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Drought and the Risk of Hospital Admissions and Mortality in western

U.S. Older Adults from 2000 to 2013: a retrospective study

April 29, 2017

Jesse D Berman, PhD Johns Hopkins Bloomberg School of Public Health

Department of Epidemiology

Background: Drought and Health

•  The UN refers to drought as, “The most far reaching of all natural disasters”

•  In 2011-2012 drought covered 65.5% of the U.S. and affected 150 million people

•  California just ended a 5-year extreme drought

What research done on drought and health? Answer: Very Little! Almost a total absence of literature worldwide

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Project Overview

•  Modify a drought measure for health analysis •  Associations between drought and cardiovascular-,

respiratory-disease, and total deaths •  Older adults (age 65+) – Medicare population

•  618 U.S. counties in 22 western states (2000-2013)

Represents the largest epidemiological investigation of drought and health. First to

investigate cardiovascular disease and mortality

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Drought Characterization and Statistical Approach

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•  Modeled health risks using a 2-stage Bayesian hierarchical model

•  Compared non-drought to either full or worsening drought periods (stratified by severity)

L

L

LSL

SL

S

LS

S

S

S S

S S

S

S

S

L

L

SL

SL

SL

S L

S

S

S

SS

SSS

S

L

SL

The Drought Monitor focuses on broad-

scale conditions. Local conditions may

vary. See accompanying text summary for

forecast statements.

http://droughtmonitor.unl.edu/

U.S. Drought Monitor October 6, 2015

Valid 8 a.m. EDT

(Released Thursday, Oct. 8, 2015)

Intensity:

D0 Abnormally DryD1 Moderate DroughtD2 Severe DroughtD3 Extreme DroughtD4 Exceptional Drought

Author:

David Miskus

Drought Impact Types:

S = Short-Term, typically less than 6 months (e.g. agriculture, grasslands)

L = Long-Term, typically greater than 6 months (e.g. hydrology, ecology)

Delineates dominant impacts

NOAA/NWS/NCEP/CPC

•  Used U.S. Drought Monitor •  3 drought categories

•  Non-drought periods •  Full drought periods •  Worsening drought periods

•  Low-severity

•  High-severity

Percent Change in Health Risks During Drought Periods

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Mortality: 1.55% (95% CI: 0.17, 2.95) Respiratory Hosp: -1.99% (95% CI: -3.56, -0.38)

** Cardio Hosp. not significant, but show strong associations

Health Risks Increase in Counties where Drought Occurs Less Frequently

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Major Implications and Significance

•  Drought exposure shows measurable and previously unidentified adverse health effects

•  The magnitude of risk increases in counties where drought is a rare exposure

•  With 46.2 million U.S. elderly, variations in drought can have major public health significance

•  The IPCC predicts increase in drought severity/duration under climate change

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Acknowledgments and Contributions

Michelle L Bell – Yale School of Forestry and Environmental Studies Keita Ebisu – California EPA (formerly Yale FES) Roger D Peng – Johns Hopkins Bloomberg School of Public Health Francesca Dominici – Harvard T.H. Chan School of Public Health Yun Wang – Harvard T.H. Chan School of Public Health

Funding o  Yale Institute of Biospheric Studies Donnelley Fellowship (Berman) o  U.S. EPA – RD83479801 (MLB, FD); RD83587101 (MLB) o  National Institute of Environmental Health Sciences – R01ES019560

(MLB, FD, RDP); R01ES019587 (MLB); R01ES024332 (FD); R21ES020152 (MLB, RDP); R21ES021427 (MLB); R21ES022585 (MLB, FD)

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Berman JD, Ebisu K, Peng RD, Dominici F, Bell ML. 2017. Drought and the Risk of Hospital Admissions and Mortality in Older Adults in the Western USA from 2000 to 2013: a retrospective study. The Lancet Planetary Health 1 (1):e17-e25.