# Air pollutants, seasonal influenza, and acute otitis media in children: a population-based analysis using 22-year hospitalization data

## TL;DR

This study links air pollution and seasonal flu to higher rates of ear infections in children using 22 years of hospital data from Hong Kong.

## Contribution

The study is the first to use a 22-year hospitalization dataset in Hong Kong to analyze the combined effects of air pollution and influenza on acute otitis media in children.

## Key findings

- Higher concentrations of oxidant gases and fine particulate matter were associated with increased risk of acute otitis media in children.
- Influenza-like illness rates showed a monotonic increase in adjusted relative risks for acute otitis media.
- Policy interventions targeting air pollution and influenza vaccination could reduce childhood ear infections.

## Abstract

Acute otitis media (AOM) is a prevalent childhood acute illness, with 13.6 million pediatric office visits annually, often stemming from upper respiratory tract infections (URI) and affected by environmental factors like air pollution and cold seasons.

Herein, we made use of territory-wide hospitalization data to investigate the relationships between meteorological factors, air pollutants, influenza infection, and AOM for children observed from 1998 to 2019 in Hong Kong. Quasi-Poisson generalized additive model, combined with a distributed-lag non-linear model, was employed to examine the relationship between weekly AOM admissions in children and weekly influenza-like illness-positive (ILI +) rates, as well as air pollutants (i.e., oxidant gases, sulfur dioxide, and fine particulate matter), while accounting for meteorological variations.

There were 21,224 hospital admissions due to AOM for children aged ≤ 15 years throughout a 22-year period. The cumulative adjusted relative risks (ARR) of AOM were 1.15 (95% CI, 1.04–1.28) and 1.07 (95% CI, 0.97–1.18) at the 95th percentile concentration of oxidant gases (65.9 ppm) and fine particulate matter (62.2 μg/m3) respectively, with reference set to their medians of concentration. The ARRs exhibited a monotone increasing trend for all-type and type-specific ILI + rates. Setting the reference to zero, the cumulative ARRs of AOM rose to 1.42 (95% CI, 1.29–1.56) at the 95th percentile of ILI + Total rate, and to 1.07 (95% CI, 1.01–1.14), 1.19 (95% CI, 1.11–1.27), and 1.22 (95% CI, 1.13–1.32) for ILI + A/H1N1, A/H3N2, and B, respectively.

Our findings suggested that policy on air pollution control and influenza vaccination for children need to be implemented, which might have significant implications for preventing AOM in children.

The online version contains supplementary material available at 10.1186/s12889-024-18962-4.