1.Maternal Exposures to COVID-19 Vaccine and Adverse Birth Outcomes:National Population Study in Korea
Kyuwon KIM ; Erdenetuya BOLORMAA ; Eunseon GWAK ; Ju-Young SHIN ; Nam-Kyong CHOI ; Young June CHOE ; Seung-Ah CHOE
Journal of Korean Medical Science 2025;40(17):e63-
Background:
This study aimed to estimate the association between mRNA coronavirus disease 2019 (COVID-19) vaccine exposure during pregnancy and the risks of preterm birth and congenital malformations leveraging a national population data.
Methods:
This retrospective cohort study utilized national data from the National Health Insurance System, linking maternal and infant records with COVID-19 vaccination registries.Newborns with congenital malformations were identified using diagnosis codes. The analysis included women aged 20–49 who gave live births between February 2022 and December 2022. Odds ratios (ORs) for preterm birth and any congenital malformation per COVID-19 vaccination during pregnancy compared to 1:4 matched unvaccinated controls, adjusted for maternal age, residential area, employment, income, disability, month of conception, prepregnancy obesity, smoking, and severe acute respiratory syndrome coronavirus 2 infection prior to pregnancy, were calculated. We compared the risk of two outcomes between BNT162b2 and mRNA-1273.
Results:
Among 106,692 women who gave birth during the study period, 8,966 (8.4%) received a COVID-19 vaccination during pregnancy. Of the newborns, 7,039 (6.6%) were preterm births and 7,658 (7.2%) had congenital malformations. COVID-19 vaccination during pregnancy was associated with a comparable risk of preterm birth (OR, 1.03; 95% confidence interval [CI], 0.77–1.36) and a similar risk of congenital malformations (0.90; 95% CI, 0.72–1.12) compared to non-vaccinees. The ORs of preterm birth (1.02; 95% CI, 0.77–1.36) and congenital malformation (0.91; 95% CI, 0.73–1.14) for mRNA-1273 were comparable to those for BNT162b2.
Conclusion
COVID-19 vaccines during pregnancy poses no increased risk of preterm birth and congenital malformations compared to those not exposed to the vaccine, with similar risk levels observed between the two mRNA vaccines. This finding provides additional evidence supporting the safety of COVID-19 vaccines.
2.Maternal Exposures to COVID-19 Vaccine and Adverse Birth Outcomes:National Population Study in Korea
Kyuwon KIM ; Erdenetuya BOLORMAA ; Eunseon GWAK ; Ju-Young SHIN ; Nam-Kyong CHOI ; Young June CHOE ; Seung-Ah CHOE
Journal of Korean Medical Science 2025;40(17):e63-
Background:
This study aimed to estimate the association between mRNA coronavirus disease 2019 (COVID-19) vaccine exposure during pregnancy and the risks of preterm birth and congenital malformations leveraging a national population data.
Methods:
This retrospective cohort study utilized national data from the National Health Insurance System, linking maternal and infant records with COVID-19 vaccination registries.Newborns with congenital malformations were identified using diagnosis codes. The analysis included women aged 20–49 who gave live births between February 2022 and December 2022. Odds ratios (ORs) for preterm birth and any congenital malformation per COVID-19 vaccination during pregnancy compared to 1:4 matched unvaccinated controls, adjusted for maternal age, residential area, employment, income, disability, month of conception, prepregnancy obesity, smoking, and severe acute respiratory syndrome coronavirus 2 infection prior to pregnancy, were calculated. We compared the risk of two outcomes between BNT162b2 and mRNA-1273.
Results:
Among 106,692 women who gave birth during the study period, 8,966 (8.4%) received a COVID-19 vaccination during pregnancy. Of the newborns, 7,039 (6.6%) were preterm births and 7,658 (7.2%) had congenital malformations. COVID-19 vaccination during pregnancy was associated with a comparable risk of preterm birth (OR, 1.03; 95% confidence interval [CI], 0.77–1.36) and a similar risk of congenital malformations (0.90; 95% CI, 0.72–1.12) compared to non-vaccinees. The ORs of preterm birth (1.02; 95% CI, 0.77–1.36) and congenital malformation (0.91; 95% CI, 0.73–1.14) for mRNA-1273 were comparable to those for BNT162b2.
Conclusion
COVID-19 vaccines during pregnancy poses no increased risk of preterm birth and congenital malformations compared to those not exposed to the vaccine, with similar risk levels observed between the two mRNA vaccines. This finding provides additional evidence supporting the safety of COVID-19 vaccines.
