• 제목/요약/키워드: cohort effects

검색결과 327건 처리시간 0.03초

Effects of self-ligating brackets and other factors influencing orthodontic treatment outcomes: A prospective cohort study

  • Jung, Min-Ho
    • 대한치과교정학회지
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    • 제51권6호
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    • pp.397-406
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    • 2021
  • Objective: The purpose of this study was to evaluate the effects of self-ligating brackets (SBs) and other factors that influence orthodontic treatment outcomes. Methods: This two-armed cohort study included consecutively treated patients in a private practice. The patients were asked to choose between SBs and conventional brackets (CBs); if any patient did not have a preference, he or she was randomly allocated to the CB or SB group. All patients were treated using an identical archwire sequence. Evaluated parameters were as follows: treatment duration, number of bracket failures, poor oral hygiene, poor elastic wear, extraction, use of orthodontic mini-implants (OMI), OMI failure, American Board of Orthodontics (ABO) Discrepancy Index (DI), arch length discrepancy, and ABO Cast-Radiograph Evaluation (CRE) score. Stepwise regression analysis was performed to generate the equation for prediction of the CRE. Results: The final sample comprised 134 patients with an average age of 22.73 years. The average DI, CRE, and treatment duration were 21.81, 14.25, and 28.63 months, respectively. Analysis of covariance showed a significant difference in CRE between the CB and SB groups after adjusting for the effects of confounding variables. Stepwise regression analysis using four variables, namely extraction, SB use, poor elastic wear, and additional appliance use, could explain only 25.2% of the variance in the CRE. Conclusions: Although the CRE was significantly better for CBs than for SBs, the clinical significance of this result seems to be limited. Extraction, SB use, poor elastic wear, and additional appliance use may have significant effects on treatment outcomes.

Effects of garlic intake on cancer: a systematic review of randomized clinical trials and cohort studies

  • Lee, Jounghee;Zhao, Naisi;Fu, Zhuxuan;Choi, Jihee;Lee, Hae-Jeung;Chung, Mei
    • Nutrition Research and Practice
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    • 제15권6호
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    • pp.773-788
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    • 2021
  • BACKGROUND/OBJECTIVES: Due to the rapid increase of global cancer incidence and mortality and a high level of interest in cancer prevention, a systematic review of garlic intake and cancer risk is needed. SUBJECTS/METHODS: We implemented a systematic review to examine the effects of varying levels of garlic intake on cancer. We conducted comprehensive literature searches in three electronic databases (MEDLINE, Embase, and Web of Science) for studies published between database inception and July or September of 2018. Two investigators independently screened abstracts and full-texts, extracted data, and assessed risk of bias (RoB). A total of one medium-quality randomized controlled trial (RCT) and 13 cohort studies graded as high RoB were included. RESULTS: The 1-year follow-up results from a RCT showed that a significant decrease in the number and size of colorectal adenomas among participants with colorectal adenomas who received high-dose aged garlic extract (AGE) compared with those who received low-dose AGE (P < 0.05). The results of prospective observational studies provided inconsistent associations of colorectal cancer risk with garlic supplements and garlic intake as food. CONCLUSIONS: In summary, the AGE was effective in reducing the number and magnitude of colorectal adenomas in one RCT, but there were inconsistent associations between garlic intake and colorectal cancer in cohort studies. Therefore, we could not draw a firm conclusion regarding the effects of garlic on cancer, because the current strength of evidence is inadequate due to a lack of number of high-quality RCTs.

