Background: Adolescent unintended pregnancies can have detrimental effects on maternal and fetal health, impacting the social lives of young parents. Globally, there is an emphasis on preventing unintended pregnancies in adolescents through comprehensive contraceptive education. This study examined contraception practices and determinants among sexually active Korean adolescents. Methods: This study analyzed raw data from the 2018 and 2021 Korea Youth Risk Behavior Survey conducted by the Korea Disease Control and Prevention Agency. The cohort consisted of 6,042 adolescents who reported sexual experience, categorized into those always practicing contraception and those not. We scrutinized factors related to sexual behavior, such as contraception and sex education, as well as other social and behavioral factors. Results: Among sexually active adolescents, 47.9% of males and 48.1% of females consistently used contraception. The most prevalent contraceptive method was condoms (male 58.1%; female 59.6%). However, a significant portion of adolescents were not using contraception (male 29.4%; female 21.7%). Females who did not consistently use contraception exhibited higher pregnancy rates (2.4% vs. 11.3%). Consistent contraceptive users tended to live with their families and reported less sexual experience after drinking alcohol. Despite a decline in sexual education in schools from 2018 to 2021, the proportion of adolescents consistently using contraception increased. Conclusion To prevent unintended pregnancies among sexually active adolescents, consistent use of appropriate contraceptive methods is crucial.Comprehensive education on contraception should be extended beyond schools to include homes and primary healthcare settings. Policymakers and healthcare providers should consider these consequences when devising strategies to reduce unintended pregnancies among adolescents.

Background: Adolescent unintended pregnancies can have detrimental effects on maternal and fetal health, impacting the social lives of young parents. Globally, there is an emphasis on preventing unintended pregnancies in adolescents through comprehensive contraceptive education. This study examined contraception practices and determinants among sexually active Korean adolescents. Methods: This study analyzed raw data from the 2018 and 2021 Korea Youth Risk Behavior Survey conducted by the Korea Disease Control and Prevention Agency. The cohort consisted of 6,042 adolescents who reported sexual experience, categorized into those always practicing contraception and those not. We scrutinized factors related to sexual behavior, such as contraception and sex education, as well as other social and behavioral factors. Results: Among sexually active adolescents, 47.9% of males and 48.1% of females consistently used contraception. The most prevalent contraceptive method was condoms (male 58.1%; female 59.6%). However, a significant portion of adolescents were not using contraception (male 29.4%; female 21.7%). Females who did not consistently use contraception exhibited higher pregnancy rates (2.4% vs. 11.3%). Consistent contraceptive users tended to live with their families and reported less sexual experience after drinking alcohol. Despite a decline in sexual education in schools from 2018 to 2021, the proportion of adolescents consistently using contraception increased. Conclusion To prevent unintended pregnancies among sexually active adolescents, consistent use of appropriate contraceptive methods is crucial.Comprehensive education on contraception should be extended beyond schools to include homes and primary healthcare settings. Policymakers and healthcare providers should consider these consequences when devising strategies to reduce unintended pregnancies among adolescents.

Background: Adolescent unintended pregnancies can have detrimental effects on maternal and fetal health, impacting the social lives of young parents. Globally, there is an emphasis on preventing unintended pregnancies in adolescents through comprehensive contraceptive education. This study examined contraception practices and determinants among sexually active Korean adolescents. Methods: This study analyzed raw data from the 2018 and 2021 Korea Youth Risk Behavior Survey conducted by the Korea Disease Control and Prevention Agency. The cohort consisted of 6,042 adolescents who reported sexual experience, categorized into those always practicing contraception and those not. We scrutinized factors related to sexual behavior, such as contraception and sex education, as well as other social and behavioral factors. Results: Among sexually active adolescents, 47.9% of males and 48.1% of females consistently used contraception. The most prevalent contraceptive method was condoms (male 58.1%; female 59.6%). However, a significant portion of adolescents were not using contraception (male 29.4%; female 21.7%). Females who did not consistently use contraception exhibited higher pregnancy rates (2.4% vs. 11.3%). Consistent contraceptive users tended to live with their families and reported less sexual experience after drinking alcohol. Despite a decline in sexual education in schools from 2018 to 2021, the proportion of adolescents consistently using contraception increased. Conclusion To prevent unintended pregnancies among sexually active adolescents, consistent use of appropriate contraceptive methods is crucial.Comprehensive education on contraception should be extended beyond schools to include homes and primary healthcare settings. Policymakers and healthcare providers should consider these consequences when devising strategies to reduce unintended pregnancies among adolescents.