3.Maternal Exposures to COVID-19 Vaccine and Adverse Birth Outcomes:National Population Study in Korea
Kyuwon KIM ; Erdenetuya BOLORMAA ; Eunseon GWAK ; Ju-Young SHIN ; Nam-Kyong CHOI ; Young June CHOE ; Seung-Ah CHOE
Journal of Korean Medical Science 2025;40(17):e63-
Background:
This study aimed to estimate the association between mRNA coronavirus disease 2019 (COVID-19) vaccine exposure during pregnancy and the risks of preterm birth and congenital malformations leveraging a national population data.
Methods:
This retrospective cohort study utilized national data from the National Health Insurance System, linking maternal and infant records with COVID-19 vaccination registries.Newborns with congenital malformations were identified using diagnosis codes. The analysis included women aged 20–49 who gave live births between February 2022 and December 2022. Odds ratios (ORs) for preterm birth and any congenital malformation per COVID-19 vaccination during pregnancy compared to 1:4 matched unvaccinated controls, adjusted for maternal age, residential area, employment, income, disability, month of conception, prepregnancy obesity, smoking, and severe acute respiratory syndrome coronavirus 2 infection prior to pregnancy, were calculated. We compared the risk of two outcomes between BNT162b2 and mRNA-1273.
Results:
Among 106,692 women who gave birth during the study period, 8,966 (8.4%) received a COVID-19 vaccination during pregnancy. Of the newborns, 7,039 (6.6%) were preterm births and 7,658 (7.2%) had congenital malformations. COVID-19 vaccination during pregnancy was associated with a comparable risk of preterm birth (OR, 1.03; 95% confidence interval [CI], 0.77–1.36) and a similar risk of congenital malformations (0.90; 95% CI, 0.72–1.12) compared to non-vaccinees. The ORs of preterm birth (1.02; 95% CI, 0.77–1.36) and congenital malformation (0.91; 95% CI, 0.73–1.14) for mRNA-1273 were comparable to those for BNT162b2.
Conclusion
COVID-19 vaccines during pregnancy poses no increased risk of preterm birth and congenital malformations compared to those not exposed to the vaccine, with similar risk levels observed between the two mRNA vaccines. This finding provides additional evidence supporting the safety of COVID-19 vaccines.
4.Maternal Exposures to COVID-19 Vaccine and Adverse Birth Outcomes:National Population Study in Korea
Kyuwon KIM ; Erdenetuya BOLORMAA ; Eunseon GWAK ; Ju-Young SHIN ; Nam-Kyong CHOI ; Young June CHOE ; Seung-Ah CHOE
Journal of Korean Medical Science 2025;40(17):e63-
Background:
This study aimed to estimate the association between mRNA coronavirus disease 2019 (COVID-19) vaccine exposure during pregnancy and the risks of preterm birth and congenital malformations leveraging a national population data.
Methods:
This retrospective cohort study utilized national data from the National Health Insurance System, linking maternal and infant records with COVID-19 vaccination registries.Newborns with congenital malformations were identified using diagnosis codes. The analysis included women aged 20–49 who gave live births between February 2022 and December 2022. Odds ratios (ORs) for preterm birth and any congenital malformation per COVID-19 vaccination during pregnancy compared to 1:4 matched unvaccinated controls, adjusted for maternal age, residential area, employment, income, disability, month of conception, prepregnancy obesity, smoking, and severe acute respiratory syndrome coronavirus 2 infection prior to pregnancy, were calculated. We compared the risk of two outcomes between BNT162b2 and mRNA-1273.
Results:
Among 106,692 women who gave birth during the study period, 8,966 (8.4%) received a COVID-19 vaccination during pregnancy. Of the newborns, 7,039 (6.6%) were preterm births and 7,658 (7.2%) had congenital malformations. COVID-19 vaccination during pregnancy was associated with a comparable risk of preterm birth (OR, 1.03; 95% confidence interval [CI], 0.77–1.36) and a similar risk of congenital malformations (0.90; 95% CI, 0.72–1.12) compared to non-vaccinees. The ORs of preterm birth (1.02; 95% CI, 0.77–1.36) and congenital malformation (0.91; 95% CI, 0.73–1.14) for mRNA-1273 were comparable to those for BNT162b2.
