Purpose: Social distancing policies and school closures in South Korea induced by coronavirus disease 2019 have raised concerns about a lower chance of exposure to sunlight in children and adolescents. This study investigates changes in the vitamin D status of children and adolescents following the pandemic. Methods: This retrospective study includes healthy children aged 3–18 years who visited Hanyang University Hospitals in Seoul or Guri during pre-coronavirus disease 2019 (COVID-19) and post-COVID-19 pandemic periods. August 2017 to July 2019 is defined as the pre-COVID-19 pandemic period, while the period from July 2020 to July 2021 is defined as post-COVID-19 or "during the pandemic." Propensity scores were used to match the prepandemic and pandemic groups 1:1 based on age, sex, season of blood collection, and body mass index z-score to compare vitamin D status among subjects. Results: Among 786 eligible children, 506 were matched using propensity scores. There were no significant differences in mean serum 25-hydroxyvitamin D (25(OH) D) levels (20.1±6.5 ng/mL vs. 19.9±6.3 ng/mL, P>0.05) or vitamin D deficiency rates (53.0% vs. 54.9%, P>0.05) between the prepandemic and pandemic groups. Seasonal analysis revealed lower mean serum 25(OH)D levels during the pandemic in winter/spring seasons in comparison to these levels in subjects in prepandemic winter/spring seasons (19.1±3.8 ng/mL vs. 17.2±3.7 ng/mL, P=0.006). Conclusion During the COVID-19 pandemic, Korean children and adolescents showed similar serum 25(OH)D levels and vitamin D status to the prepandemic period, with a significant decrease in these measures observed in winter/spring seasons only. Prolonged confinement, such as in pandemic circumstances, underscores the need for vigilant monitoring of vitamin D status and supplementation, particularly in high-risk seasons.

Purpose: Social distancing policies and school closures in South Korea induced by coronavirus disease 2019 have raised concerns about a lower chance of exposure to sunlight in children and adolescents. This study investigates changes in the vitamin D status of children and adolescents following the pandemic. Methods: This retrospective study includes healthy children aged 3–18 years who visited Hanyang University Hospitals in Seoul or Guri during pre-coronavirus disease 2019 (COVID-19) and post-COVID-19 pandemic periods. August 2017 to July 2019 is defined as the pre-COVID-19 pandemic period, while the period from July 2020 to July 2021 is defined as post-COVID-19 or "during the pandemic." Propensity scores were used to match the prepandemic and pandemic groups 1:1 based on age, sex, season of blood collection, and body mass index z-score to compare vitamin D status among subjects. Results: Among 786 eligible children, 506 were matched using propensity scores. There were no significant differences in mean serum 25-hydroxyvitamin D (25(OH) D) levels (20.1±6.5 ng/mL vs. 19.9±6.3 ng/mL, P>0.05) or vitamin D deficiency rates (53.0% vs. 54.9%, P>0.05) between the prepandemic and pandemic groups. Seasonal analysis revealed lower mean serum 25(OH)D levels during the pandemic in winter/spring seasons in comparison to these levels in subjects in prepandemic winter/spring seasons (19.1±3.8 ng/mL vs. 17.2±3.7 ng/mL, P=0.006). Conclusion During the COVID-19 pandemic, Korean children and adolescents showed similar serum 25(OH)D levels and vitamin D status to the prepandemic period, with a significant decrease in these measures observed in winter/spring seasons only. Prolonged confinement, such as in pandemic circumstances, underscores the need for vigilant monitoring of vitamin D status and supplementation, particularly in high-risk seasons.

Purpose: Social distancing policies and school closures in South Korea induced by coronavirus disease 2019 have raised concerns about a lower chance of exposure to sunlight in children and adolescents. This study investigates changes in the vitamin D status of children and adolescents following the pandemic. Methods: This retrospective study includes healthy children aged 3–18 years who visited Hanyang University Hospitals in Seoul or Guri during pre-coronavirus disease 2019 (COVID-19) and post-COVID-19 pandemic periods. August 2017 to July 2019 is defined as the pre-COVID-19 pandemic period, while the period from July 2020 to July 2021 is defined as post-COVID-19 or "during the pandemic." Propensity scores were used to match the prepandemic and pandemic groups 1:1 based on age, sex, season of blood collection, and body mass index z-score to compare vitamin D status among subjects. Results: Among 786 eligible children, 506 were matched using propensity scores. There were no significant differences in mean serum 25-hydroxyvitamin D (25(OH) D) levels (20.1±6.5 ng/mL vs. 19.9±6.3 ng/mL, P>0.05) or vitamin D deficiency rates (53.0% vs. 54.9%, P>0.05) between the prepandemic and pandemic groups. Seasonal analysis revealed lower mean serum 25(OH)D levels during the pandemic in winter/spring seasons in comparison to these levels in subjects in prepandemic winter/spring seasons (19.1±3.8 ng/mL vs. 17.2±3.7 ng/mL, P=0.006). Conclusion During the COVID-19 pandemic, Korean children and adolescents showed similar serum 25(OH)D levels and vitamin D status to the prepandemic period, with a significant decrease in these measures observed in winter/spring seasons only. Prolonged confinement, such as in pandemic circumstances, underscores the need for vigilant monitoring of vitamin D status and supplementation, particularly in high-risk seasons.

