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BackgroundPrevious studies have found an association between warm temperature and asthma hospitalisation. They have reported different sex- and age-related vulnerabilities, nevertheless little is known about how this effect has changed over time and how it varies in space. This study aims to evaluate the association between asthma hospitalisation and warm temperature and investigate vulnerabilities by age, sex, time, and space.MethodsWe retrieved individual-level data on summer asthma hospitalisation at high temporal (daily) and spatial (postcodes) resolution during 2002-2019 in England from the NHS Digital. Daily mean temperature at 1km x 1km resolution was retrieved from the UK Met Office. We focused on lags 0-3 days. We employed a case-cross over study design and fitted Bayesian hierarchal Poisson models accounting for possible confounders (rainfall, relative humidity, wind speed, national holidays, and recurrent hospitalisations).ResultsAfter accounting for confounding, we found a 0.85% (95% Credible Interval: 0.64% to 1.07%) increase in the asthma hospitalisation risk for every 1°C increase in the ambient summer temperature. The effect was highest for males aged 15-65 (2.44%, 1.99% to 2.90%). During 2002-2007 we observed a 2.23% (1.86% to 2.60%) increase in hospitalisation risk per 1°C increase in temperature, whereas inconclusive evidence for the periods 2008-2013 and 2014-2019. Populations in Yorkshire and the Humber and East Midlands were the most vulnerable.ConclusionThis study provides evidence of an association between warm temperature and hospital admission for asthma, which was attenuated over time suggesting adaptive mechanisms to heat exposure or differences in lifestyle, comorbid conditions, and occupation over time.

BackgroundThere is emerging evidence suggesting a link between ambient heat exposure and chronic obstructive pulmonary disease (COPD) hospitalisations. Individual and contextual characteristics can affect population vulnerabilities to COPD hospitalisation due to heat exposure. This study quantifies the effect of ambient heat on COPD hospitalisations and examines population vulnerabilities by age, sex, and contextual characteristics.MethodsIndividual data on COPD hospitalisation at high geographical resolution (postcodes) during 2007-2018 in England was retrieved from the small area health statistics unit. Maximum temperature at 1 km×1km resolution was available from the UK Met Office. We employed a case-cross over study design and fitted Bayesian conditional Poisson regression models. We adjusted for relative humidity and national holidays, and examined effect modification by age, sex, green space, average temperature, deprivation and urbanicity.ResultsAfter accounting for confounding, we found a 1.47% (95% Credible Interval 1.19% to 1.73%), increase in the hospitalisation risk for every 1°C increase in temperatures above 23.2°C (lags 0-2 days). We reported weak evidence of an effect modification by sex and age. We found a strong spatial determinant of the COPD hospitalisation risk due to heat exposure, that was alleviated when we accounted for contextual characteristics. 1 851 (95% CrI 1 576 to 2 079) COPD hospitalisations were associated with temperatures above 23.2°C annually.ConclusionOur study suggests that resources should be allocated to support the public health systems, for instance through developing or expanding heat-health alerts, to challenge the increasing future heat-related COPD hospitalisation burden.Key MessagesWhat is the key question?What is the short-term effect of heat exposure on COPD hospitalisation and which contextual/societal factors affect population vulnerability?What is the bottom line?For every 1°C increase in summer temperatures higher than 23.2°C, the risk of COPD hospitalisation increases by 1.47%, and populations in the North and in the South East are more vulnerable.Why read on?This large nationwide study in England using individual data quantifies the effect of heat exposure on COPD hospitalisations; these findings inform future policies regarding preparedness and resilience of public health systems against the increasing COPD burden due to the increasing temperatures.