• Title, Summary, Keyword: cohort analysis

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Incidence of Scarlet Fever in Children in Jeju Province, Korea, 2002-2016: An Age-period-cohort Analysis

  • Kim, Jinhee;Kim, Ji-Eun;Bae, Jong-Myon
    • Journal of Preventive Medicine and Public Health
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    • v.52 no.3
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    • pp.188-194
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    • 2019
  • Objectives: Outbreaks of scarlet fever in Mexico in 1999, Hong Kong and mainland China in 2011, and England in 2014-2016 have received global attention, and the number of notified cases in Korean children, including in Jeju Province, has also increased since 2010. To identify relevant hypotheses regarding this emerging outbreak, an age-period-cohort (APC) analysis of scarlet fever incidence was conducted among children in Jeju Province, Korea. Methods: This study analyzed data from the nationwide insurance claims database administered by the Korean National Health Insurance Service. The inclusion criteria were children aged ${\leq}14years$ residing in Jeju Province, Korea who received any form of healthcare for scarlet fever from 2002 to 2016. The age and year variables were categorized into 5 groups, respectively. After calculating the crude incidence rate (CIR) for age and calendar year groups, the intrinsic estimator (IE) method was applied to conduct the APC analysis. Results: In total, 2345 cases were identified from 2002 to 2016. Scarlet fever was most common in the 0-2 age group, and boys presented more cases than girls. Since the CIR decreased with age between 2002 and 2016, the age and period effect decreased in all observed years. The IE coefficients suggesting a cohort effect shifted from negative to positive in 2009. Conclusions: The results suggest that the recent outbreak of scarlet fever among children in Jeju Province might be explained through the cohort effect. As children born after 2009 showed a higher risk of scarlet fever, further descriptive epidemiological studies are needed.

Two Dimensional Cluster Analysis of Air Quality by Time and Area (지역.시간별을 고려한 이차원 대기환경 군집 분석)

  • Wee, Seong-Seung;Kim, Jae-Hoon;Ahn, Chi-Kyung;Choi, Byong-Su;Kim, Dae-Seon
    • Journal of Environmental Science International
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    • v.17 no.5
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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.

Measles Infections and Measles Vaccinations Rates for the Past 10 Years in Kang Wha -A Cohort Observation- (강화 지역주민의 과거 10년간 홍역이환율 및 예방접종율의 변화 -출생년도별 코호트 분석-)

  • Lee, Yong-Ho
    • Journal of Preventive Medicine and Public Health
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    • v.14 no.1
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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.

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A study on the factors affecting the follow-up participation in birth cohorts

  • Park, Bohyun;Choi, Eun Jeung;Ha, Eunhee;Choi, Jong Hyuk;Kim, Yangho;Hong, Yun-Chul;Ha, Mina;Park, Hyesook
    • Environmental health and toxicology
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    • v.31
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    • pp.23.1-23.6
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    • 2016
  • Objectives A stable follow-up participation rate is a very important factor for validity in a cohort study. This study analyzed the factors that affect the participation rate at one hospital-based birth cohort in South Korean. Methods The participants were recruited from the Mothers' and Children's Environmental Health study between 2006 and 2010. The analysis targeted 1751 mothers who participated in a birth cohort. We conducted analyses of general characteristics during pregnancy and those of infants at birth that affect the participation rate of the 6-month follow-up survey. Results The participation rate for the 6-month follow-up survey was 60.4%. The participation rate in the follow-up of the subsequent period decreased within a 5% to 10% range compared to the number of subjects. The participation rate of premature infants was 16.9% lower than that of a full-term infant (52.6% vs. 69.5%). Analysis showed a 16.7% difference between the participation rate of low-birthweight infants in follow-ups (53.7%) and the participation rate of infants with normal weight (70.4%). The participation rate of mothers who were employed during pregnancy was significantly lower for the 6-month follow-up compared to the participation rate of mothers who were unemployed during pregnancy. Conclusions In this study, factors such as premature birth, low-birthweight, and the employment status of the mother during pregnancy affected the participation rate of the follow-up survey for the birth cohort at six months. A specific strategy is needed to encourage survey participation for the high risk groups in the follow-ups.

Early gonadotropin-releasing hormone antagonist start improves follicular synchronization and pregnancy outcome as compared to the conventional antagonist protocol

  • Park, Chan Woo;Hwang, Yu Im;Koo, Hwa Seon;Kang, Inn Soo;Yang, Kwang Moon;Song, In Ok
    • Clinical and Experimental Reproductive Medicine
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    • v.41 no.4
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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.