코호트 효과를 고려한 확률적 사망률 예측 모형의 비교 연구 (A comparative study of stochastic mortality models considering cohort effects)

  • 김순영
    • 응용통계연구
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    • 제34권3호
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    • pp.347-373
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    • 2021
  • 지난 50여 년 동안 우리나라의 사망률 감소 패턴에 대한 탐색적 연구에 의하면 연령별 사망률이 모든 연령에서 감소했지만, 특정한 사망률이 개선되고 있는 패턴은 연령과 기간에 따라 다르다는 것을 알 수 있다. 여자가 남자보다 사망률 개선이 뚜렷하고 특히 시간이 지나면서 특정그룹에서의 사망률 개선이 두드러짐에 따라 전반적으로 사망 시간 추세에 구조적인 변화가 존재함을 확인하였다. 이에 본 연구에서는 우리나라 여자 사망률 자료를 이용하여 미래 사망률 예측을 위해 코호트 효과를 고려한 다양한 확률적 사망률 모형을 살펴보았다. 또한 분석 결과를 바탕으로 2067년까지 연령별 사망률과 예측기대수명을 작성하고 통계청(KOSIS)에서 제공하는 장래 연령별 사망률과 기대수명과 비교하였다. 자료이용기간에 따라 최적의 모형이 상이하나 적합력과 예측력을 전반적으로 고려했을 때 우리나라 여자 사망률은 코호트 효과를 고려한 PLAT 모형이 적절하다 볼 수 있을 것이다.

Effects of Contralateral Seventh Cervical Nerve Transfer on Upper Extremity Motor Function in the Patients with Spastic Hemiplegia after Stroke: a Retrospective Cohort Study

  • Wonjae Choi
    • Physical Therapy Rehabilitation Science
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    • 제11권4호
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    • pp.502-508
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    • 2022
  • Objective: Contralateral seventh cervical nerve transfer (contralateral C7 transfer) is a newly attempted method to restore upper extremity motor function in the patients with spastic arm paralysis. The aim of this study was to investigate the effects of contralateral C7 transfer on upper extremity motor function in the patients with spastic hemiplegia after stroke. Design: A retrospective cohort study. Methods: Thirty-four patients with spastic hemiplegia after stroke was investigated. All patients registered between January 2020 and February 2021. The subjects were assessed on upper extremity motor function, cognition, and spasticity before and after contralateral C7 transfer. The upper extremity motor function was measured using the Fugl-Meyer upper extremity scale and box & block test. The cognition and spasticity were assessed by Korean version mini mental state examination (K-MMSE) and modified Ashworth scale from baseline to 8 weeks after the surgery. Results: The Fugl-Meyer upper extremity scale and modified Ashworth scale were significantly improved after contralateral C7 transfer (p<0.05). However, box & block test and K-MMSE were no significant changes after the surgery (p>0.05). Conclusions: This study suggested that the contralateral C7 transfer was a feasible and practical approach to improve upper extremity motor function in the patients with spastic hemiplegia after stroke, but further study is required to identify the long-term effects after the contralateral C7 transfer.

Dietary Patterns and Nutrient Intakes of Individuals with Circulatory Diseases: Ansan-Ansung Cohort Data from the Korean Genome and Epidemiology Study

  • Kim, Kyoung Yun;Yun, Jung-Mi
    • 한국식생활문화학회지
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    • 제35권3호
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    • pp.311-322
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    • 2020
  • Recently, there is growing interest in studying the dietary patterns that affect the risk of circulatory system diseases (CSDs). We investigated the relationship between CSDs and dietary patterns through a follow-up study in Korea (2001-2016). The participants of this study were obtained from the Korean Genome and Epidemiology Study (KoGES). This study was a large community-based cohort study (the Ansan-Ansung areas) conducted to assess the effects of various factors, especially diet, on the onset of chronic diseases among the Korean population aged 40-69 yrs. Baseline data were collected from 2001 to 2002, and follow-up studies were performed every 2 yrs, with over 7 follow-up studies performed (2015-2016). Three dietary patterns were identified using factor analysis: "vegetable and seafood (men)/soup and stew (women)" pattern, "sweet foods and breads-rice cake" pattern, and "multigrain rice and cooked white rice" pattern. None of the dietary patterns were significantly associated with the risk of CSDs in either men or women. Our follow-up study is meaningful as it investigated whether the dietary patterns of individuals according to sex affects the development of CSDs.

