Browsing by Author "Reif, John, committee member"
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Item Open Access Excessive weight gain and gestational diabetes melitus (GDM), hypertensive states, and Cesarean deliveries among Wyoming women(Colorado State University. Libraries, 2016) Chance, Alicia, author; Bachand, Annette, advisor; Reif, John, committee member; Melby, Chris, committee member; Magzamen, Sheryl, committee memberBackground The proportion of women gaining more weight during pregnancy has become an increasing public health issue. Recent data show that nationally, about half of pregnant women gain more weight than the current Institute of Medicine guidelines. Further, over gaining during pregnancy can lead to a number of adverse outcomes for both the mother as well as the fetus. In this study our aim was to determine if, and to what extent, excessive gestational weight gain increased the risk of gestational diabetes mellitus, hypertensive conditions and incidence of Cesarean deliveries among Wyoming women. Methods Birth certificates from all Wyoming residence were collected between January 2006 and August 2010. More than 36,000 records were obtained. Logistic regression models were used, to evaluate the associations between excessive weight gain and gestational diabetes, hypertensive conditions and cesarean deliveries. Confounders and effect modifiers were also assessed. Results Among the entire population we found that 49% gained more weight than recommended. Further, 2% had gestational diabetes, 4.9% had a hypertensive condition and 25% had a cesarean delivery. We found that women who were classified as having excessive weight gain were not significantly more likely to have an increased risk of gestational diabetes. Women with excessive weight gain were 2 times more likely to have a hypertensive state (OR: 2.148; 95% CI: 1.85-2.49) and were 30% more likely to have a Cesarean delivery (OR: 1.29; 95% CI: 1.22-1.37). None of our 16 potential confounders, identified a priori, were identified to significantly affect this relationship. Several interaction variables were significantly associated. When the endpoint of interest was hypertension there were two interactions that were associated. Among women who had excessive weight gain, women who had adequate plus prenatal care, compared to women with adequate were 50% more likely to have a hypertensive condition. Among women who had excessive weight gain, women who were American Indian, compared to white were half as likely to have a hypertensive condition. When the endpoint of interest was Cesarean deliveries there were three interactions that were associated. Among women who had excessive weight gain, women who had three or more children, compared to women who had none were 20% less likely to have a Cesarean delivery. Among women who had excessive weight gain, women who were had less than a high school level of education, compared to women with a college level of education were 20% less likely to have a Cesarean delivery. Lastly, among women who had excessive weight gain, women who were classified as a race of other, compared to white women were 25% more likely to have a Cesarean delivery. Conclusion The results from this study show that excessive weight gain is associated with twice the risk of having a hypertensive condition and 30% increased risk in having a Cesarean delivery. These results add to the accumulating body of evidence to help explain the risk of excessive weight gain and how optimal gain depends on maternal characteristics.Item Open Access Molecular epidemiology of Giardia and Cryptosporidium in dogs and cats in Chiang Mai, Thailand(Colorado State University. Libraries, 2013) Tangtrongsup, Sahatchai, author; Salman, Mo, advisor; Lappin, Michael, advisor; Ballweber, Lora, committee member; Reif, John, committee memberGiardia duodenalis and Cryptosporidium spp. are the common causes of diarrhea in humans and animals, including domestic and wildlife, throughout the world. The species complex G. duodenalis and the genus Cryptosporidium consist of host-adapted and zoonotic genotypes/species. Companion animals, especially dogs and cats, can be infected by the host-adapted as well as the zoonotic genotype/species of these organisms. Therefore, these animals have been questioned regarding their potential to serve as reservoirs for human transmission. In this dissertation, an epidemiological study of Giardia and Cryptosporidium as well as the molecular characterization of these organisms in dogs and cats in Chiang Mai, Thailand was completed. A greater understanding of the prevalence and risk factors associated with Giardia and Cryptosporidium infection can aid veterinarians in the control and prevention of these important diseases. Furthermore, the potential for zoonotic transmission will be reduced. In Chapter 1, Giardia and Cryptosporidium and its epidemiology in dogs and cats are reviewed as well as an update on the situation regarding giardiasis and cryptosporidiosis in Thailand. In Chapter 2, a preliminary study to determine the prevalence of Giardia and Cryptosporidium infection in dogs and cats in Chiang Mai, Thailand is described. Fecal samples were collected for two months (July and August, 2008). The genotype/species of these two organisms were determined as well as the risks associated with infection such as age, sex, diarrhea status, housing type and the presence of co-infection of Cryptosporidium (for Giardia infection) or the presence of Giardia in the case of Cryptosporidium infection. It was shown that Giardia and Cryptosporidium infections were common in dogs in Chiang Mai and that dogs could be a potential reservoir for zoonotic transmission to humans. In Chapter 3, the larger cross-sectional study is described. Samples were collected a year later from August 2009 to February 2010. The objectives were to determine the effect of seasonality (wet months or rainy vs. dry months or winter), to determine the potential