The burden of acute respiratory infection attributable to fine particulate matter brought by dust storms among children under 5years of age in low- and middle-income countries.

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Long-term exposure to fine particulate matter brought by dust storms (dust PM2.5) poses a significant risk to children's health, particularly those in low- and middle-income countries (LMICs). To quantify the impact of dust PM2.5 on children, current research focuses on acute respiratory infection (ARI) as a key health outcome, given its significant contribution to child mortality. However, the relationship used to evaluate the disease burden is mainly based on the total PM2.5 concentration, neglecting the specific effect of dust PM2.5 distinct from other PM2.5.This study aimed to develop a dust-specific exposure-response function (ERF) of ARI in children <5 years of age (U5-ARI) for future risk assessments. We combined population data derived from the Demographic and Health Survey covering 53 LMICs, with environmental data, including the gridded concentration of dust PM2.5. ARI in children <5 years of age (U5-ARI) was the outcome of interest, which was defined by a standard questionnaire-based method. The dust PM2.5 exposure was derived from the integration of two well-recognized datasets, and matched to each participant at the community level. We analyzed the linear association between the annual average dust PM2.5 concentration and the odds of U5-ARI with logistic regression and fixed effects after adjusting for multiple covariates. We also used the spline method to develop a dust-specific ERF. Based on the function, we estimated the burden of dust-associated U5-ARI across 100 LMICs and compared it with the results from two well-established functions of total PM2.5 mass. The analysis of 1,223,118 children showed that a 10μg/m3 increase in dust PM2.5 was associated with a 7.43% (95% confidence interval [CI]: 4.77-10.15%) increase in the odds of U5-ARI. The spline model indicated that the risk of U5-ARI increased monotonically and linearly with dust PM2.5 concentration with no evident effect threshold. In 2017, based on the dust-specific ERF, across the 100 LMICs, the number of dust-associated U5-ARI was estimated to be 159,000 (95% CI: 153,000-165,000), which was consistently higher than the estimates from ERFs based on total PM2.5 mass (142,000 [95% CI: 97,000-181,000] or 114,000 [95% CI: 80,000-153,000]). The long-term dust PM2.5 exposure contributed to 12-13% of all the children affected by U5-ARI between 2000 and 2017. The geographic hotspots were the arid and populous areas of South Asia and Africa. This study provides critical insight into the association between long-term exposure to dust PM2.5 and the health of children in LMICs, highlighting the need for specific ERFs to distinguish the adverse effects of different PM2.5 components. Personal protection during sand dust storms can be an effective intervention to safeguard the respiratory health of children.