• 한국환경과학회지
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• 제17권5호
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• pp.517-524
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• 2008

The purpose of this study was to investigate the characteristics of air quality using data from which obtain local air quality monitoring system for cohort study in Chungju, Korea. We analyzed the concentration data of $NO_2,\;SO_2$, and $PM_{10}$ in Chungju and industrial cities in 2006. We compared a industrial area with a cohort study area using by bicluster algorithm. In the case of $SO_2$, the rate of the cluster time was $10{\sim}60%$ and the cluster time number of two areas was similar. In the case of $NO_2$ and $PM_{10}$, the number of cluster time between a industrial area and cohort study area was clearly different.

• Journal of Preventive Medicine and Public Health
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• 제14권1호
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• pp.43-51
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• 1981

The objective of the study is to measure the changes in measles infection and measles vaccination rates for the past 10 years in a rural area, Kang Wha. The study population were the entire children who were born between 1971 and 1950 in three townships (Sunwon, Naegae, Buleun) in Kangwha County. Two interview surveys were carried out during the 10 years of period, one in 1977 and the other in 1981. The data were collected by Family Health Workers through interview with structured questionnaires. The diagnosis of measles was mainly based on histories, symptoms and sighs of the disease. If a mother had reported measles history of her child, a public physician reviewed and decided the final diagnosis of the reported case. A retrospective cohort observation was done in order to see the trends of measles infections and measles vaccinations. The major findings were as follows; 1. The 5 year prevalence rate of measles vaccinations was 51.3% between 1971 and 1975 and 71.9% between 1976 and 1980 respectively. The difference between two periods was statistically significant (P<0.05). The secular trend of measles vaccinations showed increasing tendency from 1971 to 1978 and since then kept maintained. 2. In the birth cohort analysis of measles vaccinations, the vaccination rates, in general, were higher in the later cohort groups than that of earlier cohort groups. 9. The 5-year experience rates for measles infections were 24.3% between 1971 and 1975 and 17.2% between 1976 and 1980 respectively. This difference was statistically significant(P<0.05). The secular trend of experience rates for measles infections showed decreasing tendency from 1971 to 1980 except an outbreak in 1976. 4. The birth cohort analysis of experience rates for measles infections showed that the rate was higher in the later cohort groups than that of the earlier cohort groups. This decreasing tendency was prominent between $1973{\sim}1974$ and $1976{\sim}1977$. 5. The distribution of age specific incidence rates for measles infections showed unimodal curve with the peak at the age of 12 to 18 months. This findings were same in both two surveys. 6. Seasonal variations of the measles infections showed two peaks, one major peak in March through May and the another minor peak in September through December. 7. The 5-year reduction rate for measles infections among those vaccinated was 90.4% between 1971 and 1975 and 88% between 1976 and 1980.

• Asian Pacific Journal of Cancer Prevention
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• 제14권1호
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• pp.275-279
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• 2013

Objectives: A number of studies have shown that chronic hepatitis B virus infection is implicated in susceptibility to pancreatic cancer. However, the results are still controversial. This meta-analysis aimed to quantitatively assess the relationship between chronic hepatitis B virus infection and incidence of pancreatic cancer of cohort and case-control studies. Methods: A literature search was performed for entries from 1990 to 2012 using PUBMED and EMBASE. Studies were included if they reported odds ratios (ORs) and corresponding 95% CIs of pancreatic cancer with respect to the infection of hepatitis B virus. Results: Eight studies met the inclusion criteria, which included five case-control studies and three cohort studies. Compared with individuals who have not infection of hepatitis B virus, the pooled OR of pancreatic cancer was 1.403 (95%CI: 1.139-1.729, P=0.001) for patients with hepatitis B virus infection. Sub-group analysis by study design showed that the summary OR was 1.43 (95%CI: 1.06-1.94, P=0.021) when pooling case-control studies and 1.31 (95%CI: 1.00-1.72, P=0.05) when pooling cohort studies. Conclusion: Findings from this meta-analysis suggest that chronic hepatitis B virus infection may increase the risk of pancreatic cancer. This relationship needs to be confirmed by further follow-up studies.

