I'm surprised that the article didn't touch on differences in childhood mortality rates. The theory proposed has always made a lot of sense to me. However, I would expect any reporting on the topic to consider the extent to which the allergy-sufferers amongst us (such as myself) made it through childhood because of better early childhood medical care, thus skewing the later-in-life allergies and autoimmune disease stats downwards.
I wondered the same thing. As a follow-up to wazoox's comment, I looked into the mortality rates of the areas for the studies.
I couldn't find the infant mortality rates of Petrozavodsk, so I went to region (Republic of Karelia) instead:
Infant mortality rate of Karelia in 2000 [1]:
14.4 %
Of Finland: [2]
2.6 - 4.5 %
So at a 3-7x higher incident rate, infant mortality does seems like a reasonable hypothesis. I wouldn't jump on the one-explanation-covers-it-all stance though. Someone else in this thread mentioned Helmenthic therapy, using parasites in a controlled manner to treat for allergies. If this treatment has seen positive results, perhaps both your point and the proposed theory explain the higher incidence of auto-immune diseases in first world countries.
Agreed that both probably have an impact. I imagine that there's some sort of scientific method out there to tease out the impacts of the two factors, probably via an aggregation of a number of such studies.
That seems obvious, however AFAIK infant mortality is not much higher in eastern Europe and Russia than in the west, so this probably doesn't apply there.
The NYTimes had a similar article a month ago describing the exact same Russian and Finnish populations and suggesting lack of microbes might be related to celiac disease:
I'm pretty sure there was a HN discussion on this, but I can't find it.
Edit: in reply to another comment, the article claims that the two populations are culturally, linguistically and genetically related, so genetics don't explain the differences.
Is this really news or even a new idea? The idea that being exposed to "dirt" or plentiful foreign germs/organisms can build the immune system is one I have been aware of for as long as I can remember. Maybe it just hasn't been "proved" yet.
To my understanding, the way this idea is being applied in research is new. There is a difference between the presence of germs 'boosting' the immune system and a lack of germs causing the immune system to target -- and severely damage -- the entirely wrong enemy, as in the case of an autoimmune disorder.
The article reports an interesting observation: "Still, the 500-mile boundary between Finland and this Russian republic marks one of the steepest standard-of-living gradients in the world: Finns are seven times richer than their neighbors across the border. 'The difference is even greater than between Mexico and the U.S.,' Knip tells me."
Then the article gets into the main point: "Soon, studies from around the world showed similarly surprising results. But it was germ-laden dirt that seemed to matter, not air pollution. The children of full-time farmers in rural Switzerland and Bavaria, for example, had far fewer allergies than their non-farming peers. And a study following more than 1,000 babies in Arizona showed that, unless parents also had asthma, living in houses with dogs reduced the chances of wheezing and allergies later in life. Researchers proposed that the more microbial agents that children are exposed to early in life, the less likely they are to develop allergies and autoimmune diseases later on. Studies also showed that baby mice kept in sterile environments were more likely to face autoimmune disease, seeming to back what came to be called the 'hygiene hypothesis.'"
I'm still puzzling how hygiene (in this sense) can be measured accurately over the course of a lifetime, as my mother is a farmer's daughter who grew up in the Great Plains during the Dust Bowl era, and thus was probably exposed to plenty of allergens, but she has long struggled with hay fever and other allergy symptoms. My wife grew up in even poorer circumstances early in the development of a developing country, and spent a few years of her childhood literally living on a dirt floor. But she has allergies now too. I wonder how well exposure to dirt or to germs can really be quantified at the individual level for reliable treatment/control studies of this issue, rather than this kind of cross-sectional population comparison. For example, do I really, as a parent, have any clear idea whether my children get more exposure to dirt or less exposure to dirt than the typical American child who is allowed to play outdoors and build sand castles and mud dams? I have no idea, and I'm not sure anyone has an idea.
