The association between phthalate exposure and pubertal development

Antiandrogenic effect of phthalates have been reported; however, results regarding the effect of phthalate exposure in pubertal children have been inconsistent. We aimed to investigate the relationship between phthalate exposure and pubertal development, especially whether high molecular weight phthalates (HMWP) and low molecular weight phthalates (LMWP) are differently associated in boys and girls. Urinary phthalate metabolites (4 HMWPs and 3 LMWPs) in Korean children (236 boys and 202 girls, aged 10 to 12 years) were measured. The association between phthalate levels and pubertal development (pubertal stages self-reported by parents and sex steroid levels) was analyzed by generalized linear regression after adjusting for age, body mass index z score, and premature birth and/or low birth weight. Both the highest quartile of HMWP (Q4 vs Q1, adjusted odds ratio [OR], 0.238; 95% confidence interval [CI], 0.090-0.627; p = 0.004) and LMWP (Q4 vs Q1, adjusted OR, 0.373; 95% CI, 0.151-0.918; p = 0.032) were inversely associated with pubertal stages in boys, whereas the highest quartile of LMWP (Q4 vs Q1, adjusted OR, 2.431; 95% CI, 1.024-5.768; p = 0.044) was significantly related to advanced pubertal stages in girls. Testosterone levels in boys were significantly lower at the highest quartile of HMWP (adjusted β = - 0.251; 95% CI, - 0.476 to - 0.027; p = 0.028). However, in girls, we could not find any significant relationship between HMWP or LMWP and estradiol levels.

CONCLUSIONS

Our results suggest that phthalate exposure, especially exposure to the HMWP, may have inverse association with male pubertal development. Further investigation is required to verify the relationship of phthalate exposure and pubertal development in girls.

WHAT IS KNOWN

• Exposure to phthalates may have antiandrogenic effects. • Studies on the association between phthalates and pubertal development have yielded inconsistent results.

WHAT IS NEW

• Phthalate levels were inversely associated with self-reported pubertal stages in boys. • Exposure to phthalates might have a negative influence on male pubertal development.

Familial male-limited precocious puberty due to an activating mutation of the LHCGR: a case report and literature review

Familial male-limited precocious puberty (FMPP) is a rare form of gonadotropin-independent precocious puberty that is caused by an activating mutation of the LHCGR gene. Herein, we report a case of FMPP with a mutation of the LHCGR gene in a Korean boy with familial history of precocious puberty through 3 generations. A 16-month-old boy presented with signs of precocious puberty, including pubic hair, acne, and increased growth velocity. The patient's grandfather and father had a history of precocious puberty and profound short stature. On physical examination, the patient had prepubertal testes with pubic hair development appropriate for Tanner stage II. The stretched penile length was 7 cm (>2 standard deviation score), and observed bone age was that of a 4-year-old boy. Laboratory findings showed high serum testosterone (5.74 ng/mL [appropriate for Tanner IV-V]; normal range, <0.05 ng/mL) with suppressed luteinizing hormone (<0.07 mIU/mL) and normal serum level of follicular stimulating hormone (0.56 mIU/mL; normal range, 0.38-1.11 mIU/mL). Genetic testing revealed a pathogenic variant of LHCGR (c.1730 C>T (p.Thr577Ileu)), confirming FMPP. Bicalutamide and anastrozole were administered, and pubertal progression was sufficiently suppressed without any specific side effects. To our knowledge, this is the first case of genetically confirmed FMPP in Korea.

Assessment of Neurodevelopment and Growth in Congenital Hypothyroidism: Serial 6-Year Follow-up Study of 408 Patients

CONTEXT

The link between congenital hypothyroidism (CH) and neurodevelopment is suggested, yet studies applying quantifiable measures are lacking. Moreover, socioeconomic disparities and subtle variation in timing of approach make the relationship difficult to detect.

OBJECTIVE

To evaluate associations between CH and abnormalities in neurodevelopment and growth and determine the critical period for intervention.

METHODS

We utilized a nationwide database to conduct a longitudinal analysis of 919 707 children. Exposure to CH was identified using claims-based data. The primary outcome of interest was suspected neurodevelopmental disorder, as measured using the Korean Ages & Stages Questionnaires (K-ASQ) administered annually from 9 to 72 months of age. Secondary outcomes were height and BMI z-scores. After randomly matching cases and controls at a 1:10 ratio, we employed inverse probability of treatment weighting and generalized estimating equation models for our analyses. We conducted subgroup analysis based on the age of treatment initiation.

RESULTS

The prevalence of CH in our population was 0.05% (n = 408). Relative to the control group, the CH group had higher risk of suspected neurodevelopmental disorders (propensity score-weighted odds ratio: 4.52; 95% CI: 2.91, 7.02), and significantly increased risk in each of the 5 K-ASQ domains. No time interactions were noted at any rounds for the outcomes according to when the neurodevelopmental assessment was conducted (all P for interaction >.05). The CH group also had higher risk for low height-for-age z-score, but not for elevated BMI-for-age z-score. In subgroup analysis, delayed medication for CH correlated with worse neurodevelopmental outcomes.

CONCLUSION

The CH group had worse neurodevelopmental outcomes and reduced height-for-age z-score. Outcomes were worse when onset of treatment was increasingly delayed.

2022 Clinical practice guidelines for central precocious puberty of Korean children and adolescents

The Committee of Central Precocious Puberty of Korean Pediatrics and Adolescents of the Korean Society of Pediatric Endocrinology has newly developed evidence-based 2022 clinical practice guidelines for central precocious puberty in Korean children and adolescents. These guidelines provide the grade of recommendations, which includes both the strength of recommendations and the level of evidence. In the absence of sufficient evidence, recommendations are based on expert opinion. These guidelines have been revised and supplement the previous guidelines "Clinical Guidelines for Precocious Puberty 2011," and are drawn from a comprehensive review of the latest domestic and international research and the grade of recommendation appropriate to the domestic situation. This review summarizes the newly revised guidelines into 8 key questions and 27 recommendations and consists of 4 sections: screening, diagnosis, treatment, and long-term outcome of central precocious puberty.

