Global warming could increase the risk of hypoglycemia

Global warming is likely to increase the number of people requiring hospitalization due to extremely low blood sodium levels – a condition known as hyponatremia.

A new study from the Karolinska Institutet in Sweden predicts that a temperature increase of 2°C would increase the burden on hospitals from this disease by almost 14%.

“Our study is the first to provide precise estimates of the influence of temperature on the risk of hyponatremia – findings that could be used to inform health care planning for climate change adaptation,” says the study’s first author and deputy principal of the institute’s Department of Clinical Sciences and Education. lecturer Buster Mannheimer.

Climate change is expected to trigger an increase in average global temperatures over the coming decades, leading to myriad heat-related consequences for human health.

One of these is hyponatremia, which can result from various diseases such as heart, kidney, and liver failure, as well as excessive sweating or fluid intake that dilutes the sodium concentration in the blood. .

Our bodies need sodium to maintain normal blood pressure, support nerve and muscle function, and regulate water balance in and around our cells.

If blood sodium levels drop, it can lead to nausea, dizziness, muscle cramps, seizures, and even coma.

It is well known that cases of hyponatremia increase during the summer months in temperate countries.

Yet data on temperature thresholds above which risks amplify are lacking, complicating clinical planning and predictions of health burden in future climate scenarios.

In the current study, the researchers linked data on Sweden’s entire adult population to information on average 24-hour temperatures over a nine-year period.

During this period, more than 11,000 people were hospitalized with a primary diagnosis of hyponatremia, most of whom were women with a median age of 76 years.

Average daily temperatures ranged from -10°C to 26°C.

The researchers found an almost tenfold higher risk of hospitalization due to hyponatremia on the hottest days, compared to the cooler times.

Women and the elderly were at greatest risk, with people aged 80 or older 15 times more likely to be hospitalized for hyponatremia during heat waves.

The incidence of this condition was largely stable from -10°C to 10°C, but increased rapidly at temperatures above 15°C.

When the researchers applied the data to a prognostic model predicting global warming of 1°C and 2°C – in line with the United Nations Intergovernmental Panel on Climate Change (IPCC) climate projections for 2050 – they found that hospitalizations due to hyponatremia could be expected to increase by 6.3% and 13.9% respectively.

“We think these estimates are quite conservative, as we didn’t take into account secondary diagnoses of hyponatremia, extreme weather events, or an aging population,” says Jonatan Lindh, co-last author of the study. and associate professor in the institute’s Department of Laboratory Medicine.

“Without adaptation measures, this suggests that over the coming decades, rising global temperatures alone will increase the burden of hyponatremia on health systems.”

It should be noted that Sweden is in the continental climatic zone, with buildings suitable mainly for cold temperatures.

Therefore, the thresholds observed in this study may be representative only of cold temperate regions.

The conclusions are published in the Journal of Clinical Endocrinology and Metabolism.

Teresa H. Sadler