• 제목/요약/키워드: biostatistics

검색결과 959건 처리시간 0.025초

Association Between the FAS/FASL Polymorphisms and Gastric Cancer Risk: A Meta-Analysis

  • Tian, Jing;Pan, Feng;Li, Jing;Ma, Yan;Cen, Han;Pan, Hai-Feng;Pan, Yue-Yin;Ye, Dong-Qing
    • Asian Pacific Journal of Cancer Prevention
    • /
    • 제13권3호
    • /
    • pp.945-951
    • /
    • 2012
  • Objective: FAS/FASL gene promoter polymorphisms have been repeatedly associated with gastric cancer risk, but findings are inconclusive across studies. To address a more precise estimation of the relationship, a meta-analysis was performed. Methods: Data were collected from the Pubmed, Medline and EMBASE databases, with the last report up to 1 December, 2011. Crude ORs with 95% CIs were used to assess the strength of the association by (1) the additive, (2) the codominant, (3) the dominant, and (4) the recessive models. Results: A total of seven studies, including six studies on FAS -1377G>A polymorphism, five studies on FAS -670A>G polymorphism, and six studies on FASL -844T>C polymorphism, were identified in the current meta-analysis. Overall, an association of FAS -1377G>A (AA versus GG: OR = 1.313, 95% CI = 1.045-1.650, Ph = 0.347, $I^2$ = 10.8) and FASL -844T>C (CC versus TT: OR = 1.352, 95% CI = 1.043-1.752, Ph = 0.461, $I^2$ = 0.0) polymorphisms with gastric cancer was found in the codominant model. However, we did not detect any association between gastric cancer and the FAS -670A>G polymorphism. In the subgroup analysis by ethnicity, similar elevated risks were also observed in Asian population for FAS -1377G>A (AA versus GG: OR = 1.309, 95% CI = 1.041-1.646, Ph = 0.240, $I^2$ = 27.3) and FASL -844T>C (CC versus TT: OR = 1.420, 95% CI = 1.081-1.865, Ph = 0.524, $I^2$ = 0.0) polymorphisms. Conclusions: This meta-analysis indicated that FAS -1377G>A and FASL -844T>C polymorphisms might be associated with gastric cancer risk.

Nonparametric Procedures for Finding Minimum Effective Dose in a One-Way Layout

  • Kim, Hyeonjeong;Kim, Dongjae
    • Communications for Statistical Applications and Methods
    • /
    • 제9권3호
    • /
    • pp.693-701
    • /
    • 2002
  • When the lowest dose level compared with zero-dose control has significant difference in effect, it is referred as minimum effective dose (MED). In this paper, we discuss several nonparametric methods for finding MED using updated rank at each sequential test step in small sample size and suggest new nonparametric procedures based on placement. Monte Carlo Simulation is adapted to compare power and Familywise Error Rate(FWE) of the new procedures with those of discussed nonparametric tests for finding MED.

Maximum Tolerated Dose Estimation Applied Biased Coin Design in a Phase I Clinical Trial

  • Kim, Yu Rim;Kim, Dongjae
    • Communications for Statistical Applications and Methods
    • /
    • 제19권6호
    • /
    • pp.877-884
    • /
    • 2012
  • Phase I trials determine the maximum tolerated dose(MTD) and the recommended dose(RD) for subsequent Phase II trials. In this paper, a MTD estimation method applied to a biased coin design is proposed for Phase I Clinical Trials. The suggested MTD estimation method is compared to the SM3 method and the NM method (Lee and Kim, 2012) using a Monte Carlo simulation study.

Usefulness of AB/BA/AA/BB Crossover Design

  • Nam, Jusun;Kim, Dongjae
    • Communications for Statistical Applications and Methods
    • /
    • 제10권1호
    • /
    • pp.115-123
    • /
    • 2003
  • In this paper, we discuss the usefulness of AB/BA/AA/BB crossover design sense of sample size. The result is that the AB/BA/AA/BB crossover design is more economical than AB/BA one if large carryover effect exists and so is it in the comparison with completely randomized design within-subject correlation is large.

Nonparametric Method Using Placement in One-way Layout

  • Chung, Taek-Su;Kim, Dong-Jae
    • Communications for Statistical Applications and Methods
    • /
    • 제14권3호
    • /
    • pp.551-560
    • /
    • 2007
  • Kruskal and Wallis (1952) proposed typical nonparametric method in one-way layout problem. A special feature of this procedure is use of rank in mixed samples. In this paper, the new procedure based on placement as extension of the two sample placement tests described in Orban and Wolfe (1982) was proposed. Some critical values in small sample cases and comparative results of a Monte Carlo power study are presented.

Nonparametric Procedure for Identifying the Minimum Effective Dose with Ordinal Response Data

  • Kang, Jongsook;Kim, Dongjae
    • Communications for Statistical Applications and Methods
    • /
    • 제11권3호
    • /
    • pp.597-607
    • /
    • 2004
  • The primary interest of drug development studies is identifying the lowest dose level producing a desirable effect over that of the zero-dose control, which is referred as the minimum effective dose (MED). In this paper, we suggest a nonparametric procedure for identifying the MED with binary or ordered categorical response data. Proposed test and Williams' test are compared by Monte Carlo simulation study and discussed.

