ADHD, Febrile Seizures, Swimming Lessons – PediaCast 079

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  • Prevalence of ADHD Following Divorce
  • Which Viruses are More Likely to Cause Febrile Seizures?
  • Baby Swimming Lessons – The Hidden Dangers



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Dr. Mike Patrick: Bandwidth for PediaCast is provided by Nationwide Children's Hospital. For every child, for every reason.


Announcer: Welcome to PediaCast, a pediatric podcast for parents, the Research Edition. And now, direct from Birdhouse Studios, here is your host Dr. Mike.

Dr. Mike Patrick: Thank you, Katie. And hello to all of you. Welcome to PediaCast episode number 79 for Monday, November 12,2007. Divorce, febrile seizures and baby swimming. It is a Research Edition. We like to call our Research Round Up around here. And hopefully we’ll get out an entire set of five shows this week. That is the plan anyway.


But you know what they say about the best laid plans. We had an early Thanksgiving this past weekend at the in laws. Now, anyone else do that? You have Thanksgiving just on thanksgiving. Being a doctor you get kind of used and it’s not just doctors, I mean other service oriented jobs as well. You got to work holidays and you have crazy schedules and weekends and evenings and all these. So really since I was a resident, even when I was in medical school, really we have to do this. I mean, with two sets of families and when can you get everyone together and sometimes the actual holiday is not the best time. So Thanksgiving at Karen’s parents with her siblings and their children was this past weekend. Yes, it a little early but it’s when they made the trip up to Cleveland and had a great time. So, we’re back and rearing to go for this week. We have a great interview coming up if everything goes as planned. You know how plans go.


Tomorrow, Dr. Bob Sears, author of The Vaccine Book is going to stop by. We’re going to talk about that. So, stick around. Of course, we’ll going to have some more shows this week with an answer to your questions and speaking of that, if you have a question that you would like to ask or a topic that you would like to hear about or lead on a great interview, you’re a personal friends with the presidential candidate, want them to swing by PediaCast, be my guest. The contact page is at the website at Just click on the Contact Link. You can also email or call the voice line at 347-404-KIDS.

Also don’t forget the information presented in PediaCast is for general educational purposes only. We do not diagnose medical conditions or formulate treatment plans for specific individuals. If you have a concern about your child’s health, call your doctor and arrange a face to face interview and hands on physical examination.


Also your use of this audio program is subject to the PediaCast Terms of Use Agreement which you can find at And with that in mind, we will back with our Research Round Up right after this short break.


We have three pretty good studies this week for our Research Round Up. This first one is the prevalence of methylphenidate use among Canadian children following parental divorce. So, to break that down, it’s just how common is it that kids get prescribed ADHD medicine at least in Canadian children after their parents are divorced.


Now this was an epidemiological study conducted by a sociologist in Edmonton, Alberta and was published in the Journal of the Canadian Medical Association in June 2007.

Now, the question before the sociologist was that in previous studies, it had suggested that children living in a single parent or a step parent based house hold were more likely to be treated for ADHD compared to children living with both biological parents. But no prospective study had been done on this. It was all done retrospectively. They will just find kids who had ADHD in raw medicine and then look back and see how many of them came from together homes with mom and dad, both biological parents present, how many were single parent homes, that kind of thing. But this time, researchers wanted to study kids who were initially living with both biological parents at the start of the study who then experienced a divorce and transition into a single parent or step parent environment and then see if the rate of ADHD treatment increased in this kids following the divorce.


So, the author used a sample of children that has been used in Canada for many different studies. It’s called the National Longitudinal Study of Children and Youth. And it’s a national survey in Canada that was initiated in 1994. And basically the survey data is collected every couple of years. And they ask a bunch of questions of the children and the parents. And basically they’re in this big group. There’s 13,439 households with at least one child who is under the age of 12 in 1994 when the study began. And all told in those households, there are 22,831 children in this group that they’ve been studying. Now the author wanted some more manageable numbers and he chose 599 kids from the group.


