Identifying Louisiana communities at the crossroads of environmental and social vulnerability, COVID-19, and asthma

Abstract

The COVID-19 pandemic has disproportionately affected the socially and environmentally vulnerable, including through indirect effects on other health conditions. Asthma is one such condition, which may be exacerbated by both prolonged adverse in-home exposures if quarantining in unhealthy homes and prolonged outdoor exposures if the ambient air quality is unhealthy or hazardous. As both are often the case in Environmental Justice (EJ) communities, here we have analyzed data at the census tract (CT) level for Louisiana to assess any correlation between social and environmental vulnerability, and health issues like COVID-19 and asthma. Higher Social Vulnerability Index (SVI), Particulate Matter less than 2.5 μm in diameter (PM2.5) and Ozone levels were associated with higher rates of cumulative COVID-19 incidence at various time points during the pandemic, as well as higher average annual asthma hospitalization rates and estimated asthma prevalence. Further, cumulative COVID-19 incidence during the first three months of the pandemic was moderately correlated with both asthma hospitalizations and estimated prevalence, suggesting similar underlying factors may be affecting both conditions. Additionally, 137 CTs were identified where social and environmental vulnerabilities co-existed, of which 75 (55%) had high estimated prevalence of asthma. These areas are likely to benefit from asthma outreach that considers both social and environmental risk factors. Fifteen out of the 137 CTs (11%) not only had higher estimated prevalence of asthma but also a high burden of COVID-19. Further research in these areas may help to elucidate any common social determinants of health that underlie both asthma and COVID-19 burdens, as well as better clarify the possible role of the environment as related to the COVID-19 burden in Louisiana.

Fig 1. COVID-19 and asthma in areas with high social and/or environmental vulnerability.

(A) High SVI was associated with higher average cumulative COVID-19 incidence rates early in the pandemic, whereas PM_2.5 was associated with higher rates later in the pandemic. Cumulative COVID-19 incidence was elevated in areas of high Ozone at all points during the pandemic. (B) Asthma hospitalization as well as estimated asthma prevalence followed a similar pattern with higher rates of both being associated with high SVI and high Ozone. Error bars indicate 95% confidence intervals; asterisks (*) indicate areas that are significantly higher than “All CTs” and pounds (#) indicate areas significantly lower than “All CTs” (p<0.05; T-test).

Fig 2. Spatial analysis of social and environmental vulnerability, asthma and COVID-19.

Darker colors for each measure indicate higher percentile ranks. Most counties in LA had census tracts with SVI (A) above the median. Ozone (B) and PM_2.5 (C) were higher in the northwest and southeastern parts of the state. Indoor environmental quality concerns (mostly in the form of mold complaints) were also reported from all over the state (D). Estimated prevalence of asthma (E) was often above the median in census tracts located in the northwestern, western, southern and southeastern parishes. At the 12-month time point, cumulative COVID-19 incidence rates (F) were higher in the northern, northwestern and southeastern parts of the state.

Fig 3. Identifying census tracts with EJ concerns.

Census Tracts were defined as being of EJ concern if the Overall SVI was at or above the 75^th percentile, along with at least one of the environmental variables (RHI, PM_2.5 or Ozone) at or above the 75^th percentile for the state (A). Map shows the number of the CTs of EJ concern by Parish (B). Most of them were located in the major urban areas, with a few spread across the rural areas of the state.

Fig 4. Identifying EJ communities with high COVID-19 and asthma burdens.

(A) Of the 137 census tracts that were deemed of EJ concern, 75 (55%) had estimated prevalence of asthma at or above the 75^th percentile for the state. The majority of these CTs were located in the major urban areas, with others spread across the more rural areas of the state (B). A similar pattern was observed for CTs that were of concern for EJ, asthma as well as COVID-19. About a third of the 15 EJ CTs deemed areas of concern for both asthma and COVID-19 were located in the northwestern part of the State in Caddo Parish (C).