Incidence, Trends and Epidemiology of Cancers in North West of Iran

  • Zahedi, Atefeh;Rafiemanesh, Hosein;Enayatrad, Mostafa;Ghoncheh, Mahshid;Salehiniya, Hamid
    • Asian Pacific Journal of Cancer Prevention
    • /
    • 제16권16호
    • /
    • pp.7189-7193
    • /
    • 2015
  • Background: Cancer is a leading cause of death throughout the world. Increasing life expectancy and aging population are important factors for increasing cancer incidences in developing countries. National programs are essential for prevention and control of cancer in any society. This study aimed to investigate cancer epidemiology and trends in the province of Hamadan, located in Northwest Iran. Materials and Methods: This analytical study was carried out based on cancer registry data from 2004 to 2009 in the province of Hamadan, analyzed using STATA (version 12) software for descriptive tests and Join point 4.1.1.1 software for analytical tests. Results: There were 7,767 registered cases of cancer during the 6 years studied. Of the total cases registered, 59.1% (4,592 cases) involved men and 40.9% (3,175 cases) occurred in women. Age-standardized incidence rates (ASR) increased from 72.9 to 132.0 in males and 48.2 to 115.0 in females during the 6 years of the study (p<0.001). The most common cancers were skin, stomach, breast, bladder, and leukemia. In women, teh most common were breast, skin, stomach, colorectal, and leukemia, in that order, and in men skin, stomach, bladder, leukemia, and prostate cancers. Conclusions: The cancer incidence is greater in men that women in this region but with increasing trends in both sexes. Planning regarding education in prevention of exposure to risk factors and control strategies is required to decrease the incident cases. Screening programs for common cancers in older age groups might be helpful to reduce the disease impact.

Application of a Non-Mixture Cure Rate Model for Analyzing Survival of Patients with Breast Cancer

  • Baghestani, Ahmad Reza;Moghaddam, Sahar Saeedi;Majd, Hamid Alavi;Akbari, Mohammad Esmaeil;Nafissi, Nahid;Gohari, Kimiya
    • Asian Pacific Journal of Cancer Prevention
    • /
    • 제16권16호
    • /
    • pp.7359-7363
    • /
    • 2015
  • Background: As a result of significant progress made in treatment of many types of cancers during the last few decades, there have been an increased number of patients who do not experience mortality. We refer to these observations as cure or immune and models for survival data which include cure fraction are known as cure rate models or long-term survival models. Materials and Methods: In this study we used the data collected from 438 female patients with breast cancer registered in the Cancer Research Center in Shahid Beheshti University of Medical Sciences, Tehran, Iran. The patients had been diagnosed from 1992 to 2012 and were followed up until October 2014. We had to exclude some because of incomplete information. Phone calls were made to confirm whether the patients were still alive or not. Deaths due to breast cancer were regarded as failure. To identify clinical, pathological, and biological characteristics of patients that might have had an effect on survival of the patients we used a non-mixture cure rate model; in addition, a Weibull distribution was proposed for the survival time. Analyses were performed using STATA version 14. The significance level was set at $P{\leq}0.05$. Results: A total of 75 patients (17.1%) died due to breast cancer during the study, up to the last follow-up. Numbers of metastatic lymph nodes and histologic grade were significant factors. The cure fraction was estimated to be 58%. Conclusions: When a cure fraction is not available, the analysis will be changed to standard approaches of survival analysis; however when the data indicate that the cure fraction is available, we suggest analysis of survival data via cure models.

Current Evidence on the Relationship Between Two Polymorphisms in the NBS1 Gene and Breast Cancer Risk: a Meta-analysis

  • Zhang, Zhi-Hua;Yang, Lin-Sheng;Huang, Fen;Hao, Jia-Hu;Su, Pu-Yu;Sun, Ye-Huan
    • Asian Pacific Journal of Cancer Prevention
    • /
    • 제13권11호
    • /
    • pp.5375-5379
    • /
    • 2012
  • Introduction: Published studies on the association between Nijmegen breakage syndrome 1(NBS1) gene polymorphisms and breast cancer risk have been inconclusive, and a meta-analysis was therefore performed for clarification. Methods: Eligible articles were identified by a search of MEDLINE and EMBASE bibliographic databases for the period up to March 2012. The presence of between-study heterogeneity was investigated using the chi-square-based Cochran's Q statistic test. When there was statistical heterogeneity, the random effects model was chosen; otherwise, fixed effects estimates were reported as an alternative approach. Results: A total of 11 eligible articles (14 case-control studies) were identified, nine case-control studies were for the 657del5 mutation (7,534 breast cancer cases, 14,034 controls) and five case-control studies were for the I171V mutation (3,273 breast cancer cases, 4,004 controls). Our analysis results indicated that the 657del5 mutation was associated with breast cancer risk (carriers vs. non-carriers: pooled OR =2.63, 95% CI: 1.76-3.93), whereas the I171V mutation was not (carriers vs. non-carriers: pooled OR =1.52, 95% CI: 0.70-3.28). Conclusion: The present meta-analysis suggests that the 657del5 gene mutation in the NBS1 gene plays a role in breast cancer risk, while the I171V mutation does not exert a significant influence.