El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / OBJECTIVE: An estimated 20-30% of patients with primary Clostridium difficile infection (CDI) develop recurrent CDI (rCDI) within 2 weeks of completion of therapy. While the actual mechanism of recurrence remains unknown, a variety of risk factors have been suggested and studied. The aim of this systematic review and meta-analysis was to evaluate current evidence on the risk factors for rCDI. DESIGN: We searched MEDLINE and 5 other databases for subject headings and text related to rCDI. All studies investigating risk factors of rCDI in a multivariate model were eligible. Information on study design, patient population, and assessed risk factors were collected. Data were combined using a random-effects model and pooled relative risk ratios (RRs) were calculated. RESULTS: A total of 33 studies (n=18,530) met the inclusion criteria. The most frequent independent risk factors associated with rCDI were age≥65 years (risk ratio [RR], 1.63; 95% confidence interval [CI], 1.24-2.14; P=.0005), additional antibiotics during follow-up (RR, 1.76; 95% CI, 1.52-2.05; P<.00001), use of proton-pump inhibitors (PPIs) (RR, 1.58; 95% CI, 1.13-2.21; P=.008), and renal insufficiency (RR, 1.59; 95% CI, 1.14-2.23; P=.007). The risk was also greater in patients previously on fluoroquinolones (RR, 1.42; 95% CI, 1.28-1.57; P<.00001). CONCLUSIONS: Multiple risk factors are associated with the development of rCDI. Identification of modifiable risk factors and judicious use of antibiotics and PPI can play an important role in the prevention of rCDI.

MSc (Med), Population-Based Field Epidemiology, School of Public Health, Faculty of health Sciences, University of the Witwatersrand / Introduction: The achievements of the United Nations’ millennium development goals (MDGs) are not possible in isolation. Adult health and mortality with the exception of maternal health is one of the health issues that were openly missing among the list of MDGs. But eradicating extreme poverty and hunger would not be possible if the economically active population is not supported to be healthy and to live longer. Little has been done on adult health, especially to reduce mortality as compared to child health. Adult mortality is expected to equal or exceed child mortality in sub-Saharan Africa if nothing is done. There are varying factors associated with specific-causes of adult deaths within and among different settings. Obtaining more and better data on adult deaths and understanding issues relating to adult deaths in Africa are crucial for long life and development. Objectives: The study seeks to (i) describe causes of adult mortality, (ii) estimate adult cause-specific mortality rates and trends and (iii) identify risk factors of cause-specific mortality in the Ifakara Health and Demographic Surveillance System (IHDSS) population from 2003 – 2007 among adults aged 15 – 59 years. Methodology: The data for the study was extracted from the database of the Ifakara Health and Demographic Surveillance System (IHDSS) in Tanzania from 2003-2007. It was an open cohort study. The cohort was selected based on age (15-59years) and active residency from 1st January 2003 to 31st December 2007. Survival estimates were computed using Kaplan-Meier survival technique and adult mortality rates were estimated expressed per 1000 person years observed (PYO). Verbal autopsy method was used to ascertain causes of deaths. Cox proportional hazards method was used to identify socio-demographic factors associated with specific-causes of adult deaths. v Findings: A total 65,548 adults were identified and followed up, yielding a total of 184,000 person years. A total of 1,352 deaths occurred during the follow-up. The crude adult mortality rate (AMR) estimated over the period was 7.3/1000PYO. There was an insignificant steady increase in annual AMR over the period. The AMR in 2007 increased by 11% over year 2003. Most people died from HIV/AIDS (20.4%) followed by Malaria (13.2%). The AMR for the period was 2.49 per 1000PYO for communicable disease (CD) causes, 1.21 per 1000PYO for non communicable disease (NCD) causes and 0.53 per 1000PYO for causes related to accidents/injuries. Over the study period, deaths resulting from NCDs increased significantly by 50%. The proportion of deaths due to NCDs in 2003 was 16% increasing to 24% in year 2007. Adult deaths from Accidents/Injuries were significantly higher among men (hazard ratio (HR) = 2.2) after adjusting for socioeconomic status (SES), level of education and household size. For communicable and NCDs, most people died at home while for Accidents/Injuries most people died elsewhere (neither home nor health facility). The risk factors that were found to be associated with adult deaths due to NCDs were age and level of education. An improvement in level of education saw a reduction in the risk of dying from NCDs ((HR(Primary)=0.67, 95%CI:0.49, 0.92) and (HR(beyond Primary)=0.11, 95%CI:0.02, 0.40) after adjusting for age and sex. Age, SES and “entry type” were the factors found to be associated with dying from communicable diseases among the adults. In-migrants were 1.7 times more likely to die from communicable disease causes than residents having adjusted for age, household size, educational level, employment status of the head of household and SES. Conclusion: HIV/AIDS is the leading cause of adult deaths in IHDSS area followed by malaria. Most adult deaths occurred outside health facility in rural areas. This could probably be explained by the health seeking behavior and or health care accessibility in vi the rural area of sub-Saharan Africa. NCDs are increasing as a result of demographic and epidemiological transitions taking place in most African countries including Tanzania. Without preventions the rural community in Tanzania will soon face increased triple disease burden; (CD), NCD and Accident/Injuries. Policies on accident/injury preventions in developing countries will be effective if based on local evidence and research.

