How Much Does Pesticide Exposure Affect Farmers?

Concern over the health risks of long-term exposure to pesticides and industrial chemicals is well-founded, but devilishly hard to quantify.

Epidemiology and clinical trials are useful, but limited because they’re either too broad or too narrow in scope. It’s hard to get things just right.

However, studying the long-term health patterns of farmers is a unique opportunity, because they have direct exposure to industrial pesticides throughout their working life, and they often eat the food they produce. It’s the closest thing society has to a natural experiment, for better or worse.

The Health Characteristics of Farmers

Farmers, and more specifically farm workers who spend their day in the fields, are typically healthier than the average american. They have lower mortality rates in general, and specifically from heart disease, diabetes, lung cancer, and other “diseases of convenience.”

However, it was noticed in the 1970’s that farmers typically had higher incidence rates of diseases not commonly found in the general population. The illnesses include leukemia, brain cancer, lymphoma, and CNS disorders. A look at a map of leukemia incidence rates in the US confirms this observation. The disease is most common in rural midwestern states, and industrial farming areas along the west coast:

Studies done in other western nations have shown a similar result.

Cancer Rates in Migrant Farm Workers

At first most studies done on the health effects of being a farmer were conducted on the farm owners themselves. There’s a problem with this, since they’re not usually the ones working in the fields. Those jobs disproportionately belong to Mexican immigrants, which makes measurement difficult because the Census Bureau doesn’t technically know they exist.

However, California provides a natural remedy to this issue.  For one, every cancer victim in the state gets recorded into a database, regardless of whether they’re a citizen or not, and data like ethnicity and occupation are noted. California farmland is also heavy on crops like vegetables, fruits, and nuts, which are very labor intensive, and so prolonged pesticide exposure is more consistent.

A good study to illustrate the effect of pesticides on migrant farm workers was published by the Cancer Registry of Central California that compared cancer rates of farm workers and the population at large between 1987 and 1997. The results are about what you’d expect. Lower overall mortality (farming is hard work!), healthier hearts and blood glucose regulation, but an unusually large portion of weird diseases related to the brain, nervous system, and skin.

So What To Think About Pesticides?

There’s a little bit of good and bad news when you look at this. The good news is that being a farmer on a field riddled with pesticides doesn’t all by itself doom you to a life of bad health. The life of a farmer has lots of health benefits, and they often offset the negative effects of pesticide exposure. But the pesticide exposure is consistently linked with a variety of diseases.  And they’re fairly nasty ones.

At the very least this points to the importance of always washing your food before you eat it. I’d like to say it also suggests the importance of eating organic, but eating organic doesn’t mean you’re not consuming pesticides, only that you’re consuming organic ones.

Research and References on Pesticide Exposure and Farmers

Blair, Aaron, et. al. Agricultural Exposures and Cancer. National Cancer Institute, and Environmental Health Perspectives. 1995, Vol. 103, pgs. 205-208

URL: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1518967/

Mills, Paul, et. al. Cancer Incidence in the United Farmworkers of America (UFW), 1987-1997. Cancer Registry of Central California.

URL: http://www.action.ufw.org/white_papers/cancerfw.pdf

U.S. Cancer Statistics Working Group. United States Cancer Statistics: 1999–2007 Incidence and Mortality Web-based Report. Atlanta (GA): Department of Health and Human Services, Centers for Disease Control and Prevention, and National Cancer Institute; 2010.