Dissertationen zum Thema „Risk factors“

Despite high prevalence rates of work-related musculoskeletal disorders (WMSDs), the causes and pathways of WMSD development are not fully understood. Multiple factors (physical, psychosocial, and individual) have been associated with WMSD development, but causal inferences are not available due to lack of experimental designs. Because the responses, validity, and reliability of measured outcomes under multiple-exposure environments are not known, the current work analyzed the effects of multiple WMSD risk factors on several measurement methods. Forty-eight participants completed four trials of simulated manufacturing work at different levels of physical and psychosocial exposure for one psychosocial dimension (job control, job demands, time pressure, or social support). The three independent variables significantly affected outcomes, including muscle activity, heart rate, task performance, discomfort and workload ratings, and psychosocial environment perceptions. Social interaction should take priority over working in isolation, and pressure to achieve high performance should be minimized to reduce WMSD risk. A secondary data analysis determined measurements that could estimate WMSD risk efficiently. Convergent and discriminant validity was assessed to retain methods that provided unique information and minimized overlap between similar methods. For the given manufacturing environment, one muscle activity measure, heart rate mean and variability, one set of workload and discomfort ratings, and a psychosocial questionnaire were the best WMSD risk measurement methods. The third study assessed the test-retest reliability of the outcome measures of an additional trial involving 24 participants. Workload and discomfort appeared reliable under high levels of physical exposure but not under psychosocial manipulations. Physiological measures were reliable for <50% of parameters. The psychosocial questionnaire was reliable under favorable social support but not high physical exposure and favorable job control. The final study determined the number of psychosocial factors experienced through factor analysis on psychosocial questionnaire responses from the main experiment. Participants could distinguish psychosocial dimensions in the work environment, and this questionnaire may be used in experimental settings to measure perceptions of the psychosocial environment. The current research provided a basis for measuring physical and psychosocial exposure simultaneously in occupational settings. Using this knowledge may allow practitioners to focus on interventions and designs that reduce WMSD risk exposure.
Ph. D.

Thesis (Ph. D.)--University of Missouri-Columbia, 2007.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on September 19, 2007) Vita. Includes bibliographical references.

Abstract Sciatica is a common musculoskeletal disorder, especially among the working-age population. It causes huge costs to society through work absenteeism and hospital treatments. The common cause of sciatica is the herniated lumbar disc compressing the nerve root. The neurological deficit resulting from this compression can be either sensory or motor-related. Earlier studies have shown both genetic and environmental factors to exist in the aetiology of sciatica. The aim of this study was to investigate how individual, physical and work-related risk factors associate with sciatica, and to determine the prevalence of sciatic pain among Finnish adolescents. The data used in this study were from large, population-based Finnish surveys: the Northern-Finland Birth Cohort 1986, the Mobile Clinic Health Examination Survey, the Mini-Finland Health Survey, Health 2000, the Young Finns Study, and the Helsinki Health Studies. The results of this study showed that sciatic symptoms are already common among adolescents. Young women in particular reported sciatic pain more often than men. Low back pain at the age of 16 predicted sciatic pain at the age of 18. Physically demanding work, smoking and obesity were found to predict an increased risk of hospitalization for sciatica. In the Mobile Clinic Health Examination Survey, leisure-time physical activity protected men from hospitalization for sciatica, whereas among women obesity increased this risk. Occupation also modified the effects of various risk factors. In the Mini-Finland Health Survey, overweight and obese participants who had been exposed to whole body vibration in their work were at a higher risk of hospitalization due to sciatica. In addition, lifting and carrying heavy objects at work, or sedentary work involving the handling of heavy objects predicted an increased risk of hospitalization for sciatica. Heavy or very heavy work protected against hospitalization for sciatica. A meta-analysis of four prospective cohort studies showed that walking and cycling to work reduced the risk of hospitalization for sciatica. This thesis extends our knowledge regarding the risk factors for sciatica. Its results show that these risk factors are complex and can modify each other’s effects. Thus, further research on the interactions of the various risk factors is needed
Tiivistelmä Iskias on etenkin työikäisten keskuudessa yleinen sairaus, joka aiheuttaa paljon työkyvyttömyyttä ja sairaalahoitoja ja siten kustannuksia yhteiskunnalle. Iskiaksen taustalla on yleensä välilevyn pullistuma, joka painaa hermojuuria. Hermojuuren puristuksesta aiheutuva neurologinen puutosoire voi olla joko sensorinen tai motorinen. Aiemmat tutkimukset ovat osoittaneet iskiaksen taustalla olevan sekä geneettisiä että ympäristötekijöitä. Tämän tutkimuksen tavoitteena oli selvittää yksilöllisten, fyysisten ja työhön liittyvien riskitekijöiden yhteyttä iskiakseen sekä tutkia iskiaskivun yleisyyttä suomalaisilla nuorilla aikuisilla. Aineistoina tutkimuksessa käytettiin laajoja väestöpohjaisia suomalaisia aineistoja: Pohjois-Suomen syntymäkohorttia 1986, Autoklinikka- ja Mini-Suomi-aineistoja sekä Terveys 2000-, Young Finns- ja Helsinki Health Study -tutkimuksia. Tutkimuksessa selvisi, että iskiasoireet ovat yleisiä jo nuorilla aikuisilla ja etenkin naiset raportoivat iskiaskipua useammin miehiin verrattuna. 16-vuotiaana ilmennyt alaselkäkipu oli myös yhteydessä iskiasoireisiin 18 vuoden iässä. Työn fyysisen rasittavuuden, tupakoinnin ja lihavuuden todettiin lisäävän sairaalahoitoon johtaneen iskiaksen riskiä. Autoklinikka-aineistossa vapaa-ajan fyysinen aktiivisuus suojasi miehiä sairaalahoitoon johtaneelta iskiakselta, naisilla taas ylipaino lisäsi iskiaksen riskiä. Lisäksi ammatti näytti muokkaavan riskitekijöiden assosiaatioita. Mini-Suomi-aineistossa ylipainoiset ja lihavat henkilöt, jotka olivat altistuneet työssään koko kehon tärinälle, olivat korkeammassa riskissä sairaalahoitoon johtaneen iskiaksen suhteen. Töissä raskaiden esineiden nostaminen tai kantaminen tai painavien esineiden käsittelyä sisältävä istumatyö lisäsivät myös iskiaksen riskiä. Raskas tai erittäin raskas fyysinen työ taas näytti suojaavan sairaalahoitoon johtaneelta iskiakselta. Neljän prospektiivisen kohorttitutkimuksen meta-analyysissä selvisi, että työmatkapyöräily tai -kävely vähensivät sairaalahoitoon johtaneen iskiaksen riskiä. Tämä väitöstutkimus kasvattaa ymmärtämystä iskiaksen taustalla olevista riskitekijöistä. Tulokset osoittavat, että iskiaksen riskitekijät ovat moniulotteisia ja voivat muokata toistensa vaikutuksia, joten lisätutkimusta eri riskitekijöiden välisistä interaktioista tarvitaan

Dementia is a devastating disorder that commonly affects people over the age of 65. Alzheimer's disease and vascular dementia are the most common forms of dementias. A number of studies have implicated cardiovascular risks as important factors in the development of dementia. These risks include high-risk behaviors such as smoking and risks related at least partially to health behaviors such as diet and exercise. This study examines a group of cardiovascular risk factors, as defined by the Framingham study, to ascertain if they are predictors of dementia. A retrospective chart review of 481consecutive patients seen in a geriatric medicine clinic produced a sample of 177 individuals diagnosed with dementia and 304 individuals without a dementia diagnosis. Relative risk ratio (RRR) results indicate that a history of hypertension (RRR= 1.80, p = .009) and a history of hypercholesterolemia (RRR = 1.85, p = .016) are significant predictors of Alzheimer's disease. A history of tobacco use (RRR = 2.18, p = .01) is a significant predictor of vascular dementia. Stepwise regression analyses indicate that hypercholesterolemia is an independent predictor of dementia (b = -.113, p = .009) and hypercholesterolemia (b = -.104, p = .018) and hypertension (b = -.094, p = .031) clustered together have an additive risk factor effect. These results are discussed in terms of the importance of specific health behaviors in the development and possible prevention of dementia.

