According to a new ecological study led by the University of Miami Miller School of Medicine, understanding how social determinants of health play a role in COVID-19 infections could help with the development of strategies to prevent the spread of the virus.
Social determinants of health are conditions in the place where people live, learn, work, and interact, which in turn affect a wide range of health and quality-of-life risks and outcomes.
The cross-sectional study — published in the November issue of the Journal of General Internal Medicine — found that COVID-19 infection is associated specifically with economic disadvantage and stress reported in a particular geographical area and not with its racial/ethnic distribution.
“These findings are consistent with reports from many other conditions. Racial health disparities are driven by socio-economic disadvantage and not by biological or genetic differences,” said study lead author Ana Palacio, M.D., M.P.H., professor of clinical medicine in the Miller School’s Department of Public Health Sciences. “Therefore, as we consider the steps to contain the pandemic, addressing or mitigating social determinants of health should be among the top priorities.”
“Our findings highlight the importance of integrating clinical, social and geographic data in a privacy compliant manner. Where we live affects our health trajectory,” added study senior author Leonardo Tamariz, M.D., M.P.H., professor of medicine in the Miller School’s Department of Medicine. “Having this information is pivotal to develop the necessary policies or programs to improve health outcomes in our community.”
Dr. Palacio and Dr. Tamariz analyzed 95,594 COVID-19 positive cases across 79 ZIP codes within Miami-Dade County. They found that the highest COVID-19 incidence was for ZIP code 33125, where residents had a median household income of $21,106, 6 percent were Black, and 93 percent were Hispanic. Within this ZIP code, there were 69.8 COVID-19 cases per 1,000 inhabitants.
The lowest incident rate ratio, they found, was for ZIP code 33146, which had a median household income of $96,609, had 3 percent Black residents and 53 percent Hispanic residents. There were 26.1 COVID-19 cases per 1,000 inhabitants within this ZIP code.
Dr. Palacio and Dr. Tamariz conducted the study using COVID-19 cases reported by the Florida Department of Health’s COVID-19 data and surveillance dashboard, which reports the cumulative number of positive COVID-19 tests by county and by ZIP code. Using 2010 Census data, experts imputed race/ethnicity from each ZIP code, as well as described median household income, race, and ethnicity distributions by ZIP code.
The study included two sources of social determinants of health data. The first was ZIP code-level data from 2010 Census population data using Mami-Dade projections. Data included total population, race and ethnicity, median household income, and average household size by ZIP code to match how the COVID-19 cases are reported in Florida.
The second source was individual-level self-reported social determinants of health from a survey of 11,113 primary care UHealth patients — collected between September 2016 and April of 2019 — who responded to a validated questionnaire based on the recommendations of the National Academy of Medicine. The individual-level data included race and ethnicity, education, financial strain, stress, social isolation scale, health literacy, and delays in receiving health care.
Another important finding from the study is that self-reported stress aggregated to the ZIP code level is directly associated with COVID-19 infection.
The study says that potential explanations for the expanding evidence of COVID-19 disparities generally include the higher prevalence of comorbidities among racial/ethnic minority populations and the socio-economic factors that may affect minorities’ ability to physically distance.
The study showed that groups most at risk of COVID-19 infection indeed had low median household income — according to ZIP code-level data — and also had a higher proportion of people reporting financial difficulties paying for basic needs, such as food or medications. Groups with these characteristics are potentially less likely to have the option of staying at home for long periods of time and more likely to be exposed for work-related demands.
“Our prior work has found that these same neighborhoods suffer the highest rates of cardiovascular disease, creating a perfect storm for these communities,” said Dr. Tamariz. “They have higher stress levels, more comorbidities and less ability to socially distance.”
“Creating policies that improve living conditions in these communities would not only improve COVID-19 outcomes but also outcomes in cardiovascular disease and other conditions,” added Dr. Palacio. “Inaction could lead to increasing the health disparities gap between the affluent and less affluent neighborhoods for years to come.”