• Fisheries and Aquatic Sciences
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• 제7권3호
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• pp.141-147
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• 2004

Sixteen polycyclic aromatic hydrocarbons (PAHs) were analyzed in seventy marine organisms (40 species) from the Korean coast. PAHs were present in all the organisms. The level of total PAHs in the organisms varied from 0.45 to 224 ng/g dry weight and the carcinogenic PAHs varied from 0.05 to 49.8 ng/g dry weight. The PAHs residues according to the marine organisms showed a highest content in bivalve species, and followed by crustaceans, cephalopods, fish and gastropods. Human dietary intake of total PAHs through marine organism in Korea was estimated to be 4.12 ng/kg body weight/day and 0.67 ng/kg body weight/day for carcinogenic PAHs. The relative contributions of individual species to the total dietary intake of PAHs were in the order of bivalves $(53.4{\%})$, fish $(21.9{\%})$, crustaceans $(15.3{\%})$, cephalopods $(8.8{\%})$ and gastropods $(0.6{\%})$. Daily dietary intake of $PAH_{TEQ}$ expressed as a TEQ value was estimated to be 0.13 pg TEQ/kg body weight/day, which did not exceed a tolerable daily intake (TDI) proposed by the KFDA and the WHO as well as the UK toxicity committee. Lifetime cancer risk due to ingestion of marine species by the Korean adult was evaluated using the equation estimating exposure of food ingestion. Although approximately $23{\%}$ of cumulative frequency of the sampled marine species exceeded the cancer risk guideline, lifetime cancer risk associated with marine organism consumption was negligible. Results indicate that dietary intake of PAHs through the consumption of the Korean marine organisms seems to be safe for human ingestion with negligible cancer risk.

• Journal of Korean Neurosurgical Society
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• 제59권1호
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• pp.11-16
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• 2016

Objective : We conducted a retrospective cohort study to elucidate the natural course of unruptured intracranial aneurysms (UIAs) at a single institution. Methods : Data from patients diagnosed with UIA from March 2000 to May 2008 at our hospital were subjected to a retrospective analysis. The cumulative and annual aneurysm rupture rates were calculated. Additionally, risk factors associated with aneurysmal rupture were identified. Results : A total of 1339 aneurysms in 1006 patients met the inclusion criteria. During the follow-up period, 685 aneurysms were treated before rupture via either an open surgical or endovascular procedure. Six hundred fifty-four UIAs were identified and not repaired during the follow-up period. The mean UIA size was $4.5{\pm}3.2mm$, and 86.5% of the total UIAs had a largest dimension <7 mm. Among these UIAs, 18 ruptured at a median of 1.6 years (range : 27 days to 9.8 years) after day 0. The annual rupture risk during a 9-year follow-up was 1.00%. A multivariate Cox proportional hazards analysis revealed that the aneurysm size and a history of subarachnoid hemorrhage (SAH) were statistically significant risk factors for rupture. For an aneurysms smaller than 7 mm in the absence of a history of SAH, the annual rupture risk was 0.79%. Conclusion : In our study, the annual rupture risk for UIAs smaller than 7 mm in the absence of a history of SAH was higher than that of Western populations but similar to that of the Japanese population.

• Asian Pacific Journal of Cancer Prevention
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• 제14권5호
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• pp.2783-2787
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• 2013

To assess the risk of cancer incidence after medical radiation exposure for coronary artery disease (CAD), a retrospective cohort study was conducted based on Taiwan's National Health Insurance Research Database (NHIRD). Patients with CAD were identified according to the International Classification of Diseases code, 9th Revision, Clinical Modification (ICD-9-CM), and their records of medical radiation procedures were collected from 1997 to 2010. A total of 18,697 subjects with radiation exposure from cardiac imaging or therapeutic procedures for CAD were enrolled, and 19,109 subjects receiving cardiac diagnostic procedures without radiation were adopted as the control group. The distributions of age and gender were similar between the two populations. Cancer risks were evaluated by age-adjusted incidence rate ratio (aIRR) and association with cumulative exposure were further evaluated with relative risks by Poisson regression analysis. A total of 954 and 885 subjects with various types of cancers in both cohorts after following up for over 10 years were found, with incidences of 409.8 and 388.0 per 100,000 person-years, respectively. The risk of breast cancer (aIRR=1.85, 95% confidence interval: 1.14-3.00) was significantly elevated in the exposed female subjects, but no significant cancer risk was found in the exposed males. In addition, cancer risks of the breast and lung were increased with the exposure level. The study suggests that radiation exposure from cardiac imaging or therapeutic procedures for CAD may be associated with the increased risk of breast and lung cancers in CAD patients.

