(1) Identify a policy that is not usually intended to be a health policy but that you think may have important health implications.
Policy surrounding the planning and implementation of public transportation (bus, light rail) locations/routes has the potential to have important health implications.
(2) Describe why an evaluation of that policy is informative (primarily about the policy, or primarily a test of hypothesized mediators?)
Many people, especially those in cities rely on public transportation as their way to move around, to get to and from work, the grocery store, health maintenance appointments, etc. This is especially true for those of lower socioeconomic status with a lower household income who cannot afford to have a personal vehicle. For those people, how close they are to public transportation and how convenient and reliable the transportation is (schedules that run early and late with frequent buses/trains) has the ability to impact health. Evaluation of policy surrounding the planning/zoning/implementation of public transportation in a city would be informative as an investigation into the policy itself – how it is decided what routes go into what neighborhoods and why one neighborhood may be chosen over another.
(3) Specify the outcomes and populations you think most affected or least affected by the policy.
Outcomes most affected by the policy may include obesity since lack of access to public transportation may limit the options from where people choose to purchase food. If no grocery stores are in close proximity to a person’s home and they have no way to get to one, then neighborhood convenience stores or fast food restaurants become the only options. This then leads to unhealthy eating patterns which may lead to obesity. Another outcome affected by public transportation locations/routes planning and implementation may be ability to adhere to health maintenance recommendations (i.e. attendance at medical follow-up appointments). Without a way to reliably get to a hospital or clinic visit due to inaccessible public transportation, people may not be able to attend appointments and therefore may become more frequent users of the emergency department services for health care and chronic health conditions (i.e. diabetes, hypertension) may be poorly controlled and present in the late stages of disease because patients were unable to have close routine outpatient follow-up with providers due to a logistical inability to reach the hospital.
(4) Propose a study design to evaluate the policy
I would propose an observational study where patients’ proximity to public transportation is studied. The participant’s address/zip code could be used to map distance to public transportation, number of public transport options they have, and frequency of trains/buses. Outcomes to study would be BMI and a food diary/log to assess eating habits and therefore extrapolate where people are purchasing their food. Another outcome to study would be number of times participants with chronic health conditions were able to attend scheduled clinic visits and how often they visited the emergency department for treatment related to their condition. A group with easy access to public transportation (possibly described as less than 4 blocks to a public transportation option) would then be compared to a group with poor access to public transportation (possibly defined as greater than 4 blocks to a public transportation option).
(5) Describe biggest challenge to implementing and drawing inferences about the impact of the policy on health
One challenge to drawing inferences about the impact of public transportation location/zoning/routes policies on health is that there are confounders to consider in this analysis. For the obesity analysis, exercise should decrease obesity and it could be said that a farther distance from public transportation necessitates that people walk more, thereby increasing exercise compared to those who live close to the transportation. Therefore, we may expect those who live farther from the transportation to have lower obesity rates rather than higher. For the analysis of health maintenance, one confounder may be that people of low income and low SES may not make their health maintenance appointments because of other reasons that transportation alone. For example, people may need to work to bring money into the household and they may prioritize this over health maintenance visits.