Date Published: June 17, 2019
Publisher: Public Library of Science
Author(s): Bezawit Adugna Bahru, Christine Bosch, Regina Birner, Manfred Zeller, Bishwajit Ghose.
The increase in the frequency of extreme events due to climate change poses a serious challenge to achieving the Sustainable Development Goal 2 of ending hunger by 2030. While evidence exists on the impact of drought on under-five children, its effect during late childhood and early adolescence remains less investigated.
This study estimates the impact of concurrent and long-term exposure to drought on linear growth during late childhood and early adolescence.
Four rounds (2002–2013) of data from the young lives Cohort Study dataset (n = 2000) was used. The associations of concurrent and long-term exposure to drought and Height-for-age z-score was analysed using structural equation modelling techniques. The study also explored the mediating role of interim period growth in the association of early exposure to drought and undernutrition at later age and the role of the Productive Safety Net Program in buffering the impact of drought on child nutrition.
Results show that both concurrent and long-term exposure to drought was negatively associated with Height-for-age z-score (p < 0.001). Exposure to drought at age 5, 8, and 12 years is associated with lower Height-for-age z- score at age 5, 8, and 12 years respectively. Exposure to drought at age 5 years was also negatively associated with Height-for-age z-score at age 12 years (p < 0.001). This association was mainly indirect (89%) and mediated through reduced child growth in subsequent years. Participation in productive safety net program by drought-affected children reduces but does not completely offset the negative effects of drought on Height-for-age z-score (p < 0.1). Moreover, girls were more likely to suffer poor growth than boys. Drought exposure after the 1,000 days window could have a lasting impact on child growth. Given the importance of this period for child physical and mental development, children beyond the 1,000 days window should also be a focus of disaster relief programs.
Climate change represents a serious challenge to meet the Sustainable Development Goal 2−’end hunger, achieve food security and improved nutrition and promote sustainable agriculture’ by 2030 and leaves billions at risk of food insecurity, undernutrition, and illnesses . It will lead to a more frequent occurrence of droughts, floods, cyclones, and heat waves . In low and middle-income countries, such events are often associated with a decrease in agricultural production, a decrease in consumption, food insecurity, and child undernutrition [3–7].
Previous studies have reported a negative impact of drought on chronic undernutrition among children [3–5, 12, 13]. Moreover, studies have shown the negative impacts of climatic shocks during childhood on nutritional status during adolescence , schooling, and adult health . Exposure to climatic shocks during early childhood reduces child growth potential in growing up to subsequent years (i.e. catch up and growth faltering). Although much of the focus on the long-term impact of drought on child undernutrition has been on under-five children, exposure to drought after the 1,000 days window might have a long-lasting impact that transcends from its effect on the concurrent period to affecting nutritional status at later age. That means exposure to drought at age 5 years might also affect nutrition at age 5 years which further reduces child growth potential in growing up to the subsequent growth period (age 8 and 12 years). Similarly, exposure to drought at age 8 years might affect nutritional status at age 8 years which further reduces child growth potential in growing up to age 12. Based on that a path model summarizing the direct and indirect association of exposure to drought at age 5, 8, and 12 years (Drou5, Drou8, and Drou12 respectively) and HAZ score at age 5, 8, and 12 years (HAZ5, HAZ8, and HAZ12 respectively) was formulated. The path diagram in Fig 1 summarizes this relationship (Fig 1).
Child chronic undernutrition remains one of the pressing public health concerns in Ethiopia [46–49]. The causes are multifactorial and climate is one of the most important factors [8, 25, 49]. Nonetheless, the literature on the long-term impacts of climatic shocks has largely focused on children under 5 years and largely draws on cross-sectional data. Existing longitudinal studies relied only on two-time points and fixed effect model. The direction and significance of associations vary by the type of anthropometric index, country and extreme weather event under consideration and hence the evidence is inconclusive. This study estimates a path model of the association of exposure to concurrent and long-term exposure to drought at various stages of the child’s development and HAZ scores using four rounds of data from the YL cohort study. Results show that concurrent and long-term exposure to drought is negatively associated with child growth. The impact of exposure to drought at the age of 5 and 8 years on the HAZ score at the age of 12 years is mainly indirect and is mediated through reduced child growth in subsequent periods. Consistently, previous studies have also reported the negative effect of drought on child nutritional status. Using data on under 5 years old children, Alderman et al.  have reported that exposure to drought decreases the HAZ score of 12–36 months old Tanzanian children and further reduces height during their adolescence .