Background: Many risk factors for venous thromboembolism have been identified, but two particular exposures - the use of combined oral contraceptives and long-distance air travel - have generated considerable concern in recent years. In contrast, a possible link between venous thromboembolism and a third exposure - the use of psychotropic drugs - was first raised in the 1950s, but has received surprisingly little attention. Information about all three exposures and the risk of fatal events is limited. These risks were examined in three inter-related national population-based studies. Methods: The underlying study population included all men and women aged 15 - 59 years who died in New Zealand between 1990 and 2000, for whom the underlying cause of death was pulmonary embolism. The potential associations between fatal pulmonary embolism and the use of oral contraceptives and psychotropic drugs were explored in a general practice records-based case-control study. Non-users were the reference category for all analyses. Contraceptive supply data were used to estimate the absolute risk of death from pulmonary embolism in users of oral contraceptives. A second case-control study, in which computer-assisted telephone interviews were undertaken with the next of kin of cases who had been resident in New Zealand, and with sex and age-matched controls randomly selected from the electoral roll, investigated the possible association between long-distance air travel and fatal pulmonary embolism. Finally, the absolute risk of dying from pulmonary embolism following a long-distance flight was estimated in a descriptive study based on official migration data and deaths in recent air travellers. Results: The adjusted odds ratio for use of any oral contraceptive in the three months before the index date (the onset of the fatal episode) was 13.1 (95% CI 4.4 - 39.0). The odds ratio for formulations containing desogestrel and gestodene was about three times higher than the point estimate for levonorgestrel products; preparations containing cyproterone acetate appeared to carry the highest risk. The estimated absolute risk of fatal pulmonary embolism in current users of oral contraceptives was 10.5 (95% CI 6.2 - 16.6) per million woman-years. The adjusted odds ratio for current use of any antipsychotic was 13.3 (95% CI 2.3 - 76.3). Low-potency antipsychotics carried a 20-fold increase in risk; thioridazine was the main drug involved. Antidepressant use was also associated with a significantly increased risk (adjusted odds ratio 4.9 [95% CI 1.1 - 22.5]). Compared with non-travellers, people who had undertaken a flight of more than eight hours� duration in the preceding four weeks were eight times more likely to die from pulmonary embolism (odds ratio 7.9 [95% CI 1.1 - 55.1]). The absolute risk of fatal pulmonary embolism following air travel of more than eight hours was 1.3 (95% CI 0.4 - 3.0) per million arrivals. Conclusions: The present research was the first to have estimated the relative risks of fatal pulmonary embolism in relation to three exposures: oral contraceptive use in a population in which preparations containing desogestrel and gestodene preparations were widely used, conventional antipsychotics, and long-distance air travel. The findings were consistent with previous, and subsequent, studies of non-fatal events. Increased risks of fatal pulmonary embolism in users of antidepressants, and in people with an intellectual disability, have not been described previously and warrant further investigation. Referral and diagnostic biases are very unlikely in these studies of fatal events, and other types of bias and possible confounding are considered unlikely explanations for the findings.

Background: The highly driven and often excessive exercise seen in eating disorder patients can be defined as a compulsive behaviour, and is often performed for weight control reasons, as well as for mood regulatory purposes. Compulsive exercisers often exercise in a rigid and rule-driven manner and predominantly report no enjoyment from the activity. Importantly, compulsive exercise has negative clinical implications, such as prolonging eating disorder treatment and representing a key factor in eating disorder relapse. However, despite these negative clinical implications and the large percentage of patients that may experience these harmful and detrimental behaviours, the body of literature examining the aetiology of compulsive exercise is relatively scarce and lacks a coherent theoretical underpinning. Objectives: This thesis aimed to provide the first known investigations into the possible correlates and risk factors for compulsive exercise in adolescent boys and girls. Main Findings: The key prospective predictors of compulsive exercise found in this thesis were self-perfectionism and obsessive-compulsiveness for boys. For girls, internal dysfunctional emotion regulation and a perceived media pressure to be thin were the key risk factors for compulsive exercise. Implications: The results from the thesis suggest that psychological factors are important in the development of compulsive exercise in boys, whereas in girls, a combination of dysfunctional emotion regulation and socio-cultural pressure to be thin could lead to the development of compulsive exercise cognitions and attitudes. Further research is needed to replicate and extend these results, although these thesis findings still provide useful empirical evidence to inform prevention and early intervention programmes for compulsive exercise in adolescents.

Despite the existence of extensive literature regarding risk management, there still seems to be lack of knowledge in identification of Critical Success Factors (CSFs) in this area. In this research Grounded Theory is implemented to identify CSFs in Risk Management Systems (RMS). Factor analysis and one-sample t-test are then used to refine and rank the CSFs based on the results of a survey which has been performed among Risk Management practitioners in various types of Swedish corporations. CSFs are defined from three different perspectives: (a) the factors that have influence on the inclination and readiness of corporation for implementing RMS. (b) the factors that are important during the design and implementation of RMS in corporation and can significantly affect the success of RMS design and implementation and (c) the factors that are crucially important to successfully run, maintain and administrate RMS after the closure of the project of RMS design and Implementation.

This systematic approach towards understanding the taxonomy of the success dimension in RMS is important for re-enforcing effective risk management practices.

