Subsequent CCA developed in 2% of the patients with hepatic resection for benign BDS until 10 years and was associated with poorer prognoses than concomitant CCA. Future studies focused on the long-term surveillance for CCA in such patients are needed.

Aim: Rotaviruses have been associated with biliary atresia. This study investigated whether the rotavirus vaccine, which was introduced to Korea in 2008, had an impact on the incidence of biliary atresia.Methods: We identified all rotavirus infections (n = 436 826) and biliary atresia cases (n = 528) diagnosed from 2006 to 2015 from insurance and health databases. The annual and seasonal incidence of biliary atresia and rotavirus infection rates in neonates and children were calculated. The difference in the risk of biliary atresia between rotavirusinfected and non-infected neonates was analysed.

Objective To quantify familial risk of endometriosis among full siblings and examine interactions between family history and smoking, age at menarche or body mass index (BMI).Design, setting and population Population-based nationwide cohort study.Methods Using data from the Korean National Health Insurance and Screening Programme databases on kinship, healthcare utilisation, lifestyle and anthropometrics, we identified 2 109 288 women with full siblings and their environmental risk factors from 2002 to 2018. Familial risks were estimated using Cox proportional-hazards models, represented as incidence risk ratios (IRR) with 95% CI. Interaction between family history and smoking, age at menarche or BMI were assessed on an additive scale.Main outcome measures IRR of endometriosis among women with and without affected siblings.Results From 19 195 women with affected siblings, 1126 developed endometriosis with an incidence of 35.45/10 000 person-years. Familial risk of endometriosis with versus without affected siblings was increased to IRR 2.75 (95% CI 2.25-3.36), and the highest risk was with affected twins (IRR 6.98;. Women with both a family history and either smoking, early menarche or low BMI had a significantly higher risk of endometriosis compared with the general population and can be regarded as a high-risk group, the IRRs were 4.28 (95% CI 2.43-7.55), 3.47 (95% CI 2.82-4.26) and 3.09 (95% CI 2.68-3.56), respectively. Substantial effect modification of the associations was noted by smoking and early menarche, as their combined risk with family history exceeded the sum of their individual risks, which was also statistically significant.Conclusion Genetic factors are the primary contributor to the familial aggregation of endometriosis. Significant geneenvironment interaction exists between family history and smoking or early menarche.

Objectives We analyzed the incidence and mortality rates of second pancreatic ductal adenocarcinoma (PDAC) among survivors of digestive cancers in South Korea. Methods We evaluated data from the Korea National Health Insurance to identify individuals with digestive cancers in 2005 to 2015. The standardized incidence ratios (SIRs) of second PDACs and survival rates were evaluated. Results Among 772,534 patients with first digestive cancers, 1696 (0.22%) developed second PDACs. The incidence of second PDACs increased until 10 years since the first cancer diagnosis. Patients with biliary tract cancers (BTCs) showed a higher incidence of second PDACs than did those with gastrointestinal cancers or hepatocellular carcinoma. In ages 20 to 49 years, SIRs (95% confidence interval) were higher in survivors of hepatocellular carcinoma (3.08; 1.04–3.08), gastric cancer (3.40; 1.90–3.40), colorectal cancer (5.00; 2.75–5.00), gallbladder cancer (58.52; 11.81–58.52), intrahepatic cholangiocarcinoma (86.99; 1.73–86.99), extrahepatic cholangiocarcinoma (89.41; 27.42–89.41), and ampulla of Vater cancer (156.78; 48.08–156.78). In ages 50 to 64 years, colorectal cancer (1.42; 1.04–1.42), gastric cancer (1.66; 1.29–1.66), and BTCs revealed higher SIRs. In ages more than 65 years, SIR was increased only in BTCs. Second PDACs revealed a more favorable prognosis than first PDACs. Conclusions Careful surveillance for second PDACs after curative treatment of BTCs and colorectal cancers should be considered.

ObjectivePopulation‐based studies of the familial aggregation of gout are scarce, and gene/environment interactions are not well studied. This study was undertaken to evaluate the familial aggregation of gout as well as assess interactions between family history and obesity or alcohol consumption on the development of gout.MethodsUsing the Korean National Health Insurance database, which includes information regarding familial relationships and risk factor data, we identified 5,524,403 individuals from 2002 to 2018. Familial risk was calculated using hazard ratios (HRs) with 95% confidence intervals (95% CIs) to compare the risk in individuals with and those without affected first‐degree relatives. Interactions between family history and obesity/alcohol consumption were assessed on an additive scale using the relative excess risk due to interaction (RERI).ResultsIndividuals with a gout‐affected first‐degree relative had a 2.42‐fold (95% CI 2.39, 2.46) increased risk of disease compared to those with unaffected first‐degree relatives. Having both a family history of gout and being either overweight or having moderate alcohol consumption was associated with a markedly increased risk of disease, with HRs of 4.39 (95% CI 4.29, 4.49) and 2.28 (95% CI 2.22, 2.35), respectively, which exceeded the sum of their individual risks but was only statistically significant in overweight individuals (RERI 0.96 [95% CI 0.85, 1.06]). Obese individuals (RERI 1.88 [95% CI 1.61, 2.16]) and heavy drinkers (RERI 0.36 [95% CI 0.20, 0.52]) had a more prominent interaction compared to overweight individuals and moderate drinkers, suggesting a dose‐response interaction pattern.ConclusionOur findings indicate the possibility of an interaction between gout‐associated genetic factors and obesity/alcohol consumption.