INTRODUCTION Cardiovascular diseases (CVD) are more common in kidney transplant recipients (KTRs) than in the general population. The high incidence of CVD in the KTRs can be attributed to traditional risk factors, additional risk factors associated with graft dysfunction and those specifically related to transplantation. Carotid intima-media thickness (cIMT) is a proven surrogate of atherosclerosis; it correlates with vessel pathology and is precisely imaged using ultrasound technology. This study was aimed at determining the prevalence and predictors of cardiovascular risk among KTRs at the Charlotte Maxeke Johannesburg Academic Hospital (CMJAH) and to examine the relationship between cardiovascular risk factors and carotid intima media thickness. METHODS Patients aged 18 years and above who received a kidney transplant at the CMJAH between January 2005 and December 2009 were recruited. A questionnaire that captured cardiovascular risk factors was administered. Patients records were assessed for information on their post transplant follow up. All patients had echocardiography and carotid doppler done for measurement of intima-media thickness. The Framingham Risk Score was used to categorize patients into low, moderate, high risk and very high risk groups. Results were analyzed using statistical package for social sciences (SPSS) version 17, p value of 0.05 was considered significant. RESULTS One hundred (KTRs) 63 male (63%) and 37 female (37%) were recruited ranging in age from 19 to 70 years, with a mean age of 42.2 ± 12.42. Thirty six patients (36%) were found to have high cardiovascular risk. Multiple regression showed proteinuria (p = 0.022), higher cumulative steroid dosage (p = 0.028), elevated serum triglycerides (p = 0.04) and the presence of plaques in the carotid artery (p = 0.012) as predictors of higher cardiovascular risk.Carotid intima-media thickness correlates with higher CVD risk. Fourteen patients (14%) had a carotid artery plaque. Twenty five patients (25%) had cIMT of >0.7 mm. CONCLUSION Kidney transplant recipients in CMJAH were found to have high cardiovascular risk (36%) and carotid intima-media thickness correlates with this high CVD risk. Routine follow up of KTRs should include measurement of cIMT as it provides a simple non-invasive assessment of subclinical atherosclerosis.

ABSTRACT Odontogenic abscesses and Ludwig’s angina are infections commonly seen by maxillofacial surgeons. Both infections have periapical or periodontal origin and caused by oral bacteria. Ludwig’s angina is an aggressive and fast spreading infection compared to odontogenic abscess. The origin and the responsible bacteria of these infections are similar but the development and response is different in patients. There is no comprehensive study that has investigated the bacterial and host factors involved in the development of there infections. The aim of this study was to compare the presence of bacteria and enzymes in to the pus samples collected from patients with odontogenic abscess and Ludwig’s angina. Furthermore, various haematological and immunological tests were also compared between the two study groups. Forty two patients presenting with localized odontogenic abscesses and 15 with Ludwig’s angina were selected. Patient was examined according to standard protocol and history was recorded. Bloods were collected for haematology and immunology tests and pus was collected for microbiology and enzymatic tests. The results showed that highly virulent bacteria such as Staphylococcus aureus and black pigmented bacteroides were prevalent, increase in c-reactive protein, white blood cell count, IL6 and decrease in urea, circulating immune complexes and IgE in patients with Ludwig’s angina. Development of Ludwig’s angina could be due to the aggressive bacteria, their byproducts and low immune response compared to the odontogenic abscesses.