La present tesi és una aportació a el coneixement de nous factors de risc per al tumor testicular de cèl·lules germinals (TTCG). El TTCG presenta una etiologia multifactorial, atribuïble a un retard en la diferenciació dels gonocitos fetals. El TTCG és més freqüent en homes amb una espermatogènesi alterada, suggerint una possible etiopatogènia comuna. El cromosoma I conté gens essencials per a una correcta espermatogènesi, les regions de l'factor d'azoospèrmia (AZF). La regió AZF més dinàmica és la regió AZFc que presenta punts fràgils que predisposa a reordenaments. El reordenament parcial més rellevant des del punt de vista clínic de la regió AZFc és la deleció gr / gr. S'ha relacionat la delació gr / gr amb un major risc de desenvolupar un TTCG, però la falta d'informació sobre els paràmetres seminals dels pacients no ha permès d'aclarir si l'associació observada està relacionada amb l'espermatogènesi alterada o si és un factor de risc independent. A més, encara queda per establir si altres tipus de delecions i duplicacions de la regió AZFc presenten relació amb el TTCG. La primera part d'aquesta tesi s'enfoca en l'estudi dels reordenaments parcials de la regió AZFc al TTCG. S'han analitzat 497 pacients amb TTCG i 2030 controls sense TTCG. Un 3.8% dels pacients amb TTCG presentaven algun tipus de deleció parcial de la regió AZFc respecte a l'2.5% de el grup control (p = 0.078). La deleció parcial més freqüent va ser la deleció gr / gr, mentre que els altres tipus de delecions parcials de la regió AZFc van resultar ser molt rares. Segons el fenotip seminal, es va observar un major risc de TTCG en pacients normozoospérmicos portadors de delecions parcials de la regió AZFc respecte als controls normozoospérmicos. No hi va haver diferències significatives entre pacients i controls segons les duplicacions parcials de la regió AZFc. Es va mostrar que les alteracions en la dosi de el gen DAZ confereixen un major risc de TTCG. Aquests resultats confirmen que un dèficit de l'contingut gènic de la regió AZFc juga un paper important en la etiopatogènesi de l'TTCG. En particular, la deleció gr / gr confereix un risc significatiu per al desenvolupament de l'TTCG independentment dels paràmetres seminals. Els factors ambientals també estan involucrats en la etiopatogènesi de l'TTCG, especialment si interfereixen en un període específic de el desenvolupament testicular, en el denominat ""masculinization programming window"" (MPW). Un desequilibri hormonal en aquest període compromet a la correcta funció de les cèl·lules fetals de Sertoli i Leydig, originant la síndrome de disgenèsia testicular (SDT). La distància anogenital (DAG) és considerada un biomarcador de l'acció dels andrògens durant el MPW. La DAG més curta ha estat relacionada amb tots els components de l'SDT, excepte amb el TTCG. La segona part d'aquesta tesi valora l'associació entre la DAG i el TTCG. A més avalua el paper de l'polimorfisme CAG de el gen AR en el desenvolupament de l'TTCG i la DAG. Es van analitzar a 156 pacients amb TTCG i 110 controls sans normozoospérmicos. Es va observar una distància anopeneana (DAGap) i una distància anoescrotal (dagues) significativament més curta en els TTCG respecte als controls. Es van definir uns punt de tall (DAGap: 130mm; dagues: 53mm) que indiquen un major risc de TTCG en aquells individus que es trobin per sota d'aquests valors. No s'ha trobat relació entre el polimorfisme CAG i el TTCG o la longitud de la DAG. En conclusió, les dades revelen que els pacients amb una DAG més curta presenten un major risc de TTCG, recolzant la teoria sobre la influència de l'desequilibri androgènic durant el desenvolupament fetal en l'etiopatogènia de l'TTCG.
La presente tesis es una aportación al conocimiento de nuevos factores de riesgo para el tumor testicular de células germinales (TTCG). El TTCG presenta una etiología multifactorial, atribuible a un retraso en la diferenciación de los gonocitos fetales. El TTCG es más frecuente en varones con una espermatogénesis alterada, sugiriendo una posible etiopatogenia común. El cromosoma Y contiene genes esenciales para una correcta espermatogénesis, las regiones del factor de azoospermia (AZF). La región AZF más dinámica es la región AZFc que presenta puntos frágiles que predispone a reordenamientos. El reordenamiento parcial más relevante desde el punto de vista clínico de la región AZFc es la deleción gr/gr. Se ha relacionado la delación gr/gr con un mayor riesgo de desarrollar un TTCG, pero la falta de información sobre los parámetros seminales de los pacientes no ha permitido de clarificar si la asociación observada está relacionada con la espermatogénesis alterada o si es un factor de riesgo independiente. Además, aún queda por establecer si otros tipos de deleciones y duplicaciones de la región AZFc presentan relación con el TTCG. La primera parte de esta tesis se enfoca en el estudio de los reordenamientos parciales de la región AZFc en el TTCG. Se han analizado 497 pacientes con TTCG y 2030 controles sin TTCG. Un 3.8% de los pacientes con TTCG presentaban algún tipo de deleción parcial de la región AZFc respecto al 2.5% del grupo control (p= 0.078). La deleción parcial más frecuente fue la deleción gr/gr, mientras que los otros tipos de deleciones parciales de la región AZFc resultaron ser muy raras. Según el fenotipo seminal, se observó un mayor riesgo de TTCG en pacientes normozoospérmicos portadores de deleciones parciales de la región AZFc respecto a los controles normozoospérmicos. No hubo diferencias significativas entre pacientes y controles según las duplicaciones parciales de la región AZFc. Se mostró que las alteraciones en la dosis del gen DAZ confieren un mayor riesgo de TTCG. Estos resultados confirman que un déficit del contenido génico de la región AZFc juega un papel importante en la etiopatogénesis del TTCG. En particular, la deleción gr/gr confiere un riesgo significativo para el desarrollo del TTCG independientemente de los parámetros seminales. Los factores ambientales también están involucrados en la etiopatogénesis del TTCG, especialmente si interfieren en un periodo específico del desarrollo testicular, en el denominado "masculinization programming window" (MPW). Un desequilibrio hormonal en este periodo compromete la correcta función de las células fetales de Sertoli y Leydig, originando el síndrome de disgenesia testicular (SDT). La distancia anogenital (DAG) es considerada un biomarcador de la acción de los andrógenos durante el MPW. La DAG más corta ha sido relacionada con todos los componentes del SDT, excepto con el TTCG. La segunda parte de esta tesis valora la asociación entre la DAG y el TTCG. Además evalúa el papel del polimorfismo CAG del gen AR en el desarrollo del TTCG y la DAG. Se analizaron a 156 pacientes con TTCG y 110 controles sanos normozoospérmicos. Se observó una distancia anopeneana (DAGap) y una distancia anoescrotal (DAGas) significativamente más corta en los TTCG respecto a los controles. Se definieron unos punto de corte (DAGap: 130mm ;DAGas: 53mm) que indican un mayor riesgo de TTCG en aquellos individuos que se encuentren por debajo de estos valores. No se encontró relación entre el polimorfismo CAG y el TTCG o la longitud de la DAG. En conclusión, los datos revelan que los pacientes con una DAG más corta presentan un mayor riesgo de TTCG, apoyando la teoría sobre la influencia del desequilibrio androgénico durante el desarrollo fetal en la etiopatogenia del TTCG.
This thesis is a contribution to the knowledge of new risk factors for testicular germ cell tumor (TTCG). TTCG has a multifactorial etiology, attributable to a delay in the differentiation of fetal gonocytes. TTCG is more frequent in men with altered spermatogenesis, suggesting a possible common etiopathogenesis. The Y chromosome contains essential genes for correct spermatogenesis, the azoospermia factor (AZF) regions. The most dynamic AZF region is the AZFc region that presents fragile points that predispose to rearrangements. The most clinically relevant partial rearrangement of the AZFc region is the gr / gr deletion. gr / gr cheating has been associated with an increased risk of developing TTCG, but the lack of information on the seminal parameters of the patients has not made it possible to clarify whether the observed association is related to altered spermatogenesis or if it is a factor of independent risk. Furthermore, it remains to be established whether other types of deletions and duplications of the AZFc region are related to TTCG. The first part of this thesis focuses on the study of partial rearrangements of the AZFc region in the TTCG. 497 patients with TTCG and 2030 controls without TTCG have been analyzed. 3.8% of the patients with TTCG presented some type of partial deletion of the AZFc region compared to 2.5% of the control group (p = 0.078). The most frequent partial deletion was the gr / gr deletion, while the other types of partial deletions of the AZFc region were found to be very rare. According to the seminal phenotype, a higher risk of TTCG was observed in normozoospermic patients carrying partial deletions of the AZFc region compared to normozoospermic controls. There were no significant differences between patients and controls according to the partial duplications of the AZFc region. Alterations in the dose of the DAZ gene were shown to confer an increased risk These results confirm that a deficit in the gene content of the AZFc region plays an important role in the etiopathogenesis of TTCG. In particular, the gr / gr deletion confers a significant risk for the development of TTCG regardless of seminal parameters. Environmental factors are also involved in the aetiopathogenesis of TTCG, especially if they interfere in a specific period of testicular development, in the so-called "masculinization programming window" (MPW). A hormonal imbalance in this period compromises the correct function of the fetal Sertoli and Leydig cells, causing the testicular dysgenesis syndrome (TDS). The anogenital distance (DAG) is considered a biomarker of the action of androgens during MPW. The shorter DAG has been related to all components of the SDT, except the TTCG. The second part of this thesis assesses the association between the DAG and the TTCG. It also evaluates the role of the CAG polymorphism of the AR gene in the development of TTCG and DAG. 156 patients with TTCG and 110 healthy normozoospermic controls were analyzed. A significantly shorter anopeneal distance (DAGap) and anoscrotal distance (DAGas) were observed in TTCG compared to controls. Cut-off points were defined (DAGap: 130mm; DAGas: 53mm) that indicate a greater risk of TTCG in those individuals who are below these values. No relationship was found between the CAG polymorphism and the TTCG or the length of the DAG. In conclusion, the data reveal that patients with a shorter DAG have a higher risk of TTCG, supporting the theory about the influence of androgen imbalance during fetal development on the etiopathogenesis of TTCG.

