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.

Agriculture, Environmental Incentive Payments, and Water Quality in the Chesapeake Bay

Nonpoint sources (NPS) pollution from agriculture is the leading source of water quality impairment in U.S. rivers and streams, and a major contributor to lakes, wetlands, estuaries and coastal waters (U.S. EPA 2016). Using data from a survey of farmers in Maryland, this dissertation examines the effects of a cost sharing policy designed to encourage adoption of conservation practices that reduce NPS pollution in the Chesapeake Bay watershed. This watershed is the site of the largest Total Maximum Daily Load (TMDL) implemented to date, making it an important setting in the U.S. for water quality policy. I study two main questions related to the reduction of NPS pollution from agriculture. First, I examine the issue of additionality of cost sharing payments by estimating the direct effect of cover crop cost sharing on the acres of cover crops, and the indirect effect of cover crop cost sharing on the acres of two other practices: conservation tillage and contour/strip cropping. A two-stage simultaneous equation approach is used to correct for voluntary self-selection into cost sharing programs and account for substitution effects among conservation practices. Quasi-random Halton sequences are employed to solve the system of equations for conservation practice acreage and to minimize the computational burden involved. By considering patterns of agronomic complementarity or substitution among conservation practices (Blum et al., 1997; USDA SARE, 2012), this analysis estimates water quality impacts of the crowding-in or crowding-out of private investment in conservation due to public incentive payments. Second, I connect the econometric behavioral results with model parameters from the EPA’s Chesapeake Bay Program to conduct a policy simulation on water quality effects. I expand the econometric model to also consider the potential loss of vegetative cover due to cropland incentive payments, or slippage (Lichtenberg and Smith-Ramirez, 2011). Econometric results are linked with the Chesapeake Bay Program watershed model to estimate the change in abatement levels and costs for nitrogen, phosphorus and sediment under various behavioral scenarios. Finally, I use inverse sampling weights to derive statewide abatement quantities and costs for each of these pollutants, comparing these with TMDL targets for agriculture in Maryland.