Conclusion
COVID-19 vaccines during pregnancy poses no increased risk of preterm birth and congenital malformations compared to those not exposed to the vaccine, with similar risk levels observed between the two mRNA vaccines. This finding provides additional evidence supporting the safety of COVID-19 vaccines.
5.Safety of Biologics and Small Molecules for Inflammatory Bowel Diseases in Organ Transplant Recipients
Ga Hee KIM ; Minjun KIM ; Kyuwon KIM ; Jung-Bin PARK ; Ji Eun BAEK ; June Hwa BAE ; Seung Wook HONG ; Sung Wook HWANG ; Dong-Hoon YANG ; Byong Duk YE ; Jeong-Sik BYEON ; Seung-Jae MYUNG ; Suk-Kyun YANG ; Sang Hyoung PARK
Yonsei Medical Journal 2024;65(5):276-282
Purpose:
This study aimed to evaluate the safety of biologics and small molecules for the treatment of inflammatory bowel diseases (IBD) in patients receiving antirejection therapies after organ transplants.
Materials and Methods:
We reviewed the medical records of patients with IBD who received organ transplants at the Asan Medical Center between January 1989 and December 2021. We compared the parameters of patients receiving biologics or small molecules to those of patients without those therapies.
Results:
This study included a total of 53 patients (ulcerative colitis, 41; Crohn’s disease, 6; and gastrointestinal Behçet’s disease, 6). Among them, 15 patients were receiving biologics or small molecules and 38 were not. During a mean follow-up of 119 months, the proportion of patients experiencing severe infections was significantly higher in those treated with biologics or small molecules than in those not treated. However, other safety outcomes (e.g., malignancies, adverse events, including organizing pneumonia or hepatic failure, and death) were not different between the two groups. Kaplan–Meier curve analysis revealed no significant difference in the safety outcome rate related to the use of biologics or small molecules. During follow-up, eight patients underwent bowel resections for IBD. The rate of bowel resection was not different between the two groups.
Conclusion
The use of biologics or small molecules for patients with IBD who received organ transplants did not show a significant difference in safety outcomes. However, the possibility of severe infections must be considered.
6.Impact of Crohn’s Disease on the Survival of Patients with Small-Bowel Adenocarcinoma in Korea: A Bicenter Cohort Study
Kyuwon KIM ; Kookhwan CHOI ; Sung Wook HWANG ; Jong Pil IM ; Byong Duk YE ; Joo Sung KIM ; Kyu Joo PARK ; Suk-Kyun YANG ; Seong-Joon KOH ; Sang Hyoung PARK ;
Gut and Liver 2023;17(4):581-590
Background/Aims:
Owing to the low prevalence of small-bowel adenocarcinoma (SBA), data on the impact of Crohn’s disease (CD) on the survival of patients with SBA are lacking. Therefore, we investigated this issue in this study.
Methods:
In this bicenter cohort study, patients with histologically confirmed SBA were retrospectively enrolled and classified into two groups: sporadic SBA and CD-associated SBA. Patients with duodenal SBA were excluded. Overall survival, disease-free survival, and factors associated with survival were analyzed.
Results:
Of 128 patients with SBA, 115 had sporadic SBA and 13 had CD-associated SBA. Ileal involvement and poorly differentiated tumors were more common in the CD-associated SBA group than in the sporadic SBA group (ileal involvement, 53.8% vs 22.6%; poor differentiation, 46.2% vs 14.8%; both p<0.05). In survival analysis, overall survival showed no statistical difference between the sporadic SBA and CD-associated SBA groups (p=0.370). However, when stratified by stage, the adjusted overall survival of the CD-associated SBA group was lower in patients with an advanced disease stage (p=0.029). Disease-free survival showed the same tendency, albeit without clinical significance (p=0.097). CD (hazard ratio [HR], 2.308; p=0.047), older age (≥65 yr) at SBA diagnosis (HR, 2.766; p=0.001), and stage III/IV disease (HR, 3.151; p<0.001) were factors associated with mortality.
Conclusions
The overall survival of patients with CD-associated SBA did not differ from that of patients with sporadic SBA. However, as CD is an independent risk factor for mortality, vigilant surveillance in high-risk patients may be crucial.
