Hyo-Kyoung Nam

Vitamin D receptor gene polymorphisms and type 1 diabetes mellitus in a Korean population

Vitamin D receptor (VDR) has been suggested to play a role in the pathogenesis of type 1 diabetes mellitus (T1DM). There has been no case–control study examining the association between VDR polymorphisms and T1DM among Korean subjects with a low incidence of T1DM.

Serum FGF21 Levels in Obese Korean Children and Adolescents

Background Serum fibroblast growth factor 21 (FGF21) has been suggested to be a possible biomarker for early detection of metabolic syndrome and type 2 diabetes in adults. However, few studies have investigated the correlation between FGF21 levels and metabolic parameters in children. This study sought to evaluate the relationship between FGF21 and metabolic parameters in obese Korean children and adolescents. Methods Fasting serum FGF21 and adiponectin levels as well as fasting insulin, glucose, transaminases, and lipid profiles were measured by enzyme-linked immunosorbent assays in 45 lean and 70 obese children aged 7–14 years. Independent t-test and multivariate correlation analysis were used to evaluate the relationship between FGF21 and metabolic parameters. Results Serum FGF21 was significantly higher in obese children than in lean children. Serum FGF21 levels were positively correlated with insulin resistance index homeostasis model assessment (HOMA-IR) (r=0.355, P=0.004) and triglycerides (r=0.423, P<0.001) and were negatively correlated with high-density lipoprotein (HDL) cholesterol (r=−0.412, P<0.001). After adjustment for body mass index, triglycerides, HDL cholesterol and adiponectin, FGF21 levels showed a significant correlation with only HOMA-IR on multivariate linear regression analysis. Conclusion Serum FGF21 levels were higher in obese children and significantly correlated with HOMA-IR. Therefore, FGF21 could be a biomarker for obesity-induced insulin resistance in children and adolescents as indicated in adults.

Low levels of 25-hydroxyvitamin D in children and adolescents with type 1 diabetes mellitus: a single center experience

Purpose Low vitamin D level is common in adults with diabetes mellitus (DM). We assessed vitamin D level and its associated factors in Korean youth with type 1 DM. Methods Type 1 DM cases (n=85) and healthy controls (n=518) aged <20 years were included and grouped into 3 categories according to vitamin D level: deficiency (<20 ng/mL), insufficiency (20–30 ng/mL), or sufficiency (≥30 ng/mL). Results The mean serum vitamin D level was significantly lower (21.6±8.5 ng/mL vs. 28.0±12.0 ng/mL, P<0.001) and vitamin D deficiency prevalence was significantly higher (48% vs. 26%, P<0.001) in type 1 DM cases than in healthy controls. Logistic regression analysis revealed that type 1 DM cases were more likely to have vitamin D deficiency (P=0.004), independent of sex, age, and body mass index. Type 1 DM cases with vitamin D deficiency/insufficiency were mainly diagnosed in winter (November to April) (P=0.005), and the duration of diabetes was longer than in those with vitamin D sufficiency (P=0.046). However, season of diagnosis, duration of diabetes, prescribed daily insulin dose, and glycosylated hemoglobin and C-peptide levels were not associated with 25-hydroxyvitamin D (25(OH)D) level in type 1 DM cases after adjustment for other factors. Conclusions We recommend assessment of serum 25(OH)D level in type 1 DM cases and to treatment if findings indicate insufficiency. Further studies investigating the mechanisms underlying vitamin D deficiency in youth with type 1 DM are needed.

Small for gestational age and obesity: epidemiology and general risks

Children born small for gestational age (SGA) have several life-long consequences. Previous epidemiological studies investigated from childhood to adulthood reported that a number of chronic diseases originate in the prenatal period. With the emerging era of obesity epidemic, more concerns are related to being obese than being short-statured in SGA children. The exact mechanisms are uncertain; however, growth hormone-insulin-like growth factor axis disturbance by fetal programming and accelerated postnatal weight gain contributed to central adiposity in SGA children. In this review, we summarized the definitions and prevalence of SGA, epidemiology, and general risks of obesity in SGA children. Early interventions, before and after birth, are needed for healthy catch-up growth to prevent later obesity and related complications.

Thyroid Function in Korean Adolescents with Obesity: Results from the Korea National Health and Nutrition Examination Survey VI (2013–2015)

