Associations between Urinary Mercury/Cadmium Concentrations and Anthropometric Features in Korean Children.

Investigating the impact of urinary mercury and cadmium on anthropometric parameters in Korean children is crucial amid growing concerns about heavy metal exposure and childhood growth. Using data from the Korean National Environmental Health Survey (2015-2017), we assessed age- and sex-specific associations of urinary mercury and cadmium with height and body mass index (BMI) z-scores in 1458 children aged 3-5 (n = 571) and 6-11 years (n = 887). Overall, 5.0% had stunted height (3-5 years: 6.9%, 6-11 years: 3.8%), whereas older children exhibited higher overweight/obesity prevalence (29.2%) than younger ones did (22.2%). In 3-5-year-old boys, urinary mercury correlated negatively with height z-scores (p < 0.001), whereas in girls, urinary cadmium correlated positively (p = 0.015). Boys aged 6-11 years showed positive associations between mercury/cadmium levels and BMI z-scores (p = 0.012). Logistic regression indicated associations between urinary mercury and stunted height likelihood (p = 0.001) and between urinary cadmium and reduced overweight likelihood (p = 0.039) in 3-5-year-old boys. In boys aged 6-11 years, urinary cadmium levels were positively associated with overweight likelihood (p = 0.003). This study underscores the link between elevated urinary mercury, cadmium levels, and growth disruptions in Korean children, emphasizing the need for public health strategies for reducing childhood heavy metal exposure.

Effectiveness and safety of pamidronate treatment in nonambulatory children with low bone mineral density.

PURPOSE: Nonambulatory pediatric patients may have low bone mineral density (BMD) and increased risk of pathologic fractures. Though bisphosphonate therapy is the mainstream medical intervention in these children, clinical data regarding this treatment are limited. Therefore, this study aimed to evaluate the effectiveness and safety of bisphosphonate therapy in such children. METHODS: We conducted a retrospective study of 21 nonambulatory children (Gross Motor Function Classification System level V) with BMD z-score ≤ -2.0 who were treated with intravenous pamidronate for at least 1 year. These patients received pamidronate every 4 months at a dose of 1.0 to 3.0 mg/kg for each cycle and had regular follow-ups for at least 1 year. The main outcome measures were changes in BMD, risk rate of fracture, biochemical data, and adverse events. RESULTS: The average duration of pamidronate treatment was 2.0±0.9 years, and the mean cumulative dose of pamidronate according to body weight was 7.7±2.5 mg/kg/yr. After treatment, the mean lumbar spine bone mineral content, BMD, and height-for-age-z-score-adjusted BMD z-score (BMDhazZ) significantly improved. The relative risk of fracture after treatment was 0.21 (p=0.0032), suggesting that pamidronate treatment reduced fracture incidence significantly. The increase in the average dose per body weight in each cycle significantly increased the changes in BMDhazZ. CONCLUSION: Pamidronate treatment improved the bone health of nonambulatory children with low bone density without any significant adverse events. Independent of cumulative dosage and duration of treatment, the effectiveness of pamidronate increased significantly with an increase in the average dose per body weight in subsequent cycles.

Effects of Early Wake-Up Time on Obesity in Adolescents.

Background: Although numerous studies have reported that obesity in adolescents is related to shorter sleep duration, few studies have reported the effect of sleep timing, particularly early wake-up time, on obesity. Objectives: To investigate the association between wake-up time and adolescent obesity. Methods: Using the Korean National Health and Nutrition Examination Survey VII data, 1301 middle school and high school students were selected and grouped according to BMI. Sleep timing and lifestyle factors were evaluated using self-reported questionnaires. Results: The mean bedtime and wake-up time were 00:09 am and 07:06 am, respectively. Despite similar bedtimes, the group with overweight/obesity woke up earlier than the group with underweight/normal weight. The BMI z-score and the overweight/obesity relative risk decreased as the wake-up time was delayed, even after adjustment for covariates. Participants who woke up before 06:50 am had a 1.82-fold higher risk of having overweight/obesity than those who woke up after 07:30 am. Participants who woke up late tended to sleep longer than those who woke up early. Conclusions: Waking up early is significantly associated with an increased BMI z-score in adolescents and may be a risk factor for overweight/obesity.

Parental metabolic syndrome and elevated liver transaminases are risk factors for offspring, even in children and adolescents with a normal body mass index.