Background: The epidemic of childhood obesity is of increasing public health concern, with major implications for long-term health. Prevention strategies are urgently needed. Most of the evidence concerning risk factors for childhood obesity comes from observational studies, mainly from Western populations. In the West, socio-economic position (SEP) is often associated with potential risk factors and with childhood obesity, making these observational studies open to residual confounding. Evidence from a setting with a different confounding structure can be valuable in disentangling whether associations observed in Western settings reflect potentially reversible causal effects of risk factor or are confounded by SEP. Objectives: This thesis took advantage of a large (n=8327), population-representative Chinese birth cohort from a developed non-Western setting, Hong Kong, where the confounding structure between potential risk factors and childhood obesity is different, to examine the association of four modifiable risk factors (mode of delivery, the timing of solid food introduction, type of child care and dairy product consumption) with adiposity from infancy to early puberty. Methods: Adiposity from infancy to early puberty was proxied by age- and sex-specific body mass index (BMI) standardized scores (z-scores) from 3 months to 13 years, relative to the 2006 World Health Organization (WHO) child growth standards for 0-5 years and the 2007 WHO growth reference for 5-19 years. Overweight (including obesity) was defined according to International Obesity Task Force cut-off. I compared three marginal models (maximum likelihood estimation, generalized estimating equations and quantile regression) to ascertain the optimal way of modeling the population-averaged association of early life risk factors with BMI z-score because of the complex data structure with inevitably some missing data. All three methods were used to examine the adjusted associations of mode of delivery and the timing of solid food introduction with BMI z-score from infancy to early puberty and with overweight (including obesity) from early childhood to early puberty. Multivariable linear and logistic regression were used to examine the adjusted associations of the type of child care at 6 months, 3 years, 5 years and 11 years with BMI z-score and overweight (including obesity) at 13 years, and the association of dairy product consumption at 11 years with BMI z-score at 13 years. Results: My analyses were robust to the choice of marginal model. Mode of delivery, the timing of solid food introduction and dairy product consumption were not associated BMI z-score or overweight (including obesity), but informal child care was associated with higher BMI z-score and overweight at early puberty. Conclusions: In this population-representative birth cohort from an understudied non- Western developed setting with little patterning of childhood adiposity by SEP, informal child care (by family members and/or in-home employed help) may be a target for intervention. Conversely, cesarean section, early introduction of solid food and lack of dairy product consumption do not appear to be contributing to the current obesity epidemic. Non-replication in a different context suggests some observed associations in the West may be indicators of residual confounding rather than of causality.
published_or_final_version
Public Health
Doctoral
Doctor of Philosophy

Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 2006.
Title from first page of PDF file (viewed July 10, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.

Maltreatment affected an estimated 794,000 children in the 50 States, the District of Columbia, and Puerto Rico in 2007 (United States Department of Health and Human Services [USDHHS], 2009). The purpose of this study was to examine the risk factors of young maternal age, parents' marital status, multiple birth, preterm birth, birth defects/disability, low economic status, and parental substance abuse related to suspected maltreatment of children 3 years of age or younger from the prospective of pediatric nurse practitioners (PNPs). A cross-sectional survey design, using the Tailored Design Method, was used in this study. A convenience sample consisting of the National Association of Pediatric Nurse Practitioners (NAPNAP) email registry was used for this study with a response rate of 11%. The respondents represented all regions of the United States. Seventy-nine percent of the PNP's (n=363) who completed the survey had suspected child abuse or neglect within the last year in a child three years of age or younger compared to 21% of PNPs (n=96) who did not suspect child maltreatment within the past year. The prevalence of suspected child maltreatment in the study population was 2.35%. According to the model examining child risk factors and abuse, the log of the odds of a child being abused was negatively related to preterm birth (p = .036) and birth defects/disability (p = .001). Multiple birth was positively related but not significant (p = .359). There were no statistically significant child risk factors found in the logistical regression for neglect (preterm birth, p = .180; multiple births, p = .938; birth defects/disabilities, p = .234). When examining the abuse and neglect groups together, the log of the odds of a child being abused and neglected was negatively related to birth defects/disabilities (p = .030). Preterm birth (p = .364) and multiple birth (p = .298) were positively related to the abuse and neglect group but were not significant. According to the model examining parental risk factors and abuse, the log of the odds of a child being abused due to a parent characteristic was negatively related to low economic status, with the proxy being WIC eligibility (p = .001) and a history of substance abuse (p = .031). The regression for abuse indicated a positive, yet insignificant, relationship with young maternal age (p = .129) and single marital status (p = .816). The logistic regression for neglect indicated a positive significant relationship with a substance abuse history (p = .012). The regression for neglect indicated positive but insignificant relationships for young maternal age (p = .693), marital status (p = .343), and WIC eligibility (p = .106). There were no statistically significant parental risk factors found in the logistical regression for abuse and neglect together (young maternal age, p = .263; marital status, p = .523; WIC eligibility, p = .131; substance abuse, p = .985). Findings indicated that child maltreatment is suspected by PNPs in primary care settings, and that PNPs recognize signs and symptoms of abuse and neglect.

