Bug Sprays Linked to Autoimmune Diseases

Julie Bromberg

November 2009

Bug sprays are a convenient way to kill insects in the house, but new research suggests that women who used household insecticides1 (such as ant, termite, mosquito, and roach killers) are more likely to get two autoimmune diseases: rheumatoid arthritis and lupus.

Autoimmune diseases occur when the body’s immune system mistakes normal, healthy cells in the body for diseased cells. The immune system attacks itself and can create many different health problems. The causes of autoimmune diseases are poorly understood, but scientists believe that family history (genes) and environmental exposures (such as chemicals) can trigger autoimmune diseases.

Researchers at the National Institute of Environmental Health Sciences studied data from more than 76,000 older women about their use of insecticides. Women who reported using or mixing insecticides were more likely to be diagnosed with rheumatoid arthritis or lupus than women who did not use insecticides. Women who used insecticides more frequently (6 or more times a year) or over longer periods of time (20 years or more) had more than double the risk of disease.

Although these preliminary findings cannot prove that insecticides directly triggered these diseases, there is no other way to explain the findings. The lead scientist of the study warns that people should take precautions and limit their exposure to insecticides. Exposure to insecticides in the home can last a long time since most people keep their windows closed most of the year, and insecticides do not break down easily in the home.

Bottom Line:

Scientist are not sure which products may be harmful or how they enter the body (such as by skin contact or by inhaling fumes). Limit your exposure to insecticides:

  • Avoid using insecticides in the home except when absolutely necessary.
  • Read the labels of insecticide products and follow all safety precautions.

1. Bug repellent that is applied directly to skin is NOT considered an insecticide and was not included in this study.