Associations between long-term drought and diarrhea among children under five in low- and middle-income countries

Abstract

Climate change is projected to intensify drought conditions, which may increase the risk of diarrheal diseases in children. We constructed log-binomial generalized linear mixed models to examine the association between diarrhea risk, ascertained from global-scale nationally representative Demographic and Health Surveys, and drought, represented by the standardized precipitation evapotranspiration index, among children under five in 51 low- and middle-income countries (LMICs). Exposure to 6-month mild or severe drought was associated with an increased diarrhea risk of 5% (95% confidence interval 3-7%) or 8% (5-11%), respectively. The association was stronger among children living in a household that needed longer time to collect water or had no access to water or soap/detergent for handwashing. The association for 24-month drought was strong in dry zones but weak or null in tropical or temperate zones, whereas that for 6-month drought was only observed in tropical or temperate zones. In this work we quantify the associations between exposure to long-term drought and elevated diarrhea risk among children under five in LMICs and suggest that the risk could be reduced through improved water, sanitation, and hygiene practices, made more urgent by the likely increase in drought due to climate change.

Fig. 1

Incidence rate of diarrhea among children under age five in the latest survey in 51 countries during 1990–2019.

Fig. 2. Distribution of the number of drought-months at different timescales across all 10-km-grids in 51 countries during 1990–2019.

Source data are provided as a Source Data file. The violin plots include the median values (center lines), third and first quartiles (box limits), 1.5x the interquartile range (whiskers), and the kernel probability density.

Fig. 3. Associations between diarrhea risk among children and drought at different timescales in the crude (only adjusted for meteorological parameters, seasonality, and long-term trend) and main (further adjusted for baseline characteristics) models.

The crude and main models used the same set of observations (the set with no missing values for all variables included in the main model, N = 713,918). Generalized linear mixed effect models were used and no adjustments were made for multiple comparisons. Data were presented as mean values ± 1.96 × standard error.

Fig. 4. Associations between diarrhea among children and drought stratified by climate zone (a), round-trip time to collect water (b), water availability at handwashing site (c), and soap/detergent availability at handwashing site (d).

The sample size was 709,412, 691,452, 386,221, and 379,623 children for stratified analysis for climate zone (a), round-trip time to collect water (b), water availability at handwashing site (c), and soap/detergent availability at handwashing site (d), respectively. Statistically significant pairwise differences are marked with an asterisk. Generalized linear mixed effect models were used and no adjustments were made for multiple comparisons. Data were presented as mean values ± 1.96 × standard error. The p values are two-sided.