This dissertation provides evidence on the risk factors that are priced in bank equities. Alternative empirical models with precedent in the nonfinancial asset pricing literature are tested, including the single-factor Capital Asset Pricing Model (CAPM), three-factor Fama-French model, and Intertemporal Capital Asset Pricing Model (ICAPM). The empirical results indicate that an unconditional two-factor Intertemporal Capital Asset Pricing Model (ICAPM) model, that includes the stock market excess return and shocks to the slope of the yield curve, is useful in explaining the cross-section of bank stock returns. I find no evidence, however, that firm specific factors, such as size and book-to-market ratios, are priced in bank stock returns. These results have a number of practical implications for event studies of banking firms, estimation of bank cost of capital and investment performance, as well as regulatory initiatives to utilize market discipline to evaluate bank risk under Basel II.

Although testicular cancer is a relatively rare cancer in Canada, accounting for only 1.1% of all malignant neoplasms in males, it is the most common cancer among men 20 to 45. Understanding of the causes of testicular cancer risk in general, and the association with diet in particular, remains limited. Data from the National Enhanced Cancer Surveillance System were used to explore the relationship of diet and testicular cancer risk. There were 601 cases of testicular cancer and 744 controls available for study. We systematically examined 17 food groups, 15 nutrients, and 7 individual foods based on data collected through a 69-item food-frequency questionnaire. Our results suggest that higher dairy product intake, specifically cheese, is associated with a higher risk of testicular cancer in Canadian males. Risk differences were observed between histological subtypes of testicular cancer. This thesis provides a basis for future studies designed to address testicular cancer etiology.

Background Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system. It usually strikes during young adulthood, and 2.5 million individuals are estimated to have the disease worldwide. The causes of MS are not known, but several factors have been shown to be associated with the risk of the disease, including certain genes, vitamin D, smoking and Epstein- Barr virus infection. Little is known about how/if these factors interact. Methods Study I: The risk of MS by month of birth was investigated using MS cases from the Swedish MS registry and using general population controls. Studies II–V: We identified MS cases who had donated blood prior to disease onset, and MS cases whose mothers had donated blood during pregnancy, by cross-linking a database of MS cases, and a database of mothers of MS cases, to two local biobank cohorts. One of them consisted of blood samples collected during early pregnancy, and one with samples collected during health controls. Levels of 25(OH)D (25-hydroxyvitamin D), RBP (retinol binding protein, a surrogate marker for vitamin A), CRP (C- reactive protein), cotinine (a nicotine metabolite) and anti Epstein-Barr virus nuclear antigen-1 (EBNA-1) antibodies were measured in cases and matched controls. The risk of MS by categories of these exposures was estimated in bi- and multivariable matched logistic regression models. Results Subjects born in spring had a higher risk of MS, but no influence of early gestational levels of the measured risk factors on the risk of MS in the offspring was observed. In prospective samples from MS cases and controls, 25(OH)D levels ≥75 nmol/l, intermediate RBP levels, and elevated CRP levels in young were associated with a decreased risk of MS. Elevated cotinine levels (suggestive of smoking) and high antibody reactivity against EBNA-1 were associated with an increased risk of MS. All factors but RBP were more clearly associated with MS in young subjects. Conclusion All factors analyzed in prospectively collected samples were associated with the risk of MS, and taken together, the data indicate that the key etiopathological events that lead to MS occur before the age of 20–30. Study II provides support for trials exploring the primary preventive potential of oral vitamin D supplementation.

A group of 21 HIV-positive gay or bisexual men was compared with a matched group of 22 HIV-negative individuals. All subjects were sexually active gay or bisexual males matched for age, as well as age at first intercourse with males. Subjects completed a detailed sexual history questionnaire as well as a series of standardized measures of psychosocial functioning. Results indicated that subjects engaged in a wide range of unsafe sexual behaviours, and frequently combined drugs with sex. Scores on the Michigan Alcoholism Screening Test (MAST) were significantly correlated with lifetime condom use. Social support was also found to be significantly associated with the lifetime number of homosexual partners. Regression analysis revealed a significant negative association between MAST scores and social support and a positive relationship between social support and CD-4 cell count. The groups were found to be similar in terms of clinical levels of anxiety and depression, self-esteem in interpersonal situations, and risk-taking personality.

Objectives: The objectives of this study were to a) examine the distribution of chondrocalcinosis (CC), b) determine the risk factors of CC, and c) examine the radiographic phenotype of osteoarthritis (OA) associated with CC. Methods: Data from the Genetics of Osteoarthritis and Lifestyle (GOAL) study were used to describe the radiographic distribution of CC, and to conduct a case-control study in which cases with CC were compared with controls without CC. All participants had already completed a detailed questionnaire, been examined by a research metrologist, had radiographs of knees, hands, and pelvis, and had given urine and blood samples. All radiographs had been scored for structural radiographic changes of OA, and for the presence of CC. Frontal plane knee alignment was measured on all knee radiographs. The prevalence (95% confidence interval (CI)) of CC was calculated. The odds ratio (OR) and 95% CI were calculated for risk factors of CC, and for structural changes associated with CC in joints with OA. This was adjusted for age, gender, body mass index (BMI), and OA as appropriate, using logistic regression. Results: 3170 participants were included in this study. There were 431 cases with CC. The overall prevalence (95%CI) of CC in the GOAL population was 13.7% (12.5% - 14.9%). In the GOAL population, knee was the commonest site of CC. However, 42% of participants with CC did not have any knee involvement. There was evidence for a generalized predisposition to CC. For example, CC at one joint associated with CC at distant joints. Joints with CC clustered together more than would be expected by chance alone. At knees, wrists and hips, bilateral CC was more likely to associate with CC at distant joints than unilateral CC – also supporting the existence of a systemic predisposition to CC. After adjusting for confounding factors, there was an association between CC and increasing age, lower current BMI, and OA. The association between OA at one joint and CC at the same joint was present for all joints except for the hip. There was no association between CC and gender, diuretic intake, and selected single nucleotide polymorphisms in enzymes involved in pyrophosphate (PPi) metabolism. CC associated with peri-articular calcification, vascular calcification, low cortical bone mineral density (BMD) but not with low cancellous BMD. Self-reported arthroscopy, meniscectomy, knee injury, occupational knee joint loading and knee mal-alignment in the 3rd decade of life associated with knee CC. However, after adjusting for confounding factors including OA, there was no association between either self-reported or radiographically assessed current knee mal-alignment and knee CC. In joints with OA, the additional presence of CC at the same joint associated with a different radiographic phenotype of structural arthropathy. For example, in knees with OA, knee CC associated with attrition. In hips with OA, hip CC associated negatively with osteophytes, joint space narrowing, and sclerosis at the right hip but not at the left. Similarly, in wrists with OA, wrist CC associated with sclerosis in the right but not in the left wrist; in scapho-trapezioid joints (STJs) with OA wrist CC associated with sclerosis on both sides; in metacarpophalangeal joints with OA, wrist CC associated with cysts in the right but not in the left hand; and in 1st carpometacarpal joint with OA, wrist CC associated with cysts in the left but not in the right hand. In knees with OA, the additional presence of CC at distant joints associated with knee attrition. Those with knee CC + OA were excluded from this analysis to remove any local effects of CC. CC at distant joints did not associate with a distinct structural OA phenotype in other joints examined. Conclusion: These findings suggest that CC results form a systemic predisposition, and that it commonly occurs at other joints in the absence of knee involvement. Established risk factors of CC such as age, OA, and previous arthroscopy and/or meniscectomy were validated in this study. Several novel risk factors of CC e.g. low current BMI, low cortical BMD, and vascular calcification were identified. Several novel associations of knee CC i.e. early life knee malalignment, self-reported knee injury, and occupational knee loading were also recognised. There was convincing evidence to suggest that in joints with OA, the additional presence of CC modifies the OA phenotype, and that this varies from joint to joint.

