Short- and Long-Term Effects of Drought on Selected Causes of Mortality in Northern Bangladesh

Abstract

Drought has exacerbated morbidity and mortality worldwide. Here, a time series study was conducted in northern Bangladesh to evaluate the impact of drought on selected causes of mortality during 2007–2017. Rainfall and temperature data from six meteorological stations were used to analyze drought and non-drought periods and to categorize mild, moderate, severe, and extreme drought based on the 3-month and 12-month Standardized Precipitation Index (SPI) and Standardized Precipitation Evaporation Index (SPEI). A generalized linear model with Poisson regression with log link, a negative binomial with log link, and a zero-inflated Poisson model were used to determine associations between drought severity and mortality. The SPI and SPEI produced slightly different analysis results. Compared with the SPEI, the SPI showed a stronger and more sensitive correlation with mortality. The relative risk for respiratory disease mortality was high, and Saidpur was the most vulnerable area. Health care expenditure was negatively associated with mortality. High temperatures during the drought period were associated with suicide-related mortality in Rajshahi. The impact of drought on mortality differed with small changes in climate. The findings of this study improve our understanding of the differences between the two most used drought indicators and the impact of drought on mortality.

Analyzing the effects of drought at different time scales on cause-specific mortality in South Africa

“…In line with our results, Salvador et al [22] suggested an indication of higher risks related to a longer accumulation period (SPEI3) compared to the shortest one (SPEI1) in peninsular Spain, especially for respiratory mortality. However, other studies suggested a higher negative influence on mortality risk in shorter droughts (3 months of accumulation) compared to longer droughts (12 months of accumulation) in northern Bangladesh [24,49]. Thus, further evidence is needed to clarify existing uncertainties.…”

“…more extended droughts). Different characterization of drought events, as well as the use of different drought indices, may also influence drought-related mortality [2,4,23,24]. Meanwhile, differences found in this study across district municipalities may be explained by potential differences in the drought exposure as well as in the adaptative capacity and resilience of the populations (e.g.…”

“…An increased risk of mortality was also associated with drought events in several regions around the world including peninsular Spain [17], Lisbon [18], urban areas of Brazil [19]; and Bangladesh [24,49]. Also, Berman et al [50] indicated that worsening droughts were associated with higher rate of mortality in older people, especially in regions where droughts were less frequent.…”

“…In this study, we also found a positive but highly imprecise association between droughts and mortality due to certain infectious and parasitic diseases for short-, medium-, and very long-term drought conditions, while for long-term droughts we found a null risk. Another study conducted in Northern Bangladesh reported a positive and robust association between shorter droughts (3 months of accumulation) and infectious disease-related mortality in some regions, but not for long-term droughts (12 months of accumulation) [24]. In this context, droughts have been associated with a decrease in water quantity and quality [65], which can threaten human health [1,2,6,55].…”

“…However, evidence suggests that the magnitude and direction of drought-related mortality risk can vary by regions [e.g. 22,23], causes of death [24] and population groups [e.g. [19][20][21]23].…”