Slower progression of central puberty in overweight girls presenting with precocious breast development

PURPOSE

Overweight (OW)/obese girls tend to have an earlier pubertal onset than girls with normal weight. However, only a few studies have reported the progression of puberty in these girls. This study aimed to identify risk factors for rapid pubertal progression in OW/obese girls presenting with precocious breast development.

METHODS

This retrospective cohort study reviewed the medical records of 110 OW (body mass index [BMI] ≥85th percentile for age and sex) and 213 nonoverweight (NW, BMI <85th percentile for age and sex) girls who presented with breast budding before 8 years of age. OW girls were divided into 2 subgroups: girls with central puberty progression before 9 years of age (OW-RP) and those without (OW-SP).

RESULTS

Progression to central puberty before the age of 9 was more common in NW girls than in OW girls (83.8 % vs. 65.2 % in NW vs. OW group, p<0.001), and progression-free survival for 1, 2, and 3 years was higher in the OW group (p<0.001). In a subgroup analysis of OW girls, the OW-RP subgroup had more advanced bone age (BA) at the first visit (p=0.047) and higher initial luteinizing hormone (LH, p=0.010) levels than the OW-SP subgroup. Being NW (p=0.001) and having more advanced BA (p=0.023) at the initial workup were the risk factors for pubertal progression before age 9.

CONCLUSION

Pubertal progression seems to be slower in OW girls than in NW girls presenting with precocious breast development. However, it can progress rapidly in OW girls with particularly pronounced BA advancement and high LH levels at the initial workup.

ODP391 Neurodevelopmental and Growth Outcome of Congenital Hypothyroidism: A National Investigation of Birth Cohort Study

Objectives

The purpose was to investigate the neurodevelopmental and growth status of Congenital hypothyroidism (CH) patients compared to normal children using population-based cohort study.

Methods

The National Investigation of Birth Cohort in Korea study 2008 (NICKs-2008) consisted of the Korean National Health Insurance System (NHIS) and the National Health Screening Program for Infants and Children (NHSPIC) databases comprising children born in 2008 (n=469,248) and 2009 (n=448,459). The CH patients were enrolled with International Classifications of Diseases-10 codes and drug classification (levothyroxine over 5 years) codes. We investigated their developmental outcomes using the Korean-Ages and Stages Questionnaire (K-ASQ), and serial changes of BMI (BMI-z) and height (height -z) were compared in children with and without CH. Risk ratios were obtained using a modified Poisson regression and weighted risk differences using binomial regression.

Results

Of the 919,707 newborns, 433 children (boys, 47.7%) were diagnosed as CH (1: 2,124 of prevalence). The risk ratio (RR) for delayed development based on the results from the 5th–7th K-ASQ was higher for the total developmental area (adjusted RR = 2.77, 95% CI: 1.507-5.118) in CH patients. There was significant difference between patients with CH and controls in the assessment of gross motor, fine motor and problem-solving areas (P &lt; . 0001). At 66-71 months of age, short stature (height-z &lt; -1.63) were increased in the CH group compared with normal children (adjusted RR 2.27, 95% CI 1.328-3.865). Obese children (BMI-z &gt; 1.63) were not increased.

Conclusions

The adequate large cohort data showed that prevalence of developmental delay and short stature were higher in CH patients than normal. Careful and early intervention is needed.

Presentation: No date and time listed

Changes in Sleep Patterns in Korean Early Adolescents during Sexual Maturation

Purpose: Teenagers’ sleep patterns show physiological delays influenced by sexual maturation and other external time-related factors. However, Korean adolescents show differences in the onset of pubertal development and have shorter sleep durations than other adolescents worldwide. Therefore, we assessed sleep patterns and sexual maturation in Korean early adolescents to evaluate changes in sleep patterns in relation to sexual maturation in early adolescents with sleep deprivation.Methods: From March to August 2017, we surveyed children aged 10 to 12 years in Seongnam (Seongnam Atopy Project). We evaluated items related to sleep and sexual maturation, assessed sleep duration and sleepiness scale scores, and analyzed the relationships of sleep parameters with sex, height, weight, and sexual maturation rating (SMR).Results: In total, 620 children were included. Sleep duration was 8.63±0.81 hours in boys and 8.40±0.98 hours in girls. Sleep started from PM 11:00±AM 0:47 in boys and PM 11:13±AM 1:06 in girls, and ended at AM 7:38±AM 0:27 in boys and AM 7:34±AM 0:27 in girls. After adjusting for sex and standardized body mass index, bedtime was delayed as the SMR increased (mean delay for each rating increase, 0.251 hours; P=0.001; 95% confidence interval [CI], 0.105 to 0.397). SMR did not influence the wake-up time, although sleep duration decreased as the SMR increased (mean decrease for each rating increase, 0.258 hours; P=0.001; 95% CI, –0.403 to –0.114). The sleepiness scale scores showed no relationship with SMR. Conclusion: Sleep patterns, especially sleep duration and bedtimes, show changes with sexual maturation in adolescents, who are vulnerable to sleep deprivation.

Sex differences in body composition affect total airway resistance during puberty

BACKGROUND

During puberty, changes in body composition due to sex hormones are associated with lung mechanics. However, little is known about the mediation effect of sex differences in body composition during puberty with total airway resistance.

METHODS

We prospectively recruited 620 children (10-12 years old) from the general population and conducted a cross-sectional study. This study assessed pubertal status according to the five Tanner stages using a questionnaire, line drawings, and each subject's blood sex hormone profile. Both the impulse oscillation system for total lung mechanics and multifrequency bioelectrical impedance for body composition analyses were conducted. The effects of puberty on body composition and subsequent total lung resistance were evaluated using mediation analysis.

RESULTS

Among the 503 children enrolled, there were 261 males (51.9%) and 242 females (48.1%). In males, higher testosterone levels corresponded with reduced total lung resistance (β = -0.13, 95% CI = -0.21 to -0.05, p < 0.001), and the proportion of the mediating effect through the muscle-fat ratio was 19% (95% CI = 4 to 59, p = 0.02). In contrast, in females, pubertal status reduced total lung resistance (β = -0.27, 95% CI = -0.58 to -0.05, p = 0.04), however, the proportion of the mediating effect through the body mass index was -51% (95% CI = -244 to -4%, p = 0.04).

