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

Background

Long-term exposure to fine particulate matter brought by dust storms (dust PM_2.5) poses a significant risk to children's health, particularly those in low- and middle-income countries (LMICs). To quantify the impact of dust PM_2.5 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 PM_2.5 concentration, neglecting the specific effect of dust PM_2.5 distinct from other PM_2.5.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.

Method

We combined population data derived from the Demographic and Health Survey covering 53 LMICs, with environmental data, including the gridded concentration of dust PM_2.5. 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 PM_2.5 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 PM_2.5 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 PM_2.5 mass.

Results

The analysis of 1,223,118 children showed that a 10 μg/m³ increase in dust PM_2.5 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 PM_2.5 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 PM_2.5 mass (142,000 [95% CI: 97,000–181,000] or 114,000 [95% CI: 80,000–153,000]). The long-term dust PM_2.5 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.

Conclusion

This study provides critical insight into the association between long-term exposure to dust PM_2.5 and the health of children in LMICs, highlighting the need for specific ERFs to distinguish the adverse effects of different PM_2.5 components. Personal protection during sand dust storms can be an effective intervention to safeguard the respiratory health of children.