1.Het zwembad

1.1 Is zwemmen ongezond? De reacties ...

Ons artikel over de al dan niet bewezen schadelijke invloed van chloorgerelateerde dampen in zwembaden, lokte nog al wat reacties uit. We willen ze u niet onthouden. We bedanken hier alvast iedereen die hierop reageerde, en we probeerden om de kérn van de besluiten die de meesten trokken, hier extra te accentueren in het rood.
Het was bovendien een erg aangename ervaring: de mails die we kregen hadden een erg open en positief karakter, en getuigen van een grote bezorgdheid, zowel over de kwaliteit van het zwemwater, als over de promotie van onze sport in het algemeen.  Alvast aan iedereen die reageerde heel hartelijk dank: Marc Marchand, Pierre Malfait, Prof.A.Bernard en vele anderen!

Onze eerste reactie kwam van een voorzitter van een Belgische zwemclub, van beroep dokter:

Een goed overzicht van de problematiek.
Het artikel van de Brusselse Prof, waarvan sprake, is van in het begin
onderuit gehaald wegens slechte onderzoeksmethode (vragenlijsten)
Het is ook inderdaad zo dat zwemmen een gunstige invloed heeft op astma.
Het is niet zozeer het chloor zelf dat schadelijk is maar de chloramine
dampen die boven het water zweven.
De concentratie daarvan is sterk afhankelijk van de zuiverheid van het water
(niet de desinfectie), van  de aanwezigheid van de  huidschilfers ed in
het water dit is afhankelijk van het aantal zwemmers , de verversingstijd van het bad, enz
het verbieden van zwemshorts , het opnieuw invoeren van de badmuts voor
iedereen zijn inderdaad goede voorstellen
Naast de evt neg gevolgen van de chloorderivaten moet men stellen dat
zwemmen een zeer volledige sport is ( spierontwikkeling, ademhalingscapaciteit).

In een tweede reactie stelde dezelfde briefschrijver bovendien terecht dat  meteen stellen dat zwemmen tot asthma leidt een wel erg vergaande conclusie is!

Let wel op: 25 % van alle sporters (dus niet alleen zwemmers)  lijden aan inspanningsastma.
Dit kan behandeld worden met disodiumchromoglycaat inhalaties (lomudal, staat niet op de dopinglijst)

Wie aan wetenschappelijk onderzoek doet, staat nu eenmaal altijd bloot aan kritiek. En eigenlijk is dat maar goed ook: de kritische bemerkingen van anderen dwingen wetenschappers vaak om hun onderzoeken te verfijnen of te nuanceren. Het siert in elk geval professor A.Bernard dat hij persoonlijk én uitgebreid op onze bijdrage reageerde, én bovendien ook meteen een aantal verwijzingen naar artikels over de materie opstuurde.
Van verschillende kanten ontvingen wij trouwens het oorspronkelijke artikel van prof.Bernard, ook van de wetenschapper zélf. We publiceren hier het samenvattend gedeelte zodat u gedeeltelijk zélf kan oordelen:

Aims: To study whether exposure to nitrogen trichloride in indoor chlorinated pools may affect the respiratory
epithelium of children and increase the risk of some lung diseases such as asthma.

Methods: In 226 healthy children, serum surfactant associated proteins A and B (SP-A and SP-B), 16
kDa Clara cell protein (CC16), and IgE were measured. Lung specific proteins were measured in the
serum of 16 children and 13 adults before and after exposure to NCl3 in an indoor chlorinated pool.
Relations between pool attendance and asthma prevalence were studied in 1881 children. Asthma
was screened with the exercise induced bronchoconstriction test (EIB).

Results: Pool attendance was the most consistent predictor of lung epithelium permeability. A positive
dose-effect relation was found with cumulated pool attendance and serum SP-A and SP-B. Serum IgE
was unrelated to pool attendance, but correlated positively with lung hyperpermeability as assessed by
serum SP-B. Changes in serum levels of lung proteins were reproduced in children and adults attending
an indoor pool. Serum SP-A and SP-B were already significantly increased after one hour on the pool
side without swimming. Positive EIB and total asthma prevalence were significantly correlated with
cumulated pool attendance indices.