• Annals of Occupational and Environmental Medicine
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• 제35권
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• pp.11.1-11.17
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• 2023

Background: Studies on the relationship between organic solvent exposure and chronic kidney disease (CKD) have presented inconsistent results. Definition of CKD has changed in 2012, and other cohort studies have been newly published. Therefore, this study aimed to newly confirm the relationship between organic solvent exposure and CKD through an updated meta-analysis including additional studies. Methods: This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The search was conducted on January 2, 2023 using Embase and MEDLINE databases. Case-control and cohort studies on the relationship between organic solvent exposure and CKD were included. Two authors independently reviewed full-text. Results: Of 5,109 studies identified, a total of 19 studies (control studies: 14 and cohort studies: 5) were finally included in our meta-analysis. The pooled risk of CKD in the organic solvent exposed group was 2.44 (1.72-3.47). The risk of a low-level exposure group was 1.07 (0.77-1.49). The total risk of a high-level exposure group was 2.44 (1.19-5.00). The risk of glomerulonephritis was 2.69 (1.18-6.11). The risk was 1.46 (1.29-1.64) for worsening of renal function. The pooled risk was 2.41 (1.57-3.70) in case-control studies and 2.51 (1.34-4.70) in cohort studies. The risk of subgroup classified as 'good' by the Newcastle Ottawa scale score was 1.93 (1.43-2.61). Conclusions: This study confirmed that the risk of CKD was significantly increased in workers exposed to mixed organic solvents. Further research is needed to determine the exact mechanisms and thresholds. Surveillance for kidney damage in the group exposed to high levels of organic solvents should be conducted.

• Journal of Preventive Medicine and Public Health
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• 제56권1호
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• pp.1-11
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• 2023

In 1945, atomic bombs were dropped on Hiroshima and Nagasaki. Approximately 70 000 Koreans are estimated to have been exposed to radiation from atomic bombs at that time. After Korea's Liberation Day, approximately 23 000 of these people returned to Korea. To investigate the long-term health and hereditary effects of atomic bomb exposure on the offspring, cohort studies have been conducted on atomic bomb survivors in Japan. This study is an ongoing cohort study to determine the health status of Korean atomic bomb survivors and investigate whether any health effects were inherited by their offspring. Atomic bomb survivors are defined by the Special Act On the Support for Korean Atomic Bomb Victims, and their offspring are identified by participating atomic bomb survivors. As of 2024, we plan to recruit 1500 atomic bomb survivors and their offspring, including 200 trios with more than 300 people. Questionnaires regarding socio-demographic factors, health behaviors, past medical history, laboratory tests, and pedigree information comprise the data collected to minimize survival bias. For the 200 trios, whole-genome analysis is planned to identify de novo mutations in atomic bomb survivors and to compare the prevalence of de novo mutations with trios in the general population. Active follow-up based on telephone surveys and passive follow-up with linkage to the Korean Red Cross, National Health Insurance Service, death registry, and Korea Central Cancer Registry data are ongoing. By combining pedigree information with the findings of trio-based whole-genome analysis, the results will elucidate the hereditary health effects of atomic bomb exposure.

• Clinical and Experimental Reproductive Medicine
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• 제41권4호
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• pp.158-164
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• 2014

Objective: To assess whether an early GnRH antagonist start leads to better follicular synchronization and an improved clinical pregnancy rate (CPR). Methods: A retrospective cohort study. A total of 218 infertile women who underwent IVF between January 2011 and February 2013. The initial cohort (Cohort I) that underwent IVF between January 2011 and March 2012 included a total of 68 attempted IVF cycles. Thirty-four cycles were treated with the conventional GnRH antagonist protocol, and 34 cycles with an early GnRH antagonist start protocol. The second cohort (Cohort II) that underwent IVF between June 2012 and February 2013 included a total of 150 embryo-transfer (ET) cycles. Forty-three cycles were treated with the conventional GnRH antagonist protocol, 34 cycles with the modified early GnRH antagonist start protocol using highly purified human menopause gonadotropin and an addition of GnRH agonist to the luteal phase support, and 73 cycles with the GnRH agonist long protocol. Results: The analysis of Cohort I showed that the number of mature oocytes retrieved was significantly higher in the early GnRH antagonist start cycles than in the conventional antagonist cycles (11.9 vs. 8.2, p=0.04). The analysis of Cohort II revealed higher but non-significant CPR/ET in the modified early GnRH antagonist start cycles (41.2%) than in the conventional antagonist cycles (30.2%), which was comparable to that of the GnRH agonist long protocol cycles (39.7%). Conclusion: The modified early antagonist start protocol may improve the mature oocyte yield, possibly via enhanced follicular synchronization, while resulting in superior CPR as compared to the conventional antagonist protocol, which needs to be studied further in prospective randomized controlled trials.

