Among indigenous populations, there is significant evidence that the rates of completed suicide are much higher than in the general population. The current study examines whether the prevalence and risk factors of suicidal ideation, plans and attempts differ when comparing an American Indian reservation sample to a US general population sample. Data were from the National Comorbidity Survey (n = 5,877) and the American Indian Service Utilization, Psychiatric Epidemiology, Risk and Protective Factors Project (N = 3,084). The current findings indicate that there are few differences in the likelihood of suicidal behavior in conjunction with particular disorders or traumas. However, American Indians appeared more likely to make a suicide attempt and less likely to have suicidal thoughts in their lifetime when compared with the general population. Although preliminary and exploratory, findings provide evidence that suicide interventions for indigenous populations may require modification based on differential risk factors for suicide. / October 2008

We assessed how estimates of need-expected inpatient hospital use differ depending on whether need-expected use was estimated for a population of all Canadians, Canadian health regions, or a subpopulation of higher income Canadians, who likely had minimal healthcare access problems. Data came from the 2009/2010 Canadian Community Health Survey, a national cross-sectional survey. Using zero-inflated negative binomial regression, we modeled inpatient hospital use separately based on the three aforementioned choices of population. We adjusted for demographic, health behaviour, health status, socioeconomic, and health care supply factors. We then estimated need-expected inpatient hospital use and compared the estimates across individuals and by income and province. The three choices of population that we used in this study had similar results. Our estimates of the average need-expected use by province or income group were not sensitive to the choice of population used to estimate need-expected use.

Most epidemiologic studies of sexually transmitted diseases (STD) are based on patients seeking help or advice at various health care settings. Because many STD:s are subclinical, epidemiologic surveys can be strengthened by a population-based approach. The aims of the present study were to investigate the prevalence and incidence of STDs in a population of young women, and to assess associations between STDs and social background, education, previous genital infections, sexual behaviour, contraceptive use and reproductive experience. All women belonging to the 19-, 21-, 23- and 25-year age cohorts and living in the catchment area of a community health center, were invited by mail to participate in the study. In the presence of the investigator, participants answered a structured questionaire regarding their social background, education, previous genital infections, sexual behaviour, contraceptive use and reproductive experience. A gynecologic examination was performed. Cervical scrapes for human papillomavirus (HPV) DNA, as well as samples for wet smear, cervical pap smear, and Chlamydia trachomatis (CT) culture were taken. The presence of genital warts was noted, and a colposcopy was performed 2-5 minutes after application of 5% acetic acid on the cervix and vulva. Acetowhite changes were then assessed. A serologic test for CT and herpes simplex virus type 2 (HSV-2) antibodies were performed. Of the 816 women available, 611 (75%) participated in the study. One out of four women reported symptoms from the lower genital tract. The most common were itching, followed by discharge and soreness. There was a significant correlation between the womens" complaint of vaginal discharge, and previous CT infection, lack of lactobacilli and the presence of leucocytosis in wet smear. Twenty-two percent of the women were HPV DNA positive and acetowhitening at the cervix was observed in 16% of the women. The sensitivity of detection of HPV infection by acetowhitening of the cervix was 22% (95%CI 18%, 26%), and the specificity was 90% (95% Cl 87%, 93%). C.trachomatis culture positivity was found in 2.7% of the women and the seroprevalence of CT was 24.7 %. Atypical cytology was found in 3.4% of the women and 6.6% was HSV-2 seropositiv. Of the women studied 23.6% reported having had at least one STD previously and the laboratory analysis showed 45.4% to have had at least one STD. Multivariate logistic regression analysis showed that the number of sexual partners, age at first coitus, history of therapeutic abortion, and previous pelvic inflammatory disease (PID) was independently correlated with CT seropositivity. Lifetime number of sexual partners was the only independent risk factor for HPV. Multivariate analysis showed that increasing age, early sexual debut, and a history of spontaneous abortion were independently related to the presence of HSV-2 antibodies. The lifetime number of sexual partners and coitus on first date were independently associated with a previous STD. Conclusion, We found that one out of four women had some kind of lower genital tract complaint, almost every other women had at sometime in their life an STD, and STDs were often asymptomatic. Acetowhitening of the cervix and vulva has low sensitivity, to low to warrant its use as a predictor of subclinical HPV infection. The pattern of risk factors differed between STDs. / <p>Härtill 6 uppsatser</p> / digitalisering@umu

