Study Reports Higher Risk of Respiratory Disease Fatality in Summer Than Winter

A research team led by the Barcelona Institute for Global Health assessed the connection between ambient temperature and in-hospital mortality from respiratory diseases and found that the warm season could worsen inpatient mortality.

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This issue is rooted in global warming, which is caused by climate change. The study aimed to provide resources to help health care officials adapt.

The press release noted that the research was conducted in Madrid and Barcelona from 2006 to 2019. The researchers examined the hospital admissions in both locations and found that they were higher in the cold season and lower in the warm season. The admissions peaked in January and were lowest in August. Despite this, the maximum incidence of inpatient mortality occurred in the summer months—allowing the researchers to connect the morality rates with the temperatures.

To further their research, the researchers used data collected on daily hospital admissions and weather, including the temperature and humidity, and air pollutants (O3, PM2.5, and NO₂).

“Although it is well established that daily exposure to heat and cold is associated with a higher risk of hospital admission from a range of respiratory diseases such as pneumonia, chronic obstructive pulmonary disease (COPD) and asthma, no study had focused on the proportion of hospital admissions that result in death, and therefore, the more severe cases,” said the study authors.

The press release noted that summer temperatures were responsible for 16% to 22.1% of hospitalization deaths caused by respiratory diseases. The impact was instant, resulting in death within the first 3 days after high temperatures occurred.

“This suggests that the increase in acute respiratory outcomes during heat is more related to the aggravation of chronic and infectious respiratory diseases than to the spread of new respiratory infections, which usually take several days to cause symptoms," said Hicham Achebak, first author of the study and researcher at Inserm and ISGlobal, in a press release.

Other results from the study showed that acute bronchitis, bronchiolitis, pneumonia, and respiratory failure were impacted by the heat. However, humidity and air pollutants did not contribute to individual mortality. The study authors noted that women were less susceptible to heat compared with men.

“This is most likely due to specific physiological differences in thermoregulation. Women have a higher temperature threshold above which sweating mechanisms are activated, and a lower sweat output than men, which results in less evaporative heat loss, and therefore greater susceptibility to the effects of heat," said Jan Ballester, ISGlobal researcher and last author of the study, in a press release.

The findings suggest that warmer temperatures are connected to high risk of mortality in hospitals, as cooler temperatures have a lower risk. The study authors believe that health care providers are more prepared to deal with higher mortality rates in the winter peaks in respiratory diseases.

“Unless effective adaptation measures are taken in hospital facilities, climate warming could exacerbate the burden of inpatient mortality from respiratory diseases during the warm season," said Hicham Achebak, in a press release.

Reference

Risk of dying in hospital from respiratory causes is higher in the summer than in the winter. EurekAlert!. News release. November 7, 2023. Accessed November 8, 2023. https://www.eurekalert.org/news-releases/1006892.