7.Technical Feasibility of Quantitative Measurement of Various Degrees of Small Bowel Motility Using Cine Magnetic Resonance Imaging
Ji Young CHOI ; Jihye YUN ; Subin HEO ; Dong Wook KIM ; Sang Hyun CHOI ; Jiyoung YOON ; Kyuwon KIM ; Kee Wook JUNG ; Seung-Jae MYUNG
Korean Journal of Radiology 2023;24(11):1093-1101
Objective:
Cine magnetic resonance imaging (MRI) has emerged as a noninvasive method to quantitatively assess bowel motility. However, its accuracy in measuring various degrees of small bowel motility has not been extensively evaluated. We aimed to draw a quantitative small bowel motility score from cine MRI and evaluate its performance in a population with varying degrees of small bowel motility.
Materials and Methods:
A total of 174 participants (28.5 ± 7.6 years; 135 males) underwent a 22-second-long cine MRI sequence (2-dimensional balanced turbo-field echo; 0.5 seconds per image) approximately 5 minutes after being intravenously administered 10 mg of scopolamine-N-butyl bromide to deliberately create diverse degrees of small bowel motility. In a manually segmented area of the small bowel, motility was automatically quantified using a nonrigid registration and calculated as a quantitative motility score. The mean value (MV) of motility grades visually assessed by two radiologists was used as a reference standard. The quantitative motility score’s correlation (Spearman’s ρ) with the reference standard and performance (area under the receiver operating characteristics curve [AUROC], sensitivity, and specificity) for diagnosing adynamic small bowel (MV of 1) were evaluated.
Results:
For the MV of the quantitative motility scores at grades 1, 1.5, 2, 2.5, and 3, the mean ± standard deviation values were 0.019 ± 0.003, 0.027 ± 0.010, 0.033 ± 0.008, 0.032 ± 0.009, and 0.043 ± 0.013, respectively. There was a significant positive correlation between the quantitative motility score and the MV (ρ = 0.531, P < 0.001). The AUROC value for diagnosing a MV of 1 (i.e., adynamic small bowel) was 0.953 (95% confidence interval, 0.923–0.984). Moreover, the optimal cutoff for the quantitative motility score was 0.024, with a sensitivity of 100% (15/15) and specificity of 89.9% (143/159).
Conclusion
The quantitative motility score calculated from a cine MRI enables diagnosis of an adynamic small bowel, and potentially discerns various degrees of bowel motility.
8.Risk factors for early-onset lung cancer in Korea: analysis of a nationally representative population-based cohort
Jihun KANG ; Taeyun KIM ; Kyung-Do HAN ; Jin-Hyung JUNG ; Su-Min JEONG ; Yo Hwan YEO ; Kyuwon JUNG ; Hyun LEE ; Jong Ho CHO ; Dong Wook SHIN
Epidemiology and Health 2023;45(1):e2023101-
OBJECTIVES:
We examined the associations of socioeconomic factors, health behaviors, and comorbidities with early-onset lung cancer.
METHODS:
The study included 6,794,287 individuals aged 20-39 years who participated in a Korean national health check-up program from 2009 to 2012. During the follow-up period, 4,684 participants developed lung cancer. Multivariable Cox regression analysis was used to estimate the independent associations of potential risk factors with incident lung cancer.
RESULTS:
Older age (multivariable hazard ratio [mHR], 1.13; 95% confidence interval [CI], 1.12 to 1.14) and female sex (mHR, 1.62; 95% CI, 1.49 to 1.75) were associated with increased lung cancer risk. Current smoking was also associated with elevated risk (<10 pack-years: mHR, 1.12; 95% CI, 1.01 to 1.24; ≥10 pack-years: mHR, 1.30; 95% CI, 1.18 to 1.45), but past smoking was not. Although mild alcohol consumption (<10 g/day) was associated with lower lung cancer risk (mHR, 0.92; 95% CI, 0.86 to 0.99), heavier alcohol consumption (≥10 g/day) was not. Higher income (highest vs. lowest quartile: mHR, 0.86; 95% CI, 0.78 to 0.94), physical activity for at least 1,500 metabolic equivalent of task-min/wk (vs. non-exercisers: mHR, 0.83; 95% CI, 0.69 to 0.99) and obesity (vs. normal weight: mHR, 0.89; 95% CI, 0.83 to 0.96) were associated with lower lung cancer risk, whereas metabolic syndrome was associated with increased risk (mHR, 1.13; 95% CI, 1.03 to 1.24).
CONCLUSIONS
In young adults, age, female sex, smoking, and metabolic syndrome were risk factors for early-onset lung cancer, while high income, physical activity, and obesity displayed protective effects.