Purpose: Social distancing policies and school closures in South Korea induced by coronavirus disease 2019 have raised concerns about a lower chance of exposure to sunlight in children and adolescents. This study investigates changes in the vitamin D status of children and adolescents following the pandemic. Methods: This retrospective study includes healthy children aged 3–18 years who visited Hanyang University Hospitals in Seoul or Guri during pre-coronavirus disease 2019 (COVID-19) and post-COVID-19 pandemic periods. August 2017 to July 2019 is defined as the pre-COVID-19 pandemic period, while the period from July 2020 to July 2021 is defined as post-COVID-19 or "during the pandemic." Propensity scores were used to match the prepandemic and pandemic groups 1:1 based on age, sex, season of blood collection, and body mass index z-score to compare vitamin D status among subjects. Results: Among 786 eligible children, 506 were matched using propensity scores. There were no significant differences in mean serum 25-hydroxyvitamin D (25(OH) D) levels (20.1±6.5 ng/mL vs. 19.9±6.3 ng/mL, P>0.05) or vitamin D deficiency rates (53.0% vs. 54.9%, P>0.05) between the prepandemic and pandemic groups. Seasonal analysis revealed lower mean serum 25(OH)D levels during the pandemic in winter/spring seasons in comparison to these levels in subjects in prepandemic winter/spring seasons (19.1±3.8 ng/mL vs. 17.2±3.7 ng/mL, P=0.006). Conclusion During the COVID-19 pandemic, Korean children and adolescents showed similar serum 25(OH)D levels and vitamin D status to the prepandemic period, with a significant decrease in these measures observed in winter/spring seasons only. Prolonged confinement, such as in pandemic circumstances, underscores the need for vigilant monitoring of vitamin D status and supplementation, particularly in high-risk seasons.

Purpose: Hypoparathyroidism (hypoPTH) is the most common complication following thyroidectomy. We investigated the frequency and risk factors of hypoPTH after total thyroidectomy (TT) in pediatric patients with thyroid cancer. Methods: This retrospective study included 98 patients younger than 20 years who were diagnosed with thyroid cancer after T T during 1990–2018 and followed for more than 2 years at Seoul National University Hospital. HypoPTH was defined as receiving active vitamin D (1-hydroxycholecalciferol or 1,25-dihydroxycholecalciferol) after surgery. Results: The study included 27 boys (27.6%) and 71 girls (72.4%). The mean age at diagnosis was 14.9±3.7 years. HypoPTH occurred in 43 patients (43.9%). Twenty-one patients (21.4%) discontinued active vitamin D less than 6 months after surgery, while 14 (14.3%) continued active vitamin D for more than 2 years. Tumor multifocality (odds ratio [OR], 3.7 vs. single tumor; P=0.013) and preoperative calcium level (OR, 0.2; P=0.028) were independent predictors of hypoPTH immediately after TT. In addition, age (OR, 0.8; P=0.011) and preoperative calcium level (OR, 0.04; P=0.014) significantly decreased the risk for persistent hypoPTH requiring active vitamin D for more than 2 years. Conclusion HypoPTH occurred in 43.9% of pediatric thyroid cancer patients after TT in this study. Among them, one-third of patients continued active vitamin D medication for more than 2 years, which was predicted by young age and low preoperative calcium level.