Conclusions: Regular attendance at chlorinated pools by young children is associated with an exposure
dependent increase in lung epithelium permeability and increase in the risk of developing asthma,
especially in association with other risk factors. We therefore postulate that the increasing exposure of
children to chlorination products in indoor pools might be an important cause of the rising incidence of
childhood asthma and allergic diseases in industrialised countries. Further epidemiological studies
should be undertaken to test this hypothesis.

Bezoekers van onze website die het volledige artikel zélf willen nalezen, samen met een aantal andere artikels over de problematiek, kunnen een mailtje sturen met vermelding van hun naam, en dan sturen wij een zip-bestandje met alle artikels die wij ontvingen. Wij hopen op die manier ons steentje bij te dragen tot een genuanceerder debat over deze problematiek.

Ook over de alternatieven en oplossingen voor het chloorprobleem kregen we stapels reacties.
Wilde kreten dat "broom veel beter zou zijn" worden ook door professor Bernard sterk genuanceerd (en let op het veelbetekende "perhaps"):

I have no data about bromine but this chemical should also release nitrogen tribromide, a gas perhaps less rrritant than nitrogen trichloride although
this remains to be checked.
I have seen no data on the levels of this gas in air of indoor pools nor on its possible biological effects.

We are now drafting a series of papers on the chlorine/atopy interaction and the effects of chlorine on the lung of babies.

I will send them to you when published.

Best regards,

Professor Alfred BERNARD

Over eventuele alternatieven (Ozon, UV enz) schrijft hij in een volgende mail:

About alternatives, I have recently attended a meeting in Germany where I  have seen quite significant advances in this area based on ozone, UV (to
destroy chloramine or disinfect), Cu-Ag and ultrafiltration. I think there  are many possibilities. It is just a question of money and willing !

I think the focus should be on very young swimmers and small pools,

Best regards,

Alfred BERNARD


Een misschien simpele oplossing voor het chloorprobleem ligt volgens véél betrokkenen in ... een betere ventilatie!

Dear Sir,

See also attached an interesting  document giving the guidelines for  ventilating indoor chlorinated pools (renewal of pool air between 6 and 8
times per hour !!)

The swimming pools we have studied in Brussels have not the capacity to achieve such a high ventilation rate (max 3-4 times) and I fear this might
be the case in other pools in Belgium, especially the small ones but again this is a question of money since fresh air must be heated.

Swimming is a very good exercise (I have a private swimming pool) but exercise has never been an antidote against toxic gases!

Best regards,

A. B.

Dat Bernard het daar wel eens bij het rechte eind zou kunnen hebben, vonden we ook in een artikel dat we ontvingen van één van onze lezers, namelijk over het mogelijk effect van chloordampen op de gezondheid van de redders. Het besluit van dat artikel is simpel, en eigenlijk zou je met gezond boerenverstand -want dat is vaak nog het beste- tot dezelfde conclusie kunnen komen:

"The air above indoor swimming pools therefore needs to be assessed and managed as carefully as the water."
(Occupational asthma caused by chloramines in indoor swimming-pool air
K.M. Thickett*, J.S. McCoach*, J.M. Gerber{, S. Sadhra}, P.S. Burge* - European Respiratory Journal)

Waarom zwembaden misschien te weinig worden geventileerd heeft wellicht àlles te maken met...centjes.  Verwarmde binnenlicht vervangen door frisse maar koude en dus opnieuw te verwarmen binnenlucht kost nu eenmaal geld.