Background: Adolescent unintended pregnancies can have detrimental effects on maternal and fetal health, impacting the social lives of young parents. Globally, there is an emphasis on preventing unintended pregnancies in adolescents through comprehensive contraceptive education. This study examined contraception practices and determinants among sexually active Korean adolescents. Methods: This study analyzed raw data from the 2018 and 2021 Korea Youth Risk Behavior Survey conducted by the Korea Disease Control and Prevention Agency. The cohort consisted of 6,042 adolescents who reported sexual experience, categorized into those always practicing contraception and those not. We scrutinized factors related to sexual behavior, such as contraception and sex education, as well as other social and behavioral factors. Results: Among sexually active adolescents, 47.9% of males and 48.1% of females consistently used contraception. The most prevalent contraceptive method was condoms (male 58.1%; female 59.6%). However, a significant portion of adolescents were not using contraception (male 29.4%; female 21.7%). Females who did not consistently use contraception exhibited higher pregnancy rates (2.4% vs. 11.3%). Consistent contraceptive users tended to live with their families and reported less sexual experience after drinking alcohol. Despite a decline in sexual education in schools from 2018 to 2021, the proportion of adolescents consistently using contraception increased. Conclusion To prevent unintended pregnancies among sexually active adolescents, consistent use of appropriate contraceptive methods is crucial.Comprehensive education on contraception should be extended beyond schools to include homes and primary healthcare settings. Policymakers and healthcare providers should consider these consequences when devising strategies to reduce unintended pregnancies among adolescents.

Background: Respiratory syncytial virus (RSV), a highly transmissible virus, is the leading cause of lower respiratory tract infections. We examined molecular changes in the RSV genome before and after the coronavirus disease 2019 (COVID-19) pandemic in Korea, and investigated whether drug-resistant mutations were present. Methods: In this prospective, single-center study, RSV-positive respiratory samples were collected between September 2019 and December 2022. Long-read whole-genome sequencing (WGS) was performed, and the presence of known drug-resistant substitutions for palivizumab, nirsevimab, and suptavumab was investigated. Results: Overall, 288 respiratory samples were collected from 276 children. WGS data were available for 133 samples (71 and 62 samples from the pre- and post-pandemic periods, respectively). All RSV-A strains (n = 56) belonged to the GA2.3.5 (ON1) genotype, whereas all RSV-B strains (n = 77) belonged to the GB5.0.5a (BA) genotype. No significant differences in genotypes were observed between the pre- and post-pandemic periods. In addition, no notable mutations related to nirsevimab or palivizumab resistance were detected in the F gene. However, the L172Q and S173L substitutions, which are known to confer resistance to suptavumab, were present in all RSV-B samples. Conclusion Despite the unprecedented interruption of RSV seasonality, there were no significant molecular changes in circulating RSV strains in Korea related to nirsevimab or palivizumab resistance before and after the COVID-19 pandemic. However, RSV-specific drug-resistance substitutions for suptavumab were identified.

Purpose: We prospectively compared the diagnostic accuracy of kidney dynamic computed tomography (KDCT), magnetic resonance imaging (MRI), and contrast-enhanced ultrasonography (CEUS) for the assessment of small renal mass (SRM) (≤4 cm). Materials and Methods: Seventy-six patients with SRM (mean age, 58.4±13.1 years) who underwent renal biopsy (n=11) or nephrectomy (partial or radical) (n=65) were enrolled. All patients underwent KDCT, MRI, and CEUS before renal biopsy or nephrectomy. Results: The mean maximal tumor size was 21.0±9.8 mm. The mean R.E.N.A.L nephrometry score was 7.0±1.7. Fifty-six patients had renal cell carcinoma (RCC) (clear cell, 42; papillary, 7; chromophobe, 5; succinate dehydrogenase deficient, 1; unspecified RCC, 1). Twenty patients had a benign tumor (angiomyolipoma, 11; oncocytoma, 3; others, 6). Clinicopathologic variables were comparable in RCC and benign groups. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of KDCT were 89.3%, 10.0%, 73.5%, and 25.0%, respectively. The sensitivity, specificity, PPV, and NPV of MRI were 89.3%, 10.0%, 73.5%, and 25.0%, respectively. The sensitivity, specificity, PPV, and NPV of CEUS were 85.7%, 50.0%, 82.8%, and 55.6%, respectively. The diagnostic accuracy of KDCT, MRI, and CEUS were 68.4%, 68.4%, and 76.3%, respectively. In a subgroup analysis based on clinical tumor size of 10 mm and 20 mm, CEUS also showed the highest diagnostic accuracy. Conclusions CEUS had the highest specificity, PPV, and NPV and may help improve the assessment of SRM.

Background: and Purpose This study aimed to evaluate whether extracellular-vesicle-incorporated microRNAs (miRNAs) are potential biomarkers for cancer-related stroke. Methods: This cohort study compared patients with active cancer who had embolic stroke of unknown sources (cancer-stroke group) with patients with only cancer, patients with only stroke, and healthy individuals (control groups). The expression profiles of miRNAs encapsulated in plasma exosomes and microvesicles were evaluated using microarray and validated using quantitative real-time polymerase chain reaction. The XENO-QTM miRNA assay technology was used to determine the absolute copy numbers of individual miRNAs in an external validation cohort. Results: This study recruited 220 patients, of which 45 had cancer-stroke, 76 were healthy controls, 39 were cancer controls, and 60 were stroke controls. Three miRNAs (miR-205-5p, miR-645, and miR-646) were specifically incorporated into microvesicles in patients with cancer-related stroke, cancer controls, and stroke controls. The area under the receiver operating characteristic curves of these three miRNAs were 0.7692–0.8510 for the differentiation of patients with cancer-stroke from cancer-controls and 0.8077–0.8846 for the differentiation of patients with cancer-stroke from stroke controls. The levels of several miRNAs were elevated in the plasma exosomes of patients with cancer, but were lower than those in plasma microvesicles. An in vivo study showed that systemic injection of miR-205-5p promoted the development of arterial thrombosis and elevation of D-dimer levels. Conclusion Stroke due to cancer-related coagulopathy was associated with deregulated expression of miRNAs, particularly microvesicle-incorporated miR-205-5p, miR-645, and miR-646. Further prospective studies of extracellular-vesicle-incorporated miRNAs are required to confirm the diagnostic role of miRNAs in patients with stroke and to screen the roles of miRNAs in patients with cancer.