Introduction: The parent-child correlation in metabolic syndrome (MetS) and elevated transaminases is sparsely researched. We assessed the correlation of parental MetS and elevated transaminase status with these conditions in their children. Methods: Data of 4,167 youths aged 10-18 years were analyzed in a population-based survey, and the parental characteristics were stratified by the presence or absence of MetS or alanine aminotransferase (ALT) elevation in their children. The prevalence of these conditions in children was analyzed according to their parents' status. Logistic regression analyses were performed with MetS and ALT elevation in youth as the dependent variables. Results: The proportions of MetS and ALT elevation were higher in parents of children with MetS and ALT elevation than in those without, even among youths without obesity. In logistic regression analyses, age, body mass index-standard deviation score (BMI-SDS), and ALT elevation were positively associated with MetS, whereas age, male sex, BMI-SDS, protein intake, and MetS were positively associated with ALT elevation. Higher protein intake was related to ALT elevation, whereas metabolic components and nutritional factors were closely related in parents and their children. Odds ratios (OR) of ALT elevation for MetS was 8.96 even after adjusting nutritional factors in the children. The OR was higher for ALT elevation in the children of parents with MetS and ALT elevation compared to those without. ORs for MetS and ALT elevation in the children of parents with MetS were higher than those of children of parents without MetS, even after adjusting for nutritional intake. ORs for ALT elevation were higher in the children of parents with ALT elevation than those without, even after adjusting for nutritional intake and BMI of parents as well as the nutritional intake, age, sex, and BMI-SDS of the children. Conclusion: MetS and elevated liver transaminase statuses in children were associated with those of their parents even after adjusting for nutritional factors, and the relationships were more prominent in the youth without obesity.

The influence of pituitary volume on the growth response in growth hormone-treated children with growth hormone deficiency and idiopathic short stature.

Purpose: Magnetic resonance imaging (MRI) can be used for assessing the morphology of pituitary gland. The purpose of this study was 1) to determine whether the pituitary volume (PV) distinguish growth hormone (GH) deficiency from idiopathic short stature (ISS) and 2) to validate an association between PV and severity of GH deficiency and 3) to compare the PV between good and poor response groups in children with GH deficiency and ISS. Methods: Data were collected from the medical records of 152 children with short stature who underwent GH stimulation test, sella MRI, and GH treatment. Estimated PV were calculated using the formula of an ellipsoid. We compared the PV in patients with GH deficiency with that of patients with ISS. In addition, we assessed the association between PV and severity of GH deficiency, and growth response after treatment. Results: No difference was observed in the PV between patients with GH deficiency and ISS. The PV seemed to be smaller as the degree of GH deficiency was severe (P=0.082). The PV in good response group was smaller than that in poor response group in patients with GH deficiency (P< 0.005). The PV showed no association with responsiveness to GH treatment in patients with ISS (P=0.073). Conclusions: The measurement of PV cannot be used for differential diagnosis between GH deficiency and ISS. In patients with GH deficiency, the PV tend to be smaller as the severity of GH deficiency even though no statistical significance, and may be a good response predictor for GH treatment.

Bone Age Estimation and Prediction of Final Adult Height Using Deep Learning.

PURPOSE: The appropriate evaluation of height and accurate estimation of bone age are crucial for proper assessment of the growth status of a child. We developed a bone age estimation program using a deep learning algorithm and established a model to predict the final adult height of Korean children. MATERIALS AND METHODS: A total of 1678 radiographs from 866 children, for which the interpretation results were consistent between two pediatric endocrinologists, were used to train and validate the deep learning model. The bone age estimation algorithm was based on the convolutional neural network of the deep learning system. The test set simulation was performed by a deep learning program and two raters using 150 radiographs and final height data for 100 adults. RESULTS: There was a statistically significant correlation between bone age interpreted by the artificial intelligence (AI) program and the reference bone age in the test set simulation (r=0.99, p<0.001). In the test set simulation, the AI program showed a mean absolute error (MAE) of 0.59 years and a root mean squared error (RMSE) of 0.55 years, compared with reference bone age, and showed similar accuracy to that of an experienced pediatric endocrinologist (rater 1). Prediction of final adult height by the AI program showed an MAE of 4.62 cm, compared with the actual final adult height. CONCLUSION: We developed a bone age estimation program based on a deep learning algorithm. The AI-derived program demonstrated high accuracy in estimating bone age and predicting the final adult height of Korean children and adolescents.

