Archive for December, 2010

Are your kids too clean? Are you kidding?

Friday, December 10th, 2010

Several stories appeared in the media over the past couple of weeks about a new study that purports to show higher rates of hay fever and allergies in households that use antibacterial soap. Most antibacterial soaps contain the antibiotic Triclosan, and the theory of this new study is that when you kill too many bugs (because of overuse of antibiotics like Triclosan in soap), kids’ immune systems don’t get the stimulation they need to mature normally, and as a result “attack” the body in the form of allergies and hayfever.

Several things to say about this. Firstly, as you’ve read here before, you don’t need antibacterial soap for proper hand hygiene – regular soap and water work just fine. Secondly, overuse of antibiotics is indeed a bad idea. Evidence does not yet implicate Triclosan in causing more serious infections or germ resistance the way we see with other antibiotics like the ones we and our kids take by mouth, but why use antibiotics if you don’t need them?

But the real question for today is: Does being clean harm kids? The implications of studies like the one mentioned is that kids today may be “too clean.”  This premise is called the “hygiene hypothesis.” What exactly is the “hygiene hypothesis” and do you need to add it to your holiday worry list?

It is true that over the past decades, there has been an increase in the diagnoses of allergic disorders (e.g. asthma, hayfever), as well as autoimmune diseases (e.g. inflammatory bowel disease and lupus), both of which represent over-exuberant immune system reactions (see Chapter 4 in GERM PROOF YOUR KIDS – The Complete Guide to Protecting (without Overprotecting) Your Family from Infections). Conventional wisdom held for many years that the cause of these increases may be related to environmental pollution and toxins (i.e. the junk in the air is causing more wheezing type diseases, and the junk in our diet is causing more bowel inflammation, for example).

In the late 1990s, after reunification, a German investigator compared the occurrence rates of allergic diseases among East Germans living under impoverished and unhygienic conditions with those of West Germans living in more pristine and generally wealthier environments. Rather than seeing the expected higher allergy and asthma levels in the poor population, she saw the opposite – the “cleaner” Germans had more allergies and asthma. This led to the “hygiene hypothesis” that states the following: a certain critical mass of germs and “dirt” is required for the healthy maturation of the immune system. If we clean too much, and prevent too many infections, kids will develop aberrant immune system responses that result in more allergies and autoimmune diseases. That is, the immune system needs to be “taught” to respond normally to everyday challenges and to its own body; that “learning” requires a certain amount of germs and dirt, without which the immune system goes awry.

What are the scientific data to support this hypothesis? Right now, we have the potential for a classic “epiphenomenon”, the existence of two “truths” that may or may not be related to each other. Truth #1 is there are increasing diagnoses of allergies and autoimmune disorders; truth #2 is that those disorders tend to occur with higher frequency in wealthier socioeconomic environments (like the ones, for example, that use antibacterial soaps!). In Africa, where hygienic conditions are poor, the incidence of allergic and autoimmune disorders is lower than in the West. Is this genetic, or due to the beneficial effects of poor hygiene? Similarly low levels of allergic and autoimmune disorders are diagnosed in SE Asia, but that trend reverses itself when SE Asians immigrate to Western countries – their children have Western rates of allergic and autoimmune disorders; that seems to dispel a purely genetic explanation.

But maybe we are simply better at making the diagnoses of those disorders in the West. What factors other than “cleanliness” are associated with a higher socioeconomic class in the West and could explain the observation? Clearly there are many differences between Western societies and African and Asian societies that extend well beyond simple hygiene parameters. And how plausible is it that, with the extraordinary number of exposures kids get everyday at day care, school, and in the backyard (see Chapter 2 in GERM PROOF YOUR KIDS – The Complete Guide to Protecting (without Overprotecting) Your Family From Infections, there is still a deficit of critical germs and dirt resulting in allergic and autoimmune responses by the immune system?

Although the data are lacking for a true “nexus”, that is a proven connection between the two “truths” noted above, advocates of the “hygiene hypothesis” have asserted that overuse of antibiotics, including those in personal cleaning products like soaps and shampoos, contributes to the excessively clean environments that pose a risk for our kids (although the West Germans with lower rates of allergies and autoimmune disorders in the late 1990s did not have antibiotic-containing soaps yet). Addressing the antibiotic exposure factor, a paper published in March, 2006 assessed 8 previously published studies of kids who had received antibiotics in the first year of life and assessed whether that exposure predisposed them to asthma later in life. A small statistical association was found, when all 8 studies were combined, to suggest there may be a somewhat increased risk of asthma following early in life antibiotics – the authors caution that the quality of the original 8 studies was such that a meaningful conclusion cannot yet be drawn on this subject. A single study published in June, 2007 implicated antibiotics in the first year of life and the absence of a dog in the house during the first year of life as risk factors for asthma!

At this time, I recommend that you continue to have your kids wash their hands (simple soaps are fine; see Chapter 9 in GERM PROOF YOUR KIDS – The Complete Guide to Protecting (without Overprotecting) Your Family from Infections), take antibiotics when needed (but only when needed; see Chapter 5 in GERM PROOF YOUR KIDS – The Complete Guide to Protecting (without Overprotecting) Your Family from Infections), and receive all of their childhood immunizations (more on the concern that vaccines make kids too clean in Chapter 7 in GERM PROOF YOUR KIDS – The Complete Guide to Protecting (without Overprotecting) Your Family from Infections). Maintaining a clean home will reduce the number of infections passed around in your household – infections that keep your kids out of school and you out of work. Those infections can also be dangerous and even life-threatening (e.g. food borne infections). Household disinfection in “hot zones” like the kitchen, bathroom, and laundry room is prudent and effective.  Community sanitation of water will prevent a retreat to the days of epidemics of cholera and cryptosporidiosis; maintaining air quality standards and removing household cigarette smoke exposure have been proven (proven!) to reduce asthma and other respiratory ailments.

