High prevalence of vitamin D insufficiency or deficiency in young adolescents in Korea

Correlating neighborhood-level deprivation and pediatric metabolic dysfunction-associated steatotic liver disease

OBJECTIVES

The primary objective of this study is to further explore associations between social influencers of health and markers of disease severity at the time of presentation of patients with pediatric metabolic dysfunction-associated steatotic liver disease (MASLD) using neighborhood-level Area Deprivation Index (ADI) scores.

METHODS

A retrospective cross-sectional study was conducted among 344 pediatric MASLD patients. Each patient received an ADI score based on their 9-digit zip code. Groups were defined as low (≤5) and high (6≥) ADI. Associations between ADI and symptomatology and laboratory values at presentation, as well as initial liver biopsy pathology were tested via analyses of covariance, χ2 testing, and logistic regressions.

RESULTS

The mean ADI was 6.54 (standard deviation = 2.09). ADI groups did not significantly differ in age of presentation, type of presentation, or associated conditions, except for the higher ADI group having on average lower vitamin D levels (26.70 vs. 29.91, p = 0.02) and being two times more likely to also be diagnosed with low high-density lipoprotein (HDL) levels (p = 0.04, 95% CI 1.04-3.89). Mean transaminases and histopathologic nonalcoholic fatty liver disease (NAFLD) Activity Scores did not significantly differ between ADI groups.

CONCLUSIONS

Pediatric patients with MASLD in this study span the entire spectrum of neighborhood deprivation. There were no differences in presentation characteristics or severity of MASLD, aside from lower HDL-cholesterol and vitamin D values in the high ADI group. Area deprivation was not predictive of more severe disease as assessed by serum transaminases and liver biopsy NAFLD activity scores.

Monthly versus daily administration of vitamin D3 in children: a retrospective propensity score-matched study

Objectives

We aimed to evaluate the efficacy and safety of monthly vitamin D3 administration compared to a daily dosing regimen in healthy children with vitamin D deficiency.

Methods

This retrospective study included vitamin D deficient (serum 25-hydroxyvitamin D [25(OH)D] < 20 ng/mL) children with precocious puberty who received gonadotropin-releasing hormone agonist every 4 weeks between December 2019 and November 2022. We used propensity scores to 1:1 match daily (1,000 IU daily) and monthly (25,000 IU per 4 weeks) administration of vitamin D3 based on age, sex, body mass index Z-scores, season of blood collection, and baseline serum 25(OH)D concentrations.

Results

Of 299 children, 192 were matched based on propensity scores (126 girls and 66 boys, 10.5 ± 1.4years). After a mean follow-up of 5.9 months (standard deviation [SD] 2.5 months), the monthly group showed a statistically significant increase in serum 25(OH)D concentrations (10.9 ± 5.3 vs. 8.2 ± 7.2 ng/mL; p = 0.018), higher corrected dose-response (12.3 ± 5.9 vs. 8.2 ± 7.2 ng/mL increase per 1,000 IU daily; p = 0.002), and a higher proportion of patients attaining 25(OH)D > 20 ng/mL (78.1% vs. 58.3%,; p=0.005) compared with the daily group. No cases of hypercalcemia were observed in either group.

Conclusions

Monthly administration of vitamin D3 may be an effective and safe alternative to correct hypovitaminosis D in pediatric population, possibly attributed to enhanced compliance.

Serum 25-Hydroxyvitamin D Levels in Type 2 Diabetes Patients in North China: Seasonality and the Association between Vitamin D Status and Glycosylated Hemoglobin Levels

Background and Aims

Previous studies have reported a correlation between vitamin D levels and seasonality in healthy populations. However, there are few studies on the seasonal variation in vitamin D levels and its relationship with glycosylated hemoglobin (HbA1c) in patients with type 2 diabetes mellitus (T2DM). The objective of this study was to investigate seasonal changes in serum 25-hydroxyvitamin D [25(OH)D] levels and the associations between these vitamin D concentrations and HbA1c levels in T2DM patients in Hebei, China.

Methods

A cross-sectional study of 1,074 individuals with T2DM was conducted from May 2018 to September 2021. Levels of 25(OH)D in these patients were assessed based on both sex and season, and relevant clinical or laboratory variables that could impact vitamin D status were also considered.

Results

In the T2DM patient cohort, the mean blood 25(OH)D levels were 17.05 ng/mL. A total of 698 patients (65.0%) had insufficient serum 25(OH)D levels. The vitamin D deficiency rates were significantly higher in the winter and spring compared to the autumn (P < 0.05), indicating that seasonal fluctuations can have a significant impact on 25(OH)D levels. The levels of vitamin D inadequacy were highest in the winter (74%), and females were more likely than males to be deficient (73.4% vs. 59.5%, P < 0.001). In comparison to the winter and spring, both males and females showed higher 25(OH)D levels in the summer (P < 0.001). HbA1c levels were 8.9% higher in those with vitamin D deficiencies than in nondeficient patients (P < 0.001). HbA1c and vitamin D levels were negatively correlated (r = -0.119, P < 0.001).

Conclusion

Vitamin D deficiencies are particularly prevalent among T2DM patients in Hebei, China, with exceptionally high rates in the winter and spring. Female T2DM patients were at an elevated risk of vitamin D deficiency, and vitamin D levels were negatively correlated with HbA1c.

Vitamin D deficiency and cardiometabolic risk factors in adolescents: systematic review and meta-analysis

Vitamin D deficiency is associated with an increase in the occurrence of cardiometabolic events, but the evidence of this relationship in adolescence is still limited. Thus, we analyzed the association between vitamin D deficiency and cardiometabolic risk factors in adolescents. Observational studies were searching in PubMed/Medline, Embase, Scopus, Web of Science, Science Direct, Lilacs, and Google Scholar database. Random effects models were used to summarize standardized mean differences for as a summary measure. The certainty of the evidence was verified using the Cochrane recommendations. A total of 7537 studies were identified, of which 32 were included in the systematic review and 24 in the meta-analysis.Vitamin D deficiency was associated with increased systolic pressure (SMD = 0.22; 95%CI = 0.10; 0.34), diastolic pressure (SMD = 0.23; 95%CI = 0.10; 0.35), glycemia (SMD = 0.13; 95%CI = 0.05; 0.12), and insulin (SMD = 0.50; 95%CI = 0.15; 0.84), an increase in the HOMA index (SMD = 0.48; 95%CI = 0.36; 0.60), high triglyceride values (SMD = 0.30; 95%CI = 0.11; 0.49), and reduced HDL concentrations (SMD= -0.25; 95%CI = -0.46; -0.04). No statistically significant association was observed for glycated hemoglobin, LDL cholesterol, and total cholesterol. Most of the studies presented low and moderate risks of bias, respectively. The certainty of the evidence was very low for all the outcomes analyzed. Vitamin D deficiency was associated with increased exposure to the factors linked to the occurrence of cardiometabolic diseases in adolescents. Systematic Review Registration: PROSPERO (record number 42,018,086,298).