Purpose: Variation in morphology in the proximal femur and pelvis (e.g. acetabular dysplasia, non-spherical femoral head) can biomechanically compromise the hip joint and predispose to hip osteoarthritis (OA). Such morphological variation may in part explain the heritability of hip OA. The objective of this study was to evaluate a range of 2-dimensional morphological measures on standard radiographs to determine: normal range, right: left symmetry, age and gender differences; and to investigate whether they are associated with the risk of hip OA. Methods: A nested case control study was undertaken in 566 unilateral hip OA cases and 1108 controls in the established Nottingham Genetics of Osteoarthritis and Lifestyle (GOAL) database. Unaffected hips of unilateral hip OA cases were compared to the normal controls, under the assumption that similar morphological features would be observed for the affected hips prior to the development of hip OA. Definition of radiographic hip OA was joint space width (JSW) ~ 2.5 mm. Standardized antero-posterior (AP) radiographs of the pelvis were used to measure the morphological features. Measurements were performed by a single observer and the reproducibility was evaluated at baseline, mid and end of the study. Normal values, thresholds (mean±1.96SD) and symmetry of the features were derived from the control subjects. The intra-observer reliability was examined using intra-class correlation coefficient (ICC). Odds ratio (OR) and 95% confidence interval (Cl) were calculated for association. Logistic regression was used to adjust for age, gender and body mass index (BM!). Measurements were divided into tertiles to examine dose response. ii Results: The intra-observer reliability

A globalização dos mercados financeiros das últimas décadas trouxe ao centro da discussão de finanças internacionais o conceito de risco-país. A importância do risco para a economia de um país está relacionada ao fato de que, em um ambiente de alta mobilidade de capital, ele acaba sendo um importante balizador da taxa de juros doméstica. Para que se possa compreender a evolução do risco de um país, medido pelo spread de seus títulos no mercado internacional, não basta entender a influência das características específicas dos países, mas é fundamental também avaliar o papel dos choques internacionais. Dentro deste arcabouço, o objetivo central desta dissertação é avaliar de maneira mais precisa o papel das variáveis externas na determinação dos spreads dos países emergentes. Mostraremos que para entender os choques externos sobre os spreads emergentes não basta observar os movimentos da taxa de juros livre de risco, como se supõe na literatura tradicional, mas também é preciso fazer considerações acerca da aversão ao risco dos investidores internacionais, e do contágio entre os países emergentes durante períodos de crise.
The globalization in the financial markets during the last decades brought the concept of country risk to the center of the discussion in international finance. The importance of country risk is related to the fact that, in a high capital mobility environment, it becomes a important determinant of the domestic interest rate. To understand the evolution of the risk of a country, measured by the spread of its bonds in the international markets, it is important not only to comprehend the influence of its specific fundamentals, but also to evaluate the role of the external shocks. In this framework, the central goal of this dissertation is to evaluate more accurately the role of the external variables in the determination of the spreads of the emerging countries. It will be shown that to understand the external shocks it is not enough to observe only the movements of the free risk interest rate, as the traditional literature assume, but it is also necessary to take into account the risk aversion of the international investors, and the contagion between emerging economies during crisis time.

Mestrado em Finanças
Na literatura financeira, existem vários estudos com o objetivo de entender melhor como determinar as diferenças individuais nas atitudes perante o risco. Estas diferenças entre os indivíduos prendem-se à maneira como eles se comportam perante situações que involvam risco, nas quais a implementação de uma ação carrega um risco. Nos dias actuais é importante perceber quais são os factores que influenciam o comportamento individual de risco, isto é quais as variáveis socio-demográficas que levam a diferentes perfis de risco. No entanto, os diversos autores tem diferentes opiniões sobre este tema, existindo várias escalas que medem o nível de risco de diferentes formas, consequentemente alcançando diferentes conclusões. Usando uma amostra de estudantes do ISEG de diferentes programas, os dados foram recolhidos com base num questionário distribuido online. De forma a aceder à relação entre as diferentes variáveis sócio-demográficas, as atitudes de risco foram medidas usando duas escalas anteriormente bem estabelecidas, que avaliam em diferentes situações as atitudes e comportamentos individuais de risco. Os resultados mostram que algumas variáveis sócio-demográficas têm influência no perfil de risco dos investidores (por exemplo o sexo), enquanto outras aparentam não ter qualquer impacto. Estas descobertas podem vir a ser importantes no futuro para as empresas ter um melhor conhecimento das necessidades dos seus investidores.
In the financial literature, there are several studies with the goal to understand better how to assess individual differences in attitude towards risk. These differences among individuals rely on the way they behave in risky situations, in which the implementation of an action carries a risk. Nowadays it is important to understand which factors influence an individual's risk behavior, which sociodemographic features lead to different profiles. However, authors have different opinions on this matter and there are several scales that measure risk in different ways, consequently achieving different conclusions. Using a sample of ISEG students of different degrees and programs, data was collected based on a questionnaire distributed online. To assess the relationship between the different socio-demographic variables, risk attitudes were measured using two wellestablished existing scales which evaluate in different situations an individual's risk attitudes and behaviors. The results show that some socio-demographic variables have influence in the risk profile of the investors (e.g. gender), while other do not seem to have impact. These findings might be important in the future for companies to better understand their investors' needs.
info:eu-repo/semantics/publishedVersion

