• Title/Summary/Keyword: Biostatistics

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Changing Trends of Types of Skin Cancer in Iran

  • Razi, Saeid;Rafiemanesh, Hosein;Ghoncheh, Mahshid;Khani, Yousef;Salehiniya, Hamid
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.12
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    • pp.4955-4958
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    • 2015
  • Background: Skin cancer is the most common type of cancer worldwide. It has an increasing trend. This study investigated the epidemiological trend and morphological changes in skin cancer in Iran. Materials and Methods: This study was done using existing data, extracted from the National Cancer Registry System and the Disease Management Center of Iranian Ministry of Health between 2003 and 2008. Data on epidemiologic trend was analyzed using Joinpoint software package. Results: The incidence of skin cancer is increasing in Iran, and more in men than women. There was a declining trend for basal cell carcinoma. Basal squamous cell carcinoma and melanoma had an increasing trend. The increase of skin cancer was related to squamous cell carcinoma. Conclusions: Our findings indicated that the increase of skin cancer was attributed to squamous cell carcinoma. It is necessary to be planning for the control and prevention of this disease as a priority for health policy makers.

Five-Year Survival and Median Survival Time of Nasopharyngeal Carcinoma in Hospital Universiti Sains Malaysia

  • Siti-Azrin, Ab Hamid;Norsa'adah, Bachok;Naing, Nyi Nyi
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.15
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    • pp.6455-6459
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    • 2014
  • Background: Nasopharyngeal carcinoma (NPC) is the fourth most common cancer in Malaysia. The objective of this study was to determine the five-year survival rate and median survival time of NPC patients in Hospital Universiti Sains Malaysia (USM). Methods: One hundred and thirty four NPC cases confirmed by histopathology in Hospital USM between $1^{st}$ January 1998 and $31^{st}$ December 2007 that fulfilled the inclusion and exclusion criteria were retrospectively reviewed. Survival time of NPC patients were estimated by Kaplan-Meier survival analysis. Log-rank tests were performed to compare survival of cases among presenting symptoms, WHO type, TNM classification and treatment modalities. Results: The overall five-year survival rate of NPC patients was 38.0% (95% confidence interval (CI): 29.1, 46.9). The overall median survival time of NPC patients was 31.30 months (95%CI: 23.76, 38.84). The significant factors that altered the survival rate and time were age (p=0.041), cranial nerve involvement (p=0.012), stage (p=0.002), metastases (p=0.008) and treatment (p<0.001). Conclusion: The median survival of NPC patients is significantly longer for age ${\leq}50$ years, no cranial nerve involvement, and early stage and is dependent on treatment modalities.

An Iterative Normalization Algorithm for cDNA Microarray Medical Data Analysis

  • Kim, Yoonhee;Park, Woong-Yang;Kim, Ho
    • Genomics & Informatics
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    • v.2 no.2
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    • pp.92-98
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    • 2004
  • A cDNA microarray experiment is one of the most useful high-throughput experiments in medical informatics for monitoring gene expression levels. Statistical analysis with a cDNA microarray medical data requires a normalization procedure to reduce the systematic errors that are impossible to control by the experimental conditions. Despite the variety of normalization methods, this. paper suggests a more general and synthetic normalization algorithm with a control gene set based on previous studies of normalization. Iterative normalization method was used to select and include a new control gene set among the whole genes iteratively at every step of the normalization calculation initiated with the housekeeping genes. The objective of this iterative normalization was to maintain the pattern of the original data and to keep the gene expression levels stable. Spatial plots, M&A (ratio and average values of the intensity) plots and box plots showed a convergence to zero of the mean across all genes graphically after applying our iterative normalization. The practicability of the algorithm was demonstrated by applying our method to the data for the human photo aging study.