Effect of catch-up sleep on obesity in Korean adolescents: a nationwide cross-sectional study.

Background: Adolescents have weekday/weekend sleep discrepancies and may compensate for weekday sleep debt through sleep extension on weekends. Objective: We investigated the effects of total sleep duration on weekdays/weekends on obesity and determined if weekend catch-up sleep has an ameliorating effect on obesity in Korean adolescents. Methods: Using data from the KNHANES VII, 1,306 middle and high school students were assessed for total sleep duration on weekdays, weekends, and the entire week, as well as weekend sleep extension. Participants were classified into four groups according to weekend sleep extension. Results: Total sleep duration and weekend sleep duration were negatively associated with body mass index z-score. Increased weekend sleep duration and sleep extension on weekends decreased the relative risk of overweight/obesity with each 30 min increment, reducing the risk by a factor of 0.39 and 0.93, respectively. The risk of overweight/obesity in adolescents who slept less than 6 h on weekdays increased by a factor of 1.93 when they slept for less than 3 h on weekends. Conclusion: Weekend catch-up sleep had a negative dose-dependent association with obesity in Korean adolescents. Sleeping longer on weekends may be associated with a decreased risk of obesity, even if the adolescent obtains less sleep during weekdays. However, further prospective studies are needed to establish the causality between extended weekend sleep and obesity.

Trends in HOMA-IR values among South Korean adolescents from 2007-2010 to 2019-2020: a sex-, age-, and weight status-specific analysis.

BACKGROUND/OBJECTIVES: An increase in obesity prevalence may lead to an increase in the HOMA-IR value. This study aimed to investigate changes in age- and sex-specific homeostasis model assessment of insulin resistance (HOMA-IR) values among South Korean adolescents, using data from the Korean National Health and Nutrition Examination Survey (KNHANES) IV, V, and VIII conducted between 2007-2010 and 2019-2020. SUBJECTS/METHODS: Overall, 4621 adolescents aged 10-18 years were evaluated, including 3473 from the 2007-2010 dataset and 1148 from the 2019-2020 dataset. The mean HOMA-IR values and percentile curves were evaluated by age, sex, and weight status. RESULTS: The mean HOMA-IR values peaked at puberty in both sexes and further increased during puberty in the 2019-2020 dataset (boys 5.21, 95% confidence interval [CI] 4.16-6.26; girls 5.21, 95% CI 3.09-7.33) compared with the 2007-2010 dataset (boys 3.25, 95% CI 3.04-3.47; girls 3.58, 95% CI 3.31-3.85). Both groups (with normal-weight and overweight/obesity) exhibited a peak HOMA-IR value during puberty in both sexes and both datasets, although the group with overweight/obesity had a higher and wider peak age range. While the mean HOMA-IR values did not change in adolescents with normal-weight, they increased during puberty and post-puberty in boys with overweight/obesity. CONCLUSIONS: HOMA-IR values should be interpreted considering sex, weight status, and pubertal stages. In particular, during the pubertal period, insulin resistance (IR) can coexist not only due to weight-related factors but also as a result of the distinct hormonal changes characteristic of puberty. Over the 10-year period, the mean HOMA-IR values increased in the group with overweight/obesity during puberty and post-puberty, highlighting the need for active intervention to prevent metabolic complications in adolescents with overweight/obesity.

The mediating effects of parenting style on the relationship between parental stress and behavioral problems in girls with precocious puberty in Korea: a cross-sectional study.

BACKGROUND: This study aimed to examine the mediating effects of parenting style on the relationship between parental stress and behavioral problems of girls with precocious puberty. METHODS: This cross-sectional study analyzed a convenience sample of 200 mothers of girls with precocious puberty at a university hospital located in a metropolitan area. The Parental Stress measurement, Parents as Social Context Questionnaire, and Korean version Child Behavior Checklist (K-CBCL) 6-18 were measured via self-report questionnaires. Descriptive, t-test, Pearson correlation, and bootstrapping analyses were used to analyze the data. RESULTS: Negative parenting styles had a full mediating effect on the relationship between parental stress and internalizing and externalizing behavioral problems. CONCLUSIONS: Care plans for parents of girls with precocious puberty should be designed and applied in health care settings to reduce internalizing and externalizing behavioral problems by decreasing negative parenting styles.

Effects of Androgen Treatment on Growth in Patients with 5-α-Reductase Type 2 Deficiency.