CONCLUSION

The muscle-fat ratio in adolescent males had a synergistic effect with testosterone on improving total airway resistance, whereas improvements in lung resistance by pubertal status were partially masked by body mass index in adolescent females. In conclusion, body composition changes during puberty between males and females have differing effects on total airway resistance.

Hypertriglyceridemia with acute pancreatitis in a 14-year-old girl with diabetic ketoacidosis

Diabetic ketoacidosis (DKA) is a medically fatal condition in poorly controlled hyperglycemia or newly diagnosed diabetes mellitus. Severe hypertriglyceridemia (HTG) is an uncommon complication of DKA and can be associated with acute pancreatitis (AP). We present the clinical manifestations, laboratory findings, and management of AP associated with HTG in a 14-year-old girl with DKA. The patient, with a 7-year history of type 2 diabetes presented with epigastric pain, 1 month after stopping insulin injection. DKA, severe HTG, and AP were diagnosed based on the laboratory and imaging tests. She recovered from DKA after conventional treatment for DKA, and her triglyceride (TG) level was reduced from 10,867 mg/dL to the normal range after 7 days of admission without antilipid medication. Given that her C-peptide level was not too low and considering her negative diabetes-related antibodies and high TG level, targeted gene panel sequencing was performed on the genes associated with diabetes and HTG. We identified a heterozygous mutation, c.4607C>T (p. Ala1537Val), in ABCC8 related to maturityonset diabetes of the young (MODY) 12. To our knowledge, this is the first reported case of HTG-induced AP with DKA in a patient with MODY. In addition, we reviewed the literature for pediatric cases of HTG with DKA. In patients with DKA, timely awareness of severe HTG related to insulin deficiency is crucial for improving the consequences of AP. We recommend considering AP in all DKA patients presenting with severe HTG to ensure early and proper management.

Statin Use and COVID-19 Infectivity and Severity in South Korea: Two Population-Based Nationwide Cohort Studies

Background

Basic studies suggest that statins as add-on therapy may benefit patients with COVID-19; however, real-world evidence of such a beneficial association is lacking.

Objective

We investigated differences in SARS-CoV-2 test positivity and clinical outcomes of COVID-19 (composite endpoint: admission to intensive care unit, invasive ventilation, or death) between statin users and nonusers.

Methods

Two independent population-based cohorts were analyzed, and we investigated the differences in SARS-CoV-2 test positivity and severe clinical outcomes of COVID-19, such as admission to the intensive care unit, invasive ventilation, or death, between statin users and nonusers. One group comprised an unmatched cohort of 214,207 patients who underwent SARS-CoV-2 testing from the Global Research Collaboration Project (GRCP)-COVID cohort, and the other group comprised an unmatched cohort of 74,866 patients who underwent SARS-CoV-2 testing from the National Health Insurance Service (NHIS)-COVID cohort.

Results

The GRCP-COVID cohort with propensity score matching had 29,701 statin users and 29,701 matched nonusers. The SARS-CoV-2 test positivity rate was not associated with statin use (statin users, 2.82% [837/29,701]; nonusers, 2.65% [787/29,701]; adjusted relative risk [aRR] 0.97; 95% CI 0.88-1.07). Among patients with confirmed COVID-19 in the GRCP-COVID cohort, 804 were statin users and 1573 were matched nonusers. Statin users were associated with a decreased likelihood of severe clinical outcomes (statin users, 3.98% [32/804]; nonusers, 5.40% [85/1573]; aRR 0.62; 95% CI 0.41-0.91) and length of hospital stay (statin users, 23.8 days; nonusers, 26.3 days; adjusted mean difference –2.87; 95% CI –5.68 to –0.93) than nonusers. The results of the NHIS-COVID cohort were similar to the primary results of the GRCP-COVID cohort.

Conclusions

Our findings indicate that prior statin use is related to a decreased risk of worsening clinical outcomes of COVID-19 and length of hospital stay but not to that of SARS-CoV-2 infection.

Assessment of vitamin D, exercise, and lipid profile associated with excessive daytime sleepiness in school children

Previous research reported associations of excessive daytime sleepiness (EDS) with a low vitamin D level, obesity, and sexual maturity. The aim of this study was to identify the association and rank the importance of these with EDS. This study examined 618 children who were 10-12 year-old. The pediatric daytime sleepiness scale (PDSS) was used to evaluate EDS and sleep patterns. EDS was defined as a total PDSS score above 17. We ranked the importance of the relationship of these factors with EDS using random forest analysis. EDS (n = 111, 18%) was positively associated with more advanced pubertal stage in girls, chronic cough, urticaria, and allergic rhinitis. Multivariable analysis with adjustment for confounding indicated that children with low level of 25-hydroxyvitaminD₃ (25(OH)D₃ (<20 ng/mL) and high-density lipoprotein-cholesterol (HDL-C) (<40 mg/dL) levels had an increased risk of EDS (25(OH)D₃:adjusted odds ratio [aOR] = 1.73; 95% confidence interval [CI]: 1.06 to 2.81; P = 0.028; HDL-C: aOR = 2.84; 95% CI: 1.05 to 7.68; P = 0.039). Random forest analysis indicated that 25(OH)D₃ level, exercise, and body mass index (BMI) were over three. This study indicated high levels of 25-(OH)D₃ and HDL-C and performing regular exercise decreased the risk of EDS.

Machine learning-based prediction of response to growth hormone treatment in Turner syndrome: the LG Growth Study

Background Growth hormone (GH) treatment has become a common practice in Turner syndrome (TS). However, there are only a few studies on the response to GH treatment in TS. The aim of this study is to predict the responsiveness to GH treatment and to suggest a prediction model of height outcome in TS. Methods The clinical parameters of 105 TS patients registered in the LG Growth Study (LGS) were retrospectively reviewed. The prognostic factors for the good responders were identified, and the prediction of height response was investigated by the random forest (RF) method, and also, multiple regression models were applied. Results In the RF method, the most important predictive variable for the increment of height standard deviation score (SDS) during the first year of GH treatment was chronologic age (CA) at start of GH treatment. The RF method also showed that the increment of height SDS during the first year was the most important predictor in the increment of height SDS after 3 years of treatment. In a prediction model by multiple regression, younger CA was the significant predictor of height SDS gain during the first year (32.4% of the variability). After 3 years of treatment, mid-parental height (MPH) and the increment of height SDS during the first year were identified as significant predictors (76.6% of the variability). Conclusions Both the machine learning approach and the multiple regression model revealed that younger CA at the start of GH treatment was the most important factor related to height response in patients with TS.