Purpose: Few data on the clinical course after levothyroxine (L-T4) discontinuation in pediatric patients with Hashimoto thyroiditis (HT) are available. We investigated outcomes and predictors for successful withdrawal from L-T4 among children with HT. Methods: Among 168 patients diagnosed with HT between January 2000 and March 2021 at Seoul National University Children’s Hospital and in whom L-T4 therapy was initiated during childhood, we attempted to discontinue this therapy in 47, 3 boys and 44 girls. L-T4 was restarted when patients developed overt or subclinical hypothyroidism (thyroid-stimulating hormone [TSH] levels≥10 mIU/L) after L-T4 discontinuation. Results: Median age at discontinuation was 15.4 years (12.7–18.4 years) with a median duration of L-T4 therapy of 47 months (20.3–80.3 months). During the median 30 months of follow-up (10.6–61.0 months) after L-T4 discontinuation, 33 (70.2%) developed thyroid dysfunction. Among these patients, 17 were eventually restarted on L-T4. TSH levels over 50 mIU/L at L-T4 initiation (hazard ratio, HR 3.5, P=0.002), age under 12 years at L-T4 discontinuation (HR 11.1, P=0.0001), and TSH levels higher than the upper 50% of normal (above 2.25 mIU/L in the present study) at L-T4 discontinuation (HR 2.7, P=0.014) were significantly predictive for overt hypothyroidism or subclinical hypothyroidism after L-T4 discontinuation. In addition, age under 12 years at L-T4 discontinuation was only predictive factor for restarting L-T4 medication (HR 4.3, P=0.012). Conclusion L-T4 discontinuation in pediatric patients with HT resulted in thyroid dysfunction in 70.2% of cases; 36.2% of patients who attempted discontinuation required resumption of L-T4. Older age and lower TSH levels at L-T4 discontinuation were advantageous for successful withdrawal.

Purpose: Few data on the clinical course after levothyroxine (L-T4) discontinuation in pediatric patients with Hashimoto thyroiditis (HT) are available. We investigated outcomes and predictors for successful withdrawal from L-T4 among children with HT. Methods: Among 168 patients diagnosed with HT between January 2000 and March 2021 at Seoul National University Children’s Hospital and in whom L-T4 therapy was initiated during childhood, we attempted to discontinue this therapy in 47, 3 boys and 44 girls. L-T4 was restarted when patients developed overt or subclinical hypothyroidism (thyroid-stimulating hormone [TSH] levels≥10 mIU/L) after L-T4 discontinuation. Results: Median age at discontinuation was 15.4 years (12.7–18.4 years) with a median duration of L-T4 therapy of 47 months (20.3–80.3 months). During the median 30 months of follow-up (10.6–61.0 months) after L-T4 discontinuation, 33 (70.2%) developed thyroid dysfunction. Among these patients, 17 were eventually restarted on L-T4. TSH levels over 50 mIU/L at L-T4 initiation (hazard ratio, HR 3.5, P=0.002), age under 12 years at L-T4 discontinuation (HR 11.1, P=0.0001), and TSH levels higher than the upper 50% of normal (above 2.25 mIU/L in the present study) at L-T4 discontinuation (HR 2.7, P=0.014) were significantly predictive for overt hypothyroidism or subclinical hypothyroidism after L-T4 discontinuation. In addition, age under 12 years at L-T4 discontinuation was only predictive factor for restarting L-T4 medication (HR 4.3, P=0.012). Conclusion L-T4 discontinuation in pediatric patients with HT resulted in thyroid dysfunction in 70.2% of cases; 36.2% of patients who attempted discontinuation required resumption of L-T4. Older age and lower TSH levels at L-T4 discontinuation were advantageous for successful withdrawal.

Purpose: Few data on the clinical course after levothyroxine (L-T4) discontinuation in pediatric patients with Hashimoto thyroiditis (HT) are available. We investigated outcomes and predictors for successful withdrawal from L-T4 among children with HT. Methods: Among 168 patients diagnosed with HT between January 2000 and March 2021 at Seoul National University Children’s Hospital and in whom L-T4 therapy was initiated during childhood, we attempted to discontinue this therapy in 47, 3 boys and 44 girls. L-T4 was restarted when patients developed overt or subclinical hypothyroidism (thyroid-stimulating hormone [TSH] levels≥10 mIU/L) after L-T4 discontinuation. Results: Median age at discontinuation was 15.4 years (12.7–18.4 years) with a median duration of L-T4 therapy of 47 months (20.3–80.3 months). During the median 30 months of follow-up (10.6–61.0 months) after L-T4 discontinuation, 33 (70.2%) developed thyroid dysfunction. Among these patients, 17 were eventually restarted on L-T4. TSH levels over 50 mIU/L at L-T4 initiation (hazard ratio, HR 3.5, P=0.002), age under 12 years at L-T4 discontinuation (HR 11.1, P=0.0001), and TSH levels higher than the upper 50% of normal (above 2.25 mIU/L in the present study) at L-T4 discontinuation (HR 2.7, P=0.014) were significantly predictive for overt hypothyroidism or subclinical hypothyroidism after L-T4 discontinuation. In addition, age under 12 years at L-T4 discontinuation was only predictive factor for restarting L-T4 medication (HR 4.3, P=0.012). Conclusion L-T4 discontinuation in pediatric patients with HT resulted in thyroid dysfunction in 70.2% of cases; 36.2% of patients who attempted discontinuation required resumption of L-T4. Older age and lower TSH levels at L-T4 discontinuation were advantageous for successful withdrawal.