Pharmacokinetic Drug Interaction Between Raloxifene and Cholecalciferol in Healthy Volunteers

Osteoporosis is a common skeletal disorder, often leading to fragility fracture. Combination therapy with raloxifene, a selective estrogen receptor modulator, and cholecalciferol (vitamin D₃) has been proposed to improve the overall efficacy and increase compliance of raloxifene therapy for postmenopausal osteoporosis. To our knowledge, there has been no report of any study on the pharmacokinetic interaction between raloxifene and cholecalciferol. This study aimed to evaluate the possible pharmacokinetic interactions between raloxifene and cholecalciferol in healthy adult male Korean volunteers. Twenty subjects completed this open‐label, randomized, single‐dose, 3‐period, 6‐sequence, crossover phase 1 study with a 14‐day washout period. Serial blood samples were collected from 20 hours before dosing to 96 hours after dosing. The plasma concentrations of raloxifene and cholecalciferol were determined using a validated method for high‐performance liquid chromatography with tandem mass spectrometry. The geometric mean ratios (90%CIs) for area under the plasma concentration–time curve from time 0 to the last quantifiable time point and maximum plasma concentration of raloxifene with or without cholecalciferol were 1.02 (0.87‐1.20) and 0.87 (0.70‐1.08), respectively. For baseline‐corrected cholecalciferol, geometric mean ratios (90%CIs) of area under the plasma concentration–time curve from time 0 to the last quantifiable time point and maximum plasma concentration with or without raloxifene were 1.01 (0.93‐1.09) and 0.99 (0.92‐1.06), respectively. Concurrent treatment with raloxifene and cholecalciferol was generally well tolerated. These results suggest that raloxifene and cholecalciferol have no clinically relevant pharmacokinetic drug‐drug interactions when administered concurrently. All treatments were well tolerated, with no serious adverse events.

Vitamin D Status and Factors Associated with Vitamin D Deficiency during the First Year of Life in Preterm Infants

We aimed to investigate the changes in vitamin D levels and factors associated with vitamin D deficiency (VDD) during the first year of life in Korean preterm infants. We enrolled 333 preterm infants who were born at Kyungpook National University Children’s Hospital between March 2013 and December 2019. 25-hydroxyvitamin D (25-OHD) levels and medical records were collected at birth, 6 months, and 12 months of age. The mean gestational age was 33.4 ± 2.3 weeks and mean 25-OHD levels at birth were 18.2 ± 13.5 ng/mL. The incidence of VDD was 82.8%, 30.6%, and 27.0% at birth, 6 months, and 12 months, respectively. The incidence of severe VDD (25-OHD < 10 ng/mL) was 31.5%, 1.5%, and 0%, at birth, 6 months, and 12 months, respectively. Among infants with severe VDD, the deficiency persisted in 49.6% at 6 months, and 35.3% at 12 months. The strongest predictor of VDD during follow-up was 25-OHD concentration at birth. Vitamin D supplementation at 400 IU/day did not affect vitamin D levels during the first year of life. Therefore, it is important to prevent neonatal VDD through maternal vitamin D supplementation during pregnancy. Further research is needed to determine the optimal vitamin D supplementation dose for Korean preterm infants.

Vitamin D status in pubertal children

BACKGROUND

Optimal vitamin D status has a great importance in puberty, which is a period of peak bone mineral acquisition. In this study, we aimed to assess the effect of pubertal period on vitamin D status.

METHODS

The study included totally 200 healthy children, aged between 4 and 14 years. Group 1 included 100 prepubertal, children, aged between 4 and 8 years. Group 2 included 100 pubertal children, aged between 9 and 14 years. They had no chronic illnesses. Ages, heights, weights, genders, Body Mass Indexes (BMIs), socioeconomic and educational status of families were established. Serum 25-hydroxyvitamin D (25(OH)D) levels were measured by high performance liquid chromatography (HPLC). Serum parathyroid hormone (PTH) was evaluated using an immunoradiometric assay kit. Serum calcium (Ca), phosphorus (P) and alkaline phosphatase (ALP) levels were measured.

RESULTS

We determined that 25(OH)D levels were lower with higher PTH levels in the group aged 9 to 14 years (pubertal children), compared to the group aged 4 to 8 (prepubertal children). Gender, weight, height or BMI, family socioeconomic and education status did not affect serum 25(OH)D levels of children in each group.

CONCLUSIONS

We demonstrated that vitamin D deficiency was more commonly seen in the pubertal children, compared to pre pubertal period. Children should be supported with vitamin D supplements during the puberty, which has a great importance for rapid increase in bone mass.

Prevalence and predictors of vitamin D deficiency in a nationally representative sample of Australian adolescents and young adults

Background/Objectives

Vitamin D deficiency is a public health concern worldwide. Maintaining vitamin D sufficiency during growth periods is essential. We aimed to determine the prevalence and predictors of vitamin D deficiency in Australian adolescents and young adults.

Subject/Methods

We used data from adolescents (12–17 years, n = 692) and young adults (18–24 years, n = 400) who participated in the nationally representative 2011–2013 Australian Health Survey. Serum 25-hydroxyvitamin D concentrations were measured using a method certified to international standards, with prevalence reported for <50 (vitamin D deficiency), 50–<75, ≥75 and >125 nmol/L. Independent predictors of vitamin D deficiency were determined using a survey-weighted Poisson regression model.

Results

Overall, 17% of adolescents and 32% of young adults were vitamin D deficient. In models adjusted for sex, age, region of birth, socioeconomic status, BMI and season (and education, smoking status and physical activity in young adults only), the prevalence ratio (PR) for vitamin D deficiency was more than double in participants born outside Australia (adolescents: PR 2.46; 95% confidence interval (CI) = 1.59, 3.81; young adults: PR 2.12; 95% CI = 1.46, 3.07), and also varied by season (adolescents: spring vs summer PR 2.47; 95% CI = 1.22, 5.01 and winter vs summer PR 2.01; 95% CI = 1.03, 3.92; young adults: winter vs summer; PR 3.32; 95% CI = 1.69, 6.53). Other predictors of vitamin D deficiency were overweight compared with healthy weight (adolescents) and lower physical activity (young adults).

Conclusions

Strategies based on safe sun exposure and dietary approaches are needed to achieve and maintain adequate vitamin D status, particularly in young adults.

Influence of Severe Vitamin D Deficiency on the Clinical Course of Inflammatory Bowel Disease

BACKGROUND

Previous studies have shown vitamin D status to be associated with disease activity in patients with inflammatory bowel disease (IBD), but its influence on the clinical course of IBD has not been established.

AIMS

We aimed to analyze whether the serum 25-hydroxyvitamin D3 [25(OH)D] status is associated with clinical characteristics and affects the risk of surgery in patients with IBD.

METHODS

From the IBD registry of the Asan Medical Center, we identified all patients who had at least one 25(OH)D measurement; we then analyzed the association between clinical factors and 25(OH)D status. 25(OH)D was considered borderline deficient, deficient, and severely deficient at levels of < 30, < 20, and < 10 ng/mL, respectively.

RESULTS

We included 711 Crohn's disease (CD) and 764 ulcerative colitis (UC) patients who had not undergone surgery before 25(OH)D was measured. Both in CD and in UC patients, reduced 25(OH)D was associated with higher disease activity scores and CRP levels (p < 0.001). Severe 25(OH)D deficiency was associated with ileocolonic disease and complicated behavior in CD (p < 0.05) and was relevant to the disease extent in UC (p < 0.001). Additionally, severe 25(OH)D deficiency was associated with CMV colitis in patients with UC (p < 0.001). In multivariable analysis, severe deficiency of 25(OH)D was an independent risk factor for surgery in both CD (HR 1.93, 95% confidence interval [CI] 1.38-2.70) and UC (HR 2.77, 95% CI 1.14-6.74).

CONCLUSION

Severe 25(OH)D deficiency may be a marker of a more aggressive clinical course of IBD.

Association of Vitamin D Concentrations with subjective health complaints in children and adolescents: the CASPIAN-V study

BACKGROUND

Vitamin D deficiency (VDD) is recognized as a global pandemic. Identification, any association between VDD and subjective health complaints (SHC), can be helpful to realize critical mechanisms and improve psychological and somatic symptoms. Given few studies published on this issue and the importance of its clarification, the main objective of this study was to examine the association between VDD and the SHC in children and adolescents.

