Temperature affects risk of developing gestational diabetes

by Barbara Hewitt on May 16, 2017

Women exposed to colder temperatures during pregnancy have a lower rate of gestational diabetes than those exposed to hotter temperatures, new research has found.

The work from researchers at St Michael’s hospital in Toronto, Canada, and the Institute for Clinical Evaluative Sciences (ICES) found that for every 10 degree Celsius rise in temperature, women had a 6% to 9% higher chance of developing gestational diabetes.


Overall, the prevalence of gestational diabetes was 4.6% among women exposed to extremely cold average temperatures, equal to or below -10 C, in the 30-day period prior to being screened for gestational diabetes, and increased to 7.75% among those exposed to hot average temperatures above 24 C.

The study examined 555,911 births among 396,828 women over a 12-year period. All the women studied lived in the Greater Toronto Area, but some were pregnant when the average temperature was warmer, and some when it was cooler.

Researchers looked at the relationship between the average 30-day air temperature prior to the time of gestational diabetes screening in the second trimester, and the likelihood of gestational diabetes diagnosis.

Dr. Gillian Booth, an associate professor as Toronto University’s department of medicine and lead author of the study, said the finding might seem counterintuitive, but can be explained by emerging science about how humans make different kinds of fat.

‘Many would think that in warmer temperatures, women are outside and more active, which would help limit the weight gain in pregnancy that predisposes a woman to gestational diabetes,’ she said.

‘However, it fits a pattern we expected from new studies showing that cold exposure can improve your sensitivity to insulin, by turning on a protective type of fat called brown adipose tissue, she explained.

She pointed out that a similar effect was seen for each 10-degree Celsius rise in the temperature difference between two consecutive pregnancies compared within the same woman.

In addition to a higher rate of gestational diabetes among women who were exposed to hotter temperatures during pregnancy, there was also a lower rate of gestational diabetes among Canadian women born in cooler climates versus those who were born in hot climates. Those women born in cooler climates, including Canada and the United States, and who were exposed to cold temperatures during the 30-day period prior to screening had a gestational diabetes rate of 3.6%.

Those exposed to hot temperatures had a rate of gestational diabetes of 6.3% and in comparison, women who were born in hot climates, including South Asia, Africa and the Middle East, had rates of gestational diabetes of 7.7% and 11.8% respectively.

According to the study the findings, combined with the continued rise in global temperatures, could signal an increase in the future number of gestational diabetes cases worldwide. The study report says that while changes in temperature of this magnitude may lead to a small relative increase in the risk of gestational diabetes, the absolute number of women impacted in Canada and elsewhere may be substantial.

It also says that the study results could foreshadow the effects of rising worldwide temperatures on type 2 diabetes in general.

The opinions expressed in this article do not necessarily reflect the views of the DiabetesForum.com Community and should not be interpreted as medical advice. Please see your doctor before making any changes to your diabetes management plan.

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