Browsing by Subject "Risk factors"
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Item The contribution of whole blood viscosity in assessment of vascular function(2011-05) Parkhurst, Kristin Louise; Tanaka, Hirofumi, Ph. D.; Farrar, RogerAlthough blood viscosity is an important component in determining vascular function, it is often assumed constant. Emerging evidence linking individual differences in viscosity to cardiovascular disease casts doubt on this assumption. The purpose of this study was to determine the contribution of whole blood viscosity to key measures of vascular function. To address this aim as comprehensively as possible, first, whole blood viscosity was compared with traditional risk factors for cardiovascular disease. Then flow-mediated dilation (FMD), carotid-femoral pulse wave velocity (cfPWV), and carotid artery compliance were calculated either with or without blood viscosity taken into account. Lastly, we tested whether the removal of blood viscosity could influence well-established associations between age and vascular function. Blood viscosity and vascular function were measured in 97 adults ranging in age from 18-63 years. No significant differences were observed between whole blood viscosity and traditional risk factors for cardiovascular disease. Whole blood viscosity was not significantly correlated with FMD, cfPWV, and carotid compliance. As expected, age was positively correlated with cfPWV (r=0.65, p<0.001) and negatively correlated with FMD (r=-0.21, p<0.05) and carotid compliance (r=-0.45, p<0.01). Even after controlling for viscosity, these relationships remained statistically significant (cfPWV r=0.65, p<0.001; FMD r=-0.24, p<0.05; carotid compliance r=-0.44, p<0.05). These results indicate that whole blood viscosity does not appear to significantly impact measures of vascular function and that the rationale for including whole blood viscosity in the calculation of vascular function remains weak.Item Epidemiological Investigation of Risk Factors for Microbial Contamination in Produce at the Preharvest Level(2013-11-15) Park, SangshinIn the United States, the proportion of outbreaks of microbial foodborne illnesses associated with fresh produce has increased over the past decades. A large proportion of these outbreaks have been caused by enteric pathogens, including Listeria monocytogenes, Salmonella, and Escherichia coli O157:H7. The overall objective of this dissertation was to study the risk factors for preharvest produce contamination with these three pathogens and generic Escherichia coli, as an indicator organism of fecal contamination, to improve control of foodborne illnesses associated with fresh produce. This objective was accomplished through three independent studies. The first study identified and characterized known risk factors for contamination of fruits and vegetables at the preharvest level with L. monocytogenes, Salmonella, and E. coli O157:H7 by conducting a systematic review. The review identified and evaluated 68 published research articles which indicated soil and irrigation water as the most important routes of produce contamination with pathogens. The review indicated the existence of solid evidence for several additional risk factors, including growing produce on clay-type soil, the use of contaminated or non-pH-stabilized manure fertilizer, and the use of spray irrigation with contaminated water, with a particular risk of contamination on the lower leaf surface. A total of 955 spinach samples were collected from 12 spinach farms in Colorado and Texas for the second and third study. The second study evaluated the effect of farm management and environmental factors on spinach contamination with generic E. coli at the preharvest level. The results indicated that spinach contamination was influenced by the time since last irrigation, the use of pond water for irrigation, workers? personal hygiene, the use of the field prior to planting, and the proximity of a poultry farm. The third study evaluated the role of weather and landscape factors, in addition to the farm management and environmental factors, in occurrence of spinach contamination with generic E. coli at the preharvest level. The results indicated that spinach contamination was influenced not only by the amount of rain, but also by workers? personal hygiene, the use of the spinach field prior to planting, and the use of manure fertilizer. In conclusion, the three studies have identified important risk factors for microbial contamination of produce at the preharvest. The control of several of these risk factors has already been the focus of the currently established Good Management Practices (GMP) in produce production. The novel findings suggest that the GMP may need to account for rainfall and improve workers? personal hygiene in order to further reduce produce contamination with microorganisms.Item A longitudinal study of risk factors for adolescent depression : gender differences and pathways of risk(2005-08) Bearman, Sarah Kate; Stice, EricDespite consistent evidence that adolescent girls are at greater risk for developing depression than adolescent boys (Ge, Lorenz, Conger, & Elder, 1994; Nolen-Hoeksema, 1987, 1990; Weissman, Leaf, Holzer, Myers, & Tischler, 1984), and that women continue to predominate among depressed adults throughout the lifespan (Kessler, McGonagle, Swartz, Blazer & Nelson, 1993), few studies have examined the etiologic risk factors that predict depression for adolescent girls using a prospective design or examined differential processes of risk in a sample of adolescent girls and boys. Furthermore, although a number of variables have been implicated as