Spatiotemporal analysis of heat and heat wave effects on elderly mortality in Texas, 2006-2011.

BACKGROUND Heat and heat waves have been linked to the increased risk of deaths, hospital admissions, and emergency visits. OBJECTIVES This study presents a spatiotemporal analysis of heat and heat wave effects on elderly mortality (≥65years) in Texas. METHODS We compiled a six-year daily weather and mortality counts dataset from 254 counties in Texas during 2006-2011. Heat index (HI), a combination of temperature and relative humidity, was used as the exposure metric in this study. Associations between daily all-cause elderly mortality and daily maximum HI and heat waves (≥2days of county-specific daily maximum HI>95th percentiles) were examined using a quasi-Poisson regression. A Markov random field smoother was included in the model to account for spatial autocorrelations and spatial heterogeneity. The model also controlled for long-term trend and seasonality in mortality, and the effects of day of the week. DISCUSSION On average, the lag effect of heat on elderly mortality risk lasted up to 10days, and the cumulative heat effects started to increase rapidly when daily maximum HI exceeded the 90th percentile in Texas. Elderly living in Northwest Texas and parts of West Texas were at greater risk of elderly mortality attributable to heat waves, and the highest relative risk for elderly mortality occurred in El Paso County (4.70, 95% Confidence Interval=4.33, 5.10). CONCLUSIONS Our study indicates strong geographical variations of heat wave effects on elderly mortality risk in Texas.

[1]  How-Ran Guo,et al.  Cardiovascular mortality during heat and cold events: determinants of regional vulnerability in Taiwan , 2010, Occupational and Environmental Medicine.

[2]  The potential impacts of climate variability and change on temperature-related morbidity and mortality in the United States. , 2001 .

[3]  Pavla Vaneckova,et al.  Spatial analysis of heat-related mortality among the elderly between 1993 and 2004 in Sydney, Australia. , 2010, Social science & medicine.

[4]  K. Ebi,et al.  Temperature Extremes and Health: Impacts of Climate Variability and Change in the United States , 2009, Journal of occupational and environmental medicine.

[5]  D. Cole,et al.  Temporal and spatial variation of heat-related illness using 911 medical dispatch data. , 2009, Environmental research.

[6]  Chiang-Hsing Yang,et al.  Asian Dust Storm Elevates Children’s Respiratory Health Risks: A Spatiotemporal Analysis of Children’s Clinic Visits across Taipei (Taiwan) , 2012, PloS one.

[7]  J. Schwartz,et al.  Using Forecast and Observed Weather Data to Assess Performance of Forecast Products in Identifying Heat Waves and Estimating Heat Wave Effects on Mortality , 2014, Environmental health perspectives.

[8]  C. Gronlund.  Racial and Socioeconomic Disparities in Heat-Related Health Effects and Their Mechanisms: a Review , 2014, Current Epidemiology Reports.

[9]  E. Mulkerrin,et al.  Why do older patients die in a heatwave? , 2005, QJM : monthly journal of the Association of Physicians.

[10]  Gail M. Williams,et al.  Global Variation in the Effects of Ambient Temperature on Mortality: A Systematic Evaluation , 2014, Epidemiology.

[11]  S. Wood,et al.  Generalized Additive Models: An Introduction with R , 2006 .

[12]  Katharina M. A. Gabriel,et al.  Urban and rural mortality rates during heat waves in Berlin and Brandenburg, Germany. , 2011, Environmental pollution.

[13]  Nisha Krishnan,et al.  Climate Change and Older Americans: State of the Science , 2012, Environmental health perspectives.

[14]  Christophe Declercq,et al.  Impact of the 2003 Heatwave on All-Cause Mortality in 9 French Cities , 2006, Epidemiology.

[15]  Hwa-Lung Yu,et al.  Impact of meteorological factors on the spatiotemporal patterns of dengue fever incidence. , 2014, Environment international.

[16]  Antonio Gasparrini,et al.  The Impact of Heat Waves on Mortality , 2011, Epidemiology.

[17]  M. Mather,et al.  The American Community Survey. , 2005 .

[18]  A. Chu,et al.  Satellite-based PM concentrations and their application to COPD in Cleveland, OH , 2013, Journal of Exposure Science and Environmental Epidemiology.

[19]  G. B. Buck Louis,et al.  Pre-pregnancy maternal exposure to polybrominated and polychlorinated biphenyls and gestational diabetes: a prospective cohort study , 2016, Environmental Health.

[20]  Michelle L. Bell,et al.  Weather-Related Mortality: How Heat, Cold, and Heat Waves Affect Mortality in the United States , 2009, Epidemiology.

[21]  Shilu Tong,et al.  Ambient Temperature and Morbidity: A Review of Epidemiological Evidence , 2011, Environmental health perspectives.

[22]  L. Chapman,et al.  Including the urban heat island in spatial heat health risk assessment strategies: a case study for Birmingham, UK , 2011, International journal of health geographics.

[23]  Denis Hémon,et al.  Excess mortality related to the August 2003 heat wave in France , 2006, International archives of occupational and environmental health.

[24]  Rupa Basu,et al.  High ambient temperature and mortality: a review of epidemiologic studies from 2001 to 2008 , 2009, Environmental health : a global access science source.

[25]  A. McMichael,et al.  Globalization, climate change, and human health. , 2013, The New England journal of medicine.

[26]  Matty P. Weijenberg,et al.  The impact of heat waves and cold spells on mortality rates in the Dutch population. , 2001 .

[27]  G. Brooke Anderson,et al.  Heat Waves in the United States: Mortality Risk during Heat Waves and Effect Modification by Heat Wave Characteristics in 43 U.S. Communities , 2010, Environmental health perspectives.

[28]  C. Begley,et al.  Impact of the 2011 heat wave on mortality and emergency department visits in Houston, Texas , 2015, Environmental Health.

[29]  Daniel Oudin Åström,et al.  Heat wave impact on morbidity and mortality in the elderly population: a review of recent studies. , 2011, Maturitas.

[30]  J. Schwartz,et al.  Comparing exposure metrics for classifying 'dangerous heat' in heat wave and health warning systems. , 2012, Environment international.

[31]  A Gasparrini,et al.  Distributed lag non-linear models , 2010, Statistics in medicine.