Drought and All-Cause Mortality Risk in Nebraska from 1980 to 2014 : Time-Series Analyses by Age, Sex, Race, Urbanicity and Temporality of Drought

Background : Recent studies provide strong evidence that climate change will increase drought duration and severity in many regions around the world, including the Central Plains of North America. While the agricultural and hydrological impacts of drought continue to grow, studies on drought-related health impacts are still sparse. This study aims to explore the potential impacts of drought on all-cause mortality in Nebraska from 1980 to 2014.Methods : The Evaporative Demand Drought Index (EDDI) at 1-, 6- and 12-month timescales was used to represent short-, medium- and long-term drought exposures, respectively. We used a Bayesian zero-inflated censored negative binomial (ZICNB) regression model to estimate the overall impact of drought on mortality in the total population and stratified sub-populations based on age, race, sex, and the urbanicity status of the counties.Results : The main findings indicate that there is no statistically significant association between drought and all-cause mortality in the total population. However, the joint-stratified analysis renders significant results. Our analysis showed that most of the sub-populations other than white had no significant change in the mortality rate with increase in drought exposure. Among the white male sub-populations, males aged 45-54 living in non-metro counties was associated with the highest change of mortality rate of 1.009 (95% HPD: 1.001,1.018) with increase in long-term drought condition. We also found that more sub-populations had higher rates of mortality with longer-term droughts compared to shorter-term droughts (12-month vs 1- or 6-month timescales), in both metro and non-metro counties. Further, we identified more protective drought effects in metro counties.Conclusion : Our results suggest that drought impacts sub-population strata differently. With a projected increase in the frequency and severity of drought due to climate change, understanding these relationships between drought and human health will better inform drought mitigation planning to reduce potential impacts