Biliary atresia (BA) is the major cause of cholestasis and the leading indication for liver transplantation (LT). However, the incidence of BA in Korea has not been reported. The aim of this study was to investigate the incidence and clinical outcomes of BA in Korea. We used the Korean universal health insurance database and extracted data regarding BA patients younger than 18 years of age admitted between 2011 and 2015. The incidence of BA was calculated by dividing the number of BA patients by the number of live births. Two hundred forty infants were newly diagnosed with BA. A total of 963 BA patients younger than 18 years of age were followed up for 5 years. The overall incidence of BA was 1.06 cases per 10,000 live births. The incidence of BA was 1.4 times higher for female patients than for male patients. Additionally, significant seasonal variation was observed; in particular, the incidence of BA was 2 times higher from June through August than from December through February. Congenital anomalies were found in 38 of 240 patients (15.8%). Congenital heart diseases were major associated congenital anomalies (6.3%). Several complications developed during the study period, including cholangitis (24.0%), varix (6.2%), and gastrointestinal bleeding (4.4%). Three hundred and one of the 963 BA patients under 18 years of age (31.3%) received LT for BA. The incidence of BA is higher in Korea than that in Western countries. We also report significant gender-associated differences and seasonal variation with respect to the incidence of BA.

BackgroundAn elevated alanine aminotransferase (ALT) level is a surrogate marker of non-alcoholic fatty liver disease (NAFLD), the most common liver disorder in adolescents. The majority of previous NAFLD studies in adolescents were performed in selected obese populations or had a cross-sectional design without a time-trend analysis. The purpose of this study was to estimate the prevalence and time trends of elevated ALT levels in a general adolescent population and to identify factors associated with ALT elevation.MethodsWe analysed data of adolescent participants (aged 10–18 years) from the Korean National Health and Nutrition Examination Survey 2001–2014, a representative sample of the general population in South Korea. Suspected NAFLD was defined as ALT elevation (> 30 U/L) without hepatitis B surface antigen. In all statistical analyses, sampling weight- and design-based data were used.ResultsALT was elevated in 5.3% (standard error: 0.3%) of the study population of adolescent participants (N = 8455). No significant trends were found from 2001 to 2014 in the prevalence of elevated ALT among male and female adolescents. In multiple logistic regression analysis, elevated ALT was independently associated with sex (odds ratio [OR] male versus female 4.5; 95% CI, 3.3-6.2), obesity (OR 7.6; 95% CI, 5.3-11.0), and truncal obesity (OR 2.5; 95% CI, 1.8-3.5). Furthermore, male sex, obesity, truncal obesity and high household income level were associated with log-transformed ALT levels in multiple regression analysis.ConclusionsIn Korean adolescents of both genders, the prevalence of elevated ALT levels was stable from 2001 to 2014. This study has revealed that sex, obesity, truncal obesity and household income level are associated with ALT elevation in adolescents.

Summary Background Although genetic variants of PNPLA3, TM6SF2 and SAMM50 have been reported to increase the risk of non‐alcoholic fatty liver disease (NAFLD), no pediatric studies have evaluated the association between SAMM50 and NAFLD. Objective This study aimed to investigate the risk factors, including genetic variants, of pediatric NAFLD. Methods NAFLD was defined as the presence of hepatic steatosis on ultrasound. We included 228 patients with NAFLD (body mass index‐Z [BMI‐Z] = 2.51 ± 1.01) and 225 controls (BMI‐Z = 0.22 ± 1.48). We genotyped four variants of PNPLA3 (rs738409), TM6SF2 (rs58542926) and SAMM50 (rs2073080 and rs3761472) by TaqMan allelic discrimination. The pediatric NAFLD fibrosis score, aspartate transaminase (AST)/platelet ratio index and fibrosis‐4 score were used to evaluate the degree of fibrosis. We calculated the genetic risk score for additive effects according to the sum of risk alleles. Results The mean age was 12.6 ± 3.5 years. The four genetic variants, male sex and BMI‐Z, independently increased susceptibility to NAFLD. These four variants, in addition to fasting insulin and triglycerides, remained significant risk factors with higher odds ratios in children with overweight. These variants increased the alanine aminotransferase (ALT) level and three fibrosis scores independently. As the genetic risk score increased, AST, ALT and the fibrosis scores increased independently. Conclusion PNPLA3, TM6SF2 and SAMM50 are associated with the development and severity of pediatric NAFLD. The impact of genetic variants is greater in children with overweight. The four genetic variants have synergetic effects on the severity of pediatric NAFLD.

