A study was done, based on draft cards from World War I, which examined lifespans of different people. The title of the story says it all: Farming, fatherhood signs of men who live to 100With the dangers of farming, I wouldn't have thought this to be the case. Between exposure to machinery and fertilizers and pesticides, I wonder how they could tend to live so long. It can't just be the fact that they engage in manual labor, since there are plenty of blue collar workers who live in the city as well (and they weren't listed as living quite so long). Perhaps it's a combination of manual labor, having a tangible interest in their work and their farm, and shelter from many of the stresses more common to urban life.
I think you nailed it with the stress factor. One of the number one killers today. I grew up out in the country/mountains and can tell you its a lot more stressful in suberbia than it is out in the rurals.
The link doesn't seem to be working for the article. It is a shame I would very much like to read it but I think there is a lot of factors attributing to farm life and longevity. There are pesticides for sure but in the country they are also farther away from all the other pollutants that city life brings factories and car emissions. Fast food is rampant in the cities and I think a farmer is more likely to eat more vegetables and such as they are growing them and staying away from the chemical processed foods.I'm sure that stress is a factor as you said but I bet there is a lot of diet based reasons too. As you said manual labor you can find anywhere so I would rule that out.
Maybe farmers are just happier and have a higher sense of accomplishment in their lives because of what they do for a living. I grew up on a farm and would go back to it if it wasn't for agribusiness driving all the small operators into bankruptcy or peonage.
Perhaps it was the Rural vs Urban that led to longer life. Remember in the early 1900-1920s, still a lot of coal heating and diseases associated with urban lifestyle.