Prolonged exposure to a widely used household insecticide may increase the risk for cardiovascular disease and early death, new research suggests.
Pyrethrin and its synthetic derivatives are used in garden insecticides, pet sprays, mosquito repellents and lice shampoos. They are extremely effective and cause no acute reactions in humans, but they are absorbed by the body and then metabolized and excreted in urine.
Researchers tested pyrethroid levels in urine samples from 2,116 adults selected from a large national health survey. The study, in JAMA Internal Medicine, followed the group for an average of 14 years, during which there were 246 deaths, including 41 from cardiovascular disease and 52 from cancer.
After adjusting for age, sex, body mass index, smoking, alcohol intake and other health and behavioral factors, they found that compared with those in the lowest one-third for urine levels of pyrethroids, those in the highest had a 56 percent higher rate of all-cause death, and three times the rate of death from cardiovascular disease.
The lead author, Wei Bao, an assistant professor of epidemiology at the University of Iowa, cautioned that the study had a relatively small sample. He added that a single exposure to pyrethroids, like exposure once to a puff of cigarette smoke, is unlikely to do harm.
Still, he said, “Our findings are likely to reflect the potential adverse effects of long-term exposure.”