The analysis of endocrine disruptors in patients with central precocious puberty

Background

A few studies have reported a positive association between phthalate exposure and pubertal timing, but several conflicting reports exist. The main objective of the study was to determine whether phthalate exposure was associated with central precocious puberty in girls.

Methods

This was a multicenter case-control study wherein 47 girls with central precocious puberty (CPP) and 47 controls (26 pre-pubertal girls and 21 pubertal girls) were enrolled. No obese girls were included. Five phthalate metabolites (creatinine adjusted) and bisphenol A (BPA) were measured in the first spot urine samples of these 94 girls in the early morning.

Results

The median values of monobenzyl phthalate (MBzP), mono-2-ethyl-5-carboxypentyl phthalate (MECPP), mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP), and mono-n-butyl phthalate (MnBP) were 3.1, 29.3, 18.0, 15.4, and 25.2 μg/g creatinine in the CPP group, 4.3, 53.7, 35.7, 29.1, and 66.0 μg/g creatinine in the pre-pubertal control group, and 1.7, 28.7, 21.4, 12.1, and 33.3 μg/g creatinine in the pubertal control group, respectively.

The urinary concentration of the five phthalates was significantly lower in the CPP group than in the pre-pubertal control group (P < 0.001). Conversely, there was no significant difference in the urinary concentration of the five phthalates between the CPP and pubertal control groups (P values: 0.077 for MBzP, 0.733 for MECPP, 0.762 for MEHHP, 0.405 for MEOHP, and 0.981 for MnBP). In addition, the BPA level was not significantly different between the CPP and pubertal control groups (BPA median values: 0.63 μg/g creatinine, the CPP group; 1.7 μg/g creatinine, the pubertal control group; P value = 0.092).

Conclusions

Our study showed that there was no significant difference in the urinary phthalate levels between the CPP and pubertal control groups. Moreover, phthalate metabolites were significantly lower in the CPP group than in the pre-pubertal control group. Further investigation about endocrine disruptors and pubertal progression is needed.

Variable Clinical Characteristics and Molecular Spectrum of Patients with Syndromes of Reduced Sensitivity to Thyroid Hormone: Genetic Defects in the THRB and SLC16A2 Genes

BACKGROUND/AIMS

Syndromes of reduced sensitivity to thyroid hormone can be caused by innate resistance to thyroid hormone (RTH), thyroid hormone cell transporter defects, or thyroid hormone metabolism defects. This study was performed to describe clinical, endocrinological, and molecular characteristics of patients with disorders associated with impaired sensitivity to thyroid hormone due to THRB or SLC16A2 mutations.

METHODS

This study included 5 probands (1 male and 4 females) with RTH and 6 patients with Allan-Herndon-Dudley syndrome (AHDS). Clinical features and endocrine findings were reviewed retrospectively. Molecular analysis of two candidate genes, THRB or SLC16A2, confirmed the diagnosis.

RESULTS

Among RTH patients, median age at diagnosis was 5.6 years. Three patients were classified as having generalized RTH, whereas the other 2 patients were regarded as having isolated pituitary RTH. Three novel heterozygous mutations and 2 known mutations in THRB were identified from 5 independent pedigrees. All mutations were located in the major ligand-binding domain. In AHDS patients, delayed development was apparent between 3 and 6 months of age. Direct sequencing of SLC16A2 identified 6 hemizygous missense mutations in each patient: p.I188N, p.G221R, p.A224V, p.G276R, p.W398R, and p.G401R.

CONCLUSIONS

This study identified 3 novel mutations in THRB in RTH patients and 1 novel mutation in SLC16A2 in AHDS patients. Routine neonatal screening based on the TSH assay has a limited role in detecting RTH or AHDS. Therefore, genetic testing of the candidate genes THRB and SLC16A2 should be performed for diagnosis of RTH and AHDS in patients with the suggestive clinical phenotype.

Response to vitamin D replacement in overweight and normal weight children with vitamin D deficiency

PURPOSE

It is well known that obesity is related to vitamin D deficiency (VDD). We investigated the response to vitamin D replacement in normal-weight and overweight children.

METHODS

This was a prospective study including 62 Korean children with VDD. VDD was defined as a serum 25-hydroxycholecalciferol (25(OH)D) concentration &lt;20 ng/mL. Overweight was defined as a body mass index (BMI)≥the 85th percentile (n=21), and normal weight as a BMI between the 5th and 84th percentiles (n=41). All participants received vitamin D3 supplementation (2,000 IU/day) for 8 weeks. The serum levels of 25(OH)D, PTH and biochemical parameters were measured before and after treatment.

RESULTS

The mean age was 10.0±1.4 years in normal-weight children and 10.0±2.1 years in overweight children (P=0.93). After 8 weeks of treatment, 61.9% of normal-weight children and 47.6% of overweight children achieved vitamin D sufficiency (P =0.30). The mean serum 25(OH)D levels after vitamin D replacement were 33.8±7.6 ng/mL and 30.3±6.6 ng/mL in normal-weight and overweight children, respectively (P =0.10). The mean calcium/creatinine ratios after treatment were 0.09±0.07 and 0.08±0.06 in the normal-weight and overweight groups, respectively, and no hypercalciuria was found. In multiple regression analysis, the response to vitamin D replacement was influenced by the BMI (β=-1.0, P=0.03) and sex (β=-4.0, P=0.04).

CONCLUSION

Eight weeks of vitamin D replacement (2,000 IU/day) is sufficient to overcome vitamin D deficiency in normal-weight and overweight children without any complications.