Purpose: Few data on the clinical course after levothyroxine (L-T4) discontinuation in pediatric patients with Hashimoto thyroiditis (HT) are available. We investigated outcomes and predictors for successful withdrawal from L-T4 among children with HT. Methods: Among 168 patients diagnosed with HT between January 2000 and March 2021 at Seoul National University Children’s Hospital and in whom L-T4 therapy was initiated during childhood, we attempted to discontinue this therapy in 47, 3 boys and 44 girls. L-T4 was restarted when patients developed overt or subclinical hypothyroidism (thyroid-stimulating hormone [TSH] levels≥10 mIU/L) after L-T4 discontinuation. Results: Median age at discontinuation was 15.4 years (12.7–18.4 years) with a median duration of L-T4 therapy of 47 months (20.3–80.3 months). During the median 30 months of follow-up (10.6–61.0 months) after L-T4 discontinuation, 33 (70.2%) developed thyroid dysfunction. Among these patients, 17 were eventually restarted on L-T4. TSH levels over 50 mIU/L at L-T4 initiation (hazard ratio, HR 3.5, P=0.002), age under 12 years at L-T4 discontinuation (HR 11.1, P=0.0001), and TSH levels higher than the upper 50% of normal (above 2.25 mIU/L in the present study) at L-T4 discontinuation (HR 2.7, P=0.014) were significantly predictive for overt hypothyroidism or subclinical hypothyroidism after L-T4 discontinuation. In addition, age under 12 years at L-T4 discontinuation was only predictive factor for restarting L-T4 medication (HR 4.3, P=0.012). Conclusion L-T4 discontinuation in pediatric patients with HT resulted in thyroid dysfunction in 70.2% of cases; 36.2% of patients who attempted discontinuation required resumption of L-T4. Older age and lower TSH levels at L-T4 discontinuation were advantageous for successful withdrawal.

BACKGROUND: Primary hyperoxaluria (PH), a rare inborn error of glyoxylate meta bolism causing overproduction of oxalate, is classified into three genetic subgroups: type 1–3 (PH1–PH3) caused by AGXT, GRHPR , and HOGA1 gene mutations, respectively. We performed a retrospective case series study of Korean pediatric patients with PH.METHODS: In total, 11 unrelated pediatric patients were recruited and their phenotypes and genotypes were analyzed by a retrospective review of their medical records.RESULTS: Mutational analyses revealed biallelic AGXT mutations (PH1) in nine patients and a single heterozygous GRHPR and HOGA1 mutation in one patient each. The c.33dupC was the most common AGXT mutation with an allelic frequency of 44%. The median age of onset was 3 months (range, 2 months-3 years), and eight patients with PH1 presented with end stage renal disease (ESRD). Patients with two truncating mutations showed an earlier age of onset and more frequent retinal involvement than patients with one truncating mutation. Among eight PH1 patients presenting with ESRD, five patients were treated with intensive dialysis followed by liver transplantation (n=5) with/without subsequent kidney transplantation (n=3).CONCLUSION: Most patients presented with severe infantile forms of PH. Patients with two truncating mutations displayed more severe phenotypes than those of patients with one truncating mutation. Sequential liver and kidney transplantation was adopted for PH1 patients presenting with ESRD. A larger nation-wide multicenter study is needed to confirm the genotype-phenotype correlations and outcomes of organ transplantation.
Age of Onset ; Dialysis ; Genetic Association Studies ; Genotype ; Humans ; Hydrogen-Ion Concentration ; Hyperoxaluria, Primary ; Kidney Failure, Chronic ; Kidney Transplantation ; Liver ; Liver Transplantation ; Medical Records ; Organ Transplantation ; Phenotype ; Retinaldehyde ; Retrospective Studies ; Transplants