And all of them were between the ages of 2 and 7 years of age in 1994 and all of them were living with biological parents at the beginning of the study in 1994, with both biological parents. And then basically divided the group into two. The ones that eventually got a divorced, of course didn’t you have to ask that really makes it a retrospective study doesn’t it. They put it out as a prospective study, but I mean really, he is looking at this data and going backwards, so OK, there is one criticism. So, anyway, they divided these kids into two groups. One group had eventually divorced and in the other group, there was no divorce. And then he basically looked for subsequent treatment with ADHD medicine between the differences the two groups.

Well, between 1994 and the year 2000, 13% of the study’s children experienced parental divorce.


And in the no divorce group of kids. So, they’re in the group that maintained both biological parents, 3% of the kids ended up on ADHD medication and in the divorce group, 6% of kids ended up on the ADHD medicine. So, basically there was a double the amount of ADHD medication given in the kids who experienced divorce. And the difference between those two groups was statistically significant.

The author concluded that parental divorce is associated with a significant rise in ADHD diagnosis and treatment. Now, the author does entertain several explanations for this finding. One would be is the stress of divorce on the household. The fact… Let me pause here for a minute, the author specifically says he does not believe that this represents inappropriate use of ADHD medication in the divorce group.


I mean, you could argue that if you have a baseline population shooting in ADHD as ADHD regardless of whether you are divorce or not, if it’s a biologically based illness then your social situation shouldn’t come into play for ADHD. You wouldn’t think and so if one group had more, then were they being diagnosed with it more often and does that then represent true ADHD or is it more social factors that could be solved some other way. And the author basically stating he does not believe that that is what led to the results. Probably to some degree because that’s the politically correct thing. I mean you want to do a research study that doctors are going to look at and say “Ha, look at you, you’re diagnosing this wrong”. So he entertained several explanations for this finding. One, being the stress of divorce may bring out the symptoms of ADHD.


And this one I really liked, the genetic component of ADHD, meaning that if the kids have ADHD are their parents more likely to be adults with Attention Deficit Disorder and untreated adult ADHD, some studies have shown that theirs increased divorced rates in people like that. So, you have to look at would do the parents have ADHD in was that higher in the divorce group which would make kids of those parents more likely to have ADHD. So that will be an interesting addition to the study. That was not done to see what percent of these kids their parents have ADHD. But that will be interesting.

Also, he said perhaps increased contact with the health care system following divorce, as a pediatrician that sees kids who are in a split family, I can tell you, and they probably do come in more often. Mom will bring them in after they’ve been to dads because they have this rash. And then dad wants to know what’s going on. And next time he gets the kids, he brings them in. So they do in some cases have increased contact with the health care system so then maybe they’re counseled about ADHD and have more opportunity to be diagnosed with it and put on a medicine.


So maybe in the groups that have both parents living together, there are more kids with ADHD, they’re just handling it and not having an intervention done. And of course heightened sensitivity, their problem behaviors following a divorce, again, that may lead to increase contact with the health care system.

I’m glad the author made a point of saying he did not feel this means there is over diagnosis of ADHD and the kids with divorce parents, cause it would be easy for someone to sort of look superficially at the study and say, well ADHD is a physiological disease then, how can circumstances bring it on. But I would agree with the author in saying the study does not show divorces bringing on ADHD. And there is a good point to be made that divorce rate is higher when there is untreated adult ADHD and so impulse control is an issue and sometimes impulses get away with one parent ends up in divorce.


Then those kids are more likely to have ADHD because of the genetic component. So it gives us a few things to think about. At any rate which is the point of our Research Round Up.

OK. The next one up, do different viral infections differ in their potential to cause febrile seizures. Now, this was done at the University of Hong Kong and was published in the Archives of Diseases in Children, July 2007.