METHODS

In this national cross-sectional study, 2596 Iranian children and adolescents aged 8-18 years were included. Data on SHC, anthropometric indices, physical activity, and serum levels of vitamin D were collected. Logistic regression models (crude, adjusted) were applied to examine the association between the VDD and the SHC. Statistical analysis was performed using STATA version 11. P-values< 0.05 were considered as statistically significant.

RESULTS

Serum levels of vitamin D in approximately 70% of Iranian children and adolescents were lower than 30 ng/mL. Among the SHC, irritability (40.9%) and feeling anxiety (33.7%) were the most prevalent ones. Multiple complaints in students with the VDD was 2.5 times greater than those with sufficient vitamin D concentrations (p <  0.001). Compared to the reference group, the strongest association was found between vitamin D status and difficulties in getting to sleep (OR: 2.5, 95%CI: 1.18, 3.53, p <  0.001).

CONCLUSION

VDD was observed in the considerable percentage of the study population. There were no significant differences between the two gender groups. In addition, there were significant associations between vitamin D status and most of the somatic and psychological symptoms, particularly for getting to sleep. It seems national interventional programs for vitamin D supplementation or food fortifications can be helpful.

Does the Vitamin D Deficiency Have Any Role in Severity or Prolongation of Seizure? A Pilot Study in Iran

Background:

Based on previous studies, vitamin D deficiency could lead to nerve stimulation. The purpose of the present study was to determine frequency and duration of seizures in children with idiopathic epilepsy in two groups; normal level of vitamin D versus decreased level of vitamin D.

Methods:

This pilot, comparative study was carried out in Zanjan University of Medical Sciences on total 40 children aging between 2 to 12 years old (23 male and 17 female) with the diagnosis of idiopathic epilepsy. All patients were receiving anti-epileptic drugs. The initial questionnaire was completed by each parent. Total 40 epileptic cases were examined in close follow-ups every three months, during total 9 months. Meanwhile, the frequency and duration of each seizure were recorded in questionnaire at every three-month period. Vitamin D blood samples were analyzed at the beginning of the study and after 9 months following the study. Serum levels of Vitamin D were analyzed by ELISA method (Elecsys2010, RocheCo, Germany; STAR FAX; 2100), simultaneously, Vitamin D level <30 ng/ml (nanogram per milliliter) was defined as Vitamin D deficiency. Cases were divided into two groups based on Vitamin D level. The frequency and duration of convulsions were compared in patients with normal level of vitamin D versus children with decreased level of vitamin D. Data were analyzed by Chi-square and t-test methods.

Results:

In all 40 patients, vitamin D level less than 30 ng/ml was detected in 32% (13 patients) at the beginning of study and 35% (14 patients) in 9 months later (13 patients were common between the two groups). There was no significant relationship between the frequency of seizures, the duration of seizures and vitamin D levels in patients. The relationship between positive family history of epilepsy and the number of seizures was reported significant. The frequency of vitamin D deficiency was higher in female cases in final evaluation.

Conclusion:

In the present study, a considerable correlation was detected between the frequency of seizures and positive history of seizure in the family. The frequency of vitamin D deficiency was higher in female cases in final analysis. No significant relationship was detected between the number of seizures, the mean duration of seizures and serum level of Vitamin D in children who received anticonvulsant drugs. However, vitamin D deficiency in patients was not overlooked in order to prevent known complications. We recommend a randomized clinical trial in the future with an adequate sample size. Moreover, a non-epileptic control group in study would be useful.

New parathyroid function index for the differentiation of primary and secondary hyperparathyroidism: a case-control study

BACKGROUND

Patients with primary hyperparathyroidism (PHPT) may be asymptomatic, and some may present with normocalcemic PHPT (NPHPT). Patients with vitamin D deficiency may also be asymptomatic, with normal calcium and elevated PTH concentrations. These latter patients are usually diagnosed with vitamin D deficiency-induced secondary hyperparathyroidism (VD-SHPT). Therefore, it is very difficult to distinguish PHPT and NPHPT from VD-SHPT based on calcium or PTH concentrations in clinical settings. In this case-control study, we aimed to verify the diagnostic power of a new parathyroid function index (PFindex = Ca*PTH/P).

METHODS

This study enrolled 128 patients with surgically and pathologically confirmed PHPT, including 36 with NPHPT, at a hospital in West China between January 2009 and September 2017. Thirty-seven patients with VD-SHPT and 45 healthy controls were selected from the population of a cross-sectional epidemiological study as the SHPT and healthy groups, respectively. We used the PFindex to describe the characteristics of PHPT, NPHPT, and VD-SHPT.. Differences between the four groups were compared, and a receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic power of PFindex.

RESULTS

The PHPT group had the highest PFindex (454 ± 430), compared to the other three groups (NPHPT: 101 ± 111; SHPT: 21.7 ± 6.38; healthy: 12.2 ± 2.98, all p < 0.001). A PFindex cut-off value of 34 yielded sensitivity and specificity rates of 96.9 and 97.6% and of 94.4 and 94.6% for the diagnoses of PHPT and NPHPT, respectively. The use of a PFindex > 34 to differentiate NPHPT from VD-SHPT yielded the highest positive likelihood ratio and lowest negative likelihood ratio.

CONCLUSION

The PFindex provided excellent diagnostic power for the differentiation of NPHPT from VD-SHPT. This simple tool may be useful for guiding timely decision-making processes regarding the initiation of vitamin D treatment or surgery for PHPT.

Low muscle mass is associated with osteoporosis: A nationwide population-based study

OBJECTIVES

To assess the association between low muscle mass and osteoporosis in the Korean general population.

METHODS

We analyzed 14,429 participants (6,261 men and 8,168 women) from the 2009-2011 Korean National Health and Nutrition Examination Survey (KNHANES) aged 20 years or more.

MAIN OUTCOME MEASURE

The association of low muscle mass with osteoporosis was investigated using multivariate logistic regression models that included age, marital status, residence, current smoking, monthly drinking, physical activities, strength exercise, comorbidity, and the use of dietary supplements, and in women postmenopausal status and experience of pregnancy.

RESULTS

After adjusting for covariates, low muscle mass was significantly associated with osteoporosis in the lumbar spine and femoral neck in both men (lumbar spine: OR 1.73, 95 % CI 1.08-2.76; femoral neck: OR 3.39, 95 % CI 1.69-6.80) and women (lumbar spine: OR 1.52, 95 % CI 1.17-1.97; femoral neck: OR 2.09, 95 % CI 1.56-2.80). Also, the association between low muscle mass and osteoporosis was significant in men and women in every age group except for men aged 50-64 years.

CONCLUSION

Low muscle mass was significantly associated with osteoporosis in both men and women for all age groups, except for men aged 50-64 years.

Association Between Vitamin D Deficiency and Suspected Nonalcoholic Fatty Liver Disease in an Adolescent Population

PURPOSE

Vitamin D deficiency is a condition widespread throughout the world. Recent studies have suggested that vitamin D deficiency was associated with obesity and metabolic syndrome. The purpose of the study was to examine the relationship between vitamin D deficiency and nonalcoholic fatty liver disease (NAFLD) in adolescents.

METHODS

The data were obtained from the Korean National Health and Nutrition Examination Survey from 2008-2014. A total of 3,878 adolescents were included in the study. Vitamin D deficiency was defined as a 25-hydroxyvitamin D concentration <20 ng/mL and suspected NAFLD was defined as an alanine transaminase concentration >30 U/L.

RESULTS

Vitamin D deficiency was noted in 78.9% of the studied population. Age, body mass index, waist circumference, and blood pressure, glucose, cholesterol, and triglyceride levels were significantly higher in adolescents with suspected NAFLD than in adolescents without suspected NAFLD, while the mean vitamin D level was significantly lower in adolescents with suspected NAFLD. The multivariate-adjusted odds of suspected NAFLD were higher with increased age, male gender, obesity, and metabolic syndrome. Individuals with vitamin D deficiency were at higher risk of suspected NAFLD (odds ratio, 1.77; 95% confidence interval, 1.07-2.95) after adjusting for age, gender, obesity, and metabolic syndrome.