Hypertriglyceridemia in Obese Children and Adolescents

The increasing prevalence of obesity in children and adolescents is a serious public health concern. Hypertriglyceridemia is common in obese children and adolescents, and elevated triglyceride (TG) level is a known biomarker of cardiometabolic risk. Results from genetic studies suggest that TG and TG-rich lipoproteins and, more specifically, remnant cholesterol are in the causal pathway of cardiovascular disease. However, simultaneous measurement of all remnants has not yet been established, and plasma TG level can be used as a useful marker of remnant cholesterol. Adipose tissue dysfunction, including impaired adipocyte TG storage and release of fatty acids, mediates the development of obesity-related complications. The prevalence of hypertriglyceridemia increases in overweight or obese children and is associated with other cardiometabolic risk factors. Recently, the TG/high-density lipoprotein cholesterol (HDL-C) ratio was recognized as a marker of structural vascular changes and insulin resistance in obese youth. Recent guidelines recommend universal lipid screening with nonfasting non-HDL-C measurement in children at 9–11 years of age; however, fasting lipid profiles should be measured in obese children and overweight adolescents and in those with high non-HDL-C in universal screening. The primary approach to lower TG in children includes dietary and lifestyle modifications; however, children with severe hypertriglyceridemia should also be referred to a pediatric lipid specialist.

Diurnal variation of gonadotropin levels in girls with early stages of puberty

PURPOSE

Pubertal gonadotropin secretion shows circadian pattern and the luteinizing hormone (LH) levels tend to rise in later stages of puberty in girls. We studied the usefulness of basal LH in the evaluation of central precocious puberty with emphasis on the influence of sampling time.

METHODS

Medical records of 334 girls that underwent gonadotropin-releasing hormone stimulation test (GnRHST) were reviewed. Auxological and laboratory data were compared between those with early morning (EM, before 10 AM) and late morning/afternoon (LM/A, after 10 AM) basal samples.

RESULTS

Among those in sexual maturity rating (SMR) 2, EM samples showed higher basal LH (P=0.004) compare to LM/A samples, whereas those in SMR 3 showed no difference in LH levels between EM and LM/A samples. Among girls with pubertal response, EM group showed higher basal LH (P=0.031) and follicular stimulating hormone (P=0.008) than LM/A group. The EM basal LH was more closely related with the peak stimulated LH than the LM/A basal LH did (rs=0.871 vs. rs=0.524). The optimal basal LH cutoffs to predict a pubertal response to GnRHST were 0.11 IU/L with a sensitivity of 66.7% and a specificity of 78.7% in EM group, and 0.07 IU/L with a sensitivity of 60.0% and a specificity of 78.9% in LM/A group, respectively.

CONCLUSIONS

In girls with early stages of puberty, EM basal LH is a more sensitive screening tool than the LM/A basal LH. Diurnal variation should be considered in evaluating children with precocious puberty.

The triglyceride-to-high density lipoprotein cholesterol ratio in overweight Korean children and adolescents

PURPOSE

The triglyceride-to-high-density lipoprotein cholesterol (TG/HDL-C) ratio has recently been reported as a biomarker of cardiometabolic risk in obese children and adolescents. The purpose of this study is to describe the TG/HDL-C ratio and related factors in overweight and normal weight Korean children and to evaluate whether the high TG/HDL-C ratio is associated with insulin resistance in overweight children and adolescents.

METHODS

Data from 255 overweight (aged 8.7±2.0 years) and 514 normal weight (aged 8.9±1.8 years) children and adolescents were evaluated. Glucose, insulin, total cholesterol (TC), HDL-C and TG levels were measured after overnight fasting, and the TG/HDL-C ratio, non-HDL-C and the homeostasis model assessment of insulin resistance (HOMA-IR) were calculated.

RESULTS

The TG/HDL-C ratio was higher in overweight group compared to normal weight group (P<0.001). Among overweight children and adolescents, alanine aminotransferase (P=0.018), non-HDL-C (P<0.001), and HOMA-IR (P=0.004) were different between the TG/HDL-C ratio tertile groups. The prevalence of elevated HOMA-IR was increased with increasing TG/HDL-C ratio tertiles (P for trend=0.003). On regression analysis adjusted for age and sex, the BMI (β=0.402, P=0.001) and TG/HDL-C ratio (β=0.251, P=0.014) were independently associated with HOMA-IR (adjusted R2=0.324). The TG/HDL-C ratio of 2.0 or more showed higher sensitivity (55.6%) and specificity (72.9%), when compared to TC (≥200 mg/dL), non-HDL-C (≥145 mg/dL), and LDL-C (≥130 mg/dL) for identifying overweight children with elevated HOMA-IR.

CONCLUSIONS

The TG/HDL-C ratio is independently associated with insulin resistance in overweight children and adolescents, and it can be useful in identifying those at higher cardiometabolic risk.

Delayed diagnosis of 22q11 deletion syndrome due to late onset hypocalcemia in a 11-year-old girl with imperforated anus

Neonatal hypocalcemia and congenital heart defects has been known as the first clinical manifestation of the chromosome 22q11.2 deletion syndrome (22q11DS). However, because of its wide clinical spectrum, diagnosis of 22q11DS can be delayed in children without classic symptoms. We report the case of a girl with the history of imperforate anus but without neonatal hypocalcemia or major cardiac anomaly, who was diagnosed for 22q11DS at the age of 11 after the onset of overt hypocalcemia. She was born uneventfully from phenotypically normal Korean parents. Imperforate anus and partial cleft palate were found at birth, which were surgically repaired thereafter. There was no history of neonatal hypocalcemia, and karyotyping by GTG banding was normal. At the age of 11, hypocalcemia (serum calcium, 5.0 mg/dL) and decreased parathyroid hormone level (10.8 pg/mL) was noted when she visited our Emergency Department for fever and vomiting. The 22q11DS was suspected because of her mild mental retardation and velopharyngeal insufficiency, and a microdeletion on chromosome 22q11.2 was confirmed by fluorescence in situ hybridization. The 22q11DS should be considered in the differential diagnosis of hypocalcemia at any age because of its wide clinical spectrum.

