history (birth weight, allergic diseases, hospitalization), amount of sun exposure, anthropometric data, and selected biochemical tests were used to investigate for factors associated with hypovitaminosis D.

Results

Overall, the mean ± SD level of plasma 25(OH)D was 64.0 ± 15.1 nmol/L. Hypovitaminosis D (< 75 nmol/L) was presented in 79.2% of subjects. Of these, the prevalence of vitamin D insufficiency and vitamin D deficiency were 59.7% and 19.5%, respectively. In univariate analysis, children with hypovitaminosis D (< 75 nmol/L) had a higher mean body mass index (BMI) percentile than the vitamin D-sufficient group (56.7 ± 33.9 vs. 42.6 ± 36.0; P-value = 0.04). Plasma PTH levels in the children with hypovitaminosis D were significantly higher than in the children with normal levels of vitamin D (4.34 ± 1.38 vs 3.78 ± 1.25 pmol/L; P-value = 0.04). In multivariate analysis, high BMI percentile and high PTH concentration were the parameters associated with 25(OH)D level < 75 nmol/L.

Conclusion

The prevalence of hypovitaminosis D in healthy Thai children is very high, despite their exposure to sunlight, and that prevalence increases in children with a high BMI percentile. As a result, a formal recommendation for vitamin D supplementation in Thai children should be considered.