Greater temperature variation within a day associated with increased emergency hospital admissions for asthma

• Published in: The Science of the total environment Vol. 505; pp. 508 - 513
• Main Authors: Qiu, Hong, Yu, Ignatius Tak-sun, Tse, Lap Ah, Chan, Emily Y.Y., Wong, Tze Wai, Tian, Linwei
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-02-2015
• Subjects: Adjustment; Adult; Air pollution; Asthma; Asthma - epidemiology; Child; Children; Diurnal temperature range; Emergency hospital admission; Emergency medical services; Female; Hong Kong - epidemiology; Hospitalization; Hospitals; Humans; Humidity; Male; Mathematical models; Models, Theoretical; Patient Admission - statistics & numerical data; Risk; Seasons; Temperature; Temperature variation; Time series study; Hong Kong; China, People's Rep., Hong Kong; DTR; ERR; O3; Emergency hospital admission; Time series study; Diurnal temperature range; lagn; Asthma; Temperature variation; NO2; PACF; ICD-9; PM10
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2014.10.003

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.
•We examined the association between diurnal temperature range (DTR) and asthma.•We observed greater DTR associated with increased emergency asthma hospitalizations.•The effect of DTR was independent of daily mean/minimum temperature and air pollution.•DTR exhibited significantly greater effect in cool season, in males and children.•Great DTR was an environmental risk factor for asthma exacerbation.