Browsing by Author "Rojas-Rueda, David, committee member"

Now showing 1 - 3 of 3

Open Access
Evaluating statistical methods to predict indoor black carbon in an urban birth cohort
(Colorado State University. Libraries, 2022) WeMott, Sherry D., author; Magzamen, Sheryl, advisor; Koslovsky, Matthew, committee member; Rojas-Rueda, David, committee member
Though individuals in the United States spend a majority of their time indoors, epidemiologic studies often use ambient air pollution data for exposure assessment. We used several modeling approaches to predict indoor black carbon (BC) from outdoor BC and housing characteristics to support future efforts to estimate personal air pollution exposure given time spent indoors. Households from the Healthy Start cohort in Denver, CO were recruited to host two paired indoor/outdoor low-cost air samplers for one-week sampling periods during spring 2018, summer 2018, and winter 2019. Participants also completed questionnaires about housing characteristics like building type, flooring, and use of heating and cooling systems. Sampled filters were analyzed for BC using transmissometry. Ridge, Lasso and multiple regression techniques were used to build the best predictive model of indoor BC given the available set of covariates. Leave-one-out cross-validation was used to assess the predictive accuracy of each model. A total of 27 households participated in the study, and BC data were available for 39 filters. We had limited comparable data on seasonality as winter data were excluded from the analysis due to high variability and low confidence in outdoor measurements. Shortened runtimes and other performance issues suggest insufficient weatherproofing of our monitors for low temperatures. Of the three modeling approaches, Ridge LSE showed the best predictive performance (MPSE 0.50). The final inference model included the following covariates: outdoor PM2.5, outdoor BC, hard floors, and pets in the home (adj. R2=0.27). These factors accounted for approximately 27% of the variability in indoor BC concentrations measured in Denver, CO homes. In the absence of personal monitoring, household characteristics and time-activity patterns may be used to calibrate ambient air pollution concentrations to the indoor environment for improved estimation of personal exposure.
Open Access
The association between political environment and COVID-19 mortality in selected Colorado counties
(Colorado State University. Libraries, 2023) DeBie, Kelly, author; Neophytou, Andreas, advisor; Peel, Jennifer, advisor; Gutilla, Molly, committee member; Rojas-Rueda, David, committee member
The SARS-CoV-2 virus spread worldwide triggering a global Coronavirus (COVID-19) pandemic. COVID-19 remains a public health threat today and may continue to do so into the future dependent on the emergence of variants and our ability to mitigate harm through vaccines and other public health measures. The COVID-19 pandemic struck the United States during a time of great political tension and divide under the administration of President Donald Trump. State-level variation in mitigation measures may have been influenced by political views. COVID-19 mortality rates also varied by county. This paper seeks to investigate whether the county-level political environment was associated with differences in COVID-19 mortality in the state of Colorado. We examined the association between political environment and county-level age-adjusted COVID-19 mortality rates during 2020 and 2021. Political environment is measured using data from the 2016 and 2020 Presidential election vote distribution by county, obtained from the Colorado Secretary of State. Outcome data was obtained from the Colorado Department of Public Health and Environment (CDPHE), having already been age-adjusted using direct standardization based on the 2010 Census. Any counties with 3 of fewer deaths in a calendar year were excluded, leaving a total of 48 counties in 2020 and 56 in 2021. Rate ratios and 95% confidence intervals were estimated using Quasi-Poisson regression models, separately for 2020 and 2021 mortality data. The models were adjusted for population density, the percentage of county residents without health insurance, and the demographics percentile from the Colorado EnviroScreen Environmental Justice Tool. Models were further evaluated for the presence of effect modification by population density. There are a total of 64 counties in the state of Colorado. In the 2016 election, 42 counties voted for Donald Trump. In the 2020 election, that dropped to 40 counties. Age-adjusted mortality rates ranged from 14.3-458.0 per 100,000 over the two years of data. For 2021 mortality data, the estimated mean adjusted mortality rate was 78% higher among counties where aggregated individual votes were highest in percentage for Donald Trump in 2016 as compared to counties with highest vote percentage for Hilary Clinton. (RR = 1.78; 95% CI: 1.26-2.59). For 2020, the estimated mean adjusted mortality rate was found to be 24% higher among counties voting in highest percentage for Donald Trump in 2016 as compared to counties voting in highest percentage for Hilary Clinton, though this association was not statistically significant. (RR=1.24; 95% CI: 0.81-1.94). Similar results were observed for the 2020 election data (comparing county-level voting results for Trump vs. Biden). We did not observe evidence that the association was modified by population density. This study observed an association between county-level political environment and age-adjusted COVID-19 mortality rates, specifically finding an association that became statistically significant during the pandemic. These results build on a growing body of evidence studying the links between politics and COVID-19 outcomes. Strengths of this study include the use of publicly available datasets, state-wide analysis, multiple model options with similar results indicating robustness, and utilization of a novel environmental justice metric to adjust for multiple confounders simultaneously. As this was an ecological study, inference cannot be extended to individuals. Future research may want to further explore both the individual and community political exposures that may influence mortality. It may also be suggested to investigate election data as a continuous rather than binary variable to tease out the relationship in more detail. Studies such as this may be useful as the COVID-19 pandemic is still ongoing, and in preparation for any future pandemics.
Embargo
The influence of reproductive access restrictions on health behaviors, infant mortality, and physician supply
(Colorado State University. Libraries, 2025) DeBie, Kelly Ann, author; Neophytou, Andreas, advisor; Gutilla, Molly, committee member; Keller, Kayleigh, committee member; Peel, Jennifer, committee member; Rojas-Rueda, David, committee member
In the past decade, there has been an increasing focus on restriction or elimination of abortion access in the United States. Of particular importance, the Dobbs v. Jackson Women's Health decision in 2022 overturned Roe v. Wade and eliminated the Constitutionally protected right to abortion. After Roe v. Wade became law in 1973, there was an observed decline in maternal mortality with highest impacts in Black maternal mortality, indicating differential impact of both the restriction and removal of reproductive access. It is hypothesized that removal of access will create many impacts and that those impacts may occur in a differential manner. This dissertation has explored the impacts of limiting reproductive care access on people in the United States. Utilizing a background in health policy, law, ethics, maternal mental health advocacy and doula care, I studied how these laws have impacted populations. Trends in out-of-state abortion seekers were analyzed corresponding with state based restrictions and the repeal of the constitutionally protected right to abortion in the Dobbs decision from 2022. Trends in infant mortality were studied to determine whether they are associated with state-level abortion restrictions in both aggregate data and data which has been disaggregated by race, ethnicity, and cause of death. Physician supply was analyzed to determine if there are changes in the overall supply of physicians as well as within the specialty of obstetricians and gynecologists practicing in impacted states. Reproductive care access is an essential component of healthcare, and it is crucial to understand how changes in state and federal law are impacting people's health and well-being.