Amish have low cancer rate, but why?

The article is titled as a mystery and then framed as a mystery while answering the question: lifestyle factors heavily influence cancer.

The article demonstrates this by a known factor, tabacco. Other lifestyle factors are similarly predictive and already known, like diet and pollutants (which the article mentions).

The article curiously doesn’t mention detection bias: the tendency for increased access to diagnostic tools or medical evaluations to lead to higher rates of detection/incidence. This is almost certainly true of comparing rural Armish to city dwellers, and has a demonstrated enough effect to explain the difference in non-tobacco related cancer cases between the two groups - and much more likely an influence than genetic protective differences.

The genetic angle is likely to be so minimal to be trivial, IMO.

Long story short: this isn’t very new or interesting.

There's a term for this that I learned recently for this but I'm blanking on it. It has to do with a growing strategy of looking at 2 groups when trying to solve a medical problem. And, rather than find a cure for the problem, they look for differences in the populations that prevents the problem from one of them.

The story I heard that sort of started the movement had to do with international doctors who had volunteered to be part of a childhood malnutrition treatment for some south east asian country. When they got there, the promised monetary support was not there, and they were only given a car and a driver.

So they drove around to see if there was anything they could do to help the children without the vitamin shots they thought they were going to administer and noticed there were families whose children weren't malnourished. It turned out their parents, while they were out weeding their rice fields, were grabbing foodstuff that was considered culturally undesirable. Certain weeds and other things that lived in the fields. Then they'd add what they gathered to their meals. The doctors then made it an education mission, rather than a medicine dispersion mission.

It sounds stupidly simple in retrospect, but I don't think they came by the solution easily. Like, if the food was undesirable, parents may have been very hesitant to disclose they were eating it, let alone feeding it to their children.

I don't know much about what an Amish lifestyle entails but I have to imagine their limited or non-existent exposure to modern carcinogens helps as well. I think of all the awful things I've been around only to learn later it could adversely affect my health.

Stronger by Science did a deep dive into some studies by exercise scientists into Amish activity, diet, and body composition trackers a few years back. I hope I'm relaying faithfully, but as I recall, it was something like 18,000 steps a day, 9% body fat, and ~4,000 calories of food intake for the men. The step count belies far more demanding levels of activity, as this isn't just leisurely walks in the park but hard manual farm labor. Women were much more comparable to post-industrial populations, but with the enormous confounder that they were pregnant almost all the time. Diet is just huge amounts of potatoes, grains, and pastured meat they're producing themselves.

I had a girlfriend almost 20 years ago whose family made an interesting case study. They lived on a farm in Amish country in Lancaster County, PA, but theirs was the only land that was not Amish. They were actually still off the grid electrically, but her dad was an engineer turned farmer that ran his own generators off of waste vegetable oil he collected for free from the restaurants in Philadelphia he sold food to. Their cars were also modified to run off of that. They had lifestyles otherwise much more inline with typical American lifestyles. Her dad and brother were both enormous, probably over 300 pounds each. As far as I can tell from searching right now, they seem to still be alive and a lot has been written about them over the years, along with interviews and features on YouTube.

In short, though, I think there are limitations to the assumptions you can make about carcinogen exposure just looking at non-Amish who live near the Amish. Even when you're literally next door, you've got the same air and the same water, but you travel, are much more regularly exposured to vehicle and engine exhaust, eat food that was shipped in from elsewhere. You probably don't stay in the same place your entire life.

"Updated fraction of cancer attributable to lifestyle and environmental factors in Denmark in 2018", Scientific Reports | (2022) 12:549 https://doi.org/10.1038/s41598-021-04564-2 attempts to tease out causes: 38% tobacco, alcohol 7%, obesity 9%, occupational 6%, air pollution 3%, infections (like HPV) 7%.

I would guess it's physical activity. Their diet and lifestyle are not free of all the artificial things we have like you might imagine. They even have cell phones today. But they generally have physically demanding jobs: carpentry, roofing, landscaping, farming... There are no Amish C++ devs.

Probably a combination of diet, exercise, and environment.

I am going to take a guess at limited or no use of artificial light.

It has already been shown working night shift increases chances of cancer.

This guess is on no basis other than my intuition, but I am suspicious about artificial lighting and subtle but pervasive impacts.

In case folks are curious about the Amish, I found this YouTube channel really interesting: https://m.youtube.com/@AmishAmerica

The Amish and Mennonites are basically re-inventing monastic communities around the family unit.

I wonder if these studies were to be done on Catholic monasteries and convents, what they would find.

Because monks and cloistered nuns lead the same sort of lifestyle, free of vices such as alcohol or smoking, and do a significant amount of hard manual labor, working in the fields, chores around the house, and manufacturing.

However, monks and nuns may also live in urban settings, and more often than not, they have good group health plans, and so they would have regular checkups and screenings and treatments for everything under the sun. Monks and nuns are not the sort to refuse vaccination or other preventive treatments.

It would be interesting to see differentials between these types of population. You may be able to better isolate some cause-and-effect there.

Higher activity levels, lower obesity

Amish tend to be younger.

Golly gee, could it have something to do with the food?

I mean sure. But. There's also probably lower cancer diagnosis in the first place. I imagine these folks aren't exactly quick to jump to modern medicine until absolutely necessary. Plus I imagine their average lifespan is lower for much the same reason.