We know febrile seizures are frequently caused or a frequent cause of pediatric hospital visit and parental anxiety. And viral infections are most commonly the culprit. It has been postulated that maybe some viruses are more prone to produce febrile seizures than others. So what theses authors did, is they looked at 923 hospital admissions for febrile seizure over a 5 year period, so this was a retrospective study, where they identify these kids and then went over the charts to look back at more the information about the disease and the hospitalization.


Of the 923, 565 were first time febrile seizures. All children at this hospital were admitted with symptoms of respiratory infection, and because of that they had nasal pharyngeal mucus collected. So they basically had their nose swabbed for virus detection and culture whether they had a seizure or not. And then they simply looked at the prevalence of each virus type in this nasal swab result and then basically divided the kinds into a group of kids who were hospitalized with febrile seizure versus a group of kids who did not have febrile seizures. What they found is that in the group of kids who had febrile seizure, influenza accounted for 17.6% of the admissions or 163 out of the 923 cases.


Admiral virus was only 6.8%, parainfluenza virus was 6%, RSV was 2.7% and rotavirus was 1.3%. And then of note, complex febrile seizures accounted for about a fifth, 20% and the risk of complex seizure was similar for all the different types of virus.

Now, that’s important because we talked a little bit about the difference between febrile seizures, simple febrile seizures and complex febrile seizures in our show. That was PediaCast 72. And we’ll put a link to that in the Show Notes for you. So if you’re interested in what a complex febrile seizure is, we talked all about that in PediaCast 72. But depending on which virus did not seem to make a difference on whether it was a simple febrile seizure or a complex febrile seizure.


Also the recurrence of febrile seizure, so this wasn’t the first time that was about 20% of the kids, so about a fifth of the kids, it was their second or more febrile seizure. And the risk of recurrence again was similar for the five virus type. So it didn’t seem to matter what virus it was in determining whether it was a simple versus a complex febrile seizure or if it was a first time febrile seizure versus subsequent one when they already had one in the past.

But there was a significant difference in which virus was associated with the febrile seizure and influenza was way up there with 17.6% and admiral virus next at 6.8%. So, the author’s conclusion, you want to write, make sure you include that, the authors concluded that influenza virus causes febrile seizure more often than other viruses. Now, I do have some criticism of this particular study.


First, they talked about the fact that they looked at the different virus types even in kids who did not have febrile seizures, they just mentioned that. They didn’t go on to talk about what was the occurrence rate in those kids. So, really they have no control group. And it would be nice to compare this list of viruses to a group of kids who have upper respiratory symptoms, cold like symptoms with no seizure to see if the virus prevalence is the same or different.

I mean if it’s the same, then influenza causes more febrile seizures, only because more kids have influenza. But on the other hand, if the influenza rates are lower in kids, if they’re similar in kids who don’t have the seizures but higher in kids who do, then you could say a little bit more definitively that influenza is more likely to cause febrile seizures.

Now of course, getting a large group of kids together who haven’t had febrile seizures and they just have cold symptoms, and getting their nose swabbed, that’s kind of difficult to get a group like that, cause those kids usually aren’t put in the hospital.


So, they probably didn’t have nearly as many and I suspect that’s why they didn’t include that in their statistics.

Also, I noticed that the total of the percentages of the different viruses only added up to 35% and I wonder why that is. And they didn’t mention why. What was the causative agent in the remaining 65% of kids, that will be important. Probably, I’m guessing that they didn’t mentioned it, probably rhinovirus which is what causes the common cold. And that’s usually not part of a routine viral panel because there’s so many different strains of it and it’s not typically a serious illness.

And then this also confuses me a little bit, why was rotavirus in the respiratory panel. It’s an intestinal virus. So I’m not sure why that one was even in there. I guess they found rotavirus in the nasal swab of these kids? I’m not sure about that. Or maybe they did stool studies too they just didn’t mention it.


