Examining the Association between Acculturation and Hypertension among Asian Americans in the Washington D.C. Metropolitan Area

Objective: To evaluate the association between Acculturation and hypertension among Asian Americans in the Washington, D.C. metropolitan area. Methods: A cross-sectional study was conducted of 600 Chinese, Korean, and Vietnamese adults. Logistic regression was used to investigate the relationship between acculturation variables (years in the U.S., self-rated acculturation, self-rated English fluency) and hypertension, determined from a mean of 3 blood pressure readings taken on site. Results: Compared to those who resided in the U.S. for 0-5 years, individuals who resided for 6-10 years were about 60% less likely to have hypertension (aOR= 0.36; 95% CI: 0.12, 1.05; p-value=0.06). No significant association was observed between self-rated identity and hypertension. Compared to those with poor English fluency, those who speak “so-so” English have increased odds of hypertension (aOR=1.57; 95%CI: 0.93, 2.64; p-value= 0.09). Disaggregated analysis was conducted for Asian American subgroups, which showed differences in trends of acculturation and hypertension. Conclusion: Findings suggest an association between acculturation and hypertension, guiding future studies to investigate further into these observed effects. Some subgroup differences were observed among Asian American subgroups, potentially suggesting a subgroup-focused intervention.

DISSOLVED AND GASEOUS FLUXES OF CARBON AND NITROGEN FROM URBAN WATERSHEDS OF THE CHESAPEAKE BAY

Carbon and nitrogen loading to streams and rivers contributes to eutrophication as well as greenhouse gas (GHG) production in streams, rivers and estuaries. My dissertation consists of three research chapters, which examine interactions and potential trade-offs between water quality and greenhouse gas production in urban streams of the Chesapeake Bay watershed. My first research project focused on drivers of carbon export and quality in an urbanized river. I found that watershed carbon sources (soils and leaves) contributed more than in-stream production to overall carbon export, but that periods of high in-stream productivity were important over seasonal and daily timescales. My second research chapter examined the influence of urban storm-water and sanitary infrastructure on dissolved and gaseous carbon and nitrogen concentrations in headwater streams. Gases (CO2, CH4, and N2O) were consistently super-saturated throughout the course of a year. N2O concentrations in streams draining septic systems were within the high range of previously published values. Total dissolved nitrogen concentration was positively correlated with CO2 and N2O and negatively correlated with CH4. My third research chapter examined a long-term (15-year) record of GHG emissions from soils in rural forests, urban forest, and urban lawns in Baltimore, MD. CO2, CH4, and N2O emissions showed positive correlations with temperature at each site. Lawns were a net source of CH4 + N2O, whereas forests were net sinks. Gross CO2 fluxes were also highest in lawns, in part due to elevated growing-season temperatures. While land cover influences GHG emissions from soils, the overall role of land cover on this flux is very small (< 0.5%) compared with gases released from anthropogenic sources, according to a recent GHG budget of the Baltimore metropolitan area, where this study took place.