Time Trends of Esophageal Cancer Mortality in Linzhou City During the Period 1988-2010 and a Bayesian Approach Projection for 2020

  • Liu, Shu-Zheng;Zhang, Fang;Quan, Pei-Liang;Lu, Jian-Bang;Liu, Zhi-Cai;Sun, Xi-Bin
    • Asian Pacific Journal of Cancer Prevention
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    • 제13권9호
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    • pp.4501-4504
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    • 2012
  • In recent decades, decreasing trends in esophageal cancer mortality have been observed across China. We here describe esophageal cancer mortality trends in Linzhou city, a high-incidence region of esophageal cancer in China, during 1988-2010 and make a esophageal cancer mortality projection in the period 2011-2020 using a Bayesian approach. Age standardized mortality rates were estimated by direct standardization to the World population structure in 1985. A Bayesian age-period-cohort (BAPC) analysis was carried out in order to investigate the effect of the age, period and birth cohort on esophageal cancer mortality in Linzhou during 1988-2010 and to estimate future trends for the period 2011-2020. Age-adjusted rates for men and women decreased from 1988 to 2005 and changed little thereafter. Risk increased from 30 years of age until the very elderly. Period effects showed little variation in risk throughout 1988-2010. In contrast, a cohort effect showed risk decreased greatly in later cohorts. Forecasting, based on BAPC modeling, resulted in a increasing burden of mortality and a decreasing age standardized mortality rate of esophageal cancer in Linzhou city. The decrease of esophageal cancer mortality risk since the 1930 cohort could be attributable to the improvements of socialeconomic environment and lifestyle. The standardized mortality rates of esophageal cancer should decrease continually. The effect of aging on the population could explain the increase in esophageal mortality projected for 2020.

Effects of Radiotherapy on the Risk of Developing Secondary Malignant Neoplasms in Hodgkin's Lymphoma Survivors

  • Abou-Antoun, Tamara;Mikhael, Rachelle;Massoud, Marcel;Chahine, Georges;Saad, Aline
    • Asian Pacific Journal of Cancer Prevention
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    • 제17권2호
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    • pp.749-754
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    • 2016
  • Extended follow-up of Hodgkin lymphoma (HL) survivors indicates that these patients are at high risk of secondary malignant neoplasms (SMNs) contributing to increased morbidity and mortality. This study examined the characteristics of HL survivors who developed SMNs with the aim to report any correlation with radiotherapy (RT) dose. In this retrospective multi-center cohort study of HL patients treated between 1990 and 2011 at three major teaching hospitals in Lebanon, classification was into two groups including those treated with combined modality (RT and chemotherapy-CHT) and those treated with CHT alone. Approval from the University Institutional Review Board (IRB) was obtained. Of the 112 patients evaluated, 52.7% (59) received the combined modality while 47.3% (53) received CHT alone. There were 6 cases of SMNs in the combined modality cohort and 5 cases in the CHT cohort. The mean RT dose in the combined modality cohort was 34.5 Gray (Gy) ($SD{\pm}5.3$). A statistically significant increase (1.5 fold) in the risk of developing SMNs was observed among patients who received a dose higher than 41 Gy compared to a dose between 20 to 30 Gy (OR= 1.5; 95% confidence interval= 0.674 to 3.339, p=0.012). The risk of SMNs was not significantly higher among patients who received extended field compared to involved field RT (p=0.964). This study showed that the risk of developing SMNs is higher among patients treated with RT dose greater than 31 Gy, independent of the RT type used.

농약사용과 사망률과의 관계에 대한 코호트연구 (A Cohort study on the relationship between pesticide use and mortality, and cancer mortality)

  • 오희철;남정모;이선희
    • Journal of Preventive Medicine and Public Health
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    • 제24권3호
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    • pp.390-399
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    • 1991
  • The purpose of this study is to examine the relationship between pesticide use and mortality, and cancer mortality which are recognized as health hazards of pesticides. Data were analyzed from a cohort of 6,066 people aged fifty-five or over and who have been residing in the main island of Kangwha county. Death certificates, computerized citizenship registers searches, and household interview survey lead to get more than ninety-seven percents follow-up rate for the first five year observation period. Important findings are as follows : 1. Age specific mortality rates of pesticide users are significantly lower than those of pesticides nonusers. The SMR of male is 0.80, and 0.58 for females respectively probably due to healthy worker effects. But, age specific cancer mortality rates are significantly higher than those of pesticide nonusers (SMR=1.59) in males. This finding is not observed in females (SMR=0.85), however. 2. Logistic regression analyses showed that self-reported health status, drinking, and smoking histories in male are significantly associated with total mortality rate. The histories of pesticide use are also calculated to be highly associated with cancer mortality as in univariate analyses in males. In female, self-reported health status, age of first delivery are found to be significantly related to total mortality rate. Only drinking history is calculated to be associated with cancer mortalities in females. Data from further observation of 'Kangwha cohort' and indepth analyses of these are highly expected.

