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Exposure to traffic-related air pollution and acute bronchitis in children: season and age as modifiers
  1. Lijun Bai1,2,
  2. Xi Su3,
  3. Desheng Zhao1,2,
  4. Yanwu Zhang1,2,
  5. Qiang Cheng1,2,
  6. Heng Zhang1,2,
  7. Shusi Wang1,2,
  8. Mingyu Xie1,2,
  9. Hong Su1,2
  1. 1 Department of Epidemiology and Health Statistics, School of Public Health, Anhui Medical University, Hefei, Anhui, China
  2. 2 Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Medical University, Hefei, Anhui, China
  3. 3 Department of Academic Commerce, Anhui Medical Association, Hefei, Anhui, China
  1. Correspondence to Professor Hong Su, Department of Epidemiology and Health Statistics, School of Public Health, Anhui Medical University, Hefei, Anhui 230032, China; 271244914{at}


Background Acute bronchitis (AB) is one of the principal causes of childhood morbidity. Increasing number of studies has shown that air pollution is an important environmental contributor of respiratory disease. However, evidence so far is scarce regarding the effects of air pollution on childhood AB, and it also remains unclear how the risk of AB will change by season and age.

Methods Data on hospital visits for AB in children, air pollution and meteorological factors from 1 January 2015 to 31 December 2016 were collected in Hefei, China. Time-series analysis was applied to assess the short-term effects of traffic-related air pollution on childhood AB outpatient visits. A Poisson generalised linear regression model combined with a distributed lag non-linear model was used to estimate the relationships, controlling for long-term trends, seasonal patterns, meteorological factors and other possible confounders.

Results We found that an IQR increase in concentrations of nitrogen dioxide, particulate matter <2.5 µm and carbon monoxide significantly increased the daily hospital visits for childhood AB with 4-day cumulative effect estimates (relative risks: 1.03, 95% CI 1.01 to 1.05; 1.09, 95% CI 1.07 to 1.11; 1.07, 95% CI 1.05 to 1.09). Notably, the risk estimates during the cold season are pronounced; however, no significant association was observed during the warm season. Interestingly, children aged 6–14 years were more vulnerable to air pollutants than children aged less than 1 year and within 1–5 years. However, no gender difference was observed.

Conclusion A significant association of traffic-related air pollution and increased department visits for childhood AB was observed, notably in school-age children and during the cold season.

  • environmental epidemiology
  • environmental health
  • public health
  • child health

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  • Contributors LB had the original idea for the paper and is the guarantor of the study. XS and HS designed the study. DZ, YZ and QC collected the data and organised the information. LB, HZ and SW undertook and interpreted the analysis. LB wrote the first draft. MX contributed to manuscript revision, then this was revised critically for important intellectual content by the other authors. All authors read and approved the final revised manuscript.

  • Funding This work was funded by Anhui Natural Science Fund (no 1408085 MH159).

  • Competing interests None declared.

  • Patient consent Detail has been removed from this case description/these case descriptions to ensure anonymity. The editors and reviewers have seen the detailed information available and are satisfied that the information backs up the case the authors are making.

  • Ethics approval This study was approved by the Anhui Medical University Ethics Committee.

  • Provenance and peer review Not commissioned; externally peer reviewed.