Boerhaave syndrome is a spontaneous rupture of the esophagus. It results from a sudden increase in esophageal pressure combined with negative intrathoracic pressure as seen with severe straining or vomiting. Esophageal perforation is extremely rare with an incidence of approximately 3.1 per 1,000,000 per year with a mortality rate estimated to be 20-50%. The rare occurrence and fatal nature of an esophageal perforation makes this syndrome a difficult yet important diagnosis to consider in the clinical setting. This case presents a previously healthy 47-year-old gentleman who presented to a local emergency department with syncope, vomiting, and chest pain sequentially. He reported a 24-hour history of dark stools followed by syncope, and when he regained consciousness he had three bouts of retching and expulsion of coffee-ground vomitus. Shortly after emesis, the patient developed severe and continuous pain located in his central chest that radiated to his back. Upon arrival to the hospital he was tachycardic. Blood tests revealed metabolic acidosis, increased white blood cell count, elevated lactate, and significant anemia. The patient’s hemoglobin was 7.7 gm/dL, a significant drop from the patient’s baseline level of 14. The patient received 1 unit of packed red blood cells and was sent for imaging studies. Chest X-ray and CT imaging revealed free air in the mediastinum, and a subsequent Gastrografin esophagogram study revealed a lower esophageal perforation proximal to gastroesophageal junction. The patient was rushed to the operating room for emergency surgery. An esophagogastroduodenoscopy showed no active bleeds and confirmed a distal mucosal defect suggestive of perforation. The surgery team then performed a left thoracotomy with intercostal muscle harvest and esophageal repair, with the patient needing an additional 4 units of packed red blood cells during surgery. He tolerated the surgery well and received appropriate post-op care in the ICU. A repeat Gastrografin and barium swallow esophagogram revealed no evidence of leak, strictures, or complications from the operation. A follow up CT image of the chest, abdomen, and pelvis was performed one month after hospital discharge, and results showed complete resolution of mediastinal air without evidence of esophageal leak. This case demonstrates how a spontaneous esophageal perforation can occur in previously healthy, middle aged patients with no significant GI history or identifiable risk factors. Given this information, clinicians should consider Boerhaave Syndrome when a patient of any age presents with chest pain after an episode of emesis.

This study sought to examine risk and onset patterns in anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED). Women with AN (n=71), BN (n=66), BED (n=160) and non-psychiatric controls (n=323) were compared retrospectively on risk factors, symptom onset, and diagnostic migration. Eating disorder groups reported greater risk exposure than non-psychiatric controls. AN and BED differed on premorbid personality/behavioral problems, childhood obesity, and family overeating. Risk factors for BN were shared with AN and BED. Dieting was the most common onset symptom in AN, whereas binge eating was most common in BN and BED. Migration between AN and BED was rare, but more frequent between AN and BN and between BN and BED. AN and BED have distinct risk factors and onset patterns, while BN shares similar risk factors and onset patterns with both AN and BED. Results should inform future classification schemes and prevention programs.

Amyotrophic lateral sclerosis (ALS) is a progressive debilitating disease of the upper and lower motor neurons. Median survival of ALS patients is consistently estimated at between 2-3 years from symptom onset, with some evidence that survival is increasing due to improved care. There are few well-established risk factors for ALS, and there is conflicting evidence regarding the trends in ALS incidence and mortality over the past several decades. In Chapter I we investigate the trends in ALS incidence and mortality in Denmark between 1970 and 2009. We employed age-period-cohort models to model both the incidence and mortality rates of ALS over time for the first time. We found a significant rise in ALS incidence and mortality over several decades, and we observed evidence for a birth cohort component to the rise in ALS, which is consistent with an environmental cause of ALS. In Chapter II we investigate the role of physical trauma – both head and other – in the development of ALS. We employed the Danish registries and linked health data from the hospital system to prior diagnoses for physical trauma. We found a borderline significant association between physical trauma and ALS, which grew stronger upon restricting to physical traumas before the age of 55. Chapter III concerns the risk of ALS in those employed by the military in Denmark. We linked occupational records from the Danish Pension Fund to health records of the hospital system. We found a significantly elevated rate of ALS among those who had been previously employed by the military, with the highest rates in the decade immediately following cessation of employment. These analyses strengthen the knowledge base for the epidemiology of ALS, and suggest future avenues of research to further understand the etiology of the disease.

Thesis (M.S. in Software Engineering)--Naval Postgraduate School, March 2003.
Thesis advisor(s): Norman Schneidewind, Richard Riehle. Includes bibliographical references (p. 162-168). Also available online.

Introduction: This dissertation seeks to identify novel, potentially modifiable risk factors that could be used to reduce the risk of prostate cancer (PCa) progression. Aim 1 investigates the effects of obesity and smoking on PCa progression, aim 2 studies the effects of specific medication use on PCa progression, and aim 3 identifies factors associated with faster PCa progression.Methods: Data from 140 subjects from the Watchful Waiting study followed every 3 months for up to 5 years were used. Multiple linear regressions were used to determine associations with baseline PSA. PSA velocity (rate of change of PSA over time) was used as a surrogate marker for PCa progression. Mixed effect models were used to assess the effect of obesity, smoking and medication use on PSA velocity(aim1 and 2). For aim 3, subjects were categorized as slow, intermediate and fast progressors based on tertiles of PSA velocity. In addition to the above variables, age, Gleason score, chromogranin-A, family history, selenium and free PSA were investigated as determinants of faster PCa progression using multiple logistic regressions. Analyses were run using two models, comparing slow progressors to fast progressors (model1) and slow progressors to a combination of fast and intermediate progressors (model2).Results: Aspirin use was negatively associated with baseline PSA (coefficient = -0.39 and 95% confidence interval (CI):-0.612, -0.158). Aspirin effect was statistically significant in never smokers (coefficient = -0.54, 95% CI: -0.916, -0.170) but not in ever smokers (coefficient = -0.22, 95% CI: -0.505, 0.065). Ever smoking was statistically significantly associated with higher PSA velocity compared to never smoking (coefficient = -0.001, 95% CI: 0.0002, 0.002). In aim 3, pack-years of smoking were positively associated whereas aspirin use was negatively associated with high PSA velocity in both models. Odds Ratio and 95% CI for smoking and aspirin use for model1 and 2 respectively; 1.03 (0.92, 1.13), 1.02 (1.00, 1.03), 0.24(0.06, 0.94) and 0.26(0.10, 0.68).Conclusions: Although more studies are needed before recommendations can be made, if these results are borne to be true in other studies these modifiable risk factors can be potentially be used in prevention of PCa progression.

The purpose of this study was to identify risk factors for repeated child maltreatment in Iceland. Only cases that had never been reported to child protection services before were included in this study (N=77 total). Each case was followed for 18 months. In all cases the first reported incident was neglect. In the study, a group of cases that had only been reported once (single incident) was compared with another group of cases that had been reported two or more times (repeated incidents). Risk factors were identified and compared on different levels according to an ecological model: 1) Demographics, 2) Parental figure problems, 3) Children's characteristics, 4) Family problems, 5) Social support. In addition, the two groups were compared on parental non-cooperation and services received. In a logistic regression model, the groups differed significantly on the following factors; the mother figures in the repeated incidents group had lower education level and the mothers in that group had more personal problems than the mother figures in the repeated incidents group. In addition, the repeated incidents group experienced more family dynamic problems than the single incident group.

In the United States, hysterectomy is one of the most commonly performed operations for women that is not related with pregnancy. However, not enough attention has been paid to how women's exposure to the surgery differs according to their social characteristics as well attitudinal/behavioral factors. Using cohort data from the National Longitudinal Surveys of Mature Women, this study investigated two aspects: (1) the association between socioeconomic status and hysterectomy and (2) the impact of women's attitudinal/behavioral characteristics on hysterectomy. With Cox proportional hazards analyses, this study found that women's exposure to hysterectomy significantly differs according to their social and attitudinal standings. Social characteristics that were found to be statistically significant risk factors of hysterectomy include women's eduction, employment status, and marital status. Among additional and behavioral factors, women's locus of control and number of children were identified as statistically significant risk factors. These findings may be used to enhance consumer awareness of hysterectomy and aid in policy reconstruction.