BACKGROUND: Patients with 5-α-reductase type 2 deficiency (5αRD2) require androgen treatment for the growth of normal male external genitalia. Since limited research has been conducted on the effects of androgen treatment on height in individuals with 5αRD2, we investigated the effect of androgen treatment on bone age (BA) and the height status in children with 5αRD2. METHODS: Of the 19 participants who were followed up for an average of 10.6 years, 12 received androgen treatment. BA and height standard deviation scores (SDS) were compared between the treatment and non-treatment groups, as well as between the dihydrotestosterone (DHT) and testosterone enanthate (TE) treatment groups. RESULTS: Despite the above-average height of the 19 patients with 5αRD2, the height SDS relative to BA (htSDS-BA) was below average, particularly in the androgen treatment group. DHT treatment did not lead to an increase in BA or htSDS-BA, whereas TE treatment resulted in BA advancement and decreased htSDS-BA, especially in the prepubertal period. CONCLUSIONS: DHT treatment is more favorable for height than TE treatment in patients with 5αRD2, particularly during the prepubertal period. Therefore, age and the type of androgen used should be carefully considered to minimize the risk of height reduction in these patient groups.

Insulin-like growth factor binding protein-3 induces senescence by inhibiting telomerase activity in MCF-7 breast cancer cells.

Insulin-like growth factor binding protein-3 (IGFBP-3) has been known to inhibit cell proliferation and exert tumor-suppressing effects depending on the cell type. In this study, we aimed to show that IGFBP-3 induces cellular senescence via suppression of the telomerase activity, thereby inhibiting MCF-7 breast cancer cell proliferation. We found that the induction of IGFBP-3 in MCF-7 cells enhanced the loss of cell viability. Flow cytometry revealed a higher percentage of non-cycling cells among IGFBP-3-expressing cells than among controls. IGFBP-3 induction also resulted in morphological alterations, such as a flattened cytoplasm and increased granularity, suggesting that IGFBP-3 induces a senescence-like phenotype. The percentage of IGFBP-3 expressing cells with senescence-associated ß-galactosidase activity was 3.4 times higher than control cells. Telomeric repeat amplification and real-time PCR showed that IGFBP-3 decreased telomerase activity by reducing the levels of the RNA component (hTR) and catalytic protein component with reverse transcriptase activity (hTERT) of telomerase in a dose-dependent manner. These results suggest that IGFBP-3 is a negative regulator of MCF-7 breast cancer cell growth by inducing senescence through telomerase suppression.

Comparison of growth response and adverse reaction according to growth hormone dosing strategy for children with short stature: LG Growth Study.

OBJECTIVE: Growth hormone (GH) dosage in children is conventionally determined either by body weight (BW) or body surface area (BSA). However, there is no consensus on the calculation method for proper GH treatment dose. We aimed to compare growth response and adverse reactions between BW- and BSA-based GH treatment doses for children with short statures. DESIGN: Data from 2284 GH-treated children were analyzed. Distributions of BW- and BSA-based GH treatment doses and their association with growth response parameters, including changes in height, height standard deviation score (SDS), body mass index (BMI), and safety parameters, such as changes in insulin-like growth factor (IGF)-I SDS and adverse events, were investigated. RESULTS: The mean BW-based doses were close to the recommended dose's upper limit in participants with GH deficiency and idiopathic short stature, while they were below the recommended dose in patients with Turner syndrome (TS). As age and BW increased, BW-based dose decreased, whereas BSA-based dose increased. Gain in height SDS was positively associated with BW-based dose in the TS group and negatively associated with BW in all groups. Despite having a lower BW-based dose, the overweight/obese groups had a higher BSA-based dose and higher frequencies of children with high IGF-I and adverse events than those of the normal-BMI group. CONCLUSIONS: In children of older age or with high BW, BW-based doses can be overdosed in terms of BSA. and BW-based dose positively correlated with height gain only in the TS group. BSA-based doses represent an alternative dosing strategy in children who are overweight/obese.

Changes in the Prevalences of Obesity, Abdominal Obesity, and Non-Alcoholic Fatty Liver Disease among Korean Children during the COVID-19 Outbreak.