Purpose In this study, we investigated the status of thyroid function and its association with metabolic risk factors in Korean adolescents. Methods Among 2679 subjects aged 10–19 years who participated in the Korea National Health and Nutrition Examination Survey VI (2013–2015), 1067 adolescents (M = 559, F = 508) with available data on free T4 (FT4) and thyroid-stimulating hormone (TSH) were included. Study participants were classified into normal weight [body mass index (BMI) below 85th percentile, 80.7%], overweight (85th ≤ BMI< 95th percentile, 8.7%), and obesity (BMI ≥ 95th percentile, 10.6%). Results With increasing levels of BMI category, the means of TSH increased (2.73 ± 0.06, 2.77 ± 0.02, and 3.24 ± 0.22 mIU/L, P = 0.031) and FT4 decreased (1.30 ± 0.01, 1.26 ± 0.02, and 1.25 ± 0.02 ng/mL, P = 0.001). Positive linear associations were observed between TSH and BMI z-score (P = 0.031), waist circumference (P = 0.013), waist-height ratio (P = 0.002), systolic blood pressure (P = 0.001), total cholesterol (P = 0.008), and triglyceride (P = 0.002) after adjusting for age and sex. With per-unit increase in TSH, the odds ratios of having abdominal obesity (OR = 1.18, 95% CI, 1.01–1.38) and triglyceride ≥ 150 mg/dL (OR = 1.18, 95% CI, 1.04–1.34) were significantly increased after adjusting for age, sex, and BMI. Conclusions In adolescents with obesity, TSH was higher and FT4 was lower than in adolescents with normal weight. Hyperthyrotropinemia was associated with abnormal metabolic risk factors including abdominal obesity and elevated triglyceride.

Treatment outcomes of gonadotropin-releasing hormone agonist in obese girls with central precocious puberty

Purpose This study investigated the influence of obesity on the clinical course and effect of gonadotropin-releasing hormone analog (GnRHa) treatment in girls with central precocious puberty (CPP). Methods Medical records of 182 girls with CPP treated with GnRHa were reviewed. They were divided into 2 groups: normal weight (n=108) and overweight/obesity (n=74). Chronological age (CA), bone age (BA), difference between BA and CA (BA–CA), standard deviation score (SDS) of height, body mass index (BMI), predicted adult height (PAH), and laboratory findings were compared at baseline, after 1 year, and at the end of GnRHa treatment in both groups. Results Mean BMI SDS at baseline was 0.08±0.60 in the normal weight group and 1.55±0.36 in the overweight/obesity group. Initial CA, BA, midparental height, and PAH were similar between the 2 groups. BA–CA after treatment was significantly decreased compared to baseline in both groups (P<0.001). Between the 2 groups, a decrease in BA–CA during treatment showed no significant difference. PAH at the end of treatment was significantly increased compared to baseline in both groups (P<0.001). PAH at the end of treatment in the overweight/obesity group (159.88±3.41 cm) was similar to that of the normal weight group (159.19±3.25 cm). Comparing the 2 groups according to change in BMI after treatment, there were no differences in ΔPAH, ΔBA–CA, and Δheight SDS for BA. Conclusions GnRHa treatment in obese girls with CPP improved the height outcome and had similar results in normal weight CPP girls. Obesity might not affect the efficacy of GnRHa in girls with CPP.

A case of CHARGE syndrome featuring immunodeficiency and hypocalcemia

using criteria put forth by Verloes [1], patients with CHARGE syndrome show varying phenotypes that considerably overlap those of other syndromes such as Kallmann syndrome, VACTERL association (vertebral anomalies, anal atresia, cardiac defects, tracheoesophageal fistula, esophageal atresia, renal anomalies, and limb defects), and 22q11.2 deletion syndrome [3,6,7]. Chromosome 22q11.2 deletion is observed in majority of patients with DiGeorge syndrome [8]. Patients with DiGeorge syndrome show typical features such as conotruncal cardiac anomaly, abnormal face, thymic hypoplasia, cleft palate, and hypocalcemia, which have been given an acronym CATCH22 [9]. DiGeorge syndrome is the cause of congenital A case of CHARGE syndrome featuring immunodeficiency and hypocalcemia

Vitamin D gene polymorphisms are associated with type 1 diabetes mellitus in Korean youth

Vitamin D deficiency is reported in patients with type 1 diabetes mellitus (T1DM). Allelic variations in the gene associated with vitamin D metabolism were reported to play a role in glucose metabolism. CYP2R1 and CYP27B1 gene polymorphisms were investigated as a candidate gene for T1DM in Korean youth. We measured serum level of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D in 217 subjects and defined vitamin D deficiency as 25-hydroxyvitamin D level below 20 ng/ml. Five single nucleotide polymorphisms (SNPs) in the CYP2R1 gene and three SNPs in the CYP27B1 gene were examined in 92 patients with T1DM and 125 controls. The frequency of A/G alleles of the rs12794714 was 35.9%/64.1% and 46.0%/54.0% in T1DM youth and controls, respectively (p=0.034). The G/A alleles of the rs10766196 was 37.0%/63.0% and 46.0%/54.0% in T1DM youth and controls, respectively (p=0.059). We observed that the GG homozygous genotype of rs12794714 and AA homozygous genotype of rs10766196 were more prevalent in T1DM youth than in controls (42.4% vs. 29.6%, p=0.051 and 41.3% vs. 29.6%, p=0.073, respectively). The prevalence of vitamin D deficiency was considerably higher in T1DM youth with ‘G’ allele of rs12794714 and ‘A’ allele of rs12794714. Polymorphisms in CYP2R1 gene are associated with susceptibility to T1DM in Korean youth. The pathophysiological mechanisms remain unexplained, but they could be related to an etiological role for vitamin D deficiency in T1DM.