risk factors for depressive symptoms or onset of depression among adolescents, some methodological limitations exist. The objective of this research was to examine a set of risk factors suspected to predict depression in adolescents, and to test whether gender moderates these relations. Secondly, this study examined a set of risk factors proposed by the gender additive model of depression (Stice et al., 2000; Stice & Bearman, 2001) that attempts to partially explain the increased prevalence of depressive symptoms in adolescent girls compared to boys. Finally, exploratory classification tree analyses tested for interactions between risk factors that might signal differential pathways to depression. This research provides insight into the etiology of adolescent depression as well as the disparate rate of depression among adolescent girls versus boys, and also provides direction for identifying high-risk individuals and developing effective prevention programs.Item The perception and knowledge of cardiovascular risk factors among Chinese Americans(2006-08) Yu, Teng-Yuan; Clark, Angela P.The purpose of this study was to evaluate Chinese Americans’ perceptions and knowledge about cardiovascular disease (CVD) risk factors and to determine if acculturation has systematic effects on perception of illness. Perception about the cause, seriousness, curability, and controllability of CVD were investigated. Relationships between the demographic characteristics of the participants and cardiovascular knowledge and perception were examined. The conceptual framework for this study was based on Leventhal’s (1970, 1984) Common Sense Model of Illness Representation. The influence of Kleinman’s Explanatory Model about the cultural and social consideration of illness representation was incorporated. A cross-sectional design was selected for this descriptive study with a convenience sampling technique. The target population was community-based Chinese Americans who live in the United States. Data collection was conducted using the Internet to access a population. The sample of the study was comprised of 124 adults with 68% being female. The majority of participants retained a high Asian identity. Participants identified Chinese over English for speaking, reading, writing preferences. Instruments included the Illness Perception Questionnaire-Revised (IPQ-R), Suinn-Lew Asian Self-Identity Acculturation Scale (SL-ASIA) and the Healthy Heart IQ. Findings included the following: the IPQ-R subscales were intercorrelated in a logical manner. Illness perceptions correlated positively with each other but were negatively correlated with optimistic perceptions like personal and treatment control. No difference was observed in the IPQ-R based on age, gender or educational level. Knowledge of CVD among Chinese Americans was lower than the general population. The level of acculturation had an impact on the illness perception. Acculturation level was significantly related to all seven illness perception dimensions of illness representation on the IPQ-R. There were significant relationships between acculturation level and knowledge of CVD. However, due to the low acculturation level presented by majority of participants, caution must be exercised in the interpretation of the study findings. The findings of this study have important implications for nursing practice, education, and theory. These results also provide directions for future research. Suggestions for health care professionals who care for patients with ethnic cultural backgrounds were given.Item The perceptions of bilingualism as a risk factor for stuttering(2015-05) Haque, Ayesha Nasir; Byrd, Courtney T.The purpose of this study was to examine, based on survey results of a sample of speech-language pathologists (SLPs), the degree to which a bias exists for classifying bilingualism as a risk factor for the onset and persistence of stuttering. This study also aimed to determine what if any sources (i.e. years of experience, specialization in the field of fluency, and educational history on the topics of bilingualism and stuttering) uniquely influenced SLPs' understanding of risk factors. It is hypothesized that if SLPs perceive bilingualism as an inherent risk factor, they may be more likely to falsely identify typical bilingual clients who do not present with stuttering.Item Understanding suicide and applying current research to prevent college student suicide(2016-08) Smart, Kristin Alexis; Drum, David J.; Rude, StephanieSuicide is a leading cause of death around the world and is on the rise. Suicide is considered to be the second leading cause of death for college students, (Drum, Brownson, Denmark, & Smith, 2009) and the rate of suicide completion is between 6.5 and 7.5 per 100,000 students (Silverman, Meyer, Sloane, Raffel, & Pratt, 1997). Not only are completed suicides an issue on college campuses, but suicidal thoughts and ideation are extremely prominent in this population as well. Approximately 50 percent of college students report having considered suicide at some point in their lives. 18 percent of undergraduate students and 15 percent of graduate students report having seriously considered attempting suicide with 40 to 50 percent of those students reporting multiple episodes of suicidal thought. (Drum et al., 2009). This report will look at the warning signs and risk factors for suicidal ideation and attempts, theories of suicidality, reasons students do not seek treatment, motivations or events that lead to attempting or committing suicide, the most common methods, protective factors against suicide, and finally current and future prevention methods on college campuses.