• 한국임상약학회지
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• 제29권3호
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• pp.147-155
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• 2019

Objectives: The purpose of this study was to investigate the association between fracture risk and proton pump inhibitor (PPI) use to establish evidence for defining high-risk groups of fracture among PPI users. Methods: A case-control study was performed using the National Health Insurance Sample Cohort Database from January 2002 to December 2013. The cases included all incidences of major fractures identified from January 2011 to December 2013, and up to four controls were matched to each case by age, gender, osteoporosis, and Charlson comorbidity index. Conditional logistic regression was used to calculate the adjusted odds ratio (aOR) and associated 95% confidence interval (CI). Results: Overall, 14,295 cases were identified, and 63,435 controls were matched to the cases. The aOR of fractures related to the use of PPIs was 1.06 (95% CI: 1.01-1.11). There was a statistically significant association between fracture and PPI use within 3 months of the last dose, and a trend of increasing fracture risk with increasing cumulative PPI dose. The risk of fracture was significantly higher in patients who took PPIs for more than 1 year during the 2-year observation period. Conclusion: Patients who have been using PPIs for more than 1 year should be warned about the risk of fracture during or at least 3 months after discontinuing the PPI.

• The Korean Journal of Pain
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• 제35권1호
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• pp.86-96
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• 2022

Background: To explore the association between low back pain (LBP) and pelvic pain (PP) and rectus abdominis diastasis (RAD) in postpartum women and identify the characteristics and risk factors. Methods: Women diagnosed with RAD and a history of labor and delivery, between 2009 and 2018, were identified from six hospitals within the Partners Healthcare System. Univariate and multivariable binary logistic regression analyses were used to identify the risk factors associated with pain. Results: Age at onset of RAD in the non-cesarean delivery group was earlier than those in cesarean delivery (CD) group (P = 0.017). Women who underwent CD demonstrated 4.5 times greater risk of RAD than those who had no CD exposure. The cumulative composition ratio of LBP at every age stage of the period from 8 years pre-first delivery to 8 years post-first delivery was significantly higher than the other five conditions (RAD, umbilical hernia, PP, depressive disorder [DD], and strain of muscle, fascia, and tendon [SMFT]) (P for trend < 0.001). Women with DD, SMFT, and PP were more likely to have LBP (odds ratio [OR] = 1.91, 95% confidence interval [CI] 1.06 to 3.47, P = 0.032; OR = 4.50, 95% CI 1.64 to 12.36, P = 0.003; OR = 2.14, 95% CI 1.17 to 3.89, P = 0.013; respectively). Conclusions: In postpartum women with RAD, DD, SMFT, and PP were found to be risk factors contributing to the development of LBP. Race and LBP also played roles in the development of PP.

• The Journal of Advanced Prosthodontics
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• 제3권4호
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• pp.229-235
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• 2011

PURPOSE. The aim of this retrospective study was to evaluate cumulative survival rate (CSR) of Implantium implants followed for 5 years and association between risk factors and the CSR. MATERIALS AND METHODS. A total of two hundred forty-nine Implantium Implants System (Dentium, Seoul, Korea) placed in ninety-five patients from 2004 to 2009 were investigated with several identified risk factors (sex, systemic disease, smoking, alchohol, reason of tooth loss, length, arch (maxilla or mandible), replace tooth type (incisor, canine, premolar or molar) Kennedy classification, prosthodontic type, prosthodontic design, opposite dentition, abutment type, occlusal material, occlusal unit, splint to tooth, cantilever, other surgery). Clinical examination (mobility, percussion, screw loosening, discomfort, etc.) and radiographic examination data were collected from patient records including all problems during follow-up period according to protocols described earlier. Life table analysis was undertaken to examine the CSR. Cox regression method was conducted to assess the association between potential risk factors and overall CSR. RESULTS. Five of 249 implants were failed. Four of these were lost before loading. The 5-year implant cumulative survival rate was 97.37%. Cox regression analysis demonstrated a significant predictive association between overall CSR and systemic disease, smoking, reason of tooth loss, arch, Kennedy classification and prosthodontic design (P<.05). The screw related complication was rare. Two abutment screw fractures were found. Another complications of prosthetic components were porcelain fracture, resin facing fracture and denture fracture (n=19). CONCLUSION. The 5-year CSR of Implantium implants was 97.37 %. Implant survival may be dependent upon systemic disease, smoking reason of tooth loss, arch, Kennedy classification and prosthodontic design (P<.05). The presence of systemic diseases and combination of other surgical procedures may be associated with increased implant failure.