The Effects of Socio-demographic Characteristics on Indonesian Women's Knowledge of HIV/AIDS: A Cross-sectional Study

  • Pradnyani, Putu Erma;Wibowo, Arief;Mahmudah, Mahmudah
    • Journal of Preventive Medicine and Public Health
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    • v.52 no.2
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    • pp.109-114
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    • 2019
  • Objectives: The purpose of this study was to characterize Indonesian women's knowledge of HIV/AIDS and to investigate the effects of socio-demographic characteristics thereupon with the goal of supporting the prevention and early detection of HIV/AIDS. Methods: This cross-sectional study was conducted using secondary data from the standard Indonesian Demographic and Health Survey (IDHS) in 2012. A total of 34 984 subjects ranged in age from 15 years to 49 years. Data were analyzed using the chi-square test and logistic regression to identify the effects of socio-demographic characteristics on Indonesian women's knowledge of HIV/AIDS. Results: All socio-demographic characteristics except marital status were related to knowledge of HIV/AIDS among Indonesian women in the univariate analysis (p<0.05). Multivariate analysis revealed that only age group, education level, location of residence, and wealth index were related to Indonesian women's knowledge of HIV/AIDS (p<0.05). Conclusions: Indonesian women's insufficient knowledge related to HIV/AIDS shows that the provision of accurate and comprehensive information related to HIV/AIDS are components of prevention and control interventions that should be improved. With greater knowledge, women are expected to be more likely to determine their own and their partners' human immunodeficiency virus status and to take appropriate preventive steps.

Bayesian Conway-Maxwell-Poisson (CMP) regression for longitudinal count data

  • Morshed Alam ;Yeongjin Gwon ;Jane Meza
    • Communications for Statistical Applications and Methods
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    • v.30 no.3
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    • pp.291-309
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    • 2023
  • Longitudinal count data has been widely collected in biomedical research, public health, and clinical trials. These repeated measurements over time on the same subjects need to account for an appropriate dependency. The Poisson regression model is the first choice to model the expected count of interest, however, this may not be an appropriate when data exhibit over-dispersion or under-dispersion. Recently, Conway-Maxwell-Poisson (CMP) distribution is popularly used as the distribution offers a flexibility to capture a wide range of dispersion in the data. In this article, we propose a Bayesian CMP regression model to accommodate over and under-dispersion in modeling longitudinal count data. Specifically, we develop a regression model with random intercept and slope to capture subject heterogeneity and estimate covariate effects to be different across subjects. We implement a Bayesian computation via Hamiltonian MCMC (HMCMC) algorithm for posterior sampling. We then compute Bayesian model assessment measures for model comparison. Simulation studies are conducted to assess the accuracy and effectiveness of our methodology. The usefulness of the proposed methodology is demonstrated by a well-known example of epilepsy data.

Associations between Psychological Distress and Body Mass Index among Law Enforcement Officers: The National Health Interview Survey 2004-2010

  • Gu, Ja K.;Charles, Luenda E.;Burchfiel, Cecil M.;Andrew, Michael E.;Ma, Claudia;Bang, Ki Moon;Violanti, John M.
    • Safety and Health at Work
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    • v.4 no.1
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    • pp.52-62
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    • 2013
  • Objectives: To investigate the association between psychological distress and obesity among law enforcement officers (LEOs) in the United States. Methods: Self-reported data on psychological distress based on six key questions were obtained from LEOs who participated in the National Health Interview Survey (2004-2010). We used Prochaska's cut-point of a Kessler 6 score ${\geq}5$ for moderate/high mental distress in our analysis. Mean levels of body mass index (BMI) were compared across three levels of psychological distress. Results: The average age of LEOs (n = 929) was 39.3 years; 25% were female. Overall, 8.1% of LEOs had moderate or high psychological distress; 37.5% were obese (BMI ${\geq}30$). Mean BMI increased with increasing psychological distress (no distress, BMI = $27.2kg/m^2$; mild distress, $27.6kg/m^2$; and moderate/high distress, $33.1kg/m^2$; p = 0.016) after adjustment for age, race, income, and education level among female officers only. Physical activity modified the association between psychological distress and BMI but only among male LEOs (interaction p = 0.002). Among male LEOs reporting low physical activity, psychological distress was positively associated with BMI ($30.3kg/m^2$ for no distress, 30.7 for mild distress, 31.8 for moderate/high distress; p = 0.179) after adjustment, but not significantly. This association was not significant among males reporting high physical activity. Conclusion: Mean BMI significantly increased as psychological distress increased among female LEOs. A longitudinal study design may reveal the directionality of this association as well as the potential role that physical activity might play in this association.

