Pesticides and Depression
November 14, 2014 9:47 AM   Subscribe

A landmark study indicates that seven pesticides, some widely used, may be causing clinical depression in farmers.

A NIH study finds that: There’s a significant correlation between pesticide use and depression, that much is very clear, but not all pesticides. The two types that Kamel says reliably moved the needle on depression are organochlorine insecticides and fumigants, which increase the farmer’s risk of depression by a whopping 90% and 80%, respectively.
posted by weeyin (13 comments total) 10 users marked this as a favorite
 
I wonder how much this might be related to Farmer Suicides in India (A topic that has its own Wikipedia page).
posted by symbioid at 9:54 AM on November 14, 2014 [4 favorites]


I am not that familiar with this type of data presentation, but it isn't that compelling to me. In the first table, looking at the days of exposure, there doesn't seem to be a titration effect. Furthermore, I'm not sure what would be an appropriate negative control in the other tables. I'm not sold on how they did this although I would like to believe that data. What am I missing?
posted by oshburghor at 10:17 AM on November 14, 2014


Going from the page about suicides among Indian farmers, it seems they have a lower rate of suicide than other professions.

From the wikipedia page: Farmer suicides account for 11.2% of all suicides in India.


Census 2011 says there are 118.9 million cultivators across the country. ... if we add the number of cultivators and agricultural labourers, it would be around 263 million or 22% of the population (1.2 billion).

posted by dances_with_sneetches at 10:24 AM on November 14, 2014 [2 favorites]


there doesn't seem to be a titration effect

They say the data shows a positive association in two of their three groups between depression and cumulative exposure. You can see in Table 2 that the odds ratios in the Pre-E and Pre-B groups do go up with exposure.

what would be an appropriate negative control

It would be a somehow matched group of people who weren't ever exposed to pesticides. They cite several studies in the Discussion section that claim to show increased depression in exposed workers compared to some non-exposed group (e.g. a British study comparing current and retired sheep dippers with current and retired police officers.) Too bad they can't measure depression in dipped and non-dipped sheep.

I think the main confusing part is the three different groups based on (I think) how the participants' depression was recorded and followed up on. Also the data are based on surveys which can have lots of problems, but the cumulative exposure data seems fairly convincing (Table 2) and the "ever exposed" data (Table 3) is as well since only certain pesticides seem to have a positive association.
posted by sevenless at 11:06 AM on November 14, 2014 [2 favorites]


So if there's a strong correlation here, aren't downstream effects a logical consequence?
posted by feckless fecal fear mongering at 11:11 AM on November 14, 2014


So if there's a strong correlation here, aren't downstream effects a logical consequence?

Not necessarily; there are all kinds of questions of dosage, forms of exposure (breathing it in during application as opposed to ingesting it on harvested crops), and the rates at which the relevant compounds break down that would need to be examined.
posted by yoink at 11:17 AM on November 14, 2014


From the Methods section of the study: We excluded 6,567 applicators because they were female

That's...odd. Am I missing something? The previous study they mention focused on depression in male pesticide applicators (farmers), but this new study seems like it has a wider scope, so the omission of female farmers is puzzling.

The study also pulls data only from farmers who have been diagnosed with depression by a physician, but that seems like only the tip of the iceberg, really. Anecdotally, my own experience is that depression is very widespread in farming communities, but that most people suffering from it don't realize it and think of it as the norm, or they self-medicate with drugs/alcohol/etc by reflex. I'm so curious as to how the correlation would change with that population accounted for.
posted by greenland at 11:18 AM on November 14, 2014


Lawn spray isn't regulated like pesticide for food crops, kids play on it all the time, and they eat pesticides all the time. Gee our kids aren't medicated all to hell for depression, and ADD, and. ADDH? Are they? Nah, just send those sad farmers some pills, it's great for the economy, legal drug sales
posted by Oyéah at 11:19 AM on November 14, 2014 [1 favorite]


Did juvenile cancers drop when they stopped using diazanon?
posted by Oyéah at 11:21 AM on November 14, 2014


We excluded 6,567 applicators because they were female

The sentence (in the paper) is worded poorly and has too much punctuation. They excluded 6567 people for a variety of reasons and 1358 (3%) of them were female. Including men and women together may be a confounding factor, and maybe they decided 1358 women was too small a number for the kind of analysis they wanted to do.
posted by sevenless at 11:33 AM on November 14, 2014 [1 favorite]


Maybe there's a statistical correlation between pesticides and depression, but let's add on a sprinkling of herbicides and some general pollution from other sources. Add the off-gassing from the farmer's new carpet, etc. How about that depression now, Old McDonald?


Too bad they can't measure depression in dipped and non-dipped sheep.

So you're asking if depressed sheep feel baaaa-d?
posted by BlueHorse at 11:50 AM on November 14, 2014


I come from a farm family. There was no depression that I recall in the family ranks. BUT, my father and uncle, and all of their peers died of cancer. Every single one. A woman I used to know that grew up in a couple states away said she could drive by all the farms around hers and not find a single one not affected by cancer. Some day there has to be an examination of the effect of all the chemicals that we pump into the ground without a thought.
posted by Ber at 1:07 PM on November 15, 2014 [2 favorites]


If anyone is interested, I have been told this is the actual paper: http://ehp.niehs.nih.gov/1307450/
posted by Michele in California at 2:22 PM on November 15, 2014


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