Pesticides, insecticides, herbicides and other chemical agent employed in agriculture, have been long studied for their potential dangerous effects on human health. Effects have been hypothesized on many organs and, after many researches, it has been possible to ascertain that there is a certain mutagenic, cytotoxic and also carcinogenic activity of these molecules for animals and humans of course. But apart cancers, there is a whole scientific literature that demonstrates the direct correlation between exposure to organochlorines, carbamates and organophosphorus and late neurological damage. Teratogenic and reproductive toxicities have been suspected and then dimostrated as well for many of the pesticide classes, raising concerns about the high rates of infertility and/or abortion on the rise and especially in some areas of the world. Safety protocols in agriculture do exist but there has been in the past a low awreness about the professional risks linked to pesticide exposure, mainly in the low-income areas of the world.
Now, according to new research published in the Journal of the American Heart Association, the open access journal of the American Heart Association, on-the-job exposure to high levels of pesticides raised the risk of heart disease and stroke in a generally healthy group of Japanese American men in Hawaii. The findings are the latest to emerge from the Kuakini Honolulu Heart Program, which enrolled over 8,000 Japanese American men on Oahu between 1965 and 1968. Men enrolled in the study were 45 to 68 years of age and self-reported their occupation. The group has since undergone multiple examinations and researchers are also tracking all causes of death and some disease outcomes. Data on rates of heart disease and stroke were available through December 1999, for up to 34 years of follow-up. Although the study was conducted solely in first or second-generation Japanese American men, similar results were found in Taiwan for high pesticide exposure in middle age.
Pesticide exposure was estimated using a scale from the Occupational Safety and Health Administration that assesses the intensity and length of occupational exposure for each job. Compared to men who were not exposed to pesticides at work, in the first 10 years of follow-up, the researchers found that roughly a 45% higher risk of heart disease or stroke in those with high pesticide exposure, (46% after adjusting for age, and 42% after adjusting for other heart disease risk factors as well as age). Moreover, there was no significant relationship between low to moderate exposure to pesticides and the risk of heart disease or stroke. Pesticides have a long half-life, so health effects may occur years after exposure. By analyzing different time lags, the researchers found that the maximum effect of exposure on heart disease and stroke risk was during the first 10 years. The study was conducted only in men of Japanese descent, and the results may not apply to women or other races.
Beatriz L. Rodriguez, MD, PhD, co-author of the study and professor of Geriatric Medicine at the University of Hawaii at Manoa, explained: “Previous studies have found that men and women may respond differently to pesticide exposure. One class of pesticides may give women heart attacks but not men and other pesticides may give men heart disease but not women. Hormones may also play a role in the impact of pesticide exposure and the development of cardiovascular disease. After following the men for 34 years, the link between being exposed to pesticides at work and heart disease and stroke was no longer significant. This was probably because other factors tied to aging became more important, masking the possible relation of pesticides and cardiovascular disease later in life, This study emphasizes the importance of using personal protective equipment during exposure to pesticides on the job and the importance of documenting occupational exposure to pesticides in medical records, while controlling standard heart disease risk factors”.
- Edited by Dr. Gianfrancesco Cormaci, PhD, specialist in Clinical Biochemistry.
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