Sleep Duration and Cancer Risk: a Systematic Review and Meta-analysis of Prospective Studies

  • Zhao, Hao;Yin, Jie-Yun;Yang, Wan-Shui;Qin, Qin;Li, Ting-Ting;Shi, Yun;Deng, Qin;Wei, Sheng;Liu, Li;Wang, Xin;Nie, Shao-Fa
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.12
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    • pp.7509-7515
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    • 2013
  • To assess the risk of cancers associated with sleep duration using meta-analysis of published cohort studies, we performed a comprehensive search using PubMed, Embase and Web of Science through October 2013. We combined hazard ratios (HRs) from individual studies using meta-analysis approaches. A random effect dose-response analysis was used to evaluate the relationship between sleep duration and cancer risk. Subgroup analyses and sensitivity analyses were also performed. Publication bias was evaluated using Funnel plots and Begg's test. A total of 13 cohorts from 12 studies were included in this meta-analysis, which included 723, 337 participants with 15, 156 reported cancer outcomes during a follow-up period ranging from 7.5 to 22 years. The pooled adjusted HRs were 1.06 (95% CI: 0.92, 1.23; P for heterogeneity =0.003) for short sleep duration, 0.91 (95% CI: 0.78, 1.07; P for heterogeneity <0.0001) for long sleep duration. In subgroup analyses stratified by cancer type, long duration of sleep showed an inverse relation with hormone-related cancer (HR=0.79; 95% CI: 0.65, 0.97; P for heterogeneity =0.009) and a greater risk of colorectal cancer (HR=1.29; 95% CI: 1.09, 1.52; P for heterogeneity =0.346). Further meta-analysis on dose-response relationships showed that the relative risks of cancer were 1.00 (95% CI: 0.99, 1.01; P for linear trend=0.9151) for one hour of sleep increment per day, and 1.00 (95% CI: 0.98, 1.01; P for linear trend=0.7749) for one hour of sleep increment per night. No significant dose-response relationship between sleep duration and cancer was found on non-linearity testing (P=0.5053). Our meta-analysis suggests a positive association between long sleep duration and colorectal cancer, and an inverse association with incidence of hormone related cancers like those in the breast. Studies with larger sample size, longer follow-up times, more cancer types and detailed measure of sleep duration are warranted to confirm these results.

Assessment of Breast Cancer Knowledge among Health Workers in Bangui, Central African Republic: a Cross-sectional study

  • Balekouzou, Augustin;Yin, Ping;Pamatika, Christian Maucler;Nambei, Sylvain Wilfrid;Djeintote, Marceline;Doromandji, Eric;Gouaye, Andre Richard;Yamba, Pascal Gastien;Guessy, Elysee Ephraim;Ba-Mpoutou, Bertrand;Mandjiza, Dieubeni Rawago;Shu, Chang;Yin, Minghui;Fu, Zhen;Qing, Tingting;Yan, Mingming;Mella, Grace;Koffi, Boniface
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.8
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    • pp.3769-3776
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    • 2016
  • Background: Breast cancer is the leading cause of cancer deaths among women worldwide. High breast cancer mortality has been attributed to lack of public awareness of the disease. Little is known about the level of knowledge of breast cancer in Central African Republic. This study aimed to investigate the knowledge of health professionals on breast cancer. Materials and Methods: This cross-sectional study was conducted among 158 health professionals (27 medical; 131 paramedical) in 17 hospitals in Bangui using a self-administered questionnaire. Descriptive statistical analysis, Person's ${\chi}^2$ test and ANOVA were applied to examine associations between variables with p < 0.05 being considered significant. Results: Data analyzed using SPSS version 20 indicates that average knowledge about breast cancer perception of the entire population was 47.6%, diagnosis method 45.5%, treatment 34.3% and risk factors 23.8%. Most respondents (65.8%) agreed that breast cancer is important in Central African Republic and that family history is a risk factor (44.3%). Clinical assessments and mammography were considered most suitable diagnostic methods, and surgery as the best treatment. The knowledge level was significantly higher among medical than paramedical staff with regard to risk factors, diagnosis and treatment. However the trainee group had very high significant differences of knowledge compared with all other groups. Conclusions: There is a very urgent need to update the various training programs for these professionals, with recommendations of retraining. Health authorities must create suitable structures for the overall management of cancer observed as a serious public health problem.