Even though you may show little gratitude for it on a routine basis, I know you think that your wonderful “developed” country universally has lower rates of every disease than those poor, unfortunate undeveloped areas with little health care. Am I right? And it largely has to do with better hygiene… right? Huh? Huh?
Well, we don’t and the jury is still out on even the second part too!
Allergies and Hygiene
Let me tell you about an article that caught my eye recently. It was about allergies, which we’ve all seen increase substantially during the last, let’s say, 20 years. And the increase has, so far, defied clear explanation.
Research for answers during that time has taught us many spectacular things about allergy – mainly that it’s the “extreme sport” of immunology. That is to say, it’s massively complicated!
What do we see in “real” life? First, allergic disease in total is LESS common in poor countries – with lower sanitary standards. (Huh?!) Second, allergic disease is less common if you live on a farm; or if you have crowded living conditions in general.
Additionally, if you believe the statistics and want to reduce your child’s risk of allergies: give them a pet early in life, send them to daycare, introduce fish into his diet and suck on their pacifiers to “clean” it. All of these things are associated with lower rates of allergic diseases.
Could it just be that for us in “developed” countries the gradual increase in allergic diseases started when we all started to be able to afford dishwashers and didn’t need to wash them by hand anymore?
There are those who now believe that allergic diseases are rising because we have been stopping children from becoming sensitized to the allergens around them.
The article I’m reporting came from doctors in Sweden who studied 7 and 8 year old children in two cities: Kiruna in the north and Mölndal in the southwest on the coast. Bill Hesselmar, MD from Queen Silvia Children’s Hospital in Gothenburg gave the International Study of Asthma and Allergies Questionnaire to 1029 children’s families in those cities and found uniquely unexpected results:
“allergies were less common in children from families who primarily hand-wash their dishes than in families who primarily use a dishwasher.”
The questionnaire estimates the prevalence of asthma, nasal allergies and eczema and people without dishwashers had less of ’em!
“But wait there’s more.” They also categorized children by answers as to whether or not they: served them fermented food (like sauerkraut), consumed food directly from a farm, ate home-cooked food and breastfed.
The results? Well, home-cooking and breastfeeding were difficult to evaluate, a bit ubiquitous and hard to define so they didn’t show any relation; BUT, all the other items did. And this group already had a high rate of daycare use (91%) and nearly all had siblings.
Even when they adjusted the statistics to account for demographics and family history of disease and risk factors, hand-washing their dishes (which only 12% of participating families did) linked to lower allergy rates overall to an odds ratio of 0.57 at the 95% confidence level.
As far as specific allergic diseases, eczema significantly reduced while asthma did not.
What about eating fermented food? Well, that reduced childhood allergies with an odds ratio of 053 and the 95% confidence interval; and, buying food directly from a farm gave an odds ration of 0.67 at the 95% CI.
Not only that, the study showed that the factors were rate related and additive; meaning that when multiple factors were present within the same family the “protection” added up.
The article was published online February 23 in Pediatrics, but the authors aren’t jumping to any conclusions, recognizing the limitations of a study like this. They theorize that “the bacteria left over on dishware and utensils from hand-washing, a ‘less-efficient dishwashing method,’ helped the families build tolerance to allergens.”
We know that “Low hygiene standards and increased microbial exposure are common denominators often seen in low allergy-risk settings.” We’ve seen that in many other instances. With those observations I listed at the top, there just “has to be” something to this; although hand-washing dishes is probably not the total answer. Just a mighty intriguing piece of the puzzle.
So, What Did You Learn?
You have an 8-year-old girl with wheezing from asthma and you want to know more about how the asthma developed. What should your doctor tell you about reducing the risk for allergic disease among children?
A: Live in a spacious, airy house; B: Grow up on a farm; C: Avoid fish consumption during the first 2 years of life ; or, D: Grow up in a wealthy country
This study highlighted the relationship between hand-washing dishes, eating fermented foods and buying foods directly from a farm but other studies have shown a “protective” effect related to farm life as well.
Which of these variables showed a lower risk for childhood allergic disease in the current study?
A: Machine-washing dishes; B: Avoiding food bought directly from a farm; C: Avoiding fermented foods; or, D: Hand-washing dishes
46% of children experienced allergic diseases in families that used machine dishwashing, did not buy food directly from farms, and did not eat fermented food; while, only 19% of children from families that hand-washed dishes and practiced at least one of the other 2 protective behaviors experienced allergies