Stroke is a devastating, neurological dysfunction due to brain blood supply disturbance. It is responsible for increasingly high rate of mortality and disability worldwide. This thesis comprises two original studies involving 868 patients at risk of ischemic stroke and/or hemorrhagic stroke. The first study investigated aspirin’s effect among patients with intracranial hemorrhage. Unlike Caucasians which hemorrhagic strokes account for 10-15% of all strokes; in Chinese, intracranial hemorrhages strike up to 35%. After such, anti-platelet agent like aspirin is often avoided for fear of recurrent intracranial hemorrhages, despite compelling indications. However, clinical data is limited. In this single-centered observational study, we included 440 consecutive Chinese patients with a first spontaneous intracranial hemorrhage surviving the first month performed during 1996-2010. 56 patients (12.7%) of these 440 patients were prescribed aspirin after intracranial hemorrhage (312 patient-aspirin years). After a mean follow-up of 62.2 ± 1.8 months, 47 patients had recurrent intracranial hemorrhage(10.7%, 20.6 per 1,000 patient years). Patients prescribed aspirin did not have higher risk of recurrent intracranial hemorrhage compared with those without (22.7 per 1,000 patient-aspirin years vs. 22.4 per 1,000 patient years, p=0.70). Multivariate analysis identified age > 60 years and hypertension as independent predictors for recurrent intracranial hemorrhage. In a subgroup analysis: the incidence of combined vascular events including recurrent intracranial hemorrhage, ischemic stroke, and acute coronary syndrome was statistically lower in patients prescribed aspirin than without (52.4 per 1,000 patient-aspirin years, vs. 112.8 per 1,000 patient-years, p=0.04). Implications of the results: despite having a substantial risk for recurrent intracranial hemorrhage, post-intracranial hemorrhage ones are at risk for thrombotic vascular events and management goal should thus focus on ameliorating overall cardiovascular risk instead of preventing recurrent intracranial hemorrhage. Hence, thrombo-prophylaxis should still be considered. The second study investigated the relation between premature atrial complexes and new-onset atrial fibrillation together with other cardiovascular events. Premature atrial complexes though taken as benign phenomenon, are common in patients with underlying conditions such as coronary heart disease, chronic rheumatic heart disease. While prompt management of atrial fibrillation may prevent ischemic stroke, atrial fibrillation is often unfound until ischemic stroke occurs. In this study, 428 patients without atrial fibrillation but complained of palpitations, dizziness or syncope were recruited. 107 patients with >100 premature atrial complexes/day were defined to have frequent premature atrial complexes. After a mean follow-up of 6.1 ±1.3 years, 31 patients (29%) with frequent premature atrial complexes developed atrial fibrillation compared with 29 patients (9%) with premature atrial complexes?100/day (p<0.01). Cox regression analysis revealed: frequent premature atrial complexes, age>75 years and coronary artery disease were independent predictors. In secondary endpoint (ischemic stroke, congestive heart failure, and death), patients with frequent premature atrial complexes were more at risk than those without (34.5% vs. 19.3%) (Hazard ratio: 1.95, 95% confidence interval: 1.37-3.50, p=0.001). Cox regression analysis showed: age> 75 years, coronary artery disease and frequent premature atrial complexes were independent predictors. These permit early identification of high risks patients of new atrial fibrillation and other events, thus promoting appropriate preventive treatment. / published_or_final_version / Medicine / Master / Master of Philosophy

This study examined the relative risk of perinatal complications in common childhood disorders. Specifically, the ability of perinatal complications to predict membership into children's disorders was studied. The sample consisted of 634 normal children and children with mental retardation, learning disabilities, and emotional handicaps, whose mothers completed the Maternal Perinatal Scale (WS). Seven MPS items significantly contributed to the prediction of the mentally retarded, learning disabled, emotionally handicapped, and regular education groups. The two significant discriminant functions correctly classified about 46% of the students, with the greatest misclassification occuring for those with emotional handicaps. When the separate disorders were collapsed to form a single group, eleven MPS items significantly contributed to the prediction of the special education and regular education groups. The linear composite from discriminant function analysis correctly classified about 74% of the students. Some 89% of the special education students were correctly classified. When MPS factors were used as predictors, 90% of the special education students were correctly classified. Seven MPS factors comprised the discriminant function. Relative risk ratios were computed for each perinatal item. Significant relative risk ratios included maternal weight over 151 pounds, saddle block anesthesia, no anesthesia, stress during pregnancy, prenatal care, medically induced labor, unplanned pregnancy, medication use during pregnancy, hypoxia, and cigarette use during pregnancy. An overall relative risk of 6.35 was computed based on the linear composite of perinatal variables defined by the discriminant function, suggesting that a suggesting that a synergism of perinatal complications makes a child over 6 times more likely to be placed in special education. A second overall relative risk of 3.83 was derived from the linear composite of MPS factor scores. This indicated that children with a perinatal history marked by this particular combination of perinatal complications were nearly 4 times as likely to require special educational services. Results were discussed in terms of comorbidity among special education categories. The potential use of the MPS as a screener for early intervention was also discussed. / Department of Educational Psychology