Background: The epidemic of chronic diseases is largely neglected. Although a threatening burden of chronic diseases is emerging, developing public health efforts for their prevention and control is not yet a priority for trans-national and national health policy makers. Understanding the population burden of risk factors which predict chronic diseases is an important step in reducing the impact of the diseases themselves. Objective: This thesis responds to the increasing burden of chronic diseases worldwide, and aims to illustrate the gap in chronic disease risk factor research in developing countries. The thesis describes and analyses the distribution of chronic disease risk factors in a rural setting in Indonesia. It also describes how smoking, one of the most common risk factors, is viewed by rural Javanese boys. Ultimately, therefore, this thesis aims to contribute to policy and programme recommendations for community interventions in a rural setting in Indonesia Methods: The studies were conducted in Purworejo District, where a Demographic Surveillance System (DSS) has been running since 1994. The Purworejo DSS is part of the INDEPTH network (International Network of field sites for continuous Demographic Evaluation of Populations and Their Health in developing countries). Two representative cross-sectional studies (in 2001 and 2005) were conducted to assess the chronic disease risk factors (including smoking, elevated blood pressure, and overweight and obesity). The first cross-sectional study was followed up in 2002 and 2004. In each study, a total of 3 250 participants (approximately 250 individuals in each sex and age group among 15–74 year olds stratified into 10-year intervals) were randomly selected from the surveillance database from each enumeration area in the surveillance area. Instruments were adopted from the WHO STEPS survey and adapted to local setting. Since many Indonesians start to smoke at an earlier age, a qualitative study using a focus group discussion approach was conducted among school boys aged 13-17 years old to describe and explore beliefs, norms, and values about smoking in a rural setting in Java. Result: Both the rural and urban populations in Purworejo face an unequal distribution of risk factors for chronic diseases. The burden among the most well-off group in the rural area has already reached a level similar to that found in the urban area. Most of the risk factors increased in all age, sex and socioeconomic groups during the period of 2001 to 2005. However, women and the poorest group experienced the greatest increase in risk factor prevalence. The qualitative study showed that cultural resistance against women smoking in Indonesia remains strong. Smoking is being viewed as a culturally internalised habit that signifies transition into maturity and adulthood for boys. Smoking is utilised as a means for socialisation and signifies better socioeconomic status. The use of tobacco in the construction of masculinity underlines the importance of gender specific interventions. National tobacco control policy should emphasise a smoking free society as the norm, especially among boys and men, and regulations regarding the banning of smoking should be enforced at all levels and areas of the community. Within the demographic surveillance setting, it is possible to assess the population and health dynamics. Utilisation of a standardised methodology across sites in INDEPTH will produce comparable population-based data in developing countries. Such comparisons are important in global health. A comparison of smoking transition patterns between a Vietnamese DSS and an Indonesian DSS shows that Indonesian men started smoking regularly earlier and ceased less than Vietnamese men. Compared with Vietnam, which has already signed and ratified the Framework Convention on Tobacco Control, tobacco control activities in Indonesia are still deficient. Conclusion: The thesis concludes that the rural population is not spared from the emerging burden of chronic disease risk factors. The patterning of risks across different socioeconomic groups provides a macro picture of the vicious cycle between poverty and chronic diseases. Understanding of risk factors in a local context through a qualitative study provides insight into cultural aspects relating to risk factor adoption, and will allow the fostering and tailoring of culturally appropriate interventions. Combining data from demographic surveillance sites with the WHO STEP approach to chronic disease risk factor Surveillance addresses basic epidemiological questions on chronic diseases. The use of such data is a powerful advocacy tool in public health decision-making for chronic disease prevention in developing countries. With substantial existing evidence on the effectiveness of chronic disease prevention and intervention programmes, it is vital that Indonesia to starts planning intervention programmes to control the impending chronic disease epidemic, and most importantly, to translate all this evidence into public health action. Keywords: chronic disease, risk factor, demographic surveillance system, smoking, elevated blood pressure, overweight and obesity, population-based intervention

Among indigenous populations, there is significant evidence that the rates of completed suicide are much higher than in the general population. The current study examines whether the prevalence and risk factors of suicidal ideation, plans and attempts differ when comparing an American Indian reservation sample to a US general population sample. Data were from the National Comorbidity Survey (n = 5,877) and the American Indian Service Utilization, Psychiatric Epidemiology, Risk and Protective Factors Project (N = 3,084). The current findings indicate that there are few differences in the likelihood of suicidal behavior in conjunction with particular disorders or traumas. However, American Indians appeared more likely to make a suicide attempt and less likely to have suicidal thoughts in their lifetime when compared with the general population. Although preliminary and exploratory, findings provide evidence that suicide interventions for indigenous populations may require modification based on differential risk factors for suicide.