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Cohort Profile: Gachon Regional Occupational Cohort Study (GROCS)

  • Lee, Wanhyung;Lee, Yongho;Lee, Junhyeong;Kim, Uijin;Han, Eunsun;Ham, Seunghon;Choi, Won-Jun;Kang, Seong-Kyu
    • Safety and Health at Work
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    • 제13권1호
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    • pp.112-116
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    • 2022
  • Background/Aims: The Gachon Regional Occupational Cohort Study (GROCS) is a large-scale longitudinal study of occupational safety and health data (covering Work Environment Monitoring, Workers' Health Surveillance, and Occupational Health Service) conducted by the Gachon University Gil Medical Center (GUGMC) in Incheon, Republic of Korea. We conducted GROCS to identify the health effects of workers' occupational risks, behavior, socioeconomic status, and life style. Methods: The GROCS includes data from Work Environment Monitoring, Workers' Health Surveillance, and Occupational Health Service. The baseline year for all data collection was 2018. Work Environment Monitoring was conducted in 240 companies located in Incheon. General Health Examination and Special Health Examination were performed on 32,725 and 9,504 workers, respectively. Occupational Health Services were provided to 16,883 workers in 171 companies. These data have been collected and operated at an external data management institution and were provided as a retrospective cohort after removing personal identification information. Results: In 2018, the total number of companies was 2,854, among which which 488 special Health Examination, 171 Work Environment Monitoring, and 240 Occupational Health Service. The proportion of companies undergoing Special Health Examination was 17.1%, the proportion of companies undergoing Work Environment Monitoring was 8.4%, and the proportion of Companies undergoing Occupational Health Service was 6.0%. Conclusion: GROCS expects researchers to utilize its useful and reliable resource for occupational health and surveillance with for academic or political purposes to lead to improved workers' health and working environment.

자원봉사활동과 고혈압 및 관련 현상과의 전향적 연구 (Volunteering, Hypertension Risks, and Related Phenomena: A Prospective Cohort Study)

  • 이현기
    • 한국노년학
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    • 제41권3호
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    • pp.397-420
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    • 2021
  • 본 논문은 전향적 설계를 통하여 중장년 및 노년기 성인 자원봉사와 고혈압 발생, 고혈압증세 호전, 일상생활활동 어려움발생, 약복용 및 치료 등과의 관계를 규명하고자 한다. 이를 위해 2008년~2018년까지 10년에 걸쳐 수집된 종단 패널데이터를 사용했으며 분석 코호트 약 5,867명을 표본 추출하여 멀티레벨 혼합효과일반화선형 모델로 통계분석을 수행했다. 분석결과 자원봉사를 적어도 연 200시간 이상 한 사람은 안했을 때 보다 고혈압발생위험이 3.4배 낮았고, 연 50~99시간 한 사람은 안했을 때 보다 고혈압 증세호전이 더 크게 증가하였으며, 연 200시간 이상 자원봉사를 한 사람은 안했을 때 보다 활동어려움 발생확률이 7.7배 낮았으며, 그리고 연 50~99시간 자원봉사를 한 사람은 안했을 때 보다 약 복용 및 치료 발생 확률이 2.5배 낮은 것으로 나타났다. 이 결과는 중장년 및 노년기 성인의 자원봉사는 고혈압 및 관련 현상에 유익한 개선 효과가 있다는 것을 함의한다. 그리고 연구 한계점, 추후 연구방향, 실천함의를 논의했다.