Prenatal Exposure to DDT ups the Risk of Metabolic Syndrome in Infant Girls

Female offspring born to mothers who were exposed to pesticide DDT suffer an increased risk of developing metabolic syndrome later in life.  

Exposure of pregnant women to pesticides is linked to an increased risk of pregnancy delay as well as autism spectrum disorder in the children. Due to these well documented risk factors, it is advised that pregnant women take special care and avoid contact with agricultural chemicals as much as possible. Metabolic syndrome is a combination of several medical disorders that ups the risk of diabetes, heart diseases, stroke, excess body fat and excess cholesterol levels and premature death.

In a new study, researchers at the University of California, Davis, exposed pregnant mice to pesticide DDT and found that the female offspring born to these mice faced an increased risk of developing obesity, diabetes, high cholesterol and other related conditions. This is one of the early evidence that highlights developmental exposure to DDT ups the risk of females developing metabolic syndrome later in life.

It was in the 1970s that the use of DDT was banned in the United States, but it is still used to control malaria in countries including India and South Africa.

In the current study, the researchers exposed mice to doses of DDT that is comparable to the level of DDT people living in malaria-infested regions are exposed to, and pregnant women in the U.S. who are in their 50s now.

"The women and men this study is most applicable to in the United States are currently at the age when they're more likely to develop metabolic syndrome, because these are diseases of middle- to late adulthood," said lead author Michele La Merrill, assistant professor of environmental toxicology at UC Davis.

They found that exposure to DDT before birth lowered the metabolism of female mice and also reduced their tolerance to cold temperatures. This eventually increased the likelihood of developing metabolic syndrome and other related conditions.

"As mammals, we have to regulate our body temperature in order to live," La Merrill said. "We found that DDT reduced female mice's ability to generate heat. If you're not generating as much heat as the next guy, instead of burning calories, you're storing them."

Surprisingly, females were at a higher risk of obesity, type-2 diabetes and cholesterol when compared to male mice. In males, DDT did not affect the obesity or cholesterol levels and increased the levels of glucose.

A high fat diet also caused female mice to have more problems with glucose, insulin and cholesterol but was not a risk factor for males. The sex differences require further research, the authors said.

The study was documented in the journal PLOS One.