Associations between Particulate Matter and Otitis Media in Children: A Meta-Analysis

Particulate matter (PM), a primary component of air pollution, is a suspected risk factor for the development of otitis media (OM). However, the results of studies on the potential correlation between an increase in the concentration of PM and risk of developing OM are inconsistent. To better characterize this potential association, a meta-analysis of studies indexed in three global databases (PubMed, EMBASE, and The Cochrane Library) was conducted. These databases were systematically screened for observational studies of PM concentration and the development of OM from the time of their inception to 31 March 2020. Following these searches, 12 articles were analyzed using pooled odds ratios generated from random-effects models to test for an association between an increased concentration of PM and the risk of developing OM. The data were analyzed separately according to the size of particulate matter as PM_2.5 and PM₁₀. The pooled odds ratios for each 10 μg/m³ increase in PM_2.5 and PM₁₀ concentration were 1.032 (95% confidence interval (CI), 1.005-1.060) and 1.010 (95% CI, 1.008-1.012), respectively. Specifically, the pooled odds ratios were significant within the short-term studies (PM measured within 1 week of the development of OM), as 1.024 (95% CI, 1.008-1.040) for PM_2.5 concentration and 1.010 (95% CI, 1.008-1.012) for PM₁₀ concentration. They were significant for children under 2 years of age with pooled odds ratios of 1.426 (95% CI, 1.278-1.519) for an increase in the concentration of PM_2.5. The incidence of OM was not correlated with the concentration of PM, but was correlated with an increase in the concentration of PM. In conclusion, an increase in the concentration of PM_2.5 is more closely associated with the development of OM compared with an increase in the concentration of PM₁₀; this influence is more substantial in shorter-term studies and for younger children.