MSc (Med), Biostatistics and Epidemiology, Faculty of Health Sciences, University of the Witwatersrand, 2009 / Introduction: Endometrial cancer is a gynaecological cancer that mostly affects women in their sixth and seventh decades of life. It is the fourth most common malignancy in women and ranks eighth among all causes of female cancer in terms of age-adjusted mortality. In developed and numerous developing countries endometrial cancer, as well as other types of cancer in women, is an ever-increasing threat that may be explained, among other reasons, by increased life expectancy and a reduction in fertility or birth rates. Conversely, in South Africa and most other African countries, the previous reasons do not exist, because there is a decline in life expectancy due to increased HIV, low income, and a high fertility rate. International epidemiological studies have established significant relationships between endometrial cancer and risk factors such as the woman’s age, race, early menarche and late menopause, parity, a history of breast or ovarian cancer, the use of endogenous estrogens, concomitant diabetes, family history of breast and ovarian cancer, estrogen therapy, obesity, and the use of tamoxifen. The aim of the study was to identify risk factors associated with endometrial cancer among black South African women. Method: The present case control study comprised black South African women diagnosed with a cancer in Johannesburg, between 1995 and 2005. The study included 592 women aged 27 to 90 years who were admitted to three main public hospitals in the city of Johannesburg with histologically confirmed cancers. 148 cases with endometrial cancer and 444 women with other forms of cancer were analysed. Only newly occurring cases (incident) were included. Women in the control group consisted of those with V cancers not associated with reproductive or hormonal factors, i.e. not cancers of the breast or the female reproductive system. Data handling, cleaning and analysis were done using Stata 9 (STATA). Results: Univariate analysis showed that the risk for endometrial cancer was significantly (P<0.05) affected by: miscarriages, the place of former residence, place of current residence, the use of snuff, wine consumption, age of the youngest child, diabetes, age of menarche, age of menopause, and menstrual status. Smoking was found to be a protective factor for endometrial cancer compared to other cancers. After multivariate adjustment, endometrial cancer risk was significantly (P<0, 05) associated with miscarriages, age at menarche, and earlier completion of childbearing. Smoking remained a protective factor against endometrial cancer. Conclusion: The current study reports similar results to those observed in other international investigations. The risk of endometrial cancer was higher among women who were older, women who experienced miscarriages, and those who fell pregnant early in their reproductive lives. Smoking was a protective factor against endometrial cancer compared to other cancers. However, comparing the cases of endometrial cancer with smoking-associated cancer controls (i.e. lung cancer, oesophageal cancer, and mouth cancer) might have distorted the results. A more appropriate control group for confirming the relationship between smoking and endometrial cancer would be subjects with no cancer. Also, it will be important to evaluate the risk factors for cancer among the other race groups in South Africa.

MSc (Med), Population-Based Field Epidemiology, Faculty of Health Sciences, University of the Witwatersrand / Background Complications of childbirth and pregnancy are leading causes of death among women of reproductive age. Worldwide, developing countries account for ninety-nine percent of maternal deaths. The United Nations’ fifth millennium development goal (MDG-5) is to reduce maternal mortality ratio by three fourths by 2015. Aim The aim of this study is to explore the levels, trends, causes and risk factors associated with maternal mortality as put forward by World Health Organization (WHO) in rural settings of Tanzania. Specific objectives To establish the trend of maternal mortality ratios in Rufiji health and demographic surveillance system (RHDSS) during the period 2002-2006. To determine the main causes of maternal deaths in RHDSS during the period 2002-2006. To determine the risk factors associated with maternal mortality RHDSS during the period 2002-2006. Method Secondary data analysis based on the longitudinal database from Rufiji Health and Demographic Surveillance System was used to study the risk factors and causes of maternal death. Data for a period of 5 years between 2002-2006 was used. A total of 26 427 women v aged 15-49 years were included in the study; 64 died and there were 15 548 live births. Cox proportional hazards regression was used to assess the risk factors associated with maternal deaths. Results Maternal mortality ratio was 412 per 100 000 live births. The main causes of death were haemorrhage (28%), eclampsia (19%) and puerperal sepsis (8%). Maternal age and marital status were associated with maternal mortality. An increased risk of 154% for maternal death was found for women aged 30-39 versus 15-19 years (HR=2.54, 95% CI=1.001- 6.445). Married women had a protective effect of 62% over unmarried ones (HR=0.38, 95% CI=0.176-0.839). These findings were statistically significant at the 5% level. Conclusion This analysis reinforced previous findings pointing to the fact that haemorrhage and eclampsia are the leading causes of maternal mortality in Tanzania and other developing countries. This indicates the need for better antenatal and obstetric care, particularly for women over thirty years of age, as well as implementing health care delivery strategies according to the regional specific risk factors of maternal deaths and not the global factors.

