Associations between monthly temperature anomalies and mortality among children younger than five years in low- and middle-income countries

This study examined associations between anomalous temperatures and under-five mortality (U5M) in low- and middle-income countries (LMICs). Between 1998 and 2019, data were collected on 1,745,132 live births across 56 LMICs. The median age was 27.0 months (interquartile range: 12.0, 43.0), and 51.0% were male. Monthly temperature anomalies were calculated as deviations from the long-term average temperature for the same calendar months. We developed a two-dimensional exposure-response function (ERF) based on a varying-coefficient model to examine the relationship between U5M and both long-term average temperatures and anomalous temperatures. Here we show, in the multicenter model, each 1 °C increase in positive temperature anomalies or decrease in negative temperature anomalies is associated with an 8% (95% confidence interval [CI]: 6%, 11%) or 2% (95% CI: −1%, 4%) excess risk of U5M, respectively. The two-dimensional ERF reveals considerable heterogeneity in the impact of anomalous temperatures on U5M across different temperature zones. Positive temperature anomalies pose a significant hazard to children in warm and hot zones, whereas negative anomalies are primarily hazardous in cold zones but appear protective in hot zones. The sibling-matched model demonstrates nonlinear and heterogeneous effect estimates consistent with the multicenter model findings. Anomalous temperatures of both heat and cold are associated with an increased risk of child mortality in LMICs, with the effect varying by temperature zone, reflecting the adaptive capacity of populations to local climates. There is an urgent need to develop regionally adaptive strategies to protect child health amid global climate change. Climate change is making weather more unstable, especially with unusual changes in temperature. These changes can be harmful to children's health. While we already know that short-term exposure to very hot or cold weather can increase the risk of death in children, we know less about the effects of longer-lasting unusual temperatures. In this study, we looked at how abnormal temperature changes affect child deaths in low- and middle-income countries. We found that both unusual heat and cold can raise the risk of children dying, and the impact is different in each region depending on the local climate. This means we need climate-based health plans that are tailored to different regions to better protect children's health. Li, Wu et al. investigate the associations between monthly anomalous temperatures and mortality rates for individuals under five years old in low- and middle-income countries. They find that the effects of anomalous temperature on child mortality vary by temperature zone, reflecting the adaptive capacity of populations to local climates.