Waist-to-height ratio as a screening tool for obesity and cardiometabolic risk

The waist-to-height ratio (WHtR), calculated by dividing the waist circumference (WC) by height, has recently gained attention as an anthropometric index for central adiposity. It is an easy-to-use and less age-dependent index to identify individuals with increased cardiometabolic risk. A WHtR cutoff of 0.5 can be used in different sex and ethnic groups and is generally accepted as a universal cutoff for central obesity in children (aged ≥6 years) and adults. However, the WHtR has not been validated in preschool children, and the routine use of WHtR in children under age 6 is not recommended. Prospective studies and meta-analysis in adults revealed that the WHtR is equivalent to or slightly better than WC and superior to body mass index (BMI) in predicting higher cardiometabolic risk. In children and adolescents, studies have shown that the WHtR is similar to both BMI and WC in identifying those at an increased cardiometabolic risk. Additional use of WHtR with BMI or WC may be helpful because WHtR considers both height and central obesity. WHtR may be preferred because of its simplicity and because it does not require sex- and age-dependent cutoffs; additionally, the simple message 'keep your WC to less than half your height' may be particularly useful. This review article summarizes recent publications on the usefulness of using WHtR especially when compared to BMI and WC as a screening tool for obesity and related cardiometabolic risks, and recommends the use of WHtR in clinical practice for obesity screening in children and adolescents.

Waist-to-Height Ratio as an Index for Cardiometabolic Risk in Adolescents: Results from the 1998-2008 KNHANES

PURPOSE

To describe the relationship between the waist-to-height ratio (WHtR) and cardiometabolic risk factors (CMRFs) and to evaluate the validity of WHtR in identifying adolescents with metabolic syndrome.

MATERIALS AND METHODS

We analyzed data from a pooled population of 4068 adolescents aged 10-19 years from the Korean National Health and Nutrition Examination Surveys conducted between 1998 and 2008. Overweight individuals were defined by body mass index (BMI) ≥85th percentile. Those with at least 2 CMRFs among hypertension, hyperglycemia, hypertriglyceridemia, and decreased high-density lipoprotein cholesterol (HDL-C) were classified as having multiple CMRFs.

RESULTS

WHtR was significantly related to systolic blood pressure, HDL-C, and triglycerides in both non-overweight and overweight adolescents (all p<0.01). Among overweight adolescents, the area under the curve (AUC) for WHtR in identifying multiple CMRFs was significantly greater than that for BMI (p=0.014). Metabolic syndrome was more common in overweight adolescents with a WHtR of ≥0.5 than in those with a WHtR of <0.5 (p<0.001). In non-overweight adolescents, the prevalences of multiple CMRFs (p=0.001) and metabolic syndrome (p<0.001) were higher in those with a WHtR of ≥0.5 than in those with a WHtR of <0.5. Among those without central obesity, the prevalence of multiple CMRFs was higher in those with a WHtR of ≥0.5 than in those with a WHtR of <0.5 (p=0.021).

CONCLUSION

WHtR is a simple and valid index for identifying adolescents with increased cardiometabolic risk and is related to CMRFs even in non-overweight adolescents. In adolescents already screened via BMI and waist circumference (WC), WHtR seems to be of additional help in discriminating those at higher cardiometabolic risk.

Sitosterolemia: a review and update of pathophysiology, clinical spectrum, diagnosis, and management

Sitosterolemia is an autosomal recessive disorder characterized by increased plant sterol levels, xanthomas, and accelerated atherosclerosis. Although it was originally reported in patients with normolipemic xanthomas, severe hypercholesterolemia have been reported in patients with sitosterolemia, especially in children. Sitosterolemia is caused by increased intestinal absorption and decreased biliary excretion of sterols resulting from biallelic mutations in either ABCG5 or ABCG8, which encode the sterol efflux transporter ABCG5 and ABCG8. Patients with sitosterolemia show extreme phenotypic heterogeneity, ranging from almost asymptomatic individuals to those with severe hypercholesterolemia leading to accelerated atherosclerosis and premature cardiac death. Hematologic manifestations include hemolytic anemia with stomatocytosis, macrothrombocytopenia, splenomegaly, and abnormal bleeding. The mainstay of therapy includes dietary restriction of both cholesterol and plant sterols and the sterol absorption inhibitor, ezetimibe. Foods rich in plant sterols include vegetable oils, wheat germs, nuts, seeds, avocado, shortening, margarine and chocolate. Hypercholesterolemia in patients with sitosterolemia is dramatically responsive to low cholesterol diet and bile acid sequestrants. Plant sterol assay should be performed in patients with normocholesterolemic xanthomas, hypercholesterolemia with unexpectedly good response to dietary modifications or to cholesterol absorption inhibitors, or hypercholesterolemia with poor response to statins, or those with unexplained hemolytic anemia and macrothrombocytopenia. Because prognosis can be improved by proper management, it is important to find these patients out and diagnose correctly. This review article aimed to summarize recent publications on sitosterolemia, and to suggest clinical indications for plant sterol assay.

Iron and vitamin D status in breastfed infants and their mothers

Purpose

We assessed the relationships between iron and vitamin D statuses in breastfed infants and their mothers and evaluated the determinants of iron and vitamin D deficiencies in breastfed infants.

Methods

Seventy breastfed infants aged 4-24 months and their mothers participated in this study from February 2012 to May 2013. Complete blood counts, total iron binding capacity, and levels of C-reactive protein, iron, ferritin, calcium, phosphate, alkaline phosphatase, and 25-hydroxyvitamin D (25(OH)D) in infants and their mothers were measured.

Results

A history of maternal prepregnancy anemia was associated with lower ferritin and 25(OH)D levels in both infants and their mothers. The 25(OH)D level of infants correlated with maternal 25(OH) D levels. The independent risk factors for iron deficiency in breastfed infants were the duration of breastfeeding (odds ratio [OR], 6.54; 95% confidence interval [CI], 1.09-39.2; P=0.04) and infant body weight (OR, 2.65; 95% CI, 1.07-6.56; P=0.04). The determinants for vitamin D deficiency were the infant's age (OR, 0.15; 95% CI, 0.02-0.97; P=0.046) and maternal 25(OH)D level (OR, 0.74; 95% CI, 0.59-0.92; P=0.01).

Conclusion

A maternal history of prepregnancy anemia requiring iron therapy was associated with lower current ferritin and 25(OH)D levels in both infants and their mothers. Therefore, physicians should monitor not only iron but also vitamin D levels in infants who are breastfed by mothers who had prepregnancy anemia.