Over all it was not a great study, but the outcome doesn’t really surprise me if the relationship holds true for the seizure group. And the percentages are closer together in the non-seizure group. And the reason that wouldn’t surprise me is because influenza is notorious for a rapidly rising and very high initial fever spike. So working with the idea that most febrile seizures are evoked from a rapid change in body temperature in susceptible kids then that makes sense. Because influenza is one of these viruses that typically causes a high fever spike right on the onset of the illness which goes along with what we said usually causes febrile seizures.

And again for more information on febrile seizures, just check out PediaCast 72, cause that entire episode was devoted to the topic. And of course we’ll put a link to that in the Show Notes.

OK. Our third and final research study, I found this one particularly interesting, babies and indoor swimming pools, the effects on pulmonary epithelium and the risk of later allergic and respiratory disease.


And we’ll break down exactly what this means. This is a study that was done at the Catholic University of Louvain in Brussels, Belgium, and was published in the journal, Pediatrics, June 2007.

The question before the researchers, most public swimming pools used chlorine based disinfectants and we know that these release hypochlorous acid which is a powerful oxidants, is a powerful oxidant and a biocide, meaning it kills microorganisms. Now the air just above the water’s surface particularly in indoor swimming pools where there is not a lot of air circulation, that air just above the water surface is known to be contaminated by a mist containing chlorination byproducts which then is inhaled by swimmers, and that’s the chlorine smell. That you smell when you’re in an indoor pool. And the possibility that these byproducts could cause respiratory effects in swimmers is a recent acknowledgment, and this idea was confirmed in recent European study that found and association of indoor chlorinated swimming pool use and the incidence of childhood asthma.


Well, in the United States, 5 to 10 million infants and preschool children participate in formal swimming lessons and many of these occur at indoor chlorinated pools, so the researchers wanted to find, if you have kids who are exposed as infants or young toddlers to indoor pools, are they more likely to have asthma issues down the road. So what they looked at is European study, so this was one single indoor pool in Belgium and there were 341 school children involved in the study and all of them were between the ages of 10 to 13 years old. Now of the 341, 43 of the kids had participated in an infant swimming program at that indoor pool. So here we have our two groups, 43 of them who had infant swimming lesson and the remaining 341 who did not have infant swimming lessons at this indoor pool.


And then all the kids were screened for signs of allergy. And what they did, is they looked at serum or blood chemical markers for a lung based allergic process. And what they looked for is, and this will get a little bit heavy on the science, but bear with me, they looked clara cell protein. And if that is high, then you suspect that they have a lung based allergic process. They also looked for a surfactant associated protein D. The clara cell protein should be high, the surfactant associated protein D, that should be low. If it’s high then that tells you that there is some disruption of the integrity of the deep lung. And they also looked at total IgE, which is a type of antibody and 12 aeroallergens, specific IGE’s, what does that mean?


It just means they looked for antibodies that were specific for allergens that you breath in. This is a marker of allergen exposure and sensitization, in other words you’ve been exposed to these byproducts and now you have allergic markers showing you that have allergies against them.

And then all kids were also screened for asthma by doing a medical examination and an exercise induced bronchoconstriction test and also and exhaled nitric oxide test. So they were all screened for asthma, and they were all screened for signs of allergy.

Now, what they found is that the mean levels of the antibodies, the IgE’s, which would be more of an allergic issue, was similar between the two groups. So it didn’t seem to matter if you were an infant swimmer or not, you basically have the same amount of antibodies against allergens floating around in the blood stream.


However, there was a significant in the group that had been exposed to indoor swimming lessons as infants, there was a significant decrease in the serum clara cell protein. So that’s the one you want to see high, but theirs was lower. And there was a significant increase in the serum surfactant associated protein D. And again that going to be the one you want to be low if it’s high, then that’s evidence you have some lung disruption. And then there was also a significant increase in the number of kids in the infant swimming group who did have asthma and recurrent bronchitis. And these again were statistically significant changes.