See "Warning Signs in Experimental Design and Interpretation"
by Peter Norvig, LISP hacker and director of research at Google, and "Worms, Germs, and Dirt: What Can They Teach Us About Allergies and Autoimmune Diseases?"
by Harriet Hall, M.D. for more information about what we will need to find out to be sure how much this interesting hypothesis has to do with our commonplace diseases.
As the article also points out, "These findings don’t mean that people should eschew basic hygiene. Its benefits are clear: In the past 60 years or so, our overall life expectancy has continued to rise. The trick for scientists is to determine exactly which early life exposures to germs might matter and identify the biology behind their potentially protective effect."
And because I've seen recent threads here on Hacker News that include comments underestimating just how much longevity and general health have improved in the developed world, I'll share some links on those issues, some of which I learned about from other Hacker News participants and others of which I learned about from a demography of aging researcher. Girls born since 2000 in the developed world are more likely than not to reach the age of 100, with boys likely to enjoy lifespans almost as long. The article "The Biodemography of Human Ageing" by James Vaupel,
originally published in the journal Nature in 2010, is a good current reference on the subject. Vaupel is one of the leading scholars on the demography of aging and how to adjust for time trends in life expectancy. His striking finding is "Humans are living longer than ever before. In fact, newborn children in high-income countries can expect to live to more than 100 years. Starting in the mid-1800s, human longevity has increased dramatically and life expectancy is increasing by an average of six hours a day."
helps make the picture more clear. ("Period life expectancy" is what is usually reported for a whole country. But cohort life expectancy provides a better estimate of future lifespans of young people today,
and is still steadily on the rise around the world.) Life expectancy at age 40, at age 60, and at even higher ages is still rising throughout the developed countries of the world.
The basic idea is that the human immune system has co-evolved with a number of immune suppressing parasites. Hygiene has greatly reduced the number of these parasites we're exposed to and without them the human immune system is too reactive. That extra reactivity results in our immune system attacking proteins that are harmless, like pollen or peanuts.
So hygiene is definitely extending human lifespans by preventing us from getting deadly bacterial and viral diseases. But it may indirectly be causing auto-immune diseases. The good news is it's not all that hard to introduce safe parasites back into our bodies: http://en.wikipedia.org/wiki/Helminthic_therapy
Interesting. Could that be why people with overprotective mothers (often "indoor kids", nerds) tend to have allergies? As infants their cribs and highchairs were meticulously kept clean and sterile with disinfectant wipes.
The last time I've seen information and discussion about this, I've considered the viability of humans creating an artificial parasite to replace the parasites we are missing right now.
It's a pretty cool idea. Although it's a tad simplistic way to consider the immune system, our bodies mount two types of responses: Th1 and Th2. Th1 favors our immune cells directly killing our own cells and baddies. Th2 favors our immune cells producing lots of antibodies which then tag baddies for destruction.
In Crohn's disease, our bodies, for whatever reason, seem to be skewed towards producing a really unnecessary Th1 response in the gut which causes our bodies to self-destruct the GI tract. By giving hookworms to a patient, the hope is that the needed worm-killing Th2 response (worms are too big for really an effective Th1 response and need to be coated in antibodies and essentially repeatedly nuked with cytotoxic chemicals) will shift the balance in the patient's gut from Th1 towards Th2, thus eliminating their Crohn's manifestations and symptoms. Really cool idea.
On a note related to pollen allergies, I have been suffering with pollen allergies as long as I have known. I have taken claritin/zyrtec/flonase etc only when it became very difficult to function. I have been looking for a natural cure for last 10 years. Where I currently live in US, pollen count is really high. As a kid I have lived in a poor country which wasn't hygienic, I dont think it contributed in any manner with the current allergies.
Finally this year I managed to find almost natural cure (hopefully permanent). I have been taking Apple Cider Vinegar (popular brand) with local honey for more than two months. Apparently, it seems to have changed my body's pH which helps ensure there is no auto-immune reaction to allergies. I can now go outdoors even during high pollen season. Additionally I have also given up Dairy, not sure if it contributed to the cure.