• 대한치과보철학회지
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• 제58권3호
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• pp.193-200
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• 2020

목적: 대규모 인구집단데이터를 사용하여 양측 또는 편측 완전 무치악 여부와 치매와의 관련성에 대하여 알아본다. 재료 및 방법: 만 60세 이상을 대상으로 구축된 건강보험공단 노인 코호트 데이터베이스를 사용하여 후향적 코호트 연구를 설계하였다. 실험군은 완전 무치악 코호트로 2012년 7월 1일부터 2013년 12월 31일 까지 1개 이상의 상악 또는 하악 레진상 완전의치 보험 처방 이력이 있는 사람을 대상으로 하였고, 대조군은 유치악 코호트로 같은 기간 동안 잔존치아에 대한 보존적 치아 처치 이력이 있는 사람을 대상으로 하였다. 모든 대상자들은 이 기간 동안 치매로 진단 또는 치료 받은 기록이 없었다. 성향점수매칭법에 따라 연령과 성별, 그리고 거주지역을 고려하여 실험군과 대조군을 1:1 동수로 매칭하였고, 두 코호트 집단간 2년 동안 치매로 이환된 비율을 비교하였다. 결과: 실험군과 대조군을 비교했을 때, 실험군인 양측 또는 편측 완전 무치악 환자에서 치매 발병률(12.13%)은 대조군인 유치악 환자의 치매 발병률(9.74%) 보다 유의미하게 높다는 것을 확인할 수 있었다 (P < .05). 다른 요인들과 치매와의 명확한 관련성은 확인되지 않았다. 결론: 대규모 인구집단데이터 분석을 통해 양측 또는 편측 완전 무치악 환자에서 치매 발병률이 높다는 것을 확인할 수 있었다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권18호
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• pp.7665-7671
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• 2014

Objectives: The association between body mass index (BMI) and ovarian cancer risk is unclear and requires further investigation. The present meta-analysis was conducted to assess the effect of overweight and obesity on ovarian cancer risk in the premenopausal and postmenopausal periods. Data sources: Major electronic databases were searched until February 2014 including Medline and Scopus. Reference lists and relevant conference databases were searched and the authors were contacted for additional unpublished references. Review Methods: All cohort and case-control studies addressing the effect of BMI on ovarian cancer were included, irrespective of publication date and language. The effect measure of choice was risk ratio (RR) for cohort studies and odds ratio (OR) for case-control studies. The results were reported using a random effects model with 95% confidence intervals (CIs). Results: Of 3,776 retrieved studies, 19 were ultimately analyzed including 10 cohort studies involving 29,237,219 person-years and 9 case-control studies involving 96,965 people. The results of both cohort and case-control studies showed being overweight and obesity increased the risk of ovarian cancer compared to women with normal weight during both premenopausal and postmenopausal periods: RR=1.08 (95%CI: 0.97, 1.19) and OR=1.26 (95%CI: 0.97, 1.63) for overweight and RR=1.27 (95%CI: 1.16, 1.38) and OR=1.26 (95%CI: 1.06, 1.50) for obesity. Conclusions: There is sufficient evidence that an increase in BMI can increase the risk of ovarian cancer regardless of the menopausal status, mimicking a dose-response relationship although the association is not very strong.

