Annals of DDT: Study implicates DDT in human obesity and diabetes

August 2, 2014

Press report from the University of California at Davis (unedited here):

Exposure of pregnant mice to the pesticide DDT is linked to an increased risk of obesity, diabetes, high cholesterol and related conditions in female offspring later in life, according to a study led by the University of California, Davis.

White mouse looking at camera

Caption from UC-Davis: The study is the first to show that developmental exposure to DDT increases the risk of females later developing a cluster of conditions that include increased body fat, blood glucose and cholesterol.

The study, published online July 30 in the journal PLOS ONE, is the first to show that developmental exposure to DDT increases the risk of females later developing metabolic syndrome — a cluster of conditions that include increased body fat, blood glucose and cholesterol.

DDT was banned in the United States in the 1970s but continues to be used for malaria control in countries including India and South Africa.

Scientists gave mice doses of DDT comparable to exposures of people living in malaria-infested regions where it is regularly sprayed, as well as of pregnant mothers of U.S. adults who are now in their 50s.

“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.

The scientists found that exposure to DDT before birth slowed the metabolism of female mice and lowered their tolerance of cold temperature. This increased their likelihood of developing metabolic syndrome and its host of 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.”

The study found stark gender differences in the mice’s response to DDT. Females were at higher risk of obesity, Type 2 diabetes and cholesterol, but in males, DDT exposure did not affect obesity or cholesterol levels and caused only a minor increase in glucose levels.

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 funded by the National Institute of Environmental Health Sciences.

Co-authors include Emma Karey and Michael La Frano of UC Davis; John Newman of UC Davis and the U.S. Department of Agriculture; and Erin Moshier, Claudia Lindtner, and Christoph Buettner of Mount Sinai School of Medicine.

About UC Davis

UC Davis is a global community of individuals united to better humanity and our natural world while seeking solutions to some of our most pressing challenges. Located near the California state capital, UC Davis has more than 34,000 students, and the full-time equivalent of 4,100 faculty and other academics and 17,400 staff. The campus has an annual research budget of over $750 million, a comprehensive health system and about two dozen specialized research centers. The university offers interdisciplinary graduate study and 99 undergraduate majors in four colleges and six professional schools.

Additional information:

In the past five decades, the case that DDT and its daughter metabolites damage human health in subtle but extremely destructive ways constantly mounted. Perhaps Rachel Carson was right to urge much more study of the stuff, in Silent Spring.  Perhaps the National Academy of Sciences was right when it called for a rapid phasing out of DDT use in 1970, after noting it had been one of the greatest lifesaving pesticides ever known.

In 1972 the U.S. Environmental Protection Agency prohibited use of DDT in agriculture.  Use in day-to-day indoor extermination had ended earlier; bedbugs had become almost wholly immune to DDT by 1960.  The U.S. ban was predicated on damage to wildlife, not human health.  The order allowed U.S. DDT manufacturers to continue to make the stuff for export to other nations.  Exports continued from 1972 to 1984, when the Superfund required manufacturers to clean up any pollution they may have caused.


All study for the tests and no play makes Jack and Jill perform worse on standardized tests

February 26, 2009

Newark Star-Ledger file photo of kids at recess at Newton Street School. Patti Sapone photo

Newark Star-Ledger file photo of kids at recess at Newton Street School. Patti Sapone photo

The old classroom teachers knew it.  The new, test-the-hell-out-of-the-little-brats administrators need to learn it.

Kids need physical activity to be good students.

A study published this month in the journal Pediatrics studied the links between recess and classroom behavior among about 11,000 children age 8 and 9. Those who had more than 15 minutes of recess a day showed better behavior in class than those who had little or none. Although disadvantaged children were more likely to be denied recess, the association between better behavior and recess time held up even after researchers controlled for a number of variables, including sex, ethnicity, public or private school and class size.

The lead researcher, Dr. Romina M. Barros, a pediatrician and an assistant clinical professor at the Albert Einstein College of Medicine, said the findings were important because many schools did not view recess as essential to education.

The article in the science section of the New York Times put it well:

The best way to improve children’s performance in the classroom may be to take them out of it.

A convicted murderer in prison gets an hour a day for exercise.  But our kids, the high-performing ones we depend on for our nation’s future?  We treat them worse than convicted felons?

Nota bene: Even just a little movement worksIt works for adults, too.

Resources:

  • PEDIATRICS Vol. 123 No. 2 February 2009, pp. 431-436 (doi:10.1542/peds.2007-2825) (subscription required for full text),  “School Recess and Group Classroom Behavior,” Romina M. Barros, MD, Ellen J. Silver, PhD and Ruth E. K. Stein, MD, Department of Pediatrics, Albert Einstein College of Medicine, Children’s Hospital at Montefiore and Rose F. Kennedy Center, Bronx, New York

    OBJECTIVES. This study examines the amount of recess that children 8 to 9 years of age receive in the United States and compares the group classroom behavior of children receiving daily recess with that of children not receiving daily recess.

  • See this year-old post at The Elementary Educator
  • Post in agreement from the venerable Trust for Public Lands, one of the best and best respected non-profits in America

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