My wife works in a hospital, and she has been trained to always wash her hands. I on the other hand have always said that I am building my immune system by introducing my body to germs.
Not sure whose right here, but interesting theory nonetheless.
I think that at a hospital you aren't washing your hands for yourself but for others that (probably) have compromised immune systems already. I know it kind of goes without saying.
I know that the people I know that work at a day care got sick a lot initially (and so did their partners from them) but not so much anymore. I wonder if hospital staff have that happen as well?
Since nurses & doctors work with so many patients, it's very easy for them to carry someone else's disease to another room with a weaker immune system.
It's also that there are people in hospitals who are exceptionally sick, too. I was always a lot less worried in a trauma-focused hospital than in local clinics which served local nationals with a variety of illnesses and huge numbers of parasites.
Yup. And they wash their hands before and after to avoid cross-contamination with people outside the hospital.
This is the same reason cooks are supposed to be careful about doing this as well: if they contaminate the food, that's a vector for spreading stuff. It simply matters a little less because the actual process of cooking has sanitation purposes.
I think the hygiene hypothesis implies a golden mean: enough immune challenge to keep it functioning normally, but then too much challenge is just bad.
After living in China for 4 years, my allergies are gone, and while I got sick here a lot then, I have not had a serious cold in 6 years.
The allergy experience mimics many other people who spent time in Asia. The no colds - I think it's related, but most people do still get sick. I used to get terrible colds every few months my entire life. I can now scuba dive because my ears aren't constantly damaged by frequent sickness and fluids.
My theory has always been that allergies are a symptom of an under-utilized and under-exercised immune system. Our bodies are designed to be under constant attack. Much like the US is unable to resist invading countries when the world is at peace, our immune system can't stand a sterile body with no foes.
Fun anecdote: There was a worse than usual flu season here in Boston and since a lot of other people in the office were getting sick, I was wondering if I should get the flu vaccine. Being lazy, I didn't bother with the vaccine, yet I have never once gotten the flu, despite taking a crowded bus and subway to work every day. Furthermore, I don't recall the subway or buses ever being filled with lots of sick people. I suspect most of the sick people in the office drove to work.
its always amusing to read articles from respected sources about beliefs one has held for a long time. it feels mostly obvious to me that underexposure to germs can lead to more problems than fix. i guess a lot of my beliefs could come from visiting india and less developed countries.
its quite scary how many daily/regular routines come from people with ulterior motives. reminds me of the diamond article recent published by pricenomics. most people are ok with conforming to the norm without question.
anti-bacterial soap? really? im pretty sure all bacteria is not bad, and some actually quite helpful. regular shampoo? makeup constantly blocking the pours, not allowing the skin on the face to breath? deodorant?? i wonder how the toilet paper companies convinced the entire western culture that washing their bum with their hands was disgusting. isn't it more disgusting to have a bum thats not washed?? ah the magic of the marketing department.
I'm going to filter this through my skewed outlook on the world and conclude that it's another datapoint in support of travelling the world as much as possible.
We uprooted our 10 month old son last winter and set up shop in a little fishing village in Nicaragua for a few months. He spent his time eating the local dirt while we surfed. And now we have conclusive proof that this was the Best Thing We Could Have Possibly Done for him.
Glad to hear I'm such a great parent.
This article also rings true for me from a personal perspective. I spend a lot of time in the developing world, and make a point of brushing my teeth in the local tap water and eating those poisonous lettuce leaves and local cheese that the Lonely Planet warns you so strongly against. I find that over the years I've gradually stopped getting sick at all while on the road.
I think there's something to be said for training your immune system.
More conclusive proof that tone doesn't come across well in writing. Re-read that comment and try to imagine the silly grin on the face of the author as he states things that are clearly not true even to the most biased observer as though they were fact, sure in the knowledge that he doesn't need to qualify that it's meant to be humorous, as that is clearly implied.
