Article Text

Download PDFPDF
Original article
The short-term association between asthma hospitalisations, ambient temperature, other meteorological factors and air pollutants in Hong Kong: a time-series study
  1. Holly Ching-yu Lam1,
  2. Albert Martin Li2,
  3. Emily Ying-yang Chan1,
  4. William Bernard Goggins III1
  1. 1The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong SAR
  2. 2Department of Paediatrics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR
  1. Correspondence to William B Goggins III, The Jockey Club School of Public Health and Primary Care (CUHK), Prince of Wales Hospital, Shatin, Hong Kong SAR; wgoggins{at}


Background Previous studies have found associations between meteorological variables and asthma hospitalisations but the nature of these associations has varied and few studies have been done in subtropical areas or evaluated effect modification by age.

Objectives This study aimed to evaluate associations between asthma hospitalisations and meteorological factors and to assess effect modification of these associations by age and season in Hong Kong.

Methods Poisson generalised additive models combined with distributed lag nonlinear models and piecewise linear models were used to model associations between daily asthma hospitalisations from 2004 to 2011 and meteorological factors and air pollutants, adjusting for day of week, seasonality and trend. Subgroup analyses by age and season were performed.

Results In the hot season, hospitalisations were lowest at 27°C, rose to a peak at 30°C, then plateaued between 30°C and 32°C. The cumulative relative risk for lags 0–3 days (RRlag0–3) for 30°C vs 27°C was 1.19 (95% CI 1.06 to 1.34). In the cold season, temperature was negatively associated with asthma hospitalisations. The cumulative RRlag0–3 for 12°C vs 25°C was 1.33 (95% CI 1.13 to 1.58). Adult admissions were most sensitive to temperatures in both seasons while admissions among children under 5 were least associated. Higher humidity and ozone levels in the hot season, and low humidity in the cold season were also associated with more asthma admissions.

Conclusions People with asthma should avoid exposure to adverse conditions by limiting outdoor activities during periods of extreme temperatures, combinations of high humidity and high temperature, and low humidity and low temperature, and high ozone levels.

  • Asthma Epidemiology

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Contributors HC-yL, EY-yC and WBG made substantial contributions to the conception or design of the work, or the acquisition, analysis or interpretation of the data. HC-yL, AML and WBG contributed to drafting the work or revising it critically for important intellectual content. WBG was responsible for final approval of the version published.

  • Competing interests None declared.

  • Ethics approval Ethics approval has been granted by the Survey and Behavioural Research Ethics Committee, The Chinese University of Hong Kong.

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

Linked Articles