PURPOSE: We aimed to investigate the prevalences of obesity, abdominal obesity, and non-alcoholic fatty liver disease (NAFLD) among children and adolescents during the coronavirus disease 2019 (COVID-19) outbreak. MATERIALS AND METHODS: This population-based study investigated the prevalences of obesity, abdominal obesity, and NAFLD among 1428 children and adolescents between 2018-2019 and 2020. We assessed the prevalences of obesity, abdominal obesity, and NAFLD according to body mass index, age, sex, and residential district. Logistic regression analyses were performed to determine the relationships among obesity, abdominal obesity, and NAFLD. RESULTS: In the obese group, the prevalence of abdominal obesity increased from 75.55% to 92.68%, and that of NAFLD increased from 40.68% to 57.82%. In age-specific analysis, the prevalence of abdominal obesity increased from 8.25% to 14.11% among participants aged 10-12 years and from 11.70% to 19.88% among children aged 13-15 years. In residential district-specific analysis, the prevalence of both abdominal obesity and NAFLD increased from 6.96% to 15.74% in rural areas. In logistic regression analysis, the odds ratio of abdominal obesity for NAFLD was 11.82. CONCLUSION: Our results demonstrated that the prevalences of abdominal obesity and NAFLD increased among obese Korean children and adolescents and in rural areas during the COVID-19 outbreak. Additionally, the prevalence of abdominal obesity increased among young children. These findings suggest the importance of closely monitoring abdominal obesity and NAFLD among children during COVID-19, focusing particularly on obese young children and individuals in rural areas.

The Genotype-Phenotype Correlation in Human 5α-Reductase Type 2 Deficiency: Classified and Analyzed from a SRD5A2 Structural Perspective.

The phenotype of the 5α-reductase type 2 deficiency (5αRD2) by the SRD5A2 gene mutation varies, and although there have been many attempts, the genotype-phenotype correlation still has not yet been adequately evaluated. Recently, the crystal structure of the 5α-reductase type 2 isozyme (SRD5A2) has been determined. Therefore, the present study retrospectively evaluated the genotype-phenotype correlation from a structural perspective in 19 Korean patients with 5αRD2. Additionally, variants were classified according to structural categories, and phenotypic severity was compared with previously published data. The p.R227Q variant, which belongs to the NADPH-binding residue mutation category, exhibited a more masculine phenotype (higher external masculinization score) than other variants. Furthermore, compound heterozygous mutations with p.R227Q mitigated phenotypic severity. Similarly, other mutations in this category showed mild to moderate phenotypes. Conversely, the variants categorized as structure-destabilizing and small to bulky residue mutations showed moderate to severe phenotypes, and those categorized as catalytic site and helix-breaking mutations exhibited severe phenotypes. Therefore, the SRD5A2 structural approach suggested that a genotype-phenotype correlation does exist in 5αRD2. Furthermore, the categorization of SRD5A2 gene variants according to the SRD5A2 structure facilitates the prediction of the severity of 5αRD2 and the management and genetic counseling of patients affected by it.

Microtubule Acetylation-Specific Inhibitors Induce Cell Death and Mitotic Arrest via JNK/AP-1 Activation in Triple-Negative Breast Cancer Cells.

Microtubule acetylation has been proposed as a marker of highly heterogeneous and aggressive triple-negative breast cancer (TNBC). The novel microtubule acetylation inhibitors GM-90257 and GM-90631 (GM compounds) cause TNBC cancer cell death but the underlying mechanisms are currently unknown. In this study, we demonstrated that GM compounds function as anti-TNBC agents through activation of the JNK/AP-1 pathway. RNA-seq and biochemical analyses of GM compound-treated cells revealed that c-Jun N-terminal kinase (JNK) and members of its downstream signaling pathway are potential targets for GM compounds. Mechanistically, JNK activation by GM compounds induced an increase in c-Jun phosphorylation and c-Fos protein levels, thereby activating the activator protein-1 (AP-1) transcription factor. Notably, direct suppression of JNK with a pharmacological inhibitor alleviated Bcl2 reduction and cell death caused by GM compounds. TNBC cell death and mitotic arrest were induced by GM compounds through AP-1 activation in vitro. These results were reproduced in vivo, validating the significance of microtubule acetylation/JNK/AP-1 axis activation in the anti-cancer activity of GM compounds. Moreover, GM compounds significantly attenuated tumor growth, metastasis, and cancer-related death in mice, demonstrating strong potential as therapeutic agents for TNBC.

Neurocognitive and psychosocial profiles of children with Turner syndrome.

