Asthma is a very common health condition today–in fact, I’m sure we all know someone who has been diagnosed with asthma. However, what many of us don’t know is that asthma doesn’t affect everyone equally in the United States, making it an important topic within the broader environmental justice movement.
One factor that has been shown to contribute to asthma disparities on account of demographic makeup is air pollution exposure. Previous research has found that Black and Hispanic individuals are annually exposed to higher levels of toxic air pollution, which results in worse health outcomes for minority communities. Similarly, low-income individuals are also exposed to more air pollution, suggesting that these individuals may be at a higher risk of asthma. These trends in asthma prevalence are not random, though. Within the context of environmental injustice, minority and low-income individuals experience higher rates of asthma because polluting industries are disproportionately located near marginalized communities.
Other lifestyle factors, such as obesity, also increase an individual’s risk of developing asthma, but current research doesn’t consider how these lifestyle factors interact with demographic factors to contribute to asthma.
In this study, I examined what sociodemographic, environmental, and health/lifestyle factors contribute to asthma in the Midwest. Because of the findings of my literature review, I hypothesized that air pollution (as emissions of particulate matter and nitrous oxides), income, and three health/lifestyle factors (smoking, obesity, and physical inactivity) would all have a positive correlation to asthma. In contrast, I hypothesized that poverty would show a negative relationship to asthma.
To determine the effect of each chosen independent variable on asthma, I conducted a county-level univariate analysis using air quality, health, and census data for five states in the Midwest: Illinois, Indiana, Kentucky, Michigan, and Wisconsin. I used federal-level datasets from the Environmental Protection Agency, County Health Rankings, and Centers for Disease Control’s Behavioral Risk Factor Surveillance System to ensure that my data was consistent across all five states.
For my data analysis, I ran a linear regression in Microsoft Excel for each independent variable against asthma prevalence per county by state and made a scatterplot for each variable to better visualize its relationship to asthma.
I found that, contrary to what was suggested in the literature, particulate matter and nitrous oxide emissions showed a negative or neutral correlation to asthma in all states, except for Michigan. These findings suggest that high-level air emissions data may not reflect the actual level of air pollution that individuals are exposed to and are not appropriate for this type of analysis.
Smoking, obesity and physical inactivity all showed a positive correlation to asthma in all states. The strong influence of these factors on asthma show that an individual’s lifestyle choices put them at a higher risk of developing asthma. However, some health factors (like obesity) are also influenced by other genetic and environmental influences, which shows how people may experience worse health effects because of factors they cannot control.
Income was positively correlated with asthma and poverty was negatively correlated with asthma in all states, supporting the conclusion that individuals are at a higher risk of developing asthma because of factors they cannot always control.
The findings of this study suggest that there are multiple health and demographic influences on asthma prevalence. In many cases, these factors interact with each other at the individual level to determine how a person is affected by asthma in relation to air pollution. For example, low-income individuals may not only be exposed to more air pollution, but because of their economic status, they are unable to move out of an area where they have limited access to medical care, healthy food, green spaces, and other beneficial opportunities.
This research highlights the importance of air pollution and its health implications in the context of environmental injustice as individuals are disproportionately affected by asthma because of factors they cannot always control. However, further research could benefit from the findings of this study by conducting multivariate analyses of the environment, health/lifestyle, and sociodemographic variables on asthma to determine their covariate influence.
Abigail Comer is a senior in the O’Neill School of Public and Environmental Affairs.
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