Among indigenous populations, there is significant evidence that the rates of completed suicide are much higher than in the general population. The current study examines whether the prevalence and risk factors of suicidal ideation, plans and attempts differ when comparing an American Indian reservation sample to a US general population sample. Data were from the National Comorbidity Survey (n = 5,877) and the American Indian Service Utilization, Psychiatric Epidemiology, Risk and Protective Factors Project (N = 3,084). The current findings indicate that there are few differences in the likelihood of suicidal behavior in conjunction with particular disorders or traumas. However, American Indians appeared more likely to make a suicide attempt and less likely to have suicidal thoughts in their lifetime when compared with the general population. Although preliminary and exploratory, findings provide evidence that suicide interventions for indigenous populations may require modification based on differential risk factors for suicide.

Clostridium difficile colitis (CDC) is associated with a higher risk of acute death among hospitalized ulcerative colitis (UC) patients. However, the risk of colectomy with CDC in these patients has varied across studies. No study has assessed the long-term health impact of CDC in UC patients. Therefore, the present study evaluated the impact of CDC on five-year health outcomes of hospitalized UC patients based on Ontario health administrative data. No overall association was observed between CDC and five-year risks of colectomy or death in overall cohort. However, patients who were discharged from hospital without undergoing colectomy demonstrated marginally higher five-year risks of colectomy and hospital re-admission. Mortality risk and length of stay during index hospitalization were also higher in patients with CDC. Analysis of a parallel cohort of UC patients derived using a published case definition corroborated most of these results, but demonstrated a higher five-year mortality risk with CDC.

Clostridium difficile colitis (CDC) is associated with a higher risk of acute death among hospitalized ulcerative colitis (UC) patients. However, the risk of colectomy with CDC in these patients has varied across studies. No study has assessed the long-term health impact of CDC in UC patients. Therefore, the present study evaluated the impact of CDC on five-year health outcomes of hospitalized UC patients based on Ontario health administrative data. No overall association was observed between CDC and five-year risks of colectomy or death in overall cohort. However, patients who were discharged from hospital without undergoing colectomy demonstrated marginally higher five-year risks of colectomy and hospital re-admission. Mortality risk and length of stay during index hospitalization were also higher in patients with CDC. Analysis of a parallel cohort of UC patients derived using a published case definition corroborated most of these results, but demonstrated a higher five-year mortality risk with CDC.

Doctor of Philosophy / Over the past decade, population-based cancer registry data have been used increasingly worldwide to evaluate and improve the quality of cancer care. The utility of the conclusions from such studies relies heavily on the data quality and the methods used to analyse the data. Interpretation of comparative survival from such data, examining either temporal trends or geographical differences, is generally not easy. The observed differences could be due to methodological and statistical approaches or to real effects. For example, geographical differences in cancer survival could be due to a number of real factors, including access to primary health care, the availability of diagnostic and treatment facilities and the treatment actually given, or to artefact, such as lead-time bias, stage migration, sampling error or measurement error. Likewise, a temporal increase in survival could be the result of earlier diagnosis and improved treatment of cancer; it could also be due to artefact after the introduction of screening programs (adding lead time), changes in the definition of cancer, stage migration or several of these factors, producing both real and artefactual trends. In this thesis, I report methods that I modified and applied, some technical issues in the use of such data, and an analysis of data from the State of New South Wales (NSW), Australia, illustrating their use in evaluating and potentially improving the quality of cancer care, showing how data quality might affect the conclusions of such analyses. This thesis describes studies of comparative survival based on population-based cancer registry data, with three published papers and one accepted manuscript (subject to minor revision). In the first paper, I describe a modified method for estimating spatial variation in cancer survival using empirical Bayes methods (which was published in Cancer Causes and Control 2004). I demonstrate in this paper that the empirical Bayes method is preferable to standard approaches and show how it can be used to identify cancer types where a focus on reducing area differentials in survival might lead to important gains in survival. In the second paper (published in the European Journal of Cancer 2005), I apply this method to a more complete analysis of spatial variation in survival from colorectal cancer in NSW and show that estimates of spatial variation in colorectal cancer can help to identify subgroups of patients for whom better application of treatment guidelines could improve outcome. I also show how estimates of the numbers of lives that could be extended might assist in setting priorities for treatment improvement. In the third paper, I examine time trends in survival from 28 cancers in NSW between 1980 and 1996 (published in the International Journal of Cancer 2006) and conclude that for many cancers, falls in excess deaths in NSW from 1980 to 1996 are unlikely to be attributable to earlier diagnosis or stage migration; thus, advances in cancer treatment have probably contributed to them. In the accepted manuscript, I described an extension of the work reported in the second paper, investigating the accuracy of staging information recorded in the registry database and assessing the impact of error in its measurement on estimates of spatial variation in survival from colorectal cancer. The results indicate that misclassified registry stage can have an important impact on estimates of spatial variation in stage-specific survival from colorectal cancer. Thus, if cancer registry data are to be used effectively in evaluating and improving cancer care, the quality of stage data might have to be improved. Taken together, the four papers show that creative, informed use of population-based cancer registry data, with appropriate statistical methods and acknowledgement of the limitations of the data, can be a valuable tool for evaluating and possibly improving cancer care. Use of these findings to stimulate evaluation of the quality of cancer care should enhance the value of the investment in cancer registries. They should also stimulate improvement in the quality of cancer registry data, particularly that on stage at diagnosis. The methods developed in this thesis may also be used to improve estimation of geographical variation in other count-based health measures when the available data are sparse.

