Seasonal association between ambient ozone and hospital admission for respiratory diseases in Hanoi, Vietnam

PLoS One. 2018 Sep 24;13(9):e0203751. doi: 10.1371/journal.pone.0203751. eCollection 2018.

Abstract

Background: Many studies have indicated the detrimental effect of ambient ozone to respiratory health in different countries. The levels of ozone in Hanoi, Vietnam are frequently above the WHO guideline but very few studies on the effects of ambient ozone on human health have been conducted in this location. This study aimed to examine the effects of ozone on hospital admission for respiratory diseases in Hanoi, by diseases, ages and seasons.

Methods: Hospital admissions, air pollutants and meteorological data were collected from January 2010 to June 2014. We used generalized linear models and distributed lag linear model to assess the association. In addition to full year analysis, we conducted restricted analysis of the data for two summer (from June-August) and winter (from December-February) seasons and grouped hospital admissions by diseases and ages (all ages, children 0 to 5 years and elderly >65 years). The delayed effect of ozone was assessed using lags of up to 5 days.

Results: Ozone has a stronger effect on the risk of hospital admission for respiratory diseases and wheeze-associated disorders in the winter. For respiratory diseases, children were affected by ozone more than other age groups in both winter and summer. Each increase of 10 μg/m3 of ozone is associated with an increase of 6.2% risk of admission for respiratory disease among children in the winter and 1.2% in the summer. For wheeze-associated disorders, the elderly group seemed to be more affected by ozone in full year and winter but no significant association was found between ozone and admission for wheeze-associated diseases in any age group.

Conclusions: Ozone is a risk factor for respiratory admission, especially amongst children under 5 years old in Hanoi, and ozone has a stronger effect in the winter than in the summer in this city.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Air Pollutants / analysis*
  • Child
  • Child, Preschool
  • Environmental Monitoring
  • Hospitalization / statistics & numerical data
  • Humans
  • Infant
  • Infant, Newborn
  • Linear Models
  • Middle Aged
  • Ozone / analysis*
  • Respiratory Tract Diseases / epidemiology*
  • Seasons
  • Vietnam / epidemiology

Substances

  • Air Pollutants
  • Ozone

Grants and funding

LL is funded by an Australia Award Scholarship. DP is funded by a Griffith Postdoctoral Research Fellowship. PS is funded by a National Health and Medical Research Council Senior Principal Research Fellowship. PT is funded by a Queensland University of Technology Vice-Chancellor's Research Fellowship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript