Abstract for the 2017 HEI Annual Conference
Improvements in Air Quality and Health Outcomes Among California Medicaid Enrollees Due to Goods Movement Actions (Phase II Health Effect Study)
Ying-Ying Meng1, Jason G. Su2, Michael Jerrett3,4, Edmund Seto5, John Molitor6, and Xiao Chen1
1UCLA Center for Health Policy Research, University of California–Los Angeles, USA; 2Division of Environmental Health Sciences, School of Public Health, University of California–Berkeley, USA; 3Department of Environmental Health Sciences, Fielding School of Public Health, University of California–Los Angeles, USA; 4Center for Occupational and Environmental Health (COEH), Fielding School of Public Health, University of California–Los Angeles, USA; 5Environmental & Occupational Health Sciences, University of Washington– Seattle, USA; 6School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR, USA
Background Since 2006, the California Air Resources Board and local air quality management districts have implemented an Emission Reduction Plan for Ports and Goods Movement. This study aims to examine reductions in ambient air pollution due to goods movement actions and subsequent improvements in health outcomes. In Phase I, our study results indicate that policies regulating goods movement are achieving the desired outcomes in improving air quality for the state, particularly in the goods movement corridors where most disadvantaged communities live.
Methods For the Phase II of the project, we will examine whether reductions in ambient air pollution due to goods movement actions have led to improvements in health outcomes in California Medicaid fee-for-service (FFS) beneficiaries with chronic conditions, including asthma, cardiovascular disease (CVD), chronic obstructive pulmonary disease (COPD) and diabetes. We will conduct a retrospective cohort study using six years of medical and pharmacy claims data (September 1, 2004 to August 31, 2010) from adult enrollees, ages 22 and older, residing in Los Angeles, Riverside, San Bernardino, Alameda, San Francisco, Santa Clara, San Joaquin, Fresno, Sacramento, and San Diego counties. We will create various pollution surfaces based on the models developed in Phase I and assign exposures to Medicaid beneficiaries’ home addresses to investigate associations between long-term (i.e., pre- and post-policy period) and intermediate-term (e.g., seasonal and annual) air pollution exposures and health outcomes, and to identify whether regulatory actions contributed to reductions in emergency department (ED) visits, hospitalizations, and doctor visits.
Results There are about 24,000 enrollees with continuous enrollment (less than one-month gap each year) between 2004 and 2010. Among them, 11,000 enrollees has asthma, 4,500 enrollees has cardiovascular disease including atherosclerotic disease (ADS), coronary artery disease (CAD), and congestive heart failure (CHF), 8,000 enrollees has COPD and 17,000 enrollees has diabetes. The total number of people in the cohort does not match the number of enrollees by disease because enrollees may have multiple diseases. About 15% of the patients had at least one hospitalization and 30% had ED visit(s) each year. When we used the geographic proportion of a ZIP code within each domain to provide an estimate, the enrollees are distributed in the following ways: 22% in GMCs, 45% in NGMCs, and 33% (6,800) live in CTRL areas respectively.
Conclusions The Phase II study will contribute to scientific knowledge and empirical evidence regarding whether goods movement actions will benefit low-income Californians with chronic conditions through air pollution exposure reductions and health outcome improvements. Our investigation will join a small number of studies that assess the health effects of longer-term, large scale, and more complex regulatory actions. The study also provides a unique opportunity to evaluate the adequacy of using routinely collected medical claims data for health effect studies.