The link between serum vitamin D level, sensitization to food allergens, and the severity of atopic dermatitis in infancy

OBJECTIVE

To investigate the association between serum vitamin D levels, sensitization to food allergens, and the severity of atopic dermatitis in infants.

STUDY DESIGN

We investigated serum 25-hydroxyvitamin D (25[OH]D) and specific immunoglobulin E levels to common or suspected food allergens in 226 infants with atopic dermatitis or food allergy. The severity of atopic dermatitis by the Scoring Atopic Dermatitis index and amount of vitamin D intake was measured in subcohort children. Sensitization to food allergen was categorized by the number (non-, mono-, and poly-) of sensitized allergens and the degree (undetected-, low-, and high-level) of sensitization.

RESULTS

Significant differences in 25(OH)D levels were found between groups on number (P = .006) and degree (P = .005) of food sensitization. The polysensitization group had significantly lower levels of 25(OH)D than the nonsensitization (P = .001) and monosensitization (P = .023) group. High-level sensitization group had significantly lower 25(OH)D levels compared with undetected (P = .005) and low-level (P = .009) sensitization group. Vitamin D deficiency increased the risk of sensitization to food allergens (OR 5.0; 95% CI 1.8-14.1), especially to milk (OR 10.4; 95% CI 3.3-32.7) and wheat (OR 4.2; 95% CI 1.1-15.8). In addition, the Scoring Atopic Dermatitis index was independently related to 25(OH)D levels after adjusting for the level of sensitization (adjusted R(2) = 0.112, P = .031).

CONCLUSIONS

Our results suggest that vitamin D deficiency increases the risk of sensitization to food allergens and that atopic dermatitis may be more severe in infants with vitamin D deficiency.

Vitamin D deficiency in Korean children: prevalence, risk factors, and the relationship with parathyroid hormone levels

PURPOSE

This study was performed to investigate the relationship between serum vitamin D and parathyroid hormone (PTH) levels as well as to describe the prevalence and the risk factors of vitamin D deficiency (VDD) in Korean children.

METHODS

Participants were 1,212 children aged 4 to 15 years, who visited Bundang CHA Medical Center (located at 37°N) between March 2012 and February 2013. Overweight was defined as body mass index≥85th percentile. Participants were divided into 4 age groups and 2 seasonal groups. VDD was defined by serum 25-hydroxyvitamin D (25OHD) <20 ng/mL.

RESULTS

The level of 25OHD was significantly lower in overweight group than in normal weight group (17.1±5.1 ng/mL vs. 19.1±6.1 ng/mL, P<0.001). Winter-spring season (odds ratio [OR], 4.46; 95% confidence interval [CI], 3.45-5.77), older age group (OR, 1.60; 95% CI, 1.36-1.88), and overweight (OR, 2.21; 95% CI, 1.62-3.01) were independently related with VDD. The PTH levels were significantly higher in VDD group compared to vitamin D insufficiency and sufficiency group (P<0.001). In normal weight children, 25OHD (β=-0.007, P<0.001) and ionized calcium (β=-0.594, P=0.007) were independently related with PTH, however, these associations were not significant in overweight children.

CONCLUSION

VDD is very common in Korean children and its prevalence increases in winter-spring season, in overweight children and in older age groups. Further investigation on the vitamin D and PTH metabolism according to adiposity is required.

Sitosterolemia presenting with severe hypercholesterolemia and intertriginous xanthomas in a breastfed infant: case report and brief review

CONTEXT

Sitosterolemia is an autosomal recessive disorder characterized by increased intestinal absorption of plant sterols. It is caused by mutations in genes encoding ATP-binding cassette, subfamily G5 (ABCG5) or G8 (ABCG8), and clinical features include elevated plant sterol levels, xanthomas, and accelerated atherosclerosis. Although it was originally reported in patients with normolipemic xanthomas, patients with sitosterolemia also hyperabsorb cholesterol, and serum cholesterol levels tend to be elevated.

OBJECTIVE

We report an infant with sitosterolemia who presented with severe hypercholesterolemia and intertriginous xanthomas.

CASE REPORT

A 15-month-old Korean girl presented with yellow dermal plaques over flexural areas including the wrist, neck, and gluteal folds, which were consistent with intertriginous xanthomas. The lesions were first noticed at 3 months of age when she was being exclusively breastfed. Her total cholesterol and low-density lipoprotein-cholesterol levels were 675 and 540 mg/dL, respectively. A low-fat/low-cholesterol diet and cholestyramine therapy were introduced. Unexpectedly, her serum cholesterol level decreased dramatically and normalized in 2 months. Cholestyramine was tapered off. The xanthomas also regressed and disappeared by 3 years of age. Gas chromatography-mass spectrometric analysis was performed with serum drawn at 3 years of age when her low-density lipoprotein-cholesterol was 118 mg/dL, which revealed striking elevation of her sitosterol level at 19.36 mg/dL. Direct sequencing for ABCG5 revealed compound heterozygous null mutations c.904+1G>A (p.Met302Asnfs*82) and c.1336C>T(p.Arg446*).

CONCLUSIONS

Our case suggests that sitosterolemia can present with severe hypercholesterolemia and intertriginous xanthomas. Sitosterolemia should be suspected when a patient with hypercholesterolemia shows unexpectedly good response to dietary modification or bile acid sequestrant therapy.

22q11.2 Microduplication with thyroid hemiagenesis

BACKGROUND

Chromosome 22q11.2 microduplications are extremely rarely detected; in comparison, the deletion of same region, known as the DiGeorge/velocardiofacial syndrome, occurs more frequently. Thyroid anomalies commonly occur in patients with 22q11.2 deletion syndrome, however few reports of thyroid anomalies associated with 22q11.2 microduplication have been published thus far.

CASE REPORT

We present a case of a male infant who was prenatally diagnosed with 22q11.2 microduplication and was found to have congenital hypothyroidism due to thyroid hemiagenesis after birth. Moreover, the baby had bilateral hearing impairment, bilateral cryptorchidism, and a rotated penis. At the age of 2 years, the infant was euthyroid with levothyroxine replacement, but he showed significant developmental delay.