Background: Cesarean delivery rates have been increasing since 1996, and Cesarean delivery is now the most common major operative procedure performed in the United States. Identifying risk factors for wound complications following Cesarean delivery is necessary to prevent unnecessary maternal morbidity. Methods: A case-control study was carried out and data was collected via a medical record review for patients undergoing a Cesarean delivery at the UIHC between 10/1/2011 and 12/31/2012. Results: Several modifiable risk factors were identified, and models based on patient and surgical factors performed better than the current standard NHSN risk index model. Conclusion: More robust prediction models can be created using patient and surgical factors.

Approximately 2-11% of adolescents report chronic insomnia. The study used an archival data set from ADDHealth that assessed adolescent health and health-related behaviors. Adolescents (N = 4102) provided data at baseline (Time 1) and at 1-year follow-up (Time 2). Participants were excluded if no ethnicity, gender, or insomnia data were given at Time 1 or 2. Females were more likely to report insomnia than males at Times 1 and 2. In addition, adolescents with remitted insomnia were significantly younger than adolescents without insomnia at Times 1 and 2. Analyses found a prevalence of 9.6%, a remittance of 6.2%, an incidence of 4.4%, and a chronicity of 2.9%. At Time 1 and 2, AWI were significantly more likely to have depression, suicidal behaviors, and behavioral problems in school than AWOI. At Time 2, incidence and chronic insomnia increased the risk of depression, suicidal behaviors and behavioral problems in school. Risk and protective factors analyses indicated psychological counseling was associated with both remitted and chronic insomnia and depression was associated with incidence insomnia.

BACKGROUND:Delay in seeking care is a major impediment to effective management of tuberculosis (TB) in China. To elucidate factors that underpin patient and diagnostic delays in TB management, we conducted a systematic review and meta-analysis of factors that are associated with delays in TB care-seeking and diagnosis in the country.METHODS:This review was prepared following standard procedures of the Cochrane Collaboration and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement and checklist. Relevant studies published up to November 2012 were identified from three major international and Chinese literature databases: Medline/PubMed, EMBASE and CNKI (China National Knowledge Infrastructure).RESULTS:We included 29 studies involving 38,947 patients from 17 provinces in China. Qualitative analysis showed that key individual level determinants of delays included socio-demographic and economic factors, mostly poverty, rural residence, lack of health insurance, lower educational attainment, stigma and poor knowledge of TB. Health facility determinants included limited availability of resources to perform prompt diagnosis, lack of qualified health workers and geographical barriers.Quantitative meta-analysis indicated that living in rural areas was a risk factor for patient delays (pooled odds ratio (OR) (95% confidence interval (CI)): 1.79 (1.62, 1.98)) and diagnostic delays (pooled OR (95% CI): 1.40 (1.23, 1.59)). Female patients had higher risk of patient delay (pooled OR (95% CI): 1.94 (1.13, 3.33)). Low educational attainment (primary school and below) was also a risk factor for patient delay (pooled OR (95% CI): 2.14 (1.03, 4.47)). The practice of seeking care first from Traditional Chinese Medicine (TMC) providers was also identified as a risk factor for diagnostic delay (pooled OR (95% CI): 5.75 (3.03, 10.94)).CONCLUSION:Patient and diagnostic delays in TB care are mediated by individual and health facility factors. Population-based interventions that seek to reduce TB stigma and raise awareness about the benefits of early diagnosis and prompt treatment are needed. Policies that remove patients' financial barriers in access to TB care, and integration of the informal care sector into TB control in urban and rural settings are central factors in TB control.