Parkinson's disease (PD) is a progressive, degenerative, neurological disease. The progressive disability associated with PD results in substantial burdens for those with the condition, their families and society in terms of increased health resource use, earnings loss of affected individuals and family caregivers, poorer quality of life, caregiver burden, disrupted family relationships, decreased social and leisure activities, and deteriorating emotional well-being. Currently, no cure is available and the efficacy of available treatments, such as medication and surgical interventions, decreases with longer duration of the disease. Whilst the cause of PD is unknown, genetic and environmental factors are believed to contribute to its aetiology. Descriptive and analytical epidemiological studies have been conducted in a number of countries in an effort to elucidate the cause, or causes, of PD. Rural residency, farming, well water consumption, pesticide exposure, metals and solvents have been implicated as potential risk factors for PD in some previous epidemiological studies. However, there is substantial disagreement between the results of existing studies. Therefore, the role of environmental exposures in the aetiology of PD remains unclear. The main component of this thesis consists of a case-control study that assessed the contribution of environmental exposures to the risk of developing PD. An existing, previously unanalysed, dataset from a local case-control study was analysed to inform the design of the new case-control study. The analysis results suggested that regular exposure to pesticides and head injury were important risk factors for PD. However, due to the substantial limitations of this existing study, further confirmation of these results was desirable with a more robustly designed epidemiological study. A new exposure measurement instrument (a structured interviewer-delivered questionnaire) was developed for the new case-control study to obtain data on demographic, lifestyle, environmental and medical factors. Prior to its use in the case-control study, the questionnaire was assessed for test-retest repeatability in a series of 32 PD cases and 29 healthy sex-, age- and residential suburb-matched electoral roll controls. High repeatability was demonstrated for lifestyle exposures, such as smoking and coffee/tea consumption (kappas 0.70-1.00). The majority of environmental exposures, including use of pesticides, solvents and exposure to metal dusts and fumes, also showed high repeatability (kappas >0.78). A consecutive series of 163 PD case participants was recruited from a neurology clinic in Brisbane. One hundred and fifty-one (151) control participants were randomly selected from the Australian Commonwealth Electoral Roll and individually matched to the PD cases on age (± 2 years), sex and current residential suburb. Participants ranged in age from 40-89 years (mean age 67 years). Exposure data were collected in face-to-face interviews. Odds ratios and 95% confidence intervals were calculated using conditional logistic regression for matched sets in SAS version 9.1. Consistent with previous studies, ever having been a regular smoker or coffee drinker was inversely associated with PD with dose-response relationships evident for packyears smoked and number of cups of coffee drunk per day. Passive smoking from ever having lived with a smoker or worked in a smoky workplace was also inversely related to PD. Ever having been a regular tea drinker was associated with decreased odds of PD. Hobby gardening was inversely associated with PD. However, use of fungicides in the home garden or occupationally was associated with increased odds of PD. Exposure to welding fumes, cleaning solvents, or thinners occupationally was associated with increased odds of PD. Ever having resided in a rural or remote area was inversely associated with PD. Ever having resided on a farm was only associated with moderately increased odds of PD. Whilst the current study's results suggest that environmental exposures on their own are only modest contributors to overall PD risk, the possibility that interaction with genetic factors may additively or synergistically increase risk should be considered. The results of this research support the theory that PD has a multifactorial aetiology and that environmental exposures are some of a number of factors to contribute to PD risk. There was also evidence of interaction between some factors (eg smoking and welding) to moderate PD risk.

Parkinson's disease (PD) is a progressive, degenerative, neurological disease. The progressive disability associated with PD results in substantial burdens for those with the condition, their families and society in terms of increased health resource use, earnings loss of affected individuals and family caregivers, poorer quality of life, caregiver burden, disrupted family relationships, decreased social and leisure activities, and deteriorating emotional well-being. Currently, no cure is available and the efficacy of available treatments, such as medication and surgical interventions, decreases with longer duration of the disease. Whilst the cause of PD is unknown, genetic and environmental factors are believed to contribute to its aetiology. Descriptive and analytical epidemiological studies have been conducted in a number of countries in an effort to elucidate the cause, or causes, of PD. Rural residency, farming, well water consumption, pesticide exposure, metals and solvents have been implicated as potential risk factors for PD in some previous epidemiological studies. However, there is substantial disagreement between the results of existing studies. Therefore, the role of environmental exposures in the aetiology of PD remains unclear. The main component of this thesis consists of a case-control study that assessed the contribution of environmental exposures to the risk of developing PD. An existing, previously unanalysed, dataset from a local case-control study was analysed to inform the design of the new case-control study. The analysis results suggested that regular exposure to pesticides and head injury were important risk factors for PD. However, due to the substantial limitations of this existing study, further confirmation of these results was desirable with a more robustly designed epidemiological study. A new exposure measurement instrument (a structured interviewer-delivered questionnaire) was developed for the new case-control study to obtain data on demographic, lifestyle, environmental and medical factors. Prior to its use in the case-control study, the questionnaire was assessed for test-retest repeatability in a series of 32 PD cases and 29 healthy sex-, age- and residential suburb-matched electoral roll controls. High repeatability was demonstrated for lifestyle exposures, such as smoking and coffee/tea consumption (kappas 0.70-1.00). The majority of environmental exposures, including use of pesticides, solvents and exposure to metal dusts and fumes, also showed high repeatability (kappas >0.78). A consecutive series of 163 PD case participants was recruited from a neurology clinic in Brisbane. One hundred and fifty-one (151) control participants were randomly selected from the Australian Commonwealth Electoral Roll and individually matched to the PD cases on age (± 2 years), sex and current residential suburb. Participants ranged in age from 40-89 years (mean age 67 years). Exposure data were collected in face-to-face interviews. Odds ratios and 95% confidence intervals were calculated using conditional logistic regression for matched sets in SAS version 9.1. Consistent with previous studies, ever having been a regular smoker or coffee drinker was inversely associated with PD with dose-response relationships evident for packyears smoked and number of cups of coffee drunk per day. Passive smoking from ever having lived with a smoker or worked in a smoky workplace was also inversely related to PD. Ever having been a regular tea drinker was associated with decreased odds of PD. Hobby gardening was inversely associated with PD. However, use of fungicides in the home garden or occupationally was associated with increased odds of PD. Exposure to welding fumes, cleaning solvents, or thinners occupationally was associated with increased odds of PD. Ever having resided in a rural or remote area was inversely associated with PD. Ever having resided on a farm was only associated with moderately increased odds of PD. Whilst the current study's results suggest that environmental exposures on their own are only modest contributors to overall PD risk, the possibility that interaction with genetic factors may additively or synergistically increase risk should be considered. The results of this research support the theory that PD has a multifactorial aetiology and that environmental exposures are some of a number of factors to contribute to PD risk. There was also evidence of interaction between some factors (eg smoking and welding) to moderate PD risk.

Since the last financial crisis many new approaches have emerged in an attempt to explain it. Nevertheless, little has been said about the co-evolution of systemic risk and market behavior. A brief introduction to both theories will conduct through a better understanding of the patterns behind the crisis. A comparison between some systemic risk measures and the sentiment experienced by the market give raise to a statistical relationship.

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