Analysis of the incidence of dementia in complete edentulous patients using the National Health Insurance Service-Elderly Cohort Database (NHIS-ECD) (국민건강보험공단 노인 코호트 자료를 이용한 완전 무치악 환자의 치매 발병률 분석)

  • Koo, Bonsuk;Yoo, Jin-Joo;Kim, Manyong;Lim, Hyunsun;Yoon, Joon-Ho
    • The Journal of Korean Academy of Prosthodontics
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    • v.58 no.3
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    • pp.193-200
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    • 2020
  • Purpose: To investigate the relationship between dementia and complete tooth loss on both sides or one side using large demographic data. Materials and methods: A retrospective cohort study was designed using the National Health Insurance Service-Elderly Cohort Database (NHIS-ECD) which was established for people over the age of 60. The experimental group was the complete edentulous cohort, which had a history of treatment for national health insurance covered complete denture on both sides or one side from July 1, 2012 to December 31, 2013. And the control group was the dentulous cohort, which had a history of conservative dental treatment for the same period. All subjects had no history of diagnosis or treatment of dementia during this time. These cohorts were matched 1:1 by age, gender, and place of residence according to the propensity score matching method. Then the incidence of dementia was compared between these cohorts. Results: Compared with those groups, the incidence of dementia was significantly higher in the experimental group (12.13%) than in the control group (9.74%) (P<.05). No clear association between other factors has been identified. Conclusion: The analysis of large-scale demographic data shows that the incidence of dementia is high in complete edentulous patients on both sides or one side.

Body Mass Index Effects on Risk of Ovarian Cancer: A Meta-Analysis

  • Poorolajal, Jalal;Jenabi, Ensiyeh;Masoumi, Seyyedeh Zahra
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.18
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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.

Depression and the Risk of Breast Cancer: A Meta-Analysis of Cohort Studies

  • Sun, Hui-Lian;Dong, Xiao-Xin;Cong, Ying-Jie;Gan, Yong;Deng, Jian;Cao, Shi-Yi;Lu, Zu-Xun
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.8
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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.

Effects of Regional Medical Insurance on Utilization of Medical Care in Urban Population (지역의료보험 실시전후 도시 일부주민의 의료이용양상 비교 - 소득 계층별 의료필요충족도와 주민 만족도를 중심으로 -)

  • Kim, Seok-Beom;Kang, Pock-Soo
    • Journal of Preventive Medicine and Public Health
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    • v.27 no.1
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    • pp.117-134
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    • 1994
  • The effects of regional medical insurance on utilization of medical care in urban population was examined in this study. The data was collected in a 2-year follow-up household survey conducted at Taegu city before and after implementation of the regional medical insurance. The study population was divided into 2 groups. Cohort I was the uninsured in 1989 and cohort II was the insured in 1989. After the coverage of medical insurance, physician visit rate per 1,000 population, use-disability ratio and use-restricted activity ratio in cohort I were increased compared to cohort II in both of acute and chronically ill people. The use-disability ratio and use-restricted activity ratio of the insured poor were lower than those of the insured nonpoor in both of cohort I and cohort II. The major reasons for pharmacy use were accessibility and affordability before the coverage of medical insurance in cohort I, however, after the coverage of medical insurance, the important reason was accessibility rather than affordability. In logistic regression analysis of physician visit, the significant independent variables were acute illness episode (+), chronic illness episode (+) and income (+) in both of cohort I and cohort II. In cohort I, after the coverage of medical insurance, more people replied that the medical cost of hospital and clinic was reasonable. The people who covered by the regional medical insurance were more dissatisfied with the imposed premium than those who covered by other types of medical insurance in both of cohort I and cohort II. More people in cohort II than cohort I were dissatisfied with the services from hospitals and clinics after implementation of the regional medical insurance. In conclusion. after the coverage of medical insurance, the gap between the poor and the nonpoor still exists in terms of medical care utilization.

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Association Between Metabolic Syndrome and Adiponectin according to Sasang Constitution (사상체질에 따른 대사증후군과 Adiponectin의 상관성)

  • Yu, Jun-Sang;Koh, Sang-Baek;Park, Jong-Ku
    • Journal of Sasang Constitutional Medicine
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    • v.21 no.3
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    • pp.122-130
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    • 2009
  • 1. Objectives: The objective of this study is to investigate the relationship between adiponectin and metabolic syndrome according to Sasang Constitution. 2. Methods: Six hundred sixty six participants were included in this cohort study. Sex, age, BMI(Body Mass Index), smoking, drinking, adiponectin level and Metabolic syndrome components were considerd. Sasang constitutional diagnosis was carried out by a sasang constitutional specialist using photos, questionnaires and PSSC(Phonetic System for Sasang Classification). 3. Results: In binary logistic analysis after adjustment of age, sex, BMI, smoking, drinking, adiponectin level and sasang constitution were related with Metabolic syndrome. 4. Conclusions: We suggest that adiponectin and sasang constitution are the important biomarker in Metabolic syndorme.

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