CONCLUSION

Vitamin D deficiency was associated with suspected NAFLD, independent of obesity and metabolic syndrome, in adolescents.

Association of the Vitamin D Level and Quality of School Life in Adolescents with Irritable Bowel Syndrome

There is no treatment of choice for irritable bowel syndrome, which affects up to 20% of school-aged children. This cross-sectional study evaluated the difference in the average vitamin D level between subtypes of irritable bowel syndrome, and the relationship between the vitamin D level as well as the severity of irritable bowel syndrome symptoms. We included 124 adolescents aged 10–17 years (68 boys, 56 girls; mean age 12.29 ± 1.92 years) from 2014 to 2016. Patients with irritable bowel syndrome were diagnosed by Rome III criteria and classified by clinical manifestation: irritable bowel syndrome with constipation (n = 29), irritable bowel syndrome with diarrhea (n = 63), and irritable bowel syndrome with constipation and diarrhea (n = 32). The severity of irritable bowel syndrome symptoms and school absence were evaluated. Vitamin D levels were measured by serum 25-hydroxyvitamin D. The chi-square test and analysis of variance were used. The patients’ average vitamin D level was 16.25 ± 6.58 ng/mL. There was a significant negative association of the 25-hydroxyvitamin D level with symptom severity and school absence (p = 0.022 and p < 0.001, respectively). Vitamin D supplementation could be considered as a choice of therapeutic method.

Effects of Taurine and Vitamin D on Antioxidant Enzyme Activity and Lipids Profiles in Rats Fed Diet Deficient Calcium

Calcium deficiency is a worldwide problem affecting both developed and developing countries. The deficiency in calcium leads to a marked decrease of superoxide dismutase. It is known that vitamin D protects cells against oxidative damages while taurine plays an anti-inflammatory and antioxidant role. In this study, we examined whether vitamin D and taurine supplementation had a protective effect on oxidative stress in rats fed calcium deficient diet. Female SD rats (mean weight 60 ∼ 70 g) were divided into four groups; control, taurine, vitamin D, taurine + vitamin D for 6 weeks (taurine: 2 g/100 g diet, vitamin D: 0.5 mg/100 g diet). We then analyzed the level of triglyceride (TG), total cholesterol (TC), LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C) in serum and level of TC, TG in liver. We investigated antioxidative enzyme activities such as catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px). We observed that weight gain was not significantly different in the experimental groups. Food efficiency ratio (FER) was significantly higher in the normal control group than the taurine and vitamin D groups (p < 0.05). The level of liver TC was significantly lower in taurine, vitamin D, taurine + vitamin D groups than control group (p < 0.05). The concentration of malondialdehyde (MDA) was significantly lower in the taurine group than the control group. The activity of SOD was higher in taurine group than other experimental groups (p < 0.05), but GSH-Px and CAT were not significantly different. In conclusion, taurine has a positive effect on SOD activity but not on vitamin D. Also taurine and vitamin D have a protective effect as observed in liver TC in rats fed with a diet which lacks calcium.

Prevalence of vitamin D insufficiency among children in southern china: A cross-sectional survey

Vitamin D deficiency is associated with numerous public health issues. Limited data are available for children in southern China, a region that receives abundant sunlight. We aimed to estimate the 25-hydroxyvitamin D (25(OH)D) levels in children in that area, and to determine seasonal variations in serum 25(OH)D levels. A total of 16,755 children aged 0 to 6 years, who visited the Guangdong Women and Children's Hospital for health examination between January 2016 and May 2017, were included in the present study. The serum 25(OH)D levels ranged from 10.5 to 307.4 nmol/L (mean ± standard deviation: 78.5 ± 26.3 nmol/L). The prevalence of vitamin D deficiency and insufficiency were 10.8% and 39.0%, respectively. The mean serum 25(OH)D level in spring (71.8 ± 24.9 nmol/L) was lower than that in other seasons. From January to April, we found a relatively high prevalence of vitamin D deficiency or insufficiency, both of which were also found to increase with age. Logistic regression analysis revealed that vitamin D deficiency and insufficiency were significantly associated with age and season. Deficiency and insufficiency of vitamin D are common among children in southern China, despite the area receiving sufficient sunlight.

Risk Factors for Vitamin D, Zinc, and Selenium Deficiencies in Korean Patients with Inflammatory Bowel Disease

Background/Aims

Studies on the micronutrient status of Asian patients with inflammatory bowel disease (IBD) are scarce. We evaluated the prevalence of micronutrient deficiency and verified the risk factors for micronutrient deficiency in Korean patients with IBD.

Methods

We measured the serum levels of 25-hydroxyvitamin D3 [25-(OH)D], zinc, and selenium to analyze the clinical risk factors for micronutrient levels below the reference values. In addition, we compared the 25-(OH)D levels of patients with IBD to those of age- and sex-matched healthy controls.

Results

Among the 83 patients, 74 (89.2%) had suboptimal serum 25-(OH)D levels. The mean plasma 25-(OH)D level in patients with IBD was significantly reduced compared to that of the healthy controls (12.3±6.2 ng/mL vs 20.0±6.7 ng/mL; p<0.001). The proportions of patients with lower serum zinc and selenium levels were 39.0% and 30.9%, respectively. Female sex (p=0.012) and Crohn’s disease (p=0.012) were associated with vitamin D deficiency. Patients younger than 40 years were at increased risk for zinc deficiency (p=0.045). Female sex (p=0.015) and low serum albumin level (<3.3 g/dL) (p=0.047) were risk factors for selenium deficiency.

Conclusions

Many Korean patients with IBD have vitamin D, zinc, and selenium deficiencies, suggesting the necessity for monitoring levels of these micronutrients.

Association of Serum 25-hydroxyvitamin D Levels and Liver Enzymes in a Nationally Representative Sample of Iranian Adolescents: The Childhood and Adolescence Surveillance and Prevention of Adult Noncommunicable Disease Study

Background:

Hypovitaminosis D is highly prevalent and has several adverse health effects. This study aims to assess the relationship of serum concentrations of 25-hydroxyvitamin D (25[OH] D) and liver enzymes in adolescents.

Methods:

This population-based cross-sectional survey was conducted among a nationally representative multistage sample of 1095 adolescents (52% boys), aged 10–18 years, living in different provinces of Iran. Serum 25(OH)D concentration <30 ng/mL was considered as hypovitaminosis D, and liver enzymes (alanine aminotransaminase [ALT] and aspartate aminotransaminase [AST]) of >40 U/L was considered as high level. To determine the association between serum 25(OH)D categories and elevated levels of liver enzymes, multiple regression models and linear regression analysis were applied, after adjustment for potential confounders. Odds ratios (95% confidence interval) of serum 25(OH)D and elevated liver enzymes were assessed by logistic regression analysis.

Results:

Higher rates of Vitamin D deficiency were documented among individuals with increased levels of liver enzymes. Compared to boys, median of 25(OH)D was lower in girls with elevated levels of liver function tests (12.75 vs. 25.60 ng/mL for ALT and 13 vs. 14.10 ng/mL for AST), with marginally significant gender differences regarding AST.

Conclusions:

We found a relatively high frequency of hypovitaminosis D among adolescents with abnormal liver function. Further prospective studies are needed to examine these associations from early life.