BackgroundThe aim of this study was to compare the long-term efficacy of entecavir (ETV) and lamivudine (LAM) therapy in children with chronic hepatitis B (CHB) who had not received nucleoside analogue treatment.MethodsIn this multicenter, retrospective study, we included pediatric CHB patients younger than 20 years who received ETV or LAM treatment for at least 12 months and had no concomitant diseases. All of the patients were followed up every 1 to 3 months. At each visit, the patients underwent clinical evaluation and biochemical testing.ResultsEight (53.3%), 14 (93.3%), and 2 (15.4%) of the ETV-treated patients achieved virologic suppression, alanine aminotransferase (ALT) normalization and hepatitis B e antigen (HBeAg) seroconversion, respectively, at 1 year. In the ETV group, the cumulative rate of virologic suppression at 3 years was 91.7%, which was significantly higher than that in the LAM group (P < 0.001). The mean duration of treatment before virologic suppression was shorter in the ETV group than in the LAM group (P = 0.040). The cumulative rate of seroconversion in the ETV group at 3 years was 39.4%, which was not significantly different from that in the LAM group (P = 0.439). The ETV group showed lower cumulate rates of virologic breakthrough (33.3% at 6 years) and genotypic mutation than the LAM group (P = 0.033 and P = 0.011, respectively).ConclusionETV is superior to LAM in pediatric CHB treatment because of its higher virologic suppression rate and lower cumulative rates of virologic breakthrough and genotypic mutation.

Background: The prevalence of nonalcoholic fatty liver disease (NAFLD) has increased as the obese pediatric population has increased. NAFLD causes progressive liver injury and the only effective treatment is lifestyle modifications. However, few studies have examined the dietary risk factors for pediatric NAFLD or liver fibrosis. Here, we evaluated the dietary factors associated with suspected NAFLD and potential liver fibrosis in Korean children. Methods: Data collected from 1674 children and adolescents aged 10-18 years during the 2014-2017 Korean National Health and Nutrition Examination Surveys analyzed. The 24-h recall method measured the food consumed 1 day before the survey. The "suspected NAFLD" group included excessive body mass index (BMI) subjects ≥ 85th percentile) with alanine aminotransferase (ALT) levels exceeding the upper normal limit (24.1 U/L for boys and 17.7 U/L for girls); the "healthy control" group included subjects with a BMI and ALT level below these thresholds. Sodium intake was assessed by the urinary sodium-to-urinary specific gravity unit ratio (U-Na-to-SGU ratio). A pediatric NAFLD index (PNFI) higher than 3 indicated potential liver fibrosis. Results: The overall prevalence of suspected NAFLD and potential liver fibrosis was 8.2 and 4.5%, respectively. The suspected NAFLD group had a larger proportion of males and subject with a greater height, BMI standard deviation score (BMI-SDS), systolic and diastolic blood pressure SDS, waist circumference, hemoglobin A1c, and levels of total cholesterol, triglycerides, aspartate aminotransferase (AST) and ALT than the control group. The suspected NAFLD group presented significantly higher U-Na-to-SGU ratios and cholesterol intake. The PNFI > 3 subgroup included a significantly larger proportion of males and subjects with higher BMI-SDS, AST and ALT values, and intake of water, carbohydrate, protein, calcium, phosphorus, iron and vitamin B2. After adjusting for confounders, male, BMI-SDS, AST, and protein and carbohydrate intake were independent risk factors for potential liver fibrosis. Niacin intake was an independent protective factor for potential liver fibrosis.