CONCLUSIONS

To our knowledge, this is the first case of congenital hypothyroidism with thyroid hemiagenesis in a patient showing 22q11.2 microduplication. Thyroid dysgenesis could be an additional clinical feature shared by the 22q11.2 microduplication and deletion syndrome, suggesting that the duplication and deletion of a gene may result in a common phenotype. Thyroid dysgenesis should be considered in the evaluation and management of patients with this genomic disorder.

Insulin pump therapy in transient neonatal diabetes mellitus

Neonatal diabetes mellitus (NDM) is a rare disease requiring insulin treatment. Its treatment is primarily focused on maintaining adequate glycemic control and avoiding hypoglycemia. Although insulin pump therapy is frequently administered to adults and children, there is no consensus on the use of insulin pumps in NDM. A 10 day-old female infant was referred to us with intrauterine growth retardation and poor weight gain. Hyperglycemia was noted, and continuous intravenous insulin infusion was initiated. However, the patient's serum glucose levels fluctuated widely, and maintaining the intravenous route became difficult within the following weeks. Continuous subcutaneous insulin infusion with an insulin pump was introduced on the twenty-fifth day of life, and good glycemic control was achieved without any notable adverse effects including hypoglycemia. We suggest that the insulin pump is a safe and effective mode for treating NDM and its early adoption may shorten the length of hospital stays in patients with NDM.

Strong parent-offspring association of metabolic syndrome in Korean families

OBJECTIVE

To investigate the associations of metabolic syndrome (MetS) and its components between adolescents and their parents in Korea.

RESEARCH DESIGN AND METHODS

We analyzed data for 4,657 subjects (1,404 fathers, 1,404 mothers, 957 sons, and 892 daughters) from the Korean National Health and Nutrition Examination Surveys conducted between 1998 and 2008.

RESULTS

Compared with adolescents whose parents did not have MetS, the odds ratio (95% CI) for MetS in adolescents with MetS in one parent was 4.2 (2.1-8.5) and 8.7 (3.4-22.3) in those with MetS in both parents. Among obese adolescents, the prevalence of MetS was 18.2% without parental MetS, whereas 29.2% of obese adolescents with MetS in one parent and 53.9% with MetS in both parents also had MetS (P = 0.01 for trend).

CONCLUSIONS

The risk of MetS increased significantly in adolescents with parental MetS and was especially high in those with coexisting obesity and parental MetS.

Insulin-like growth factor-binding protein-3 mediates high glucose-induced apoptosis by increasing oxidative stress in proximal tubular epithelial cells

IGF-binding protein-3 (IGFBP-3) is the major circulating carrier protein for IGF, and also acts as a potent antiproliferative agent in various cell types. Recently, IGFBP-3 was reported to mediate high glucose-induced apoptosis in mesangial cells and podocytes. In this study, we investigated the role of IGFBP-3 in high glucose-induced apoptosis in proximal tubular epithelial cells (PTEC). Expression of IGFBP-3 protein and mRNA in a porcine PTEC line (LLC-PK1 cells) was measured after exposure to either standard (5.5 mM) or high-glucose (30 mM) medium. We quantified apoptosis after treatment with small interfering RNA against IGFBP-3 (siRNA:IGFBP-3) in high-glucose medium or in cells that overexpressed IGFBP-3. Oxidative stress was measured in high-glucose medium, in the presence of siRNA:IGFBP-3, or in IGFBP-3-overexpressing cells. IGFBP-3 protein and mRNA expression in LLC-PK1 cells was higher in high-glucose medium than in standard-glucose medium. Exposure to high-glucose medium increased apoptosis, and high-glucose-induced apoptosis was abolished by siRNA:IGFBP-3. IGFBP-3 overexpression induced apoptosis in LLC-PK1 cells. Both high-glucose medium and IGFBP-3 overexpression increased reactive oxygen species, and siRNA:IGFBP-3 reduced this increase. Antioxidant treatment decreased IGFBP-3 expression and apoptosis, whereas oxidative stress from hydrogen peroxide increased IGFBP-3 expression, suggesting that oxidative stress increases IGFBP-3 expression. Our results suggest that increased IGFBP-3 expression by high glucose mediates high-glucose-induced apoptosis in PTEC. Increased oxidative stress from high glucose enhances IGFBP-3 expression, inducing apoptosis. Increased expression of IGFBP-3 by high glucose induces additional oxidative stress, which may result in amplification of hyperglycemic damage.

Determinants of plasma adiponectin levels in obese children

Adiponectin is an insulin-sensitizing adipocytokine, and recently it has been suggested as a biomarker of metabolic syndrome. We studied the relationships between adiponectin and parameters of metabolic syndrome in obese children. Fasting plasma adiponectin, insulin, glucose, lipids, and anthropometric parameters were measured in 180 obese children and 125 non-obese controls. Adiponectin was significantly decreased in obese boys and girls compared to non-obese controls. Adiponectin was inversely related to body mass index, waist circumference (WC), insulin, homeostasis model assessment for insulin resistance, and triglycerides, after adjusting for age in both genders. Adiponectin was correlated with high-density lipoprotein cholesterol (HDL-C) after adjusting for age in both genders. In multiple regression analysis, WC was independently related to adiponectin in boys, and WC and HDL-C were independently related to adiponectin in girls. In conclusion, WC, a simple measure of central adiposity, is a determinant of adiponectin in obese children.

Prevalence of microalbuminuria in young patients with type 1 and type 2 diabetes mellitus

This study was designed to determine the prevalence of microalbuminuria and the associated risk factors in patients with childhood-onset diabetes mellitus (DM). One hundred and sixty-three patients (141 with type 1 DM [DM1] and 22 with type 2 DM [DM21), aged 8 to 28 years, were evaluated for albumin excretion rate and HbA(1c). The mean duration of DM was 8.1 +/- 3.4 and 5.5 +/- 3.9 years in DM1 and DM2, respectively. Persistent microalbuminuria and macroalbuminuria were observed in 11.3% and 2.8% of patients with DM1, and 18.2% and 4.5% in patients with DM2, respectively. In DM1, the duration of DM, age of onset, and HbA(1c) levels were significant predictors of microalbuminuria. Our observations suggest that screening for microalbuminuria should be started from early adolescence in patients with DM1 and DM2.