We’ll wait and watch together to see if the “hygiene hypothesis” stands the tests of time, careful study, and reproducibility (see Chapter 12 in GERM PROOF YOUR KIDS – The Complete Guide to Protecting (without Overprotecting) Your Family from Infections). In the meantime, and until proven otherwise, clean is still better than dirty.

And, take a good look at your kids when they come home from school today – are you really worried that they are too clean?

The Key to Holiday Health is in your Hands!

Friday, December 3rd, 2010

I hope your Thanksgiving was meaningful and healthful. Now it’s time to move on to keeping your kids healthy over the holidays. It’s no secret that kids share everything, including germs. But there is a secret to keeping kids healthy this holiday season.

Hand washing is the single most effective strategy in reducing the spread of infections. From the bathroom to the classroom, from the kitchen to the playground, hand washing protects kids of all ages – and even saves lives. Here’s how to keep the sniffles, sneezes, coughs, and stomach flu away from your home this holiday season (see also:  Chapter 9 in Germ Proof Your Kids – The Complete Guide to Protecting (without Overprotecting) Your Family from Infections (ASM Press, Washington, D.C., 2008)):

Kids typically spend less than 5 seconds washing and leave the sink with their hands dripping wet. A 20-30 second wash and thorough drying will reduce the germ load by as much as a 1000-fold. Teach your kids to wash until they finish singing “Twinkle-twinkle little star” or the “ABCs”; this makes your job easy because both songs have the same tune and last exactly 20 seconds each! Use lots of water and lots of rubbing with soap to create a good lather – include the wrists, between the fingers, and around the nails – followed by lots of water again.

How kids dry their hands is also important; the drier the hands, the fewer the leftover germs. Use clean towels (paper or cloth) and thorough rubbing; electric dryers aren’t as effective in germ reduction.

Simple soap doesn’t kill germs; it cleans hands mechanically, lifting and washing away dirt and organic material that contain germs. But, simple soap works. Studies in day care and schools show that the rates of diarrhea, vomiting illnesses, respiratory infections, and absent days are reduced dramatically by simple soap and water washes.

Products that kill germs include alcohol-containing “hand sanitizers”, and antibiotic-containing “antibacterial” soaps. Alcohol kills many germs on contact, and has been incorporated into “rubs”, rinses, foams, and gels that don’t require water, making them ideal for your purse and the glove box in the car. These are safe products, but will sting if used on cuts or scrapes.

As many as 3/4 of all liquid hand soaps are labeled “antibacterial” because they contain an antibiotic. Antibacterial soaps lower germ counts on kids’ hands better than simple soaps – but the benefits in reducing actual infections are unproven. Fortunately, it does not appear that these soaps result in resistant germs. The absence of an advantage of antibacterial soaps, and the theoretical risks of increasing resistance, prompted an FDA Advisory Panel to recommend against these products for home use, in favor of simple soap. The most common antibiotic in anti-bacterial soaps is Triclosan. Use of Triclosan-containing soap has also been implicated in the rising “epidemic” of allergies and hayfever in this country. The evidence for the association is weak and circumstantial so far, but since the benefits of Triclosan appear to be limited, you might as well stick with simple, non-anti-bacterial soap (if you can still find it on the supermarket shelves!).

Liquid soap in a dispenser is less likely than bar soap to itself become contaminated with the very germs we’re trying to protect kids from.

Germs get on your kids’ hands from contacts with other people, animals, and inanimate objects. The kids then touch their eyes, nose, or mouth and the germ invades and causes infection. Good luck teaching kids not put their hands in their own or each other’s eyes, noses, or mouths, so strategically timed hand washing is the next best option. Here are the 10 most important times to wash:

1. After playing with a sick friend or sibling (or after handling things that a sick child might have handled – like in the doctor’s waiting room
2. After using the bathroom (use the hand towel to turn off the sink and open the bathroom door).
3. Before eating
4. After high-fiving the opposing team at the end of a sports competition (or any other mass-handshaking event like the receiving line at a wedding or graduation).
5. After recess
6. After school or day care
7. After playing with animals or in areas where animals hang out
8. After playing outside
9. After blowing your nose, or coughing into your hands. Although your kids cannot “give themselves an infection” by contact with their own secretions, this is a very considerate gesture that protects other kids from the germs on your kids’ hands.
10. Before bedtime

Many studies have proven that effective strategies for hand washing, like those mentioned above, will keep your kids healthier over the holidays – fewer respiratory infections and fewer gastrointestinal infections. And when the holidays are over, continue using the “secret” and your kids will miss less school and day care, and you’ll miss less work

For much more about ways that personal hygiene, household hygiene, and community hygiene can protect your family from infections this winter and year round, see Chapter 9 in Germ Proof Your Kids – The Complete Guide to Protecting (without Overprotecting) Your Family from Infections (ASM Press, Washington, D.C., 2008).