risk factors associated with Giardia and Cryptosporidium infections, as well as to determine the genotype/species of these organisms. The results suggested that Giardia infection in dogs was prevalent in the rainy season, whereas seasonality was not significantly associated with Cryptosporidium infection. Young dogs, dogs living in crowded settings, dogs having diarrhea or chronic diarrhea, and dogs shedding Cryptosporidium oocysts had a high risk for Giardia infection. Risk factors associated with Cryptosporidium infection in dogs were age less than one year and dogs having diarrhea. Giardia duodenalis assemblage A and C. parvum were identified in this study; however, the potential role in zoonotic transmission could not be determined. Chapter 4 presents a brief report on the comparison of sugar and sedimentation concentration techniques prior to immunofluorescent assay to detect Giardia cysts and Cryptosporidium oocysts. Concentration of fecal samples may enhance the detection of cysts and oocysts. However, in frozen samples the spherical structure of Giardia cysts or Cryptosporidium oocysts may be affected by the freeze-and-thaw process; therefore, the use of sugar concentration technique may not appropriate for frozen fecal samples. Chapter 5 compares the PCR assays using different target genes in detecting Giardia and Cryptosporidium in dogs and cats from Chiang Mai, Thailand. Three PCR assays for Giardia were compared, including the PCR targeting to glutamate dehydrogenase (gdh), triose phosphate isomerase (tpi), and β-giardin gene. Three PCR assays for Cryptosporidium, a heat shock protein targeting PCR and two PCR assays to detect SSU-rRNA (one step PCR vs nested PCR assays), were compared. Giardia gdh and Cryptosporidium one-step SSU-rRNA PCR assays had the highest amplification rates. Using a multilocus analysis approach, most of the Giardia isolates were dog genotypes, whereas 30%-40% of Cryptosporidium species were C. parvum. This finding may suggest a potential role of zoonotic transmission of Cryptosporidium from dogs and cats in this region of Thailand. The research described in this dissertation raises the knowledge in the field of canine and feline giardiasis and cryptosporidiosis. The results provide additional prevalence and risk analysis results for dogs and cats in Chiang Mai, Thailand. The molecular analyses suggest that the use of multilocus analysis is superior to using only one locus. In addition, the results also suggest that sugar flotation was not appropriate as a concentrating method for frozen fecal material and that sedimentation should be used when freezing of the sample is necessary.Item Open Access Spatial analysis of human Lyme disease risk in an endemic county(Colorado State University. Libraries, 2014) Kugeler, Kiersten Jenae, author; Peel, Jennifer, advisor; Reif, John, committee member; Eisen, Lars, committee member; Mead, Paul, committee member; Biggerstaff, Brad, committee memberAn understanding of the factors that drive spatial variation in human Lyme disease risk is important for appropriate development and implementation of public health interventions. Yet, these factors are poorly understood. This dissertation utilized fine-scale environmental and human Lyme disease data from a single county to quantify the spatial distribution of human Lyme disease occurring 2001-2011 and to evaluate whether spatial variation in disease risk was explained by several factors, including land use, land cover, deer density, and tick infestation on deer. All studies were conducted with data from Howard County, Maryland. The first project described spatial clustering of human Lyme disease according to residence. When compared to other areas of the County, areas with elevated disease risk were characterized by more low-density development and more red and white oak forest. The second project used multilevel (i.e., mixed effect) models to examine risk factors for human Lyme disease among all homes in Howard County. In this analysis, 8% of all variation in human disease risk was due to the census block group location of households; the remaining variation in human disease risk occurred within census block groups. Most of the variation in risk between census block groups was explained by household-level land use and land cover characteristics and census block group-level differences in forest and socio-demographics, yet some variation in risk between block groups remained unexplained with available covariates. Increased risk of Lyme disease was associated with low- and medium-density residential development, red and white oak forest, increasing proportion of the census block group classified as forest, and residing in a census block group characterized by higher income, home value, and education. The third project evaluated associations between deer density, tick infestation on deer, and human disease risk. Study findings suggested that areas with lower deer density had higher abundance of ticks on deer and higher risk of human Lyme disease. These results suggest that moderate deer reduction in inland areas, as occurs through community deer management programs, may not be a viable Lyme disease prevention measure. This dissertation advances knowledge of the fine-scale epidemiology of human Lyme disease and demonstrates the importance of using human outcome data, in addition to entomologic data, to understand variation in Lyme disease risk. These studies use advanced analytic methods to demonstrate significant sub-county spatial variation in risk of human Lyme disease, validate previously recognized risk factors for human illness, identify novel associations of a specific forest type with human disease, and demonstrate the importance of human behavior in placing humans at risk. Finally, results of this dissertation suggest that additional analyses using multilevel modeling techniques may help to provide insight regarding many remaining questions in the epidemiology of Lyme disease.