Prevalence of vitamin D deficiency in girls with idiopathic central precocious puberty

The relationship between vitamin D deficiency and idiopathic central precocious puberty (ICPP) has been recently documented. In this study, 280 girls diagnosed with ICPP and 188 normal puberty control girls of similar ages were enrolled and retrospectively studied. The ICPP group had significantly lower serum 25-hydroxyvitamin D (25[OH]D) levels than the control group. Furthermore, a nonlinear relationship was found between serum 25[OH]D and ICPP, and a cut-off point for serum 25[OH]D was found at 31.8 ng/ml for ICPP with and without adjusting the different confounding factors. Girls with serum 25[OH]D ≥ 31.8 ng/ml had a lower odds ratio (unadjusted: OR 0.36, 95% CI 0.15 to 0.83, P < 0.05; height and weight adjusted: OR 0.44, 95% CI 0.18 to 1.08, P = 0.072; BMI adjusted: OR 0.36, 95% CI 0.16 to 0.84, P < 0.05). The ICPP subjects with 25[OH]D deficiency had a higher body mass index (BMI) than the subjects from the two other subgroups. Correlation analysis showed that vitamin D level is correlated with BMI and some metabolic parameters in the ICPP group. Our study suggested that vitamin D status may be associated with ICPP risk and may have a threshold effect on ICPP.

25-hydroxyvitamin D is associated with metabolic syndrome among premenopausal women with systemic lupus erythematosus in China

Objectives

This study aimed to investigate the status of 25-hydroxyvitamin D (25(OH)D) and its association with metabolic syndrome (MS) and different MS components among premenopausal women with systemic lupus erythematosus (SLE) in China.

Patients and methods

Altogether 113 premenopausal women with SLE and the age-matched healthy cohorts were recruited in this cross-sectional study. Clinical manifestations and laboratory data including serum 25(OH)D concentration were collected. A multivariable analysis was performed to analyze the association of 25(OH)D with MS and its components.

Results

The prevalence of 25(OH)D deficiency (25(OH)D < 20 ng/ml) and MS were common (24.8% and 30.1%, respectively) in premenopausal patients with SLE in China. Analysis of the association between 25(OH)D, MS and its components demonstrated that the lower level of 25(OH)D was associated with increased MS prevalence (OR = 0.920, p = 0.012), a decreased level of high-density lipoprotein (OR = 1.059, p = 0.033) and a higher level of fasting glucose (OR = 0.810, p = 0.004). These associations were still detectible after adjustment for age, body mass index and SLE-related variables.

Conclusion

The level of 25(OH)D is associated with MS and its components in premenopausal women with SLE.

Comparison of Vitamin D Levels in Patients with and without Acne: A Case-Control Study Combined with a Randomized Controlled Trial

Background

Vitamin D plays an important role in the immune system, and its deficiency has been implicated in various skin diseases, including atopic dermatitis and psoriasis. Acne is a common inflammatory skin disease; however, the association with vitamin D remains unclear.

Objectives

We evaluated vitamin D levels in patients with acne to determine the effect of vitamin D supplementation.

Methods

This study included 80 patients with acne and 80 healthy controls. Serum 25-hydroxyvitamin D (25(OH)D) levels were measured, and demographic data were collected. Vitamin D-deficient patients were treated with oral cholecalciferol at 1000 IU/day for 2 months.

Results

Deficiency in 25(OH)D was detected in 48.8% of patients with acne, but in only 22.5% of the healthy controls. The level of 25(OH)D was inversely associated with the severity of acne, and there was a significant negative correlation with inflammatory lesions. In a subsequent trial, improvement in inflammatory lesions was noted after supplementation with vitamin D in 39 acne patients with 25(OH)D deficiency.

Limitations

Limitations of the study include the small number of patients in the supplementation study and the natural fluctuation of acne.

Conclusions

Vitamin D deficiency was more frequent in patients with acne, and serum 25(OH)D levels were inversely correlated with acne severity, especially in patients with inflammatory lesions.

Vitamin D insufficiency among children with cancer in India

BACKGROUND

Vitamin D plays an important role in regulating various homeostatic mechanisms and has yet untapped potential in cancer prevention and prognosis. Only a few studies have been done worldwide in relating the Vitamin D levels in pediatric cancer patients to the general population but none so far in an Indian setting to the best of our knowledge.

OBJECTIVE

To compare the Vitamin D levels in a group of children with cancer to that of the general pediatric population and to note differences in the prevalence of Vitamin D insufficiency and make inferences arising from demographic and therapeutic variations.

MATERIALS AND METHODS

Vitamin D levels were found by immuno-chemilumino-metric assay in 102 children (51 cases and 51 controls) over a 6 months period.

RESULTS

In comparing the Vitamin D levels of children with cancer and controls from a healthy population we found an increased incidence of Vitamin D insufficiency in cancer children (80.39%) when compared to controls (50.98%) and a much lower mean Vitamin D value in cancer children (22.8 ng/ml) when compared to controls (33 ng/dl). It was also found that cancer children above 6 years had a greater chance for developing Vitamin D insufficiency (P = 0.038) as did children suffering from hematological malignancies (P = 0.025).

CONCLUSION

Our study showed an increased prevalence of Vitamin D insufficiency in children with cancer and hence we suggest routine measurement of Vitamin D levels in children with cancer and subsequent supplementation.

Hypovitaminosis D in adolescents living in the land of sun is correlated with incorrect life style: a survey study in Campania region

PURPOSE

The aim of this study is to investigate in a population of adolescents living in Regione Campania, undergoing sun exposure at least 9 months per year the prevalence of severe deficiency (<20 ng/ml) or insufficiency (21-29 ng/ml) of 25-Hydroxyvitamin D (25(OH)D) levels and its relationship with individual body weight, use of smoking, and exercise performance.

METHODS

From October 2012 to October 2013, 373 healthy subjects (153 girls, 223 boys 11-20 years) without chronic diseases were consecutively enrolled in a campaign to prevent metabolic, cardiovascular, and oncological diseases. 25(OH)D assay, BMI, and lifestyle habitudes (smoking and exercise indoor or outdoor) were assessed.

RESULTS

In this population, median 25(OH) level was 25.0 ng/ml (95 %CI 23.8-25.2) without any difference between girls (25.0 (95 %CI 23.1-25.7)) and boys (24.3 (95 %CI 23.8-25.2)). Severe deficiency was found in 6 girls (0.02 %), while insufficiency was found in 296 patients (110 girls, 79.3 %). Normal levels were found in 71 patients (37 girls, 19 %). Vitamin D levels were significantly correlated with BMI (r = -0.429, p < 0.0001), smoking (r = -0.241; p < 0.0001), and exercise performance (r = 0.791; p < 0.0001). At the multistep regression analysis, Vitamin D levels were best predicted by exercise performance (t = 19.6, p < 0.0001), less smoking addiction (t = -4.97, p < 0.001), and lower BMI (t = -4.69, p < 0.0001).

CONCLUSIONS

The current study demonstrates that Vitamin D levels are commonly unsatisfactory in adolescents. Lower levels were found in overweight or obese adolescent, smokers and with low or absence of physical activity outdoors.

Relationship of serum 25-Hydroxyvitamin D (25[OH]D) levels and components of metabolic syndrome in prepubertal children

OBJECTIVE

The relationship between 25-hydroxyvitamin D (25[OH]D) levels and the lipid and metabolic levels of the prepubertal normal population is unclear. Our goals were to investigate the association of serum 25(OH)D concentrations with lipid and metabolic levels in Korean prepubertal children ages 7-9 y.

METHODS

We followed 205 children, ages 7-9 y in the Ewha Birth and Growth Cohort study, a prospective cohort sample established in 2001-2006, from July to August 2011. We studied the association of serum 25-hydroxyvitamin D (25[OH]D) levels with components of metabolic syndrome and insulin resistance indices using multivariate regression analysis adjusted for body mass index (BMI) z-scores.

