A study conducted at Uppsala University in Sweeden and published in Environmental International this month shows that individuals subjected to chronic low-dose exposure to organochlorine pesticides show an increased risk of a future diagnosis of cognitive impairment.

Organochlorine pesticides (OCPs) were banned in developed countries 20-30 years ago, but since they accumulate through the food chain and remain for a very long time in the human body, especially fat tissue, high levels can still be found in a majority of populations. The most commonly known of these compounds is the pesticide DDT.

The research group has previously shown associations between environmental contaminants and diabetes, atherosclerosis and stroke. Using the same large data set they have now shown that the OCPs are related to future cognitive impairment.

The so-called PIVUS study (Prospective Investigation of Uppsala Seniors) comprises around 1,000 70-year-olds in Uppsala, Sweden who have been studied over a longer period of time. The researchers measured three different OCPs in plasma from the individuals and investigated who received a diagnosis of cognitive impairment over the coming 10-year period.

The results show that individuals with high levels of three OCPs had about 3 times higher future risk of cognitive impairment than elders with low levels of OCP. These results are independent of factors such as gender, smoking, diabetes, exercise habits, alcohol intake, weight change and high blood pressure.

“Even though OCPs are well-known neurotoxins, our findings are surprising because current exposure levels of these chemicals are very low. However, our study subjects were the first generation with almost life-time exposure to these chemicals. Thus, we found evidence that low-dose, but chronic, exposure of OCPs can be harmful to the human brain,” says Lars Lind, Professor of Medicine at Uppsala University.

(Source)