Abstract
BACKGROUND: Accumulating evidence indicates associations between ambient air pollution and Kawasaki disease (KD), but the results remain inconsistent. OBJECTIVES: This systematic review and meta-analysis aimed to comprehensively summarize the current evidence on the effects of ambient air pollutants on KD. METHODS: The PubMed, Web of Science, Embase, and Scopus databases were searched up to January 18, 2025 for studies investigating the effects of ambient air pollution on KD. A fixed- or random-effects model was used to calculate pooled ORs with 95% CIs for an increase in ambient air pollutant concentration of 10 μg/m(3). The risk of bias was assessed using the Risk of Bias In Nonrandomized Studies of Exposures tool, and the quality of evidence was assessed by the Grading of Recommendations, Assessment, Development, and Evaluations framework. The protocol was registered with PROSPERO (CRD42024545321). RESULTS: Thirteen studies with 124,857 participants were included. Seven studies were at high risk of bias. The meta-analysis revealed an increased risk of KD after short-term postnatal exposure to PM(2.5) (OR: 1.011; 95% CI: 1.003-1.019; I(2) = 0%; high-quality evidence) and PM(10) (OR: 1.004; 95% CI: 1.000-1.008; I(2) = 38%; high-quality evidence), as well as long-term postnatal exposure to PM(2.5) (OR: 1.415; 95% CI: 1.179-1.697; I(2) = 41%; high-quality evidence). Prenatal exposure to carbon monoxide, nitric oxide, nitrogen oxides, and sulfur dioxide; short-term postnatal exposure to nitric oxide; and long-term postnatal exposure to carbon monoxide and nitrogen oxides were also associated with KD occurrence. CONCLUSIONS: Both prenatal and postnatal exposure to several ambient pollutants are associated with the risk of KD.