Climate change could exacerbate respiratory disease deaths during warm seasons

Global warming caused by climate change may increase the mortality burden of patients with respiratory diseases during the warm season. This is the main conclusion of a study led by the Barcelona Institute for Global Health (ISGlobal), a center supported by the “La Caixa” Foundation, and published Lancet Regional Health – Europe. The findings could help health facilities adapt to climate change.

The research team analyzed the relationship between ambient temperature and hospital mortality from respiratory diseases in the provinces of Madrid and Barcelona between 2006 and 2019. In both locations, the number of hospitalizations (resulting in death) was higher in the cold. Seasonal and low in warm season, highest in January and lowest in August. In contrast to hospitalizations, which were higher in the cold season, the highest incidence of patient deaths occurred in the summer and was strongly associated with higher temperatures.

To calculate the relationship between ambient temperature and hospital mortality, the team used data on daily hospital admissions, weather (temperature and relative humidity) and air pollutants (O).₃Prime Minister_2,5P.M₁₀ and no₂) Although it is well established that daily exposure to heat and cold is associated with a higher risk of hospitalization for respiratory diseases such as pneumonia, chronic obstructive pulmonary disease (COPD), and asthma, no studies have focused on hospitalization ratios. Admission that death, and therefore, more serious cases.

Association between high temperature and mortality

In terms of attributable burden, summer temperatures accounted for 16% and 22.1% of overall fatal hospitalizations due to respiratory diseases in Madrid and Barcelona, ​​respectively. The effects of heat were immediate, with most effects occurring within the first three days of exposure to high temperatures.

“This suggests that the increase in acute respiratory outcomes during summer is more related to the increase in chronic and infectious respiratory diseases than the spread of new respiratory infections, which typically take several days to cause symptoms,” said Hicham Achebak, first author. study and researcher at Inserm and ISGlobal, who holds a Marie Skłodowska-Curie postdoctoral fellowship from the European Commission.

Research results have shown the effect of heat on acute bronchitis and bronchiolitis, pneumonia and respiratory failure. Neither relative humidity nor air pollutants played a statistically significant role in the association of heat with mortality in patients admitted with respiratory disease. Studies have also shown that women are more vulnerable to heatstroke than men.

This is probably due to specific physiological differences in thermoregulation. Women have a higher temperature threshold above which the sweating process is activated, and a lower sweat output than men, resulting in less evaporative heat loss and therefore greater susceptibility to thermal effects.

Joan Ballester, ISGlobal researcher and final author of the study

Adapting to climate change in hospital centers

The study showed that high temperatures increased the risk of fatal hospitalizations, particularly in Barcelona, ​​while low temperatures were not associated with this variable. According to the research team, this may be related to the fact that health services are increasingly preparing to deal with the winter peak in respiratory diseases.

In this sense, the results have important implications for health adaptation policies to climate change and for estimates of climate change impacts on human health. “Unless effective adaptation measures are adopted in hospital facilities, climate warming may increase the burden of patient mortality from respiratory diseases during the warm season,” said Hicham Achebak.