Purpose: To examine the risk of dental abnormalities after exposure to tetracycline and its derivatives (TCs) in Korean children. Materials and Methods: Children aged 0–17 years with a claim for prescriptions of TCs between 2002 and 2015 were identified from the Sample Research Database 2.0 of the National Health Insurance Service. Children not exposed to TCs were selected as the control group by matching sex and age (1:4). Cumulative incidence rate and relative risk of dental abnormalities after TCs exposure were investigated. Results: The 10-year cumulative incidence rate in the 0–12 years group was 3.1% [95% confidence interval (CI), 2.3–3.9]. The 10-year cumulative incidence rates were 7.0%, 1.9%, and 1.6% in the 0–7, 8–12, and 13–17 years age groups (95% CI: 4.7–9.3, 1.2–2.6, and 1.3–1.9, respectively). There was no significant difference in the risk of dental abnormalities according to TC exposure among the age groups of 0–7 years [adjusted hazard ratio (aHR)=1.0], 8–12 years (aHR=1.1), and 13–17 years (aHR=1.2). Conclusion Short-term exposure to TCs does not appear to increase the risk of dental abnormalities in children aged 0–7 and 0–12 years. Restrictions on the use of TCs in children aged 8–12 years, in some countries, may warrant consideration.

Purpose: We aimed to investigate the risk factors and patterns of locoregional recurrence (LRR) after radical nephrectomy (RN) in patients with locally advanced renal cell carcinoma (RCC). Materials and Methods: We retrospectively analyzed 245 patients who underwent RN for non-metastatic pT3-4 RCC from January 2006 to January 2016. We analyzed the risk factors associated with poor locoregional control using Cox regression. Anatomical mapping was performed on reference computed tomography scans showing intact kidneys. Results: The median follow-up duration was 56 months (range, 1 to 128 months). Tumor extension to renal vessels or the inferior vena cava (IVC) and Fuhrman’s nuclear grade IV were identified as independent risk factors of LRR. The 5-year actuarial LRR rates in groups with no risk factor, one risk factor, and two risk factors were 2.3%, 19.8%, and 30.8%, respectively (p < 0.001). The locations of LRR were distributed as follows: aortocaval area (n=2), paraaortic area (n=4), retrocaval area (n=5), and tumor bed (n=11). No LRR was observed above the celiac axis (CA) or under the inferior mesenteric artery (IMA). Conclusion Tumor extension to renal vessels or the IVC and Fuhrman’s nuclear grade IV were the independent risk factors associated with LRR after RN for pT3-4 RCC. The locations of LRR after RN for RCC were distributed in the tumor bed and regional lymphatic area from the bifurcation of the CA to that of the IMA.

Objective: Influenza is an acute, respiratory viral disease, and may lead to complications such as pneumonia, which presents with significant morbidity and mortality. Previous studies did not have sufficient data regarding the risk factors and complications of the H1N1 flu caused by the influenza A virus subtype H1N1 during the 2009 pandemic in Korea. Therefore, this study was conducted to analyze the characteristics and risk factors of complicated influenza. Methods: Data were collected from influenza patients who visited a local emergency center in Daegu from January 2017 to December 2019. The study population was divided into three groups: influenza, influenza pneumonia, and influenza with a bacterial infection. The patients’ sex, age, influenza type, comorbidities, vital signs, symptoms, laboratory findings, and clinical outcomes were investigated for the risk analysis of complicated influenza. Results: The total number of patients was 574, of which 393 (68.5%) had influenza only, 135 (23.5%) had influenza pneumonia, and 46 (8%) had influenza with a bacterial infection. The odds ratio of complicated influenza was found using multivariate logistic regression analysis; for influenza pneumonia, it was 2.94 for patients aged over 65-years, 3.47 for those with an elevated procalcitonin level, 2.24 for cough, 6.41 for dyspnea, and 3.11 for renal disease. For influenza with bacterial infection, the odds ratio was 2.31 for males, 2.68 for over 80-year-olds, 3.75 for elevated procalcitonin levels, 7.61 for dyspnea, and 3.65 for nursing home residents. Conclusion The risk factors of complicated influenza were advanced age, elevated procalcitonin level, dyspnea, renal disease, and residing in a nursing home.