Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 May 31;12(1):9031.
doi: 10.1038/s41598-022-13168-3.

Internet searches and heat-related emergency department visits in the United States

Quinn H Adams  1 , Yuantong Sun  2 , Shengzhi Sun  2   3 , Gregory A Wellenius  4   5
Affiliations

Internet searches and heat-related emergency department visits in the United States

Quinn H Adams et al. Sci Rep. .

Abstract

Emerging research suggests that internet search patterns may provide timely, actionable insights into adverse health impacts from, and behavioral responses to, days of extreme heat, but few studies have evaluated this hypothesis, and none have done so across the United States. We used two-stage distributed lag nonlinear models to quantify the interrelationships between daily maximum ambient temperature, internet search activity as measured by Google Trends, and heat-related emergency department (ED) visits among adults with commercial health insurance in 30 US metropolitan areas during the warm seasons (May to September) from 2016 to 2019. Maximum daily temperature was positively associated with internet searches relevant to heat, and searches were in turn positively associated with heat-related ED visits. Moreover, models combining internet search activity and temperature had better predictive ability for heat-related ED visits compared to models with temperature alone. These results suggest that internet search patterns may be useful as a leading indicator of heat-related illness or stress.

PubMed Disclaimer

Conflict of interest statement

Dr. Wellenius has received consulting income from the Health Effects Institute (Boston, MA) and Google, LLC (Mountain View, CA). Ms. Adams, Mr. Sun, and Dr. Sun declare no potential conflict of interest.

Figures

Figure 1
Figure 1
Conceptual framework highlighting the relationship between exposure to heat and health outcomes highlighting the additional, previously unmeasurable intermediate vulnerability that helps identify increased exposure, behavior change, and susceptibility measured using internet search activity.
Figure 2
Figure 2
Location of the 30 Nielsen Designated Marketing Areas (DMA) defined by one or more US counties for which Google Trends and ED data was available. County and state shapefiles provided by the United States Census Bureau TIGER/Line shapefiles. Map created using ArcGIS Pro version 2.8 (Esri).
Figure 3
Figure 3
Median Spearman Correlation coefficients between Google search terms among 30 DMAs.
Figure 4
Figure 4
Spearman correlation distribution of (a) daily maximum ambient temperature and same day heat-health related Google searches and (b) heat-health related Google searches and same day heat-related ED visits across 30 DMAs.
Figure 5
Figure 5
Cumulative exposure–response curve (95% CI shaded in light blue) for the relative risk for Google searches related to maximum ambient temperature percentile over lags 0–5 days. Relative risk on the y-axis is displayed on the log scale. Reference temperature: 1st percentile of DMA-specific daily maximum ambient temperature distribution.
Figure 6
Figure 6
Cumulative exposure–response curve for the relative risk of heat-related ED visits for percentiles of DMA-specific daily maximum ambient temperature over lags 0–5 days. Reference search volume: 1st percentile of DMA-specific daily maximum ambient temperature distribution.
Figure 7
Figure 7
Cumulative exposure–response curve for the relative risk of heat-related ED visits for percentiles of DMA-specific search terms over lags 0–5 days. Reference search volume: 1st percentile of DMA-specific search volume distribution.
See this image and copyright information in PMC

References

    1. Ebi, K. L. et al. Chapter 14 : Human Health. Impacts, Risks, and Adaptation in the United States: The Fourth National Climate Assessment, Volume II. (2018) 10.7930/NCA4.2018.CH14.
    1. Smith, K. R. et al. Human health: Impacts, adaptation, and co-benefits. Clim. Chang. 2014 Impacts, Adapt. Vulnerability Part A Glob. Sect. Asp. 709–754 (2015) 10.1017/CBO9781107415379.016.
    1. Sarofim, M. et al. Temperature-Related Death and Illness 2 the Impacts of Climate Change on Human Health in the United States a Scientific Assessment. (2016) 10.7930/J0MG7MDX.
    1. Weinberger KR, Harris D, Spangler KR, Zanobetti A, Wellenius GA. Estimating the number of excess deaths attributable to heat in 297 United States counties. Environ. Epidemiol. 2020;4:e096. doi: 10.1097/EE9.0000000000000096. - DOI - PMC - PubMed
    1. Shindell D, et al. The effects of heat exposure on human mortality throughout the United States. GeoHealth. 2020;4:e2019GH000234. doi: 10.1029/2019GH000234. - DOI - PMC - PubMed

Publication types