• 한국가스학회지
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• 제20권2호
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• pp.35-42
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• 2016

포름아미드(formamide)는 암모니아 냄새의 무색 액체로 흡입 시 자극성이 강하며, 급성독성 $LD_{50}$ 5,577 mg/kg(랫드), 표적장기(간장) 전신독성의 무유해영향농도(NOAEL)는 113 mg/kg/day) 및 생식독성물질(1B)로 작업환경 노출기준은 10 ppm이었다. 포름아마이드 취급사업장에 대한 작업환경 측정결과는 25개 시료 모두가 노출기준보다 매우 낮은 농도를 보였다. 그러나 작업강도, 국소배기장치의 가동 및 보호구(방독마스크)의 착용 여부 등 작업환경에 따라 노출농도가 변할 수 있어 가상 노출 시나리오별 노출량을 산출한 결과 노출량은 $5.16mg/m^3$, $1.72mg/m^3$, $0.43mg/m^3$으로 산출되었다. 이를 전신독성 및 생식독성의 유해성을 고려한 위험성을 평가한 결과 평균값은 0.02-0.58, 누적 90% 값은 0.02-0.66, 95% 값은 0.02-0.69로 모두 1보다 낮은 대체로 안전한 값으로 산출되었다. 단, 작업 상황에 따라 순간적 고농도에 노출될 위험도 있으며, 간독성 및 생식독성 물질이기에 건강장해 예방을 위해 노출되지 않도록 취급 시 주의가 요망된다.

• 지능정보연구
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• 제26권1호
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• pp.135-149
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• 2020

인공지능을 기반으로 한 다양한 연구들이 현대사회에 많은 변화를 불러일으키고 있다. 금융시장 역시 예외는 아니다. 로보어드바이저 개발이 활발하게 진행되고 있으며 전통적 방식의 단점을 보완하고 사람이 분석하기 어려운 부분을 대체하고 있다. 로보어드바이저는 인공지능 알고리즘으로 자동화된 투자 결정을 내려 다양한 자산배분 모형과 함께 활용되고 있다. 자산배분 모형 중 리스크패리티는 대표적인 위험 기반 자산배분 모형의 하나로 큰 자산을 운용하는 데 있어 안정성을 나타내고 현업에서 역시 널리 쓰이고 있다. 그리고 XGBoost 모형은 병렬화된 트리 부스팅 기법으로 제한된 메모리 환경에서도 수십억 가지의 예제로 확장이 가능할 뿐만 아니라 기존의 부스팅에 비해 학습속도가 매우 빨라 많은 분야에서 널리 활용되고 있다. 이에 본 연구에서 리스크패리티와 XGBoost를 장점을 결합한 모형을 제안하고자 한다. 기존에 널리 사용되는 최적화 자산배분 모형은 과거 데이터를 기반으로 투자 비중을 추정하기 때문에 과거와 실투자 기간 사이의 추정 오차가 발생하게 된다. 최적화 자산배분 모형은 추정 오차로 인해 포트폴리오 성과에서 악영향을 받게 된다. 본 연구는 XGBoost를 통해 실투자 기간의 변동성을 예측하여 최적화 자산배분 모형의 추정 오차를 줄여 모형의 안정성과 포트폴리오 성과를 개선하고자 한다. 본 연구에서 제시한 모형의 실증 검증을 위해 한국 주식시장의 10개 업종 지수 데이터를 활용하여 2003년부터 2019년까지 총 17년간 주가 자료를 활용하였으며 in-sample 1,000개, out-of-sample 20개씩 Moving-window 방식으로 예측 결과값을 누적하여 총 154회의 리밸런싱이 이루어진 백테스팅 결과를 도출하였다. 본 연구에서 제안한 자산배분 모형은 기계학습을 사용하지 않은 기존의 리스크패리티와 비교하였을 때 누적수익률 및 추정 오차에서 모두 개선된 성과를 보여주었다. 총 누적수익률은 45.748%로 리스크패리티 대비 약 5% 높은 결과를 보였고 추정오차 역시 10개 업종 중 9개에서 감소한 결과를 보였다. 실험 결과를 통해 최적화 자산배분 모형의 추정 오차를 감소시킴으로써 포트폴리오 성과를 개선하였다. 포트폴리오의 추정 오차를 줄이기 위해 모수 추정 방법에 관한 다양한 연구 사례들이 존재한다. 본 연구는 추정 오차를 줄이기 위한 새로운 추정방법으로 기계학습을 제시하여 최근 빠른 속도로 발전하는 금융시장에 맞는 진보된 인공지능형 자산배분 모형을 제시한 점에서 의의가 있다.

