- Gestational diabetes occurs in women who may develop high blood sugar levels during the second trimester of pregnancy.
- Woman exposed to cold climate during pregnancy had a higher risk of developing gestational diabetes than those exposed to hotter temperatures.
Gestational diabetes is a condition in which a woman without diabetes may develop high blood sugar levels during the second trimester of pregnancy.
Women who are exposed to cold temperatures during pregnancy may have a lower rate of gestational diabetes when compared to those exposed to hotter temperatures, finds a new study from St. Michael's Hospital.
‘Risk of gestational diabetes was lower among women who were exposed to colder temperature during pregnancy than those exposed to hotter temperature.’
The research study is published online in the Canadian Medical Association Journal.
Gestational diabetes was 4.6% more prevalent among women who are exposed to extremely cold average temperatures in the 30-day prior to screening of gestational diabetes.
The level could increase to 7.7% among those who are exposed to hot average temperatures. For every 10-degree Celsius rise in temperature, around 6 to 9% are more likely to develop gestational diabetes.
The research study examined about 555,911 births among 396,828 women who lived in the Greater Toronto area for over a 12-year period. However, some of them were pregnant when the average temperature was warmer and some when it was cooler.
The research team looked at the relationship between the average 30-day air temperature that is prior to the time of gestational diabetes screening in the second trimester and likelihood of diagnosing gestational diabetes.
Dr. Gillian Booth, researcher at St.Michael's and Institute for Clinical Evaluative Sciences (ICES), said that the finding could also explain how humans could make different kinds of fat.
Dr. Booth said, "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."
"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."
The research effect was seen for each 10-degree Celsius degree rise between two consecutive pregnancies compared with the same woman.
Dr. Joel Ray, researcher at St. Michael's and ICES said, "By further limiting our analysis to pregnancies within the same woman, we controlled for a whole number of factors."
"Doing so allowed us to eliminate factors like ethnicity, income, activity and eating habits that would differ between two different women."
The research findings also revealed that higher rate of gestational diabetes was not only exposed to hotter temperatures during pregnancy.
Canadian women born in cooler climates also had a lower rate of gestational diabetes.
Of the women who were born in cooler climates including Canada and United States and exposed to cold temperature, 3.6% had gestational diabetes when compared to 6.3% of those who were exposed to hot temperature.
In comparison, women born in hot climates such as South Asia, Africa and the Middle East had gestational diabetes rates of 7.7% and 11.8% respectively.
Dr. Booth and Ray said, the findings were found to signal an increased risk of gestational diabetes cases around the world.
"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," they wrote.
Dr. Booth and Ray also said,"This is like the canary in the coal mine for the possible effects of global warming on adult onset diabetes."