Esta Tese apresenta um conjunto de técnicas propostas com o objetivo de aprimorar processos de Agrupamento de Dados (AD). O principal objetivo é fornecer à comunidade científica um ferramental para uma análise completa de estruturas implícitas em conjuntos de dados, desde a descoberta dessas estruturas, permitindo o emprego de conhecimento prévio sobre os dados, até a análise de seu significado no contexto em que eles estão inseridos. São dois os pontos principais desse ferramental. O primeiro se trata do algoritmo para AD fuzzy semi-supervisionado SSL+P e sua evolução SSL+P*, capazes de levar em consideração o conhecimento prévio disponível sobre os dados em duas formas: rótulos e níveis de proximidade de pares de exemplos, aqui denominados Dicas de Conhecimento Prévio (DCPs). Esses algoritmos também permitem que a métrica de distância seja ajustada aos dados e às DCPs. O algoritmo SSL+P* também busca estimar o número ideal de clusters para uma determinada base de dados, levando em conta as DCPs disponíveis. Os algoritmos SSL+P e SSL+P* envolvem a minimização de uma função objetivo por meio de um algoritmo de Otimização Baseado em População (OBP). Esta Tese também fornece ferramentas que podem ser utilizadas diretamente neste ponto: as duas versões modificadas do algoritmo Particle Swarm Optimization (PSO), DPSO-1 e DPSO-2 e 4 formas de inicialização de uma população inicial de soluções. O segundo ponto principal do ferramental proposto nesta Tese diz respeito à análise de clusters resultantes de um processo de AD aplicado a uma base de dados de um domínio específico. É proposta uma abordagem baseada em Mineração de Textos (MT) para a busca em informações textuais, disponibilizadas digitalmente e relacionadas com as entidades representadas nos dados. Em seguida, é fornecido ao pesquisador um conjunto de palavras associadas a cada cluster, que podem sugerir informações que ajudem a identificar as relações compartilhadas por exemplos atribuídos ao mesmo cluster / This Thesis presents a whole set of techniques designed to improve the data clustering proccess. The main goal is to provide to the scientific community a tool set for a complete analyses of the implicit structures in datasets, from the identification of these structures, allowing the use of previous knowledge about the data, to the analysis of its meaning in their context. There are two main points involved in that tool set. The first one is the semi-supervised clustering algorithm SSL+P and its upgraded version SSL+P*, which are able of take into account the available knowlegdge about de data in two forms: class labels and pairwise proximity levels, both refered here as hints. These algorithms are also capable of adapting the distance metric to the data and the available hints. The SSL+P* algorithm searches the ideal number of clusters for a dataset, considering the available hints. Both SSL+P and SSL+P* techniques involve the minimization of an objective function by a Population-based Optimization algorithm (PBO). This Thesis also provides tools that can be directly employed in this area: the two modified versions of the Particle Swarm Optimization algorithm (PSO), DPSO-1 and DPSO-2, and 4 diferent methods for initializing a population of solutions. The second main point of the tool set proposed by this Thesis regards the analysis of clusters resulting from a clustering process applied to a domain specific dataset. A Text Mining based approach is proposed to search for textual information related to the entities represented by the data, available in digital repositories. Next, a set of words associated with each cluster is presented to the researcher, which can suggest information that can support the identification of relations shared by objects assigned to the same cluster