Master of Public Health
First Committee Member
Lynette Smith, Ph.D.
Second Committee Member
Anne L. O'Keefe, M.D., M.P.H.
Third Committee Member
Tricia D. LeVan, Ph.D.
Background: Asthma and chronic obstructive pulmonary disease (COPD) are chronic diseases associated with health disparities in Douglas County, Nebraska and in the United States. Currently there is a lack of information describing the impact of environmental factors in Nebraska on the burden of emergency department (ED) visits or hospitalizations related to these chronic respiratory (CR) diseases. The aim of this study was to determine if there is an association between the numbers of seasonal viral respiratory (SVR)- related ED visits, outdoor air pollutants, aeroallergens, or meteorological factors on the number of CR- related ED visits in Douglas County, Nebraska.
Methods: We analyzed electronic health record (EHR) data from 8 of 9 hospitals in Douglas County, NE for ED visits from February 28, 2016 to December 29, 2018. Syndromic surveillance definitions were used to identify CR- and SVR- related ED visits in EHR ED data. Aeroallergen, outdoor air pollutant and temperature data were obtained. Descriptive statistics were performed on EHR and environmental data. Negative binomial models were used to determine the association between the number of CR- related weekly ED visits and the environmental factors of interest. These models were stratified to account for possible cofounding effect of patient age and season. Patient age was stratified into 3 age groups: < 18 yrs., 18-39 yrs., ≥ 40 yrs.
Results: Significant associations were observed between the number of CR- related weekly ED visits and the weekly number of SVR-related ED visits, mean weed pollen counts, mean mold spore counts, mean minimum temperature, mean carbon monoxide levels and mean fine particulate matter (PM2.5) levels. Discrepancies in significant associations between the CR- related weekly ED visits and the environmental variables were observed after stratifying the model by season and age groups. For instance, SVR-related weekly ED visits were significantly associated with an increase in CR-related weekly ED visits among the < 18 yrs. and 18 to 39 yrs. age groups in the summer, the ≥ 40 yrs. age group in the fall, and the 18 to 39 yrs. and the ≥ 40 yrs. age groups in the winter. Minimum temperature was significantly associated with the increase in CR- related weekly ED visits among the < 18 yrs. and 18 to 39 yrs. age groups in the fall. Significant associations with an increase in CR- related weekly ED visits were also observed for PM2.5 among the 18 to 39 yrs. and ≥ 40 yrs. age groups in the spring, and the < 18 yrs. and ≥ 40 yrs. age groups in the fall. Weed pollen and mold spores were also significantly associated with an increase in CR- related weekly ED visits. While significant associations were observed for weed pollen during the summer among the < 18 yrs. age group, significant associations were observed for mold spores among all age groups during spring, and among the ≥ 40 yrs. age group during summer. Carbon monoxide was associated with a decrease in CR-related weekly ED visits for the 18 to 39 yrs. age group in the fall.
Conclusions: Results of this study indicate the association between environmental factors and CR- related ED visits in Douglas County, Nebraska could be affected by not only by SVR disease cycles, temperature and other environmental factors, but also by age. Additional analyses may be needed to further explore these associations.
Gonzalez-Ramirez, Sandra; O'Keefe, Anne Mardis; LeVan, Tricia D.; and Smith, Lynette, "Using Syndromic Surveillance to Assess the Impact of Environmental Factors on Asthma- and COPD- Related ED Visits in Douglas County, Nebraska" (2019). Capstone Experience. 104.