In the summer months, the chances of hospitalization for metabolic and obesity-related disorders double, and Zaragoza is the province with the highest risk of hospitalization for complications triggered by high temperatures. They are conclusions from a detailed investigation of more than 11 million admissions in Spain in 13 years.
The mortality attributable to excess temperatures (2,155 deaths in Spain in 2023 and 3,012 the previous year, according to data from the Carlos III Health Institute) has been the subject of detailed national and international studies, but the relationship between the summer climate and the hospital admissions.
A team from the Barcelona Institute for Global Health, a center promoted by the La Caixa Foundation, and the National Institute of Health and Medical Research (Inserm) of France has studied more than 11.2 million hospital admissions between 2006 and 2019 to conclude that high temperatures have “a widespread impact on hospitalizations for specific causes.”
Heat is a major influencing factor in hospitalizations of people with metabolic and obesity-related disorders, research indicates. In these people, the probabilities of admission increase by 97.8% with high summer temperatures compared to comfort temperatures.
Also highlighted as causes of hospitalization increased by heat are kidney failure (77.7% more likely), urinary tract infection (74.6%), sepsis (54.3%), urolithiasis (49% ) or infection due to drugs (47%). Taking into account the set of diseases, high temperatures increase the probabilities of hospital admission by 10.1%.
According to Hicham Achebak, a researcher at ISGlobal and Inserm, several reasons explain why the risk of admission for obesity doubles on the hottest days. For example, in these people “heat loss responses work less effectively, as body fat acts as an insulator, making them more susceptible to heat disorders.”
The research has been published in Environmental Health Perspectives. In addition to the income figures in 48 provinces in the summer, from June to September, the team has also calculated the values ??of average daily temperatures, relative humidity and concentrations of different atmospheric pollutants.
The underlying mechanisms by which heat causes adverse health effects are unclear, but “they appear to be related to the way our body regulates its own temperature,” Achebak explains. 60% of heat is eliminated with sweat. “Subsequent reactions can affect people differently depending on a number of factors such as age, gender or pre-existing health conditions.”
Children under 1 year of age and over 85 are the groups with the highest risk of hospital admission. By sex, men showed a greater probability of hospitalization for injuries than women, while women present a greater risk for parasitic, endocrine and metabolic, respiratory or urinary diseases.
Achebak expresses surprise at the breadth of the catalog of diseases that can be complicated by the effect of heat. Paradoxically, admissions for heart failure cases only grew by 9.1%. The explanation, according to the researcher, is that many of these patients die before being able to receive hospital care. Heat triggers deaths from cardiovascular causes, but not admissions.
The study shows that the added effects of heat waves have little influence on hospitalizations and are specific for a subset of pathologies, especially non-respiratory infectious diseases, endocrine and metabolic disorders or diseases of the nervous system.
In this sense, researchers consider that the effectiveness of heat wave warning systems should be reviewed. “They should be activated not only during heat waves but also during non-persistent extreme temperatures,” reasons researcher Joan Ballester Claramunt.
Achebak specifies: “The heat plan establishes temperature thresholds from which a series of measures are activated such as awareness campaigns, notifications to health services, social services, etc. These thresholds are defined based on spikes in mortality, not hospitalizations. “We will have to evaluate the effectiveness of these plans to see what we can do to improve it.”
Will the human body adapt to the global increase in temperatures? It is possible, but it is a physiological adaptation that will take centuries or millennia, researchers maintain. If the risk of dying from excess cold or light is lower now than 20 years ago, it is not due to a physiological adjustment, but rather a socioeconomic one (extension of the use of heating, air conditioning or improvement of health services).
Among the 48 provinces studied, Zaragoza leads the increase in the risk of hospitalization due to high temperatures, with 16.6%. Behind, in the top 10 places, Gipuzcoa (16%), Zamora (14.6%), Barcelona (13.5%), Badajoz (13.4%), Álava (13.2%), Cáceres (13 ), Huesca (13), Valladolid (12.5), Bizkaia (11.9%), Navarra and Soria (11.8%).
On the other hand, Granada is the province with the lowest probability of entry (3.6%), followed by Cádiz (5.3%), Málaga (6.2%), Jaén (6.3%), Toledo (6.5%). %), Seville (6.8%), Almería (7.2%), Huelva (7.3%), Albacete (7.7%), Lugo and Girona (7.8%).
