Because of their prevalence and life-threatening implications, diabetes and obesity are among the top health problems worldwide and many factors have been attributed to these conditions including unhealthy lifestyles and diet. A new research, however, suggests that exposure to a pesticide that has long been banned in the U.S., may also be a factor to the rampancy of obesity and diabetes worldwide.
In a new study published in PLOS ONE on July 30, Michele La Merrill, from the Department of Environmental Toxicology at the University of California Davis, and colleagues found evidence suggesting that exposure to the pesticide Dichlorodiphenyltrichloroethane, or DDT, before birth increases risks for metabolic syndrome which is associated with a number of chronic health problems that include diabetes, obesity, high blood pressure and heart disease.
DDT has already been banned in the U.S. for decades but it remains used for controlling malaria in other countries including South Africa and India. For their study, the researchers exposed mice to the pesticide with doses comparable to that of the exposure of people who live in countries where it is still used to control malaria and the exposure of pregnant women in the U.S. years ago whose children are now in their 50's.
"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," La Merrill said.
The researchers found that female mice that were exposed to the pesticide before birth were associated with slower metabolism. DDT exposure also reduced the animals' heat generating ability, which increased their odds for metabolic syndrome and related health conditions. La Merrill explained that people with hampered ability to generate heat are likely storing calories instead of burning them.
"Our results suggest that perinatal DDT exposure decreases energy expenditure, and impairs the regulation of thermogenesis, glucose-, and lipid- homeostasis, which contribute to the development of insulin resistance and the metabolic syndrome in adult female mice," the researchers wrote.
La Merrill and colleagues also observed significant gender difference when it comes to response to DDT exposure. Female mice were found to be more likely to develop diabetes, obesity and cholesterol. The DDT exposure on males, on the other hand, did not affect their likelihood for obesity and their cholesterol levels. It only resulted in minor increase in blood sugar levels.
