Effect of altitude on COVID-19 mortality in Ecuador: an ecological study

Adriana Campos; Bridget Scheveck; Jeegan Parikh; Santiago Hernandez-Bojorge; Enrique Terán; Ricardo Izurieta

doi:10.1186/s12889-021-12162-0

Effect of altitude on COVID-19 mortality in Ecuador: an ecological study

BMC Public Health. 2021 Nov 12;21(1):2079. doi: 10.1186/s12889-021-12162-0.

Authors

Adriana Campos¹, Bridget Scheveck², Jeegan Parikh², Santiago Hernandez-Bojorge², Enrique Terán³, Ricardo Izurieta²

Affiliations

¹ University of South Florida, 4202 E Fowler Ave, Tampa, FL, 33620, U.S.. elba@usf.edu.
² University of South Florida, 4202 E Fowler Ave, Tampa, FL, 33620, U.S.
³ Colegio de Ciencias de la Salud, Universidad San Francisco de Quito, Campus Cumbayá, Diego de Robles s/n, Quito, 170901, Quito, Ecuador.

Abstract

Background: The SARS-CoV-2/COVID-19 pandemic has claimed nearly 900,000 lives worldwide and infected more than 27 million people. Researchers worldwide are studying ways to decrease SARS-CoV-2 transmission and COVID-19 related deaths. Several studies found altitude having a negative association with both COVID-19 incidence and deaths. Ecuadorian data was used to explore the relationship between altitude and COVID-19.

Methods: This is an ecological study examining province-level data. To explore a relationship between altitude and COVID-19, this study utilized publicly available COVID-19 data and population statistics. ANOVA, correlation statistics, and a multivariate linear model explored the relationship between different Ecuadorian altitudes against incidence, mortality, and case-fatality rates. Population statistics attributed to COVID-19 were included in the linear model to control for confounding factors.

Results: Statistically significant differences were observed in the regions of Amazónica, Sierra, Costa of Ecuador for incidence, mortality, and case fatality rates, suggesting an association between altitude and SARS-CoV-2 transmission and COVID-19 disease severity (p-value ≤0.05). In univariate analysis, altitude had a negative association to mortality rate with a 1-unit change in altitude resulting in the decrease of 0.006 units in mortality rate (p-value = 0.03). The multiple linear models adjusted for population statistics showed a statistically significant negative association of altitude with mortality rate (p-value = 0.01) with a 1-unit change in altitude resulting in the decrease in mortality rate by 0.015 units. Overall, the model helped in explaining 50% (R² = 0.4962) of the variance in mortality rate.

Conclusion: Altitude may have an effect on COVID-19 mortality rates. However, based on our model and R² value, the relationship between our variables of interest and COVID-19 mortality may be nonlinear. More research is needed to understand why altitude may have a protective effect against COVID-19 mortality and how this may be applicable in a clinical setting.

Keywords: Altitude; COVID-19; Ecological factor; Epidemiological study; Mortality rates; SARS-CoV-2.

MeSH terms

Altitude*
COVID-19*
Ecuador / epidemiology
Humans
Pandemics
SARS-CoV-2