RESULTS

The mean age of the 205 subjects was 7.89 ± 0.85 y, and the sample included 109 boys (53.2%). The average 25(OH)D levels of all participants was 25.0 ± 5.4 ng/mL. After adjustment for age and sex, triacylglycerol levels were significantly associated with 25(OH)D (β = -0.02, P = 0.02) concentrations even after adjustment for BMI z-scores (β = -0.02, P = 0.04). However, other metabolic components were not correlated with 25(OH)D status. Those with the lowest quartile of 25(OH)D levels had the highest serum triacylglycerol levels (P = 0.04, Ptrend = 0.01).

CONCLUSIONS

We found that serum 25(OH)D levels were negatively associated with serum triacylglycerol levels, even independently of adiposity, in prepubertal children. This study suggests that 25(OH)D insufficiency is related to metabolic syndrome via the derangement of triacylglycerol metabolism.

Hypovitaminosis D in adolescent females--an analytical cohort study in the United Arab Emirates

BACKGROUND

Despite living in a sunny country, hypovitaminosis D is common in women of reproductive age in Al Ain, United Arab Emirates (UAE).

AIMS AND OBJECTIVES

To establish the prevalence of hypovitaminosis D in adolescent female Emirati nationals and its risk factors.

METHODS

This was an analytical prospective cohort study of 350 female Emirati nationals aged 11-18 years attending public schools in Al Ain. Socio-economic status, diet and amount of sun exposure were evaluated by face-to-face interviews. Serum total 25 (OH) vitamin D (D2 + D3) levels were measured by electrochemiluminescence assay. The prevalence of hypovitaminosis D was calculated and the association with risk factors analysed.

RESULTS

Data were complete for 293 girls. Only one girl [prevalence 0.3%, 95% confidence interval (CI) 0.01-1.9] had vitamin D sufficiency (serum vitamin D levels >75 nmol/L). Three girls (1.0%, 95% CI 0.2-2.9) had vitamin D insufficiency (50-75 nmol/L), 58 (19.8%, 95% CI 15.0-25.5) were deficient (27.5-50 nmol/L) and 231 (78.8%, 95% CI 68.9-89.6) had severe deficiency (<27.5 nmol/L). Serum vitamin D levels declined between the ages of 11 and 13 years before progressively rising until the age of 18 years but without regaining the levels they were at the age of 11. There was no statistically significant difference between the vitamin D status groups in age, body mass index, accommodation type, family income, percentage of surface area unexposed to the sun when outdoors, consumption of oily fish or total vitamin D intake.

CONCLUSION

The finding of a high prevalence of hypovitaminosis D in adolescent females in UAE is of serious concern for their health and that of their infants during their reproductive lives. Adolescent girls with a similar social and cultural background currently living in less sunny, industrialised countries might also be at risk.

Seasonal vitamin D status of healthy schoolchildren and predictors of low vitamin D status

OBJECTIVES

The aim of the study was to assess seasonal prevalence of vitamin D deficiency according to sex and to determine the relations between serum levels of 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH) and sociodemographic characteristics in otherwise healthy schoolchildren during spring and autumn.

METHODS

In a cross-sectional study, 746 healthy students aged between 11 and 18 years were recruited during spring (n = 375) and autumn (n = 371). Sociodemographic data were collected by a questionnaire. Serum 25(OH)D, PTH, calcium, phosphate, and alkaline phosphatase were measured. Serum 25(OH)D levels were categorized as <50 nmol/L (vitamin D deficiency) and <25 nmol/L (severe deficiency).

RESULTS

Mean ± standard deviation 25(OH)D levels were 22.3 ± 10.5 nmol/L in girls and 28.5 ± 17.0 nmol/L in boys during spring (P < 0.001) and 36.5 ± 20.3 nmol/L in girls and 45.0 ± 18.5 nmol/L in boys during autumn (P < 0.001). The prevalence of vitamin D deficiency was 93% during spring and 71% during autumn. There was a negative correlation between 25(OH)D and PTH levels (P < 0.01). We determined a cutoff point of serum 25(OH)D in which the mean serum PTH concentration began to increase as 35.8 nmol/L (P < 0.0001). The age, sex, and calcium level were found to be independent predictors for vitamin D deficiency.

CONCLUSIONS

Vitamin D deficiency is prevalent among healthy schoolchildren. It is noteworthy that 25(OH)D levels were significantly lower in girls and during autumn. We recommend vitamin D supplementation for children in addition to more time spent for outdoor activities for sensible sunlight exposure.

The association between serum vitamin D level and immunoglobulin E in Korean adolescents

OBJECTIVE

Vitamin D has immune modulatory functions, and thus its relationship with allergic disease has been evaluated in a number of studies. However, no concrete link between serum IgE level and vitamin D has been established. Thus, the purpose of study was to confirm the association of serum vitamin D level with the serum IgE (total and Dematophagoides farinae specific IgE) in Korean adolescents.

METHODS

A total of 365 subjects between 10 and 18 years of age were enrolled through the Korea National Health and Nutrition Examination Survey (KNHANES). Serum levels of vitamin D, total IgE, and Dermatophagoides farinae (Df) specific IgE were measured, and data for potential confounding variables were collected. Multivariate regression analyses were used to determine the independent effects of these variables.

RESULTS

Levels of both total and Df specific IgE were positively correlated with serum concentration of vitamin D (Spearman's rho (R)=0.126, p=0.016; R=0.152, p=0.004, respectively). These results were confirmed by multivariate linear regression analysis after adjusting for sex, age, and body mass index (coefficient (B): 10.45 95% confidence interval (CI): 0.59-20.31; B: 1.06, 95% CI: 0.31-1.80, respectively). And, the association between serum vitamin D and IgE showed the different results depending on the presence or absence of Df sensitization.

CONCLUSIONS

Serum concentration of vitamin D was positively associated with levels of both total IgE and Df-specific IgE in Korean adolescents.

Vitamin D status and its relationship with metabolic syndrome risk factors among adolescent girls in Boukan, Iran

OBJECTIVE

To investigate vitamin D status and its association with components of the metabolic syndrome (MetS) in adolescent girls attending high school in Boukan, Iran during winter 2012.

DESIGN

A cross-sectional study.

SETTING

High schools of Boukan city, Iran.

SUBJECTS

A sample of 216 girls aged 14-17 years was selected by multistage random sampling from four districts of Boukan. Weight, height, waist circumference, blood pressure, daily energy intake, physical activity and serum 25-hydroxyvitamin D (25(OH)D), fasting blood glucose, TAG and HDL-cholesterol levels of all participants were evaluated. Serum 25(OH)D level <20 ng/ml was defined as vitamin D deficiency.

RESULTS

Mean serum 25(OH)D was 7.26 (sd 2.81) ng/ml and 96 % of the participants had vitamin D deficiency. According to age-modified definitions of the National Cholesterol Education Program Adult Treatment Panel III, MetS was diagnosed in 10.6% of the participants. In multivariable regression analysis after adjustment for BMI, energy intake and physical activity level, serum 25(OH)D was inversely associated with fasting blood glucose (β = -0.143, P = 0.04). No significant relationship was found between serum 25(OH)D and other components of MetS.

CONCLUSIONS

The high prevalence of vitamin D deficiency warrants national polices and interventions towards improving this major health problem among adolescent girls. Low 25(OH)D level was significantly associated with increased fasting blood glucose. Prospective studies are needed to determine the effects of vitamin D deficiency on the development of MetS and related metabolic diseases in adolescent girls.

Serum vitamin D status in children and adolescence with diabetes according to season and age

PURPOSE

It is known that children with diabetes have more severe vitamin D deficiency than healthy children. This study aimed to investigate serum vitamin D status and analyze the relationships between serum vitamin D levels and clinical parameters in children with diabetes.

METHODS

We checked serum vitamin D levels of children with diabetes aged below 18 years who were treated at our Department of Pediatrics between December 2011 and February 2012 (winter) as well as between June 2012 and August 2012 (summer). We retrospectively analyzed relationships between their serum vitamin D levels and clinical parameters.