PURPOSE: Patients with Turner syndrome (TS) have distinct neurocognitive and psychosocial characteristics. However, few clinical studies have reported neuropsychological findings in Korean patients. This study investigated the neurocognitive and psychosocial profiles of Korean children with TS. METHODS: This retrospective cross-sectional study analyzed 20 pediatric patients (<18 years) with TS at the Department of Pediatric Endocrinology at Yonsei University Severance Children's Hospital in South Korea from January 2016 to March 2019. We selected 20 age- and sex-matched controls from among those who visited the endocrinology clinic and were confirmed to have no clinical abnormalities. All participants underwent several neuropsychological tests. RESULTS: In the Korean Wechsler Intelligence Scale for Children-IV test, the Full-Scale Intelligence Quotient of the TS group was within the normal range. The Perceptual Reasoning Index, Working Memory Index, and Processing Speed Index scores were significantly lower in the TS group than in the control group. In contrast, the Verbal Comprehension Index did not differ significantly between the groups. The Comprehensive Attention Test results showed that the TS group displayed borderline visual selective attention. The social quotient score was significantly lower in the TS group than in the control group. CONCLUSION: Pediatric patients with TS in Korea displayed distinct neurocognitive and psychosocial characteristics. Patients in the TS group maintained their verbal function, but their attention, visuospatial function, and social competence were low. Our findings will contribute to the development of education programs for patients with TS to improve their neurocognitive and psychosocial functioning.

Comparison of the effect of gonadotropin-releasing hormone agonist dosage in girls with central precocious puberty.

PURPOSE: There are no definite guidelines on the optimal dosage of gonadotropin-releasing hormone (GnRH) agonist for treatment of central precocious puberty (CPP). We compared growth outcomes of GnRH agonist at different dosages in girls with idiopathic CPP to assess the optimal dosage. METHODS: This retrospective study included 86 girls with idiopathic CPP who had been treated with GnRH agonist for at least one year and had attained their final adult height. Leuprolide was given as fixed dosage (3.75 mg every 4 weeks in body weight >20 kg, n=72) or weight-based dosage (60-85 µg/kg every 4 weeks, n=14). We compared suppression of advanced puberty and treatment response between the 2 groups. RESULTS: Peak estradiol and luteinizing hormone and bone age (BA)/chronological age after injection of GnRH agonist were effectively suppressed in both groups. In both groups, the height standard deviation score (SDS) for BA increased after treatment. Final adult height (FAH) (fixed dosage group,160.8±4.1 cm and weight-based dosage group, 161.2±4.4 cm) was significantly higher than the initial predicted adult height (PAH) (155.5±3.3 and 156.1±3.6 cm, respectively) (both P<0.001) and similar to midparental height (159.8±3.3 and 160.6±3.7 cm, respectively). There were no differences in gain in height SDS for BA and gain in height (FAH-PAH at the start) between the 2 groups. CONCLUSION: There were no differences in treatment outcome between fixed dosage (3.75 mg/4 wk) and weight-based dosage (60-85 µg/kg/4wk) of GnRH agonist. Therefore, a fixed dosage of GnRH agonist can be used more conveniently for CPP treatment without growth oversuppression.

Association between early glycemic management and diabetes complications in type 1 diabetes mellitus: A retrospective cohort study.

AIMS: To investigate the association between early HbA1c levels near diagnosis and future glycemic management, and analyzed risk factors of complications in people with T1DM. METHODS: This retrospective cohort study included 201 children and adolescents with T1DM. Patient data including sex, age at diagnosis, duration of disease, HbA1c levels, HbA1c variability during the follow-up period, and diabetes complications and comorbidities were collected. RESULTS: The mean follow-up period of patients was 16.4 years. HbA1c levels in all three examined time points after diagnosis (first year, second year, and first two years) were significantly associated with recent HbA1c level, and second-year HbA1c was most closely correlated with recent HbA1c level. Elevated second-year HbA1c was a risk factor of diabetic ketoacidosis (DKA) and retinopathy, and increased variability of HbA1c was significantly related to various microvascular complications. When HbA1c is stratified into quartiles, the subjects of each quartile trend to stay within that quartile over the follow-up period. CONCLUSIONS: Early HbA1c levels were closely associated with recent HbA1c levels and diabetes complications in patients with T1DMs. Strict glucose management after diagnosis and reducing variability of HbA1c may prevent future diabetes complications and comorbidities.