- Sodium is an electrolyte essential for a wide variety of body functions.
- Hyponatremia refers to a condition where sodium levels in the blood are lower than normal.
- A new study found that hyponatremia at temperatures above 40 degrees Celsius is a leading cause of hospitalizations. 15 degrees Celcius.
- The study predicts that a rise of 2 degrees Celsius could lead to hyponatremia cases rising by 13.9%, with climate change predicted to increase global temperatures.
The human body needs sodium for various body functions — from conducting nerve impulses to regulating heart rate, digestion, brain activity, and blood pressure.
A person with MildAlthough hyponatremia is not usually a problem, it can cause symptoms such as difficulty concentrating, nausea, headaches, or rapid sodium loss. Learn more SevereIn severe cases, symptoms may include confusion, seizures, or coma.
You may experience diarrhea, vomiting, nausea, and/or kidney disease.
In a recent StudyResearchers at the Karolinska Research Institute measured the impact of outdoor temperature on the risk for hyponatremia hospitalizations.
The retrospectivePublished in: Study The Journal of Clinical Endocrinology and MetabolismThis included all of the Swedish population aged over 18 years.
Researchers used data from the National Patient Register(NPR), in Sweden, to study hyponatremia incidence rates at a given outdoor temperature in increments 1 degree Celsius. Between October 2005 and December 2014, they identified 11,213 hyponatremia patients.
Researchers obtained data from the CDC on the 24-hour mean temperature for each patient who was admitted to hospital. Swedish Meteorological and Hydrological Institute (SMHI).
Speak to Medical News TodayStudy co-author Dr. Jakob SkovOne critical finding was pointed out:
“[T]The risk of severe hyponatremia seems to rise dramatically above certain temperature thresholds. [the] elderly (unsurprisingly) are at greatest risk.”
Women and people over 80 were most at risk on the hottest days. They were 15x more likely to be admitted to hospital for hyponatremia than on cooler days.
The team also observed that hyponatremia was most prevalent in the summer months, and gradually decreased towards the winter. January saw the lowest numbers.
According to the study, an average temperature increase of 1 degree Celsius would result in a 6.3% increase of hyponatremia-related hospitalizations. Projections show that a 2 degree increase in temperature would result in a 13.9% decrease.
DiscussingDr. Skov explained the mechanism that explains the rise in cases MNT:
“Oversimplified, hyponatremia can be the result of sodium deficiency (low intake or high losses) or excess water. [T]here are two plausible explanations for heat-related hyponatremia—salt loss from sweating resulting in a sodium deficit or excessive hydration due to an exaggerated fear of dehydration. Both conditions can be easily treated, but we need to know which one is responsible.”
Dr. Skov speculated overhydration may be the most likely cause of elderly in nursing homes. However more data was needed.
MNTspoke to Joseph A Vassalotti, MD, Chief Medical Officer for the National Kidney FoundationHe was a clinical professor at Mount Sinai’s Icahn School of Medicine, but was not part of the study. He explained that hyponatremia is “a relatively common condition in up to 30% of hospitalized patients that may occur independently of a kidney problem.”
“The results suggesting an association with increased hyponatremia hospitalization with global warming are interesting,” he said.
Describing the study as “hypothesis-generating,” Vassalotti cautioned that “[It] will require investigation in other climates, countries and with more contemporary data after 2014 to confirm.”
Dr. Skov answered questions about the next steps in the research. MNTThe team will expand their findings to other countries that have warmer climates.
“The threshold of 15°C observed in Sweden (above which the risk increased rapidly) is unlikely to be relevant in warmer climates,” he said.
His team will now try to determine if there is a different threshold in areas with higher temperatures.
According to the study, hyponatremia could rise by 10% if temperatures continue to rise in the future. Researchers say that countries will need to use clinical monitoring strategies in order to protect the vulnerable and reduce their risks.
“[T]His study highlighted the risk of hyponatremia when high temperatures are applied to vulnerable populations. Consequently, these individuals should be monitored for symptoms of hyponatremia during heat waves,” Dr. Skov said.
He also acknowledged that the study was incomplete.
“By design, the study can’t explore potential mechanisms of hyponatremia (that could result in changed treatment recommendations).”