BackgroundThe purpose was to compare the efficacy between tenofovir disoproxil fumarate (TDF) and lamivudine (LMV) in children with nucleos(t)ide-naive chronic hepatitis B (CHB) infection. Patients with CHB were treated with TDF in the immune-reactive phase and compared with a historical control group of patients treated with LMV before the TDF era.MethodsHepatitis B virus (HBV) DNA titer decrements (> 3 log10 IU/mL) were monitored after treatment initiation. The treatment duration for HBV DNA clearance (< 357 IU/mL) and complete response (HBeAg loss and HBV DNA clearance) were analyzed. The follow-up period was 96 weeks.ResultsSixteen patients were treated with TDF and compared with a historical control group of 24 patients treated with LMV. HBV DNA decrement (> 3 log10 IU/mL) was achieved in 100% (16/16) of the TDF group but in only 62.5% (15/24) of the LMV group (P = 0.005) at 48 weeks. The HBV DNA clearance (< 357 IU/mL) in the TDF and LMV groups was, respectively, as follows: 62.5% (10/16) and 25.0% (6/24) at 12 weeks (P = 0.018), 81.3% (13/16) and 37.5% (9/24) at 24 weeks (P = 0.006), 93.8% (15/16) and 50.0% (12/24) at 48 weeks (P = 0.004), and 100% (16/16) and 54.2% (13/24) at 96 weeks (P = 0.001). Complete response occurred in 41.7% (5/12) of HBeAg-positive patients in the TDF group and 28.6% (6/21) of the LMV group at 96 weeks (P = 0.443).ConclusionTDF monotherapy for 96 weeks produced a significantly more effective virologic response than LMV monotherapy in children with nucleos(t)ide-naive CHB.

Background/Aims: A full colonoscopy is currently required in children and adolescents with colorectal polyps, because of their potential of neoplastic transformation and complications such as intussusception. We aimed to analyze the associations of polyp characteristics in children and adolescents with colorectal polyps. Based on these findings, we also aimed to reevaluate the necessity of conducting a full colonoscopy.Methods: Pediatric patients <18 years of age who had undergone a colonoscopic polypectomy and those with <5 colorectal polyps were included in this multicenter, retrospective study. Baseline clinicodemographics, colonoscopic and histologic findings were investigated.Results: A total of 91 patients were included. Multivariate logistic regression analysis showed that polyp size was the only factor associated with the presence of any polyps located proximal to the splenic flexure (odds ratio [OR], 2.25; 95% confidence interval [CI], 1.28 to 4.28; p=0.007). Furthermore, polyp location proximal to the splenic flexure and sessile morphology were associated with the presence of any adenomatous polyp (OR, 8.51; 95% CI, 1.43 to 68.65; p=0.023; OR, 18.41; 95% CI, 3.45 to 173.81; p=0.002, respectively). Conclusions:In children and adolescents presenting with <5 colorectal polyps, polyp size and the presence of any adenomatous polyp were positively associated with polyp location proximal to the splenic flexure. This finding supports the necessity of a full colonoscopic exam in pediatric patients with colorectal polyps for the detection of polyps before the occurrence of complications such as intussusception or neoplastic transformation.

Purpose We aimed to investigate factors that correlate with fecal calprotectin (FC) levels in children and adolescents with colorectal polyps. Methods Pediatric patients aged <19 years who underwent colonoscopic polypectomy for a juvenile polyps (JPs) and FC tests were simultaneously conducted in a multicenter, retrospective study. Baseline demographics, colonoscopic and histological findings, and laboratory tests, including FC levels, were investigated. Correlations between the factors were investigated, and linear regression analysis revealed factors that correlated with FC levels. FC levels measured after polypectomies were investigated and the FC levels pre- and post-polypectomies were compared. Results A total of 33 patients were included in the study. According to Pearson correlation analysis, the polyp size was the only factor that showed a statistically significant correlation with FC levels ( r= 0.75, p <0.001). Furthermore, according to the multivariate linear regression analysis, polyp size was the only factor that showed a statistically significant correlation with FC levels (adjusted R 2 =0.5718, β = 73.62, p <0.001). The median FC level was 400 mg/kg (interquartile range [IQR], 141.6–1,000 mg/kg), and the median polyp size was 14 mm (IQR, 9–20 mm). Nineteen patients underwent post-polypectomy FC tests. FC levels showed a significant decrease after polypectomy from a median of 445.2 mg/kg (IQR, 225–1,000) to 26.5 mg/kg (11.5–51) ( p <0.001). Conclusion FC levels significantly correlated with polyp size in children and adolescents with JPs.