RESULTS

The serum 25-hydroxyvitamin D level in children with diabetes during winter was markedly lower than during summer (10.8±5.1 ng/mL vs. 17.6±5.6 ng/mL); vitamin D deficiency was more prevalent during winter (95% vs. 62%). However, there was no difference between children with diabetes and healthy children. In children with type I diabetes mellitus, among all the clinical parameters, age had the greatest negative correlation with serum vitamin D level.

CONCLUSION

In children with diabetes, serum vitamin D levels showed marked seasonal variation. However, no clear relationship was identified between vitamin D deficiency and diabetes. This was because the control group had an equally high vitamin D deficiency rate. Additional studies including other clinical parameters after vitamin D supplementation in children with diabetes should be considered.

The association of vitamin D status with cardiometabolic risk factors, obesity and puberty in children

Low serum 25-hydroxyvitamin D3 (25(OH)D) levels have been associated with insulin resistance and cardiovascular diseases. The influences of gender, puberty and adiposity on vitamin D status and the relationship between 25(OH)D and cardiometabolic risk factors in obese and non-obese children were studied. A retrospective analysis was carried out on 168 Turkish children during late winter. Age, gender, puberty, body mass index (BMI), 25(OH)D levels and cardiometabolic risk factors including lipid profiles, high-sensitivity C-reactive protein and insulin resistance index calculated by homeostasis model assessment (HOMA-IR) were evaluated. The median age of the study population was 11 (4-16) years, and 102 children (60.7 %) were prepubertal. Overall, 98.2 % of patients had 25(OH)D levels lower than 20 ng/mL (median 10.0 (4.0-21.3) ng/mL). The 25(OH)D levels did not correlate with BMI. However, an inverse correlation was seen between serum 25(OH)D and HOMA-IR (rho = -0.656, p = 0.006) and insulin (rho = -0.715, p = 0.002) in pubertal obese subjects. Female gender and puberty were all negatively associated with 25(OH)D.

CONCLUSION

The association between vitamin D status and BMI is complex, and it does not seem to be altered by mild obesity. In addition, potential influence of puberty should be kept in mind while assessing the relationship between serum 25(OH)D and cardiometabolic risk factors.

Vitamin D status and predictors of hypovitaminosis D in Italian children and adolescents: a cross-sectional study

Hypovitaminosis D affects children and adolescents all around the world. Italian data on vitamin D status and risk factors for hypovitaminosis D during pediatric age are lacking. Six hundred fifty-two children and adolescents (range 2.0-21.0 years) living in the northwestern area of Tuscany were recruited at the Department of Pediatrics, University Hospital Pisa. None of them had received vitamin D supplementation in the previous 12 months. 25-hydroxyvitamin D (25-OH-D) and parathyroid hormone (PTH) levels were analyzed in all subjects. Severe vitamin D deficiency was defined as serum levels of 25-OH-D<25.0 nmol/L (10.0 ng/mL) and vitamin D deficiency a<50.0 nmol/L (20.0 ng/mL). Serum 25-OH-D levels of 50.0-74.9 nmol/L (20.0-29.9 ng/mL) indicated vitamin D insufficiency, whereas 25-OH-D levels ≥ 75.0 nmol/L (30.0 ng/mL) were considered sufficient. Hypovitaminosis D was defined as 25-OH-D levels<75.0 nmol/L (30.0 ng/mL). The median serum 25-OH-D level was 51.8 nmol/L, range 6.7-174.7 (20.7 ng/mL, range 2.7-70.0), with a prevalence of vitamin D deficiency, insufficiency, and sufficiency of 45.9, 33.6, and 20.5 %, respectively. The prevalence of severe vitamin D deficiency was 9.5 %. Adolescents had lower median 25-OH-D levels (49.8 nmol/L, range 8.1-174.7; 20.0 ng/mL, range 3.2-70.0) than children (55.6 nmol/L, range 6.8-154.6; 22.3 ng/mL, range 2.7-61.9, p=0.006). Non-white individuals (n=37) had median serum 25-OH-D levels in the range of deficiency (28.2 nmol/L, range 8.1-86.2; 11.3 ng/mL, range 3.2-34.5), with 36/37 having hypovitaminosis D. Logistic regression showed significant increased risk of hypovitaminosis D in the following: blood samples taken in winter (odds ratio (OR) 27.20), spring (OR 26.44), and fall (OR 8.27) compared to summer; overweight (OR 5.02) and obese (OR 5.36) subjects compared to individuals with normal BMI; low sun exposure (OR 8.64) compared to good exposure, and regular use of sunscreens (OR 7.06) compared to non-regular use. Gender and place of residence were not associated with vitamin D status. The 25-OH-D levels were inversely related to the PTH levels (r=-0.395, p<0.0001). Sixty-three out of the 652 (9.7 %) subjects showed secondary hyperparathyroidism.

CONCLUSION

Italian children and adolescents who were not receiving vitamin D supplementation had high prevalence of hypovitaminosis D. Careful identification of factors affecting vitamin D status is advisable to promptly start vitamin D supplementation in children and adolescents.

Subclinical Vitamin D Insufficiency in Korean School-aged Children

PURPOSE

Recently, vitamin D insufficiency has increased and has been correlated to growth and puberty in children. This study was conducted to find the prevalence of subclinical vitamin D insufficiency and its influence on school-aged children in Korea.

METHODS

The subjects of this study were 397 children aged 7 to 15 years who had been tested for 25-OH vitamin D3 among the outpatients of the Department of Pediatrics in Eulji General Hospital from March 2007 to February 2011. Data for age, sex, comorbidities, serum 25-OH vitamin D3, height, weight, body mass index (BMI), and sunlight exposure time were collected before and after 3 months of vitamin D administration, retrospectively.

RESULTS

Vitamin D insufficiency was present in 343 (86%) of the subjects. In the vitamin D insufficient group, chronological age was 8.96±1.72 years, mean height (z-score [z]) was 0.51±1.26, mean BMI (z) was 0.81±2.20, and bone age was 10.26±1.75 years. In the vitamin D sufficient group, chronological age was 9.61±1.77 years, mean height (z) was-0.66±0.98, mean BMI (z) was-0.01±1.16, and bone age was 9.44±2.12 years. A paired t-test showed that three months after vitamin D administration, the mean 25-OH vitamin D3 level in the insufficient group increased to 24.38 ±10.03 ng/mL and mean BMI (z) decreased to 0.67±1.06.

CONCLUSION

In Korean school-aged children, vitamin D insufficiency were relatively higher and may be closely related with higher BMI. Insufficient rise of the level of vitamin D after supplementation suggest the new supplementation guidelines, especially for Korean children.

Association between cord blood 25-hydroxyvitamin D concentrations and respiratory tract infections in the first 6 months of age in a Korean population: a birth cohort study (COCOA)

PURPOSE

Previous studies suggest that the concentration of 25-hydroxyvitamin D [25(OH)D] in cord blood may show an inverse association with respiratory tract infections (RTI) during childhood. The aim of the present study was to examine the influence of 25(OH)D concentrations in cord blood on infant RTI in a Korean birth cohort.

METHODS

The levels of 25(OH)D in cord blood obtained from 525 Korean newborns in the prospective COhort for Childhood Origin of Asthma and allergic diseases were examined. The primary outcome variable of interest was the prevalence of RTI at 6-month follow-up, as diagnosed by pediatricians and pediatric allergy and pulmonology specialists. RTI included acute nasopharyngitis, rhinosinusitis, otitis media, croup, tracheobronchitis, bronchiolitis, and pneumonia.

