title: Greater temperature variation within a day associated with increased emergency hospital admissions for asthma.
abstract: Asthma is one of the most common chronic conditions affecting both children and adults. Examining the health effects of environmental triggers such as temperature variation may have implications for maintenance of asthma control and prevention. We hypothesized that large diurnal temperature range (DTR) might be a source of additional environmental stress and therefore a risk factor for asthma exacerbation. Daily meteorological data, air pollution concentrations and emergency hospital admissions for asthma from 2004 to 2011 in Hong Kong were collected. Poisson regression models were used to fit the relationship between daily DTR and asthma, after adjusting for the time trend, seasonality, mean temperature, humidity, and levels of outdoor air pollution. Acute adverse effect of DTR on asthma was observed. An increment of 1 °C in DTR over lag0 to lag4 days was associated with a 2.49% (95% CI: 1.86%, 3.14%) increase in daily emergency asthma hospitalizations. The association between DTR and asthma was robust on the adjustment for daily absolute temperature and air pollution. DTR exhibited significantly greater effect in cool season. Males and female children appeared to be more vulnerable to DTR. Results supported that greater temperature variation within a day was an environmental risk factor for asthma exacerbation.
authors.affiliation: School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region.
authors.forename: Hong
authors.initials: H
authors.lastname: Qiu
authors.affiliation: School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region.
authors.forename: Ignatius Tak-Sun
authors.initials: IT
authors.lastname: Yu
authors.affiliation: School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region.
authors.forename: Lap Ah
authors.initials: LA
authors.lastname: Tse
authors.affiliation: School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region.
authors.forename: Emily Y Y
authors.initials: EY
authors.lastname: Chan
authors.affiliation: School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region.
authors.forename: Tze Wai
authors.initials: TW
authors.lastname: Wong
authors.affiliation: School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region. Electronic address: linweit@gmail.com.
authors.forename: Linwei
authors.initials: L
authors.lastname: Tian
mesh_terms: D000328:Adult; D001249:Asthma / Q000453:epidemiology*; D002648:Child; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006760:Hospitalization; D006801:Humans; D006813:Humidity; D008297:Male; D008962:Models, Theoretical; D010343:Patient Admission / Q000706:statistics & numerical data*; D012621:Seasons; D013696:Temperature
keywords: Asthma; Diurnal temperature range; Emergency hospital admission; Temperature variation; Time series study