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Soil Arsenic And Lead Concentrations And Preterm Birth: Investigating Racial Disparities, Sources, Neighborhood Effects, And Spatial Patterns, Pamela Harley Thornton Davis

Theses and Dissertations

Preterm birth, generally defined as birth at <37 weeks of gestation, is an important public health issue that has multiple risk factors related to characteristics of both the mother and her environment. The purpose of this dissertation was to examine potential sources of spatially interpolated (kriged) environmental concentrations of arsenic (As) and lead (Pb) in residential soils and preterm birth in a Medicaid population of mothers giving birth in South Carolina (SC) from 1996-2001. The first objective was to investigate if a racial disparity existed for estimated soil As and Pb concentrations, after adjusting for proximal and distal sources of these metals (including distance and direction to industrial facilities) in a subset of SC Medicaid mothers living in areas of SC where soil samples were collected and analyzed for these metals. The second objective was to test the hypothesis that estimated soil As and Pb concentrations were associated with increased odds of early (<34 weeks) and late (34-36 weeks) preterm births in the same subset of SC Medicaid mothers, after adjusting for individual and neighborhood level risk factors, and examine if measure of neighborhood deprivation and racial residential segregation modified these associations. The third objective was to examine if early and all preterm births, aggregated at the county level, varied spatially and/or temporally in SC for all Medicaid mothers giving birth from 1996-2001 in Bayesian models.

For the first objective, black mothers had significantly higher estimated As and Pb soil concentrations than white mothers in the study population (adjusted betas were 0.12 and 0.22 for As and Pb, respectively; all p<0.006), and proximal sources of metals (e.g., percent of Census block group are covered by roads) were more strongly associated with estimated soil As and Pb concentrations than composite As and Pb releases from industrial facilities categorized by distance from and direction to Census block groups in which maternal residences were located.

For the second objective, estimated soil concentration of neither As nor Pb were associated with increased odds of early or late preterm birth after adjusting for maternal and neighborhood level risk factors. Only individual level covariates were associated with these birth outcomes, and associations were stronger for early as compared to late preterm births. Neighborhood deprivation and racial …

The Characterization Of A Putative Protease Expressed By Sneathia Amnii, Rana Mehr

Theses and Dissertations

Preterm birth, birth prior to 37 weeks gestation, is the leading cause of neonatal mortality and morbidity worldwide. While the uterine cavity and amniotic fluid largely remain sterile throughout gestation, bacterial infections can occur and are associated with preterm birth and/or preterm premature rupture of the fetal membranes (PPROM). Sneathia amnii can be detected as a component of the vaginal flora in healthy women; however, it’s also associated with bacterial vaginosis and preterm birth. Sn35, an isolate of S.amnii, was identified and sequenced through the Vaginal Human Microbiome Project at VCU. Our objective was to classify potential virulence determinants …

The Characterization Of A Putative Virulence Factor Expressed By Sneathia Amnii, Amy Sanford

Theses and Dissertations

Preterm birth, defined at birth before 37 weeks gestation, affects millions of newborns worldwide every year. Preterm birth is a leading cause of infant morbidity and mortality. One major cause of preterm birth is preterm premature rupture of membranes (PPROM), which can be triggered by bacterial infection and inflammation. A bacterial species that has been implicated in preterm birth and other obstetric complications is Sneathia amnii. The goals of this study were to observe cytopathogenic effects caused by S. amnii strain Sn35 and identify putative virulence factors causing those effects. Sn35 was able to adhere to, invade, and damage/kill …