So the authors concluded, that exposure to indoor swimming pools, as an infant, appears to increase the risk of asthma developing during later childhood. Now, how exactly do this byproducts of chlorination affect the lung. I thought it’s interesting to take a look of that, because if we’re going to go to the assumption that swimming lessons for babies in an indoor swimming pool settings are dangerous, let’s talk a little bit about why.


Well, according to the author of this study, one culprit might be trichloramine. And trichloramine is a gas that’s formed when chlorine reacts with organic matter that’s brought in by swimmers. Now I’ll let you use your imagination as to what organic matter might be brought into a swimming pool that’s populated by infants swimmer. Let’s just say one of the chemical reactions product is going to trichloramine. And this is actually the gas that is responsible for the chlorine smell of a pool. Now, there had been other studies that show trichloramine can damage lung cells at concentrations between 355 and 490 micrograms per meter cubed. And the current guideline from the World Health Organization is to keep the concentration below 500. But here they’re showing at even concentrations in this one study is as low as 355, damaged lung cells.


So, the pool study in this study was below 500 at all times during the study in term so the amount of trichloramine. But what was it when those kids were infants, maybe it was a little bit higher and the author do suggest that the World Health Organization guidelines of 500 are probably too high. And the acceptable concentration of trichloramine should be lowered. So, that’s the chemical that they think is actually causing lung damage.

Now, what does this mean? I’m just a messenger here. Just telling you about his study. I mean, are there benefits to infant swimming lessons? Some would say yes, and others would say no. On the yes side, you’re getting these infants used to being in the water. It’s sensory stimulation. There’s a bonding with the parent. But on the no side, there is also a hypothermia risk, where kids could get their body temperature down too low especially in the infants.


And there is also the risk of aspiration if they get water in their mouth. Usually these infant classes do involve you dunking them underwater briefly. If the babies take a bid deep breath in, some pool water going to go down into the lungs and cause some issues. So, already there are some advantages and disadvantages. And now we can add another disadvantage. And so as a parent you have to look at what are the benefits what are the risk and is it worth doing. For infants, if it was my infant and I’m looking at all these and say nah, it’s now worth it, don’t do it. And for toddlers, they’re more likely going to say yes. Does the benefit of learning to swim and learning pool safety and those kind of things in a highly, highly supervised setting, is that good for toddlers? And I’d say yeah, for my toddlers it’s probably is worth the risk. Now, does my mind change if I have a strong history of family asthma? Maybe it does. So again, I’m not advising you here, I’m just saying add this to you pool of knowledge and use it when making decisions for your own children.


All right, and that’s really what PediaCast is all about anyway. Cause were not practicing medicine here, we’re just providing another source of education for moms and dads.

All right, we’re going to take a quick break and we’ll be back to wrap up the show right after this.


And as always, thanks go out to Nationwide Children’s Hospital for providing the bandwidth for PediaCast. Also, Vlad over at for providing the artwork. Thanks to all of you for stopping by and spending a little time with us. And of course thanks to my family for letting me out of my family duties to be here with you for a little while.


Pedia Scribe, the blog, the blogging arm of PediaCast which is run by my lovely wife Karen. She has “Tales from the Scales”. It’s basically a blogosphere weight loss group. And Karen got a pretty good post on that, OK, more than pretty good. It’s really good. I’m getting myself in trouble here. She calls it “Sell Your Sugar Stock”. And she discusses the evolution of her morning sugar ritual. And we’ll have a link to that, a blog post on the Show Notes for this episode at

Don’t forget, iTunes reviews. Last count we have 140. And my goal is 200 by Christmas. So if you have not stopped by the iTunes store and left us a review, I would really appreciate it if you do that. And of course the poster page has posters you can download and word of mouth, telling people about PediaCast is just lovely.


So, thanks in advance for doing that. So we do have Dr. Bob from the Sears family, who wrote “The Vaccine Book”. Hopefully he’ll be here tomorrow if all goes as planned. And until then, this is Dr. Mike saying stay safe, stay healthy, and stay involved with your kids. So long everybody.



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