• 한국산업보건학회지
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• 제31권3호
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• pp.286-293
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• 2021

Objectives: Inorganic dust is known to be a risk factor for chronic obstructive pulmonary disease (COPD) regardless of smoking and pneumoconiosis. Adaptive and innate immunity, including lymphocyte infiltrate, are involved in the pathogenesis of COPD. The purpose of this study was to analyze the lymphocyte subsets in the blood of workers exposed to inorganic dust and confirm the influencing factors. Methods: The general characteristics of the subjects (n=107) were analyzed through a personal questionnaire. Diagnosis of COPD was established according to pulmonary function tests with FEV₁/FVC post bronchodilator lower than 70%, according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines. For lymphocyte analysis, blood was stained with a fluorescent CD marker and analyzed by flow cytometry. Results: The increase in CD4⁺ T lymphocytes was associated with a decrease in age (𝛽=-0.273, p=0.008) and an increase in the cumulative smoking amount (𝛽=0.205, p=0.034). The increase in NK cells was associated with an increase in age (𝛽=0.325, p=0.001) and a decrease in cumulative smoking (𝛽=-0.220, p=0.019). The period of exposure to dust, %FVC predicted and %FEV₁/FVC, and the relative population of peripheral blood lymphocytes did not show a statistically significant relationship. Conclusions: CD4⁺ T lymphocytes and CD56⁺CD16⁺ NK cells in peripheral blood were more related to age and cumulative smoking than the duration of dust exposure. Age and smoking are major risk factors for the development of COPD, so it can be predicted that peripheral blood CD4⁺ T lymphocytes and CD56⁺CD16⁺ NK cells are related to the development of COPD in workers exposed to inorganic dust.

• 정신신체의학
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• 제28권2호
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• pp.108-115
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• 2020

연구목적 본 연구는 한국 기혼 여성에서 만성적인 친밀한 관계에서의 폭력이 자살사고에 미치는 영향에 대해 조사하였다. 방 법 2014년부터 2018년까지의 한국복지패널의 자료를 사용하였으며 매년 조사된 설문을 이용하여 언어폭력 및 신체폭력이 우울증상 및 자살사고에 미치는 영향을 분석하였다. 나이, 교육수준, 경제수준, 음주, 종교, 만성질환, 가족관계 만족도, 사회관계 만족도 등을 공변량으로 하였다. 결 과 5년 간의 언어폭력 노출지수는 우울을 1.180배, 자살사고를 1.276배 높였으며 이는 우울증상의 영향을 보정해도 유의하였다. 반면, 5년 간의 신체폭력 노출지수는 우울을 1.486배, 자살사고를 1.362배 높였으며 우울증상의 영향을 배제하였을 때는 자살사고에 유의미한 영향을 주지 않았다. 결 론 이전에는 자살 사고가 없었던 여성에게 IPV가 장기적으로 지속되었을 때 우울증상의 유무와 상관없이 자살 사고를 높일 수 있다는 것을 밝혀낸 것에 의의가 있다. 위와 같은 결과를 고려하면 IPV를 경험한 여성에 대한 정신과적 개입이 자살률을 줄이는 데 도움이 될 것이다.