Apologies. I get frustrated with irony of personal stories usually following an article which is discussing the scientific method. I rarely respond; probably should keep it that way. xP
There is research suggesting that exposure to bacteria (Mycobacterium vaccae in this case) can help cure depression. I first read about it in this article from The Economist:
It seems like without waiting for the results of this study there's a more simple solution - to protect your children from rich man's disease (of all kinds), travel with them to developing countries and live there for reasonable periods of time alongside the locals, how they live ("When in Rome"). Not only will they be more worldly, gain linguistic prowess and be better adjusted to foreign cultures in general, but they are likely to receive immune system benefits.
There is a company that is putting the hygiene hypotheses to the test. Coronado Bioscience is trying to treat Crohn's disease with pig whipworm eggs. The worms can't live in a human host, but they do develop into full worms and thus trigger the body's immune system.
The initial phase 1 studies were quite remarkable, but I'm keeping an eye out for the phase 2 studies which should provide more robust data.
I recently read a book about this very concept, the author went over hundreds of studies like the one you just read and has some interesting conclusions, in the book titled "An Epidemic of Absence"
I don't know about allergies, but I was under the impression that improving hygiene standards was directly related to the polio epidemic of 1916 [0]. I was surprised that it and maternal antibodies were not mentioned once in the linked article.
This reminds me of my general curiosity about, how our muscles develop in regards to workout during early childhood, and during our adulthood. Its a vague feeling, but I want to share it, if it helps.
I can buy trying to figure out allergies, but Type I diabetes? It's clearly hereditary, rarely showing up without some family link. Finland may have a high rate due to a lack of ethnic diversity.
Hereditary, but not in a strong sense - to quote the american diabetes association:
> In general, if you are a man with type 1 diabetes, the odds of your child getting diabetes are 1 in 17. If you are a woman with type 1 diabetes and your child was born before you were 25, your child's risk is 1 in 25; if your child was born after you turned 25, your child's risk is 1 in 100.
Even if both partners are diabetic, the risk is only 1 in 10 to 1 in 4. This strongly implies that what is heritable is the vulnerability to getting diabetes, rather than getting diabetes itself. There is, presumably, some trigger that also needs to occur.
Clearly? Identical twins do not have the same likeliness of developing T1DM. Genetics do not explain why we have had a significant global growth (~3% per year) in the number of cases of Type 1 Diabetes Melanoma (T1DM) in recent decades. There are even a number of vaccines in development (with early successes).
In many cases a T1DM diagnosed child was sick with a cold/flu immediately prior to onset of T1DM. Disease has been theorized for quite a long time to influence the immune system's reaction. A large majority of T1DM cases are diagnosed in winter, Vitamin D / sunlight has been hypothesized to play a role - more northern countries tend to have higher rates.
Even in the hereditary factor, here is research indicating that epigenetics play a role - timing of food shortages during our grandparents' lives significantly increases likeliness of T1DM. That appears to be an environmental factor tweaking our genes.
The fact that -40 C = -40 F is a random bit of trivia that not everyone can be expected to know. If it just said -40 degrees, it would be confusing to anyone who wasn't aware.
Interesting generalization, I am from a very rich country (Australia) and everyone I know is extremely hard working.(myself and my colleges are however, not rich in our land)
Everyone is living life well, studying hard or working. I am unfamiliar with any "lazy-fat-fucks" in my neck of the woods yet I should be seeing them everywhere due to your over the top criteria. (Being in a rich country)
Most of the older people I know that are "working hard" are running businesses, no 40 hour weeks there. Also Me and my friends are not wealthy but we work and study constantly. Also lots in my family work in the mines which are long 12 hours days many in a row (my Dad has it easier, only 10 days in a row of 12 hour days). I know very few people working 40 hour weeks.
Working doesn't necessarily stop at the end of the typical working week or even 40 hours in that case. Working hard can include renovating your own house, toiling in your own garden, cooking, cleaning, volunteering, networking, all sorts of things.