Background Asthma and chronic obstructive pulmonary disease (COPD) are common obstructive airway diseases with a substantial burden in terms of morbidity, mortality and costs. Smoking is the single most important risk factor for COPD, and is associated with incident asthma. It is important to know if the prevalence of asthma and COPD is increasing or decreasing in the population in order to effectively allocate health care resources. The definitions of these diseases have varied over time which makes it difficult to measure changes in prevalence. The preferred method is to estimate the prevalence with the same procedures and definitions based on cross-sectional population samples with identical age distributions in the same geographical area at different time points. Measurements of lung function (spirometry) are required to diagnose COPD, and spirometry is used to evaluate disease severity and progress of both asthma and COPD, where observed values are compared to reference values. The most commonly used reference values in Sweden are published during the mid 1980s, and there are few evaluations of how appropriate they are today based on Swedish population samples. The aim of the thesis was to estimate trends in the prevalence of asthma and COPD in relation to smoking habits, and to evaluate and estimate reference values for spirometry. Methods The project was based on population-based samples of adults from the Obstructive Lung Disease in Northern Sweden (OLIN) studies. Postal questionnaires were sent to large cohorts, recruited in 1992 (n=4851, 20-69 years), 1996 (n=7420, 20-74 years) and 2006 (n=6165, 20-69 years), respectively. The questionnaire included questions on respiratory symptoms and diseases, their comorbidities and several possible risk factors including smoking habits. Structured interviews and spirometry were performed in random samples of the responders to the 1992 and 2006 surveys, of which n=660 (in 1994) and n=623 (in 2009) were within identical age-spans (23-72 years). The trend in asthma prevalence was estimated by comparing the postal questionnaire surveys in 1996 and 2006, and the trend in COPD prevalence was estimated by comparing the samples participating in dynamic spirometry in 1994 and 2009, respectively. The prevalence of COPD was estimated based on two different definitions of COPD. Commonly used reference values for spirometry were evaluated based on randomly sampled healthy non-smokers defined in clinical examinations of participants in the 2006 postal questionnaire (n=501). The main focus of the evaluation was the global lung function initiative (GLI) reference values published in 2012, for which Z-scores and percent of predicted values were analysed. New sex-specific reference values for spirometry were estimated by linear regression, with age and height as predictors. These new OLIN reference values were also evaluated on a sample of healthy non-smokers identified in the population-based West Sweden Asthma Study. Results Although the prevalence of smoking decreased from 27.4% to 19.1%, p&lt;0.001, between 1996 and 2006, the prevalence of physician-diagnosed asthma increased from 9.4% to 11.6%, p&lt;0.001. The prevalence of symptoms common in asthma such as recurrent wheeze did not change significantly between the surveys or tended to decrease, while bronchitis symptoms such as cough and sputum production decreased significantly. The evaluation of the GLI reference values showed that the predicted values were significantly lower compared to the observed values in Norrbotten, which makes the percent of predicted too high. This was especially true for FVC percent predicted with a mean of 106%. In general, the deviations were more pronounced among women. New OLIN reference values valid for the Norrbotten sample were modelled and showed a high external validity when applied on the sample from western Sweden. The prevalence of moderate to severe COPD decreased substantially over the 15-year period between 1994 and 2009, regardless of definition. Conclusions In parallel with substantially decreased smoking habits in the population between 1996 and 2006, the prevalence of several airway symptoms decreased while the prevalence of physician-diagnosed asthma increased. These results suggest increased diagnostic activity for asthma, but may also suggest that the asthma prevalence has continued to increase. In contrast to asthma, the prevalence of COPD tended to decrease and moderate to severe COPD decreased substantially. The continuous decrease in smoking in Sweden during several decades prior to the study period is most likely contributing to these results. The evaluation of reference values showed that the GLI reference values were lower than the observed spirometric values in the population, especially for women, why the new up-to date reference values may be of importance for disease evaluation in epidemiology and in the health care as well.

Current treatment practice guidelines in a number of countries mandate the assessment of violence risk in all patients diagnosed with schizophrenia. Although more than 100 different instruments have been developed to facilitate the assessment of violence risk, few have been specifically validated for use in those with schizophrenia. Recent work instead suggests that these instruments are typically associated with lower predictive validity in samples with schizophrenia when compared to that achieved in diagnostically heterogeneous samples, leading to concerns that these instruments omit risk factors that may be specific to the prediction of violence risk in this population. The present thesis therefore aimed to investigate the predictive validity of a number of risk factors for violence in those with schizophrenia. Firstly, to identify key risk factors for violence, a meta-analysis was undertaken, finding that although a number of criminal history risk factors are strongly associated with violence risk, nonetheless a number of risk factors rarely assessed by existing violence risk assessment instruments were significantly associated with violence in those with schizophrenia; most notably a history of attempted suicide. Results of this review also suggested that although the criminal history domain is most strongly associated with violence risk, nonetheless, there is considerable variability in the magnitude of association for the individual risk factors. Study two therefore aimed to investigate this variability and found that a history of violence was most strongly associated with subsequent violence. Study three aimed to identify whether suicidal behaviour, which has rarely been considered risk factors for violence in previous work, incrementally contributes to the prediction of violence. A simple risk model composed of young age, comorbid substance use disorder, previous violence, and a history of suicidal threats, explained as much predictive validity, as measured by the area under the receiver operating characteristic curve, as established risk assessment instruments such as the HCR–20, LSI–R, PCL–R, and VRAG. Current risk assessment approaches may therefore need revision in light of these findings.

published_or_final_version / abstract / Dentistry / Master / Master of Dental Surgery

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

published_or_final_version / abstract / Psychology / Master / Master of Philosophy