9.Oral beclomethasone dipropionate as an add-on therapy and response prediction in Korean patients with ulcerative colitis
Kyuwon KIM ; Hee Seung HONG ; Kyunghwan OH ; Jae Yong LEE ; Seung Wook HONG ; Jin Hwa PARK ; Sung Wook HWANG ; Dong-Hoon YANG ; Jeong-Sik BYEON ; Seung-Jae MYUNG ; Suk-Kyun YANG ; Byong Duk YE ; Sang Hyoung PARK
The Korean Journal of Internal Medicine 2022;37(6):1140-1152
Background/Aims:
We aimed to investigate the oral beclomethasone dipropionate’s (BDP) efficacy as an add-on therapy and to clarify the predictive factor for response to oral BDP in Korean ulcerative colitis (UC) patients.
Methods:
Patients with a stable concomitant drug regimen with exposure to oral BDP (5 mg/day) within 30 days before BDP initiation were included. Partial Mayo score (pMS) was used to evaluate response to oral BDP. Clinical remission (CREM) was defined as a post-treatment pMS ≤ 1 point. Clinical response (CRES) was defined as an at least 2-point decrease in post-treatment pMS and an at least 30% decrease from baseline pMS. Patients without CREM or CRES were considered nonresponders (NRs).
Results:
Of all, 37 showed CREM, 19 showed CRES, and 44 were NRs. The CREM group included more patients with mild disease activity (75.7% vs. 43.2%, p = 0.011) than NRs. In contrast to NRs, CREM and CRES patients showed significant improvement of post-treatment erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) (ESR with p = 0.001, CRP with p = 0.004, respectively). Moreover, the initial rectal bleeding subscore (RBS) was significantly different between CREM and CRES, or NR (both with p < 0.001). In multivariate analyses, initial stool frequency subscore (SFS) of 0 and RBS of 0 were predictive factors for CREM (odds ratio [OR], 15.359; 95% confidence interval [CI], 1.085 to 217.499; p = 0.043 for SFS, and OR, 11.434; 95% CI, 1.682 to 77.710; p = 0.013 for RBS).
Conclusions
Oral BDP is an efficacious add-on therapy in Korean UC patients. Patients with initial SFS or RBS of 0 may be particularly good candidates for oral BDP.
10.Medication Adherence in Korean Patients with Inflammatory Bowel Disease and Its Associated Factors
Kyunghwan OH ; Eun Ja KWON ; Jeong Hye KIM ; Kyuwon KIM ; Jae Yong LEE ; Hee Seung HONG ; Seung Wook HONG ; Jin Hwa PARK ; Sung Wook HWANG ; Dong-Hoon YANG ; Byong Duk YE ; Jeong-Sik BYEON ; Seung-Jae MYUNG ; Suk-Kyun YANG ; Jeong Yun PARK ; Sang Hyoung PARK
The Ewha Medical Journal 2022;45(2):35-45
Objectives:
It is important that inflammatory bowel disease (IBD) patients adhere to their prescribed medication regimens to avoid the repeat exacerbations, complications, or surgeries associated with this disorder. However, there are few studies on medication adherence in patients with IBD, especially in Asian populations. So, we analyzed the factors associated with medication adherence in Korean IBD patients.
Methods:
Patients who had been diagnosed with Crohn’s disease (CD) or ulcerative colitis (UC) more than 6 months previously and receiving oral medications for IBD were enrolled. Medication adherence was measured using the Medical Adherence Reporting Scale (MARS-5), a self-reported medication adherence measurement tool.
Results:
Among 207 patients in the final study population, 125 (60.4%) had CD and 134 (64.7%) were men. The mean age was 39.63 years (SD, 13.16 years) and the mean disease duration was 10.09 years (SD, 6.33 years). The mean medication adherence score was 22.46 (SD, 2.86) out of 25, and 181 (87.4%) patients had score of 20 or higher.In multiple linear regression analysis, self-efficacy (β=0.341, P<0.001) and ≥3 dosing per day (β=–0.192 P=0.016) were revealed to be significant factors associated with medication adherence. Additionally, there was a positive correlation between self-efficacy and medication adherence (r=0.312, P<0.001). However, disease related knowledge, depression, and anxiety were not significantly associated with medication adherence.
Conclusion
To improve medication adherence among patients with IBD, a reduction in the number of doses per day and an improved self-efficacy will be helpful.

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