New research from the University of Iowa has shown that prolonged exposure to common household insecticides may increase one’s risk for developing cardiovascular disease, and dying earlier from all causes.
Commonly used in garden insecticides, pet sprays, mosquito repellents and lice shampoos, pyrethrin and its synthetic derivatives are extremely effective, and, until now, do not appear to cause any acute reactions in humans. Instead, previous research has shown that they are easily absorbed by the body where they are then metabolized and excreted in urine.
However, a new study is beginning to challenge these findings. To demonstrate this, investigators took regular urine samples from 2,116 adults from a large national health survey and tested them for levels of pyrethroid. In total, they followed the group for an average of 14 years, during which 246 died, including 41 from cardiovascular disease, and 52 from cancer.
After collecting the data, the researchers adjusted it for age, sex, body mass index, smoking habits, alcohol consumption and other health and behavioural factors. From doing this, they found that those who scored highest third for urine levels of pyrethroids had a 56% higher chance of all-cause death, and were also three times more likely to die of cardiovascular disease, than those in the lowest third for urine levels of pyrethroids.
University of Iowa occupational and environmental health professor Hans-Joachin Lehmler said, “You would think, normally, cancer is an important endpoint or the brain is an important endpoint for these kinds of chemicals...So I have to admit, from my personal perspective, that looking at cardiovascular disease — that there is actually a link — was quite unexpected.”
However, although the study has established a correlation between exposure to this insecticide, heart disease and overall death, the researchers warn that the research did not establish direct causation of death. Although the findings suggest a high chance of a link existing, further research is needed to confirm any results due to the relatively small sample studied.
The study’s lead author, Wei Bao, an assistant professor of epidemiology at the University of Iowa said that a single exposure to pyrethroids, like exposure to just one drag of a cigarette, is unlikely to cause harm. He also said, ““Our findings are likely to reflect the potential adverse effects of long-term exposure.”