The pioneering work of Ödegaard (1932) was the first to link migration and schizophrenia by reporting rates in Norwegian immigrants in Minnesota as twice that of native Minnesotans and of Norwegians in Norway. However, only in recent decades has an interest in migration and schizophrenia been rekindled as a result of reports of elevated rates of schizophrenia in Afro-Caribbean immigrants in the United Kingdom in the mid- 1960s (Hutchinson & Haasen, 2004). Later studies reported elevated rates in secondgeneration Afro-Caribbean immigrants compared to first-generation (Harrison, Owens, Holton, Neilson, & Boot, 1988). In the United States, Blacks were diagnosed with schizophrenia 2.4 times more often than Whites (Olbert, Nagendra, & Buck, 2018). However, mental health researchers in the United States generally combine all individuals of African descent as African- Americans. This practice obscures the nuances of culture and ethnicity within the Black subgroups as well as the immigrant status of Afro-Caribbeans. This research focused on the Afro-Caribbean immigrants and factors that predict risk for schizophrenia within this population. The process of migration is a complex enterprise that produces stressors and challenges, the effects of which are multifaceted. The social and environmental forces that parallel the process of migration may predispose individuals to severe psychiatric disorders such as schizophrenia. Socio-political dynamics in the host country that marginalize others of different cultural and/or racial persuasions can compound the negative effects of post-migration. Therefore, migration is considered a social determinant of health. Empirical evidence has substantiated that socio-environmental factors such as urbanicity, discrimination or socio-economic deprivation, social support, and goal striving stress are potential contributing factors to the development of psychotic disorders in immigrants. Moreover, evidence has supported that the darker the skin color of the immigrant the greater the risk (Cantor-Graae, 2007). The findings of this study confirmed that for Afro-Caribbean immigrants stressors in the post-migration phase such as discrimination, limited social support, and economic hardship that can be compounded by the number of dependent children were identified as possible predictors of risk for schizophrenia. This risk increased with length of residency and continued into the second-generation. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

The contacts and collisions that are inherent to elite Rugby Union, alongside changes to players’ physical characteristics and match activities, have raised concerns regarding the level of injury burden associated with the professional game. This programme of research was therefore undertaken to investigate injury risk in this setting. The first study of this thesis (Chapter 3) presents a meta-analytic review of injury data relating to senior men’s professional Rugby Union, which shows an overall match incidence rate of 81 per 1000 player hours; this value is high in comparison with other popular team sports. In Chapter 4, the importance of injuries in the context of performance is demonstrated by showing a substantial negative association exists between injury burden and team success measures. Chapter 5 investigates subsequent injury patterns in this population and identifies injury diagnoses with a high risk of early recurrence, whilst also demonstrating that subsequent injuries are not more severe than their associated index injury. Playing professional Rugby Union on an artificial playing surface does not influence overall acute injury risk in comparison with natural grass surfaces (Chapter 6). Chapters 7 and 8 identify intrinsic risk factors for injury (previous injury, match and training loads) for the first time in this setting, and may be used to inform policies on these pertinent issues. Finally, predictive modelling techniques show some potential for predicting the occurrence and severity of injuries, but require further refinement before they can be implemented within elite Rugby Union teams. Overall, this programme of work highlights the importance of injury prevention for all professional Rugby Union stakeholders, addresses the need to use appropriate statistical techniques to account for the dynamic and clustered nature of sport injury data, and demonstrates approaches through which the injury burden associated with elite Rugby Union may be reduced.

Patient-provided data are crucial to achieving the goal of precision medicine. These data, which include family medical history, race and ethnicity, and social and behavioral determinants of health, are essential for disease risk assessment. Despite the well-established importance of patient-provided data, there are many data quality challenges that affect how this information can be used for biomedical research. To determine how to best use patient-provided data to assess disease risk, the research reflected in this dissertation was divided into three overarching aims. In Aim 1, I focused on determining the quality of race and ethnicity, family history and smoking status in clinical databases. In Aim 2, I assessed the impact of various interventions on the quality of these data, including policy changes such as the implementation of the requirements imposed by the Meaningful Use program, and patient-facing tools for collecting and sharing information with patients. In addition to these evaluations, I also developed and evaluated a method “Relationship Inference from the Electronic Health Record” (RIFTEHR), that infers familial relationships from clinical datasets. In Aim 3, I used patient-provided data to assess disease risk both at a population level, by estimating disease heritability, and at an individual level, by identifying high-risk individuals eligible for additional screening for a common disease (diabetes mellitus) and a rare disease (celiac disease). My research uncovered several data quality concerns for patient-provided data in clinical databases. When assessing the impact of interventions on the quality of these data, I found that policy interventions led to more data collection, but not necessarily to better data quality. In contrast, patient-facing tools did increase the quality of the patient-provided data. In the absence of high-quality patient-provided data for family medical history, I developed and evaluated a method for inferring this information from large clinical databases. I demonstrated that electronic health record data can be used to infer familial relationships accurately. Moreover, I showed how the use of clinical data in conjunction with the inferred familial relationships could determine disease risk in two studies. In the first study, I successfully computed disease heritability estimates for 500 conditions, some of which had not been previously studied. In the second study, I identified that screening rates among family members that are considered to be at high-risk for disease development were low for both diabetes mellitus and celiac disease. In summary, the work represented in this dissertation contributes to the understanding of the quality of patient-provided data, how interventions affect the quality of these data, and how novel methods can be applied to troves of existing clinical data to generate new knowledge to support research and clinical care.

No description available.