Distribution of the environmental and socioeconomic risk factors on COVID-19 death rate across continental United States: A spatial nonlinear analysis

DOI: https://doi.org/10.21203/rs.3.rs-61369/v1

Abstract

The COVID-19 outbreak has become a global pandemic. Spatial variation in the environmental, health, socioeconomic, and demographic risk factors of COVID-19 death rate is not well understood. Global models and local linear models were used to estimate the impact of risk factors of the COVID-19, but these do not account for the nonlinear relationships between the risk factors and the COVID-19 death rate at various geographical locations. We proposed a local nonlinear nonparametric regression model named geographically weighted random forest (GW-RF) to estimate the nonlinear relationship between COVID-19 death rate and 47 risk factors derived from US Environmental Protection Agency, National Center for Environmental Information, Centers for Disease Control and the US census. The COVID-19 data were employed to a global regression model random forest (RF) and a local model GW-RF. The adjusted Rof the RF is 0.69. The adjusted R2 of the proposed GW-RF is 0.78. The result of GW-RF showed that the risk factors (i.e. going to work by walking, airborne benzene concentration, householder with a mortgage, unemployment, airborne PM2.5 concentration and percent of the black or African American) have a high correlation with the spatial distribution of the COVID-19 death rate and these key factors driven from the GW-RF were mapped, which could provide useful implications for controlling the spread of COVID-19 pandemic. 

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Tables

Table 1. Definitions of indicators and sources

Theme

Indicators 

Indicator meaning

Source

Atmosphere

Airborne PM2.5 concentration

Annual average ambient concentrations of PM2.5 in micrograms per cubic meter

United States Environmental Protection Agency (https://www.epa.gov/) and Centers for Diseases Control and Prevention (https://www.cdc.gov/)

Airborne benzene concentration

 Annual average concentration of benzene estimates in microgram per cubic meter

Airborne formaldehyde concentration

Annual average air concentration of formaldehyde estimates in microgram per cubic meter

Airborne acetaldehyde concentration

 Annual average air concentration of acetaldehyde estimates in microgram per cubic meter

Airborne carbon tetrachloride concentration

Annual average air concentration of carbon tetrachloride estimates in microgram per cubic meter

Climate

Air temperature

Average Daily Max Air Temperature ( )

National Center for Environmental Information (https://www.ncei.noaa.gov/)

Precipitation

 Average Daily Precipitation ( 

Sunlight exposure

Annual average sunlight exposure measured by solar irradiance ( )

Centers for Diseases Control and Prevention (https://www.cdc.gov/)

UV radiation exposure

Annual average daily dose of UV irradiance ( )

Landcover

Landcover with water

Percent of land covered by water

Land cover with forest

Percent of land covered by forest

Disaster

Drought

Number of weeks of moderate drought or worse per year

Flood

Percentage of people within fema designated flood hazard area

Health status

Disability

Percentage of population aged 5 years and over with a disability

Asthma

Percent of adults diagnosed with asthma

Obese

Percentage of adults aged 18 years and over who were obese

Overweight

Percentage of adults aged 18 years and over who were overweight

Cancer

Number of people with lung and brouchus  cancer per 1000000 population

Commuting to work

Go to work by private transportation

Percentage of workers 16 years and over who drove alone (car, truck, or van) 

United States Census Bureau (https://www.census.gov/en.html)

Go to work by public transportation

Percentage of workers 16 years and over who go to work by public transportation (excluding taxicab)

Go to work by walking

Percentage of workers 16 years and over who go to work by walking

Work at home

Percentage of workers 16 years and over who worked at home

Mean travel time to work

 Mean travel time to work (minutes) of the workers 16 years and over

Socioeconomic

Health insurance

Percentage of population without health insurance

Householder with a mortgage

Percentage of household with a mortgage

Poverty

Percentage of population whose income is below the poverty level

Service occupations

Percentage of employed population 16 years and over with service occupations

Unemployment

Percentage of population 16 years and over unemployed

Hospital

Number of hospitals

Centers for Diseases Control and Prevention (https://www.cdc.gov/)

Hospital beds

Number of hospital beds per 10000 population

People living in group quarter

Percentage of population living in group quarter

United States Census Bureau (https://www.census.gov/en.html)

People living near a park

Percentage of population living within a half mile of a park

Householder with no internet access

Percentage of households with no internet access

Median household income 

 

Mean household retirement income 

 

Mean household cash public assistance income 

 

Mean household Supplemental Security Income 

 

Demographic

Percent of males

 

 

Median age

Percent of people under 18 years 

Percent of people 65 years and over

Percent of the white race

Percent of the black or African American

Percent of American Indian and Alaska Native

Percent of Asian

Percent of native Hawaiian and other Pacific islander

Percent of Hispanic or Latino

Table 2. The statistic of local R2 of the GW-RF in modelling COVID-19 death rate, we calculated the average value of local R2 and the percentage of counties in five local R2 range (≤0.2, (0.2, 04], (0.4, 06], (0.6, 08], >0.8)

The value of local  

GW-RF

Average value 

0.59

≤0.2

1.1%

(0.2, 04]

9.5%

(0.4, 06]

38.9%

(0.6, 08]

44.8%

>0.8

5.7%

 Table 3. The proportion of counties with local primary risk factor (the risk fator with the highest value of local variable importance) on COVID-19 death rate at county level in the GW-RF.

Local primary risk factor

Proportion of counties

Go to work by walking

35%

Airborne benzene concentration

25%

Householder with a mortgage

13%

Unemployment

12%

Other risk factors

16%