• Asian Pacific Journal of Cancer Prevention
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• 제16권8호
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• pp.3233-3239
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• 2015

Background: Whether depression causes increased risk of the development of breast cancer has long been debated. We conducted an updated meta-analysis of cohort studies to assess the association between depression and risk of breast cancer. Materials and Methods: Relevant literature was searched from Medline, Embase, Web of Science (up to April 2014) as well as manual searches of reference lists of selected publications. Cohort studies on the association between depression and breast cancer were included. Data abstraction and quality assessment were conducted independently by two authors. Random-effect model was used to compute the pooled risk estimate. Visual inspection of a funnel plot, Begg rank correlation test and Egger linear regression test were used to evaluate the publication bias. Results: We identified eleven cohort studies (182,241 participants, 2,353 cases) with a follow-up duration ranging from 5 to 38 years. The pooled adjusted RR was 1.13(95% CI: 0.94 to 1.36; $I^2=67.2%$, p=0.001). The association between the risk of breast cancer and depression was consistent across subgroups. Visual inspection of funnel plot and Begg's and Egger's tests indicated no evidence of publication bias. Regarding limitations, a one-time assessment of depression with no measure of duration weakens the test of hypothesis. In addition, 8 different scales were used for the measurement of depression, potentially adding to the multiple conceptual problems concerned with the definition of depression. Conclusions: Available epidemiological evidence is insufficient to support a positive association between depression and breast cancer.

• Journal of Preventive Medicine and Public Health
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• 제27권1호
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• pp.117-134
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• 1994

대구직할시 남구 1 개동 주민을 대상으로 도시 지역의료보험 실시 전후(이하 실시 전후)의 의료 이용양상을 파악하기 위하여 실시 6개월 전인 1989년 1월에 1차조사를 하였고, 실시 1년 6개월 후인 1991년 1월에 2차조사를 하였다. 1차조사의 대상자는 1,230가구 4,939명이 었으나, 2차추적조사가 가능했던 인구는 519가구 2,277명 (추적률:46.1%)이었다. 2차조사까지 추적이 가능했던 2,277명 중 1차 조사시 보험에 가입되지 않았던 240가구 1,033명을 코호트 I군(이하 I군)으로 하였고, 1차조사시 보험에 가입되었던 279가구 1,244명을 코흐트 II군(이하 II군)으로 구분하여 조사자료를 분석하였다. 인구 1,000명당 급성이환으로 인한 의사방문율의 변화는 실시 후에 I군에서 16.5 증가한 반면, II에서는 2.4만 증가하였으며, 만성이환에서도 I군이 13.5 증가하였으나 II군은 7.2만 증가하였다. 이환 및 활동제한 의료필요 충족률도 I군에서 실시 후 뚜렷히 증가하였다. 월가구소득별 급성이환에 의한 의료필요충족률은 I군에서 40만원미만군이 1.6으로 $40{\sim}99$만원군의 4.0과 100만원이상군의 49.3에 비해 월등히 낮았다. 이러한 소견은 나머지 조사대상군과 만성이환에서도 동일하였다. 급성과 만성이환자의 병원이용 이유는 유용성, 의원의 경우는 지리적 접근성이 실시전후모두에서 가장 많았고 약국이용 이유 중 실시 전에는 접근성과 의료비지불성이 중요하였으나, 실시 후에는 의료비지불성의 중요성은 상대적으로 감소하였다. 최근 15일간 의사방문여부를 종속변수로한 multiple logistic regression analysis에서 급성이환(+), 만성이환(+) 그리고 월가구소득(+)이 실시전후 모두에서 유의한 변수였다. 실시 후 부과된 보험료에 대한 불만족률이 두군 모두 지역의료보험 가입자에서 각각 81.0%와 74.1%로 타 의료보험가입자에 비해 월등히 높았다. 실시 후 병원과 의원의 의료비와 서어비스에 불만족스럽다고 응답한 사람이 I군에 비해 II군에서 더 많았다. 이상의 소견으로 의료보험이 실시됨으로 미충족의료수요를 감소시키는 효과를 가져왔으나 실시 후에도 저소득층의 의료이용률이 고소득층에 비해 여전히 낮아 의료보험실시로 경제적 장애가 감소하였음에도 불구하고 본인부담금 등으로 인한 경제적 장애와 의료기관을 방문하는데 소요되는 시간, 대기시간 등 의료이용을 저해하는 요인이 남아있어 의료이용의 형평이 사회계층들간에 완전히 이루어지지는 않았다. 특히 만성이환의 경우, 불균형이 심하였다. 또한, 부과된보험료에 대한 불만족도가 높아 현행 보험료선정기준의 재평가 및 공정성을 향상시킬 필요성이 제기되었다.