RESULTS

The median concentration of 25(OH)D in cord blood was 32.0 nmol/L (interquartile range, 21.4 to 53.2). One hundred and eighty neonates (34.3%) showed 25(OH)D concentrations less than 25.0 nmol/L, 292 (55.6%) showed 25(OH)D concentrations of 25.0-74.9 nmol/L, and 53 (10.1%) showed concentrations of ≥75.0 nmol/L. Adjusting for the season of birth, multivitamin intake during pregnancy, and exposure to passive smoking during pregnancy, 25(OH)D concentrations showed an inverse association with the risk of acquiring acute nasopharyngitis by 6 months of age (P for trend=0.0004).

CONCLUSION

The results show that 89.9% of healthy newborns in Korea are born with vitamin D insufficiency or deficiency (55.6% and 34.3%, respectively). Cord blood vitamin D insufficiency or deficiency in healthy neonates is associated with an increased risk of acute nasopharyngitis by 6 months of age. More time spent outdoors and more intensified vitamin D supplementation for pregnant women may be needed to prevent the onset of acute nasopharyngitis in infants.

Vitamin D status and childhood health

Vitamin D is an essential component of bone and mineral metabolism; its deficiency causes growth retardation and skeletal deformities in children and osteomalacia and osteoporosis in adults. Hypovitaminosis D (vitamin D insufficiency or deficiency) is observed not only in adults but also in infants, children, and adolescents. Previous studies suggest that sufficient serum vitamin D levels should be maintained in order to enhance normal calcification of the growth plate and bone mineralization. Moreover, emerging evidence supports an association between 25-hydroxyvitamin D (25[OH]D) levels and immune function, respiratory diseases, obesity, metabolic syndrome, insulin resistance, infection, allergy, cancers, and cardiovascular diseases in pediatric and adolescent populations. The risk factors for vitamin D insufficiency or deficiency in the pediatric population are season (winter), insufficient time spent outdoors, ethnicity (non-white), older age, more advanced stage of puberty, obesity, low milk consumption, low socioeconomic status, and female gender. It is recommended that all infants, children, and adolescents have a minimum daily intake of 400 IU (10 µg) of vitamin D. Since the vitamin D status of the newborn is highly related to maternal vitamin D levels, optimal vitamin D levels in the mother during pregnancy should be maintained. In conclusion, given the important role of vitamin D in childhood health, more time spent in outdoor activity (for sunlight exposure) and vitamin D supplementation may be necessary for optimal health in infants, children, and adolescents.

Defining a cutoff point for vitamin D deficiency based on insulin resistance in children

BACKGROUND

Vitamin D deficiency is a common worldwide problem. Low levels of serum 25-hydroxy vitamin D [25(OH)D], as a marker of vitamin D deficiency, have been linked to a wide field of health problems, including metabolic diseases such as insulin resistance, type 1 and type 2 DM. There is no universal definition for cutoff value of vitamin D deficiency and it seems that it varies in different populations.

OBJECTIVE

Most previous studies have used a start rise of PTH as a criteria to detect threshold of serum 25(OH)D, However, the aim of this study was to determine a cutoff point of serum 25(OH)D for vitamin D deficiency based on HOMA-IR.

MATERIALS AND METHODS

Two hundred and ninety seven healthy children (aged 7-11 years) were enrolled. Serum 25(OH)D and PTH were measured and HOMA-IR was calculated. The ROC curve was utilized to obtain a cutoff of vitamin D deficiency based on HOMA-IR.

RESULTS

25(OH)D concentrations were inversely correlated with HOMA-IR levels (Spearman's r=-0.14, p=0.016). Serum 25(OH)D cutoff point was 11.6ng/mL (29nmol/L) in relation with HOMA-IR >2.1. By using this cutoff value, the prevalence of vitamin D deficiency was 43.4% in this study population of healthy children.

CONCLUSION

We found that serum 25(OH)D levels are inversely associated with insulin resistance. These results suggest that in MetS patients it may benefit to determine cutoff value of 25(OH)D levels based on HOMA-IR.

The association between serum 25-hydroxyvitamin d concentration and consumption frequencies of vitamin d food sources in korean adolescents

The objectives of this study were to investigate the status of vitamin D in Korean adolescents and to determine the association between serum 25-hydroxyvitamin D (25(OH)D) concentration and consumption frequencies of vitamin D food sources by season (June to November and December to May). The subjects were 1,579 adolescents aged 12-18 years participating in the 2008-2009 Korean National Health and Nutrition Examination Survey (KNHANES). Consumption frequencies of vitamin D food sources were estimated by using a qualitative food frequency questionnaire (FFQ). Thirteen food items were selected as vitamin D food sources including beef, egg, mackerel, tuna, yellow corvine, pollack, anchovy, mushroom, milk, yoghurt, ice cream, all fish and dairy products from the FFQ based on previous research. The data was analyzed using proc survey procedures. The deficiency (5.25-12 ng/mL), inadequacy (12-20 ng/mL) and sufficiency (> 20 ng/mL) proportions of serum 25(OH)D from June to November and December to May were 9.9%, 51.4%, 38.7%, and 39.4%, 51.4%, 9.2%, respectively. Mean serum 25(OH)D concentration was positively related to the consumption frequencies of mackerel, anchovy, all fish and milk. These results suggest high proportion (> 61%) of Korean adolescents were vitamin D deficiency or inadequacy, and serum 25(OH)D was associated with the consumption of vitamin D food sources including fish and milk.

Puberty dysregulation and increased risk of disease in adult life: possible modes of action

Puberty is the developmental window when the final maturation of body systems is orchestrated by hormones; lifelong sex-related differences and capacity to interact with the environment are defined during this life stage. Increased incidence in a number of chronic, multifactorial diseases could be related to environmental exposures during puberty: however, insight on the susceptibility of the peripubertal period is still limited. The estrogen/androgen balance is a crucial axis in harmonizing the whole pubertal development, pointing out the significance of exposures to endocrine disruptors. Besides the reproductive system, endocrine-related perturbations may affect the maturation of skeleton, adipose tissues, brain, immune system, as well as cancer predisposition. Thus, risk assessment of environmental stressors should duly consider specific aspects of the pubertal window. Besides endocrine-related mechanisms, suggested research priorities include signaling molecules (e.g., kisspeptins, dopamine) as xenobiotic targets and disturbances of specific pubertal methylation processes potentially involved in neurobehavioral disorders and cancer risk in adulthood.

Vitamin D deficiency in infants aged 1 to 6 months

Purpose

The aim of this study was to recognize the state of vitamin D among healthy infants aged 1 to 6 months in South Korea, and also to identify the risk factors affecting the level of vitamin D.

Methods

A total of 117 infants were enrolled in this study for 12 months, from March 1, 2011 to February 29, 2012. Serum levels of 25-hydroxyvitamin D (25[OH]D), calcium, phosphorus, and alkaline phosphatase were measured and data including birth weight, body weight, sex, feeding pattern, delivery mode, siblings and maternal age and occupation were collected. Data was mainly analyzed with independent t-test model.

Results

We determined that the prevalence of vitamin D deficiency (serum 25[OH]D<20 ng/mL [50 mmol/L]) was 48.7% in the population investigated. Particularly in breastfed infants, the prevalence of vitamin D deficiency was strikingly high (90.4%). The mean serum level of 25(OH)D in breastfed infants was lower than that of formula fed infants (9.35 ng/mL vs. 28.79 ng/mL). Also female infants showed lower mean serum level of 25(OH)D than male. Mean serum values of calcium and phosphorus had positive correlation with vitamin D state (P<0.001).

Conclusion

Vitamin D deficiency was found to be very common in infants aged 1 to 6 months in South Korea, and breast feeding was the most critical risk factor of vitamin D deficiency. Therefore we suggest to start vitamin D supplementation in South Korea, as soon as possible, to all infants, including breastfed and female infants.