RT Journal Article SR Electronic T1 Temperature variability and asthma hospitalisation in Brazil, 2000–2015: a nationwide case-crossover study JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 962 OP 969 DO 10.1136/thoraxjnl-2020-216549 VO 76 IS 10 A1 Wu, Yao A1 Xu, Rongbin A1 Wen, Bo A1 Coelho, Micheline de Sousa Zanotti Stagliorio A1 Saldiva, Paulo H A1 Li, Shanshan A1 Guo, Yuming YR 2021 UL http://thorax.bmj.com/content/76/10/962.abstract AB Background Both cold and hot temperature have been associated with the onset of asthma, but it remains largely unknown about the risk of asthma hospitalisation associated with short-term temperature fluctuation or temperature variability (TV).Objective To explore the association between short-term exposure to TV and asthma hospitalisation in Brazil.Methods Data for asthma hospitalisation and weather conditions were collected from 1816 Brazilian cities between 2000 and 2015. TV was calculated as the SD of all daily minimum and maximum temperatures within 0–7 days prior to current day. A time-stratified case-crossover design was performed to quantify the association between TV and hospitalisation for asthma.Results A total of 2 818 911 hospitalisations for asthma were identified during the study period. Each 1°C increase in 0–7 days’ TV exposure was related to a 1.0% (95% CI 0.7% to 1.4%) increase in asthma hospitalisations. The elderly were more vulnerable to TV than other age groups, while region and season appeared to significantly modify the associations. There were 159 305 (95% CI 55 293 to 2 58 054) hospitalisations, US$48.41 million (95% CI US$16.92 to US$78.30 million) inpatient costs at 2015 price and 450.44 thousand inpatient days (95% CI 156.08 to 729.91 thousand days) associated with TV during the study period. The fraction of asthma hospitalisations attributable to TV increased from 5.32% in 2000 to 5.88% in 2015.Conclusion TV was significantly associated with asthma hospitalisation and the corresponding substantial health costs in Brazil. Our findings suggest that preventive measures of asthma should take TV into account.No data are available.