Climate Change May Increase Hospitalizations due to Hyponatremia

Hyponatremia is a common electrolyte disorder characterized by low levels of sodium in the blood and it can be seen in up to 30% of all hospitalized patients. This condition can cause no symptoms when mild, but moderate to severe cases can have different symptoms, including difficulty concentrating, headaches, nausea, and when severe it can lead to confusion, seizures, and coma. 

There are several conditions that can increase the risk of hyponatremia, such as diarrhea, vomiting, excessive sweating, and having an underlying heart, liver, or kidney disease.

In a recently published study, researchers from the Karolinska Institute evaluated the effect and impact of climate change, and how the increased outdoor temperature can increase the risk of hospitalization due to hyponatremia. The study appears in The Journal of Clinical Endocrinology and Metabolism. 

Risk of Hyponatremia with Higher Temperatures

According to the new study, temperatures above 15 degrees Celcius can cause an increase in the number of people hospitalized due to hyponatremia. 

The research team used a nationwide cohort study from Sweden to study the incidence rates for hyponatremia at a given outdoor temperature, in increments of 1 degree Celsius. They identified 11,213 patients hospitalized with hyponatremia between October 2005 and December 2014. 

The researchers retrieved data on the 24-hour mean temperature of the day when each patient was admitted to the hospital from the Swedish Meteorological and Hydrological Institute (SMHI).

On the hottest days, women and those over 80 were at the highest risk, and patients over 80 were 15 times more likely to be hospitalized due to hyponatremia compared to cooler days.

The team estimated that an average increase in temperature of 1 degree Celcius will lead to a 6.3% increase in the incidence of hospitalizations due to hyponatremia, and an increase of 2 degrees would result in a 13.9% increase. 

The researchers plan to evaluate the risk in other countries with warmer temperatures because the study was performed in Sweden, where temperatures are normally much lower in comparison to other countries. 


Anna Guildford, Ph.D. (2022, Apr 1). More people may be hospitalized with low sodium levels due to climate change. Medical News Today. Retrieved from:

Buster Mannheimer, et al. Current and future burdens of heat-related hyponatremia – a nationwide register-based study. 2022. J. Clin. Endocrinol. Metab.

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