Link found between environmental toxins and stroke

(Medical Xpress) -- Individuals with elevated levels of PCBs and DDT in their blood run a greater risk of having a stroke. This is shown in a study from Uppsala University that is being published today in the scientific journal Environmental International.

"This is the first study to assess whether there is a correlation between elevated levels of organic environmental pollutants and stroke, and the results are clear," says Lars Lind, professor of cardiovascular epidemiology at Uppsala University, who performed the study together with Monica Lind, associate professor of environmental medicine.

They have previously shown that elevated levels of PCBs, and to some extent pesticides, in the blood are related to atherosclerosis of the carotid artery (link to earlier press release). The findings are based on a study comprising some 1,000 seniors in Uppsala. Since atherosclerosis of the carotid artery is an important risk factor for stroke, the researchers have conducted another analysis in which the same group was followed for five years to investigate whether a correlation could be found between PCBs and stroke.

A total of 35 individuals experienced a stroke during these five years. Those who had elevated levels of PCBs in their blood had roughly twice the risk of having a stroke compared with those with low levels, even after factoring in the effect of traditional risk factors for stroke, such as high blood pressure, diabetes, and overweight. Those who had elevated levels of pesticides, such as DDT, had roughly twice the risk of experiencing a stroke in the future.

PCBs and DDT are banned in Sweden and many other countries today, but since they are persistent, they are still prevalent in the environment. They can be ingested and stored in our bodies through the food we eat.

The study, which was carried out in collaboration with colleagues from Örebro University in Sweden, Norway, the US, and Korea, was funded by, among others, the Swedish Research Council Formas and the Swedish Research Council.