Besluit:

1.Ik denk dat professor Bernard hier zélf zijn onderzoeken in een betere context plaatste:
-de problemen liggen vooral bij kleine, en matig tot slecht geventileerde zwembaden (o.a.met een laag plafond, en jonge kinderen zijn het kwetsbaarst als het gaat om de schadelijke invloeden van toxische gassen. In dat verband kunnen we wellicht stellen dat grote zwembaden met hoge plafonds een betere luchtkwaliteit hebben.  (het nieuwe bad in Wachtebeke bijvoorbeeld)
-zwemmen is een erg gezonde sport, op recreatief vlak sterk te promoten omwille van de zeer complete spierontwikkeling, bovendien weinig belastend en met een laag blessurerisico. En dat is op competitief vlak niet anders, àls je tenminste verstanidg traint d.w.z. met aandacht voor lichaamshouding, warming-up, cooldown enz

2.Asthma wordt bij competitiezwermmers niet vaker vastgesteld dan bij andere sporters. Vaak gaat het om inspanningsasthma. En een grondig onderzoek wees uit dat de asthmaverschijnselen ook spontaan verdwijnen bij het stoppen met competitie. Van langdurige effecten is dus geen sprake.
Uit persoonlijke ondervinding heb ik bovendien geleerd dat ook het mentale aspect een niet onbelangrijke rol speelt in het beheersen van inspanningsasthma. Je zou met gemak kunnen stellen dat nààst trainingen voor lichaamshouding, techniek, kracht, uithouding en weerstand, er wellicht ook wat aandacht mag gaan naar ademhalings- en ontspanningstechnieken.

3.Er moet wellicht ook grondig werk worden gemaakt van systemen om de lucht van de zwembadruimte te controleren, en er normen voor op te stellen. Dit zal niet van een leien dakje lopen.

4.Intussen is één oplossing simpel en onweerlegbaar: méér hygiëne van de kant van de zwemmer leidt tot een verkleinde noodzaak tot desinfectie. Minder desinfectie betekent minder schadelijke dampen.
Velen wijzen in dat verband op "minder textiel". Nogal wat mensen uit de sector (o.a. redders e.d.) reageerden op ons artikel met de bedenking: wanneer gaan ze in Vlaanderen eindelijk de zwemshort verbieden? En competiezwemmers hebben er wellicht net zo min bezwaar tegen dat de badmuts weer wordt ingevoerd ook voor het "publiek zwemmen".
Een ambtenaar van het Rode Kruis die ambtshalve betrokken is bij de organisatie van wedstrijden en het uitwerken van noodprocedures in zwembaden, vertelde ons dat men "op hoog niveau" inderdaad dergelijke verboden en verplichtingen in te voeren. Maar of deze informatie ook juist is, dat weet ik niet met zekerheid.


Wordt ongetwijfeld vervolgd.

(c)wim@zwemclub.be 02/2005



bijlagen:
artikel 1: een onderzoek waarin gesteld wordt dat als je denkt dat je meer asthmapatiëntjes zou vinden onder zwemmende kinderen, dat je dan nét zo goed kan stellen dat er misschien méér blonde jongens zijn met asthma dan zwarte. En waarom niet méér met krullen? :-)

Controlling childhood asthma doesn't require splashy interventions
July 31, 2003
By Doug Kaufman

ST. LOUIS (MD Consult) - Asthma triggers in children come in many forms, but
a recent study adding indoor chlorinated swimming pools to the list may be
all wet.

"They could have looked at kids with blond hair, if they did the same study,
and shown that blond hair makes you have asthma," said Dr. Sharon Smith, a
pediatrics professor at Washington University School of Medicine in St.
Louis. "That's about how much their data supports their conclusions. It's
terrible. They looked at three different groups of people, and then drew
very broad conclusions that their data doesn't support."

The article, "Lung hyperpermeability and asthma prevalence in
schoolchildren: Unexpected associations with the attendance at indoor
chlorinated swimming pools," was published in the June 2003 issue of
Occupational and Environmental Medicine. But for Dr. Smith, who also serves
as an emergency attending physician in the St. Louis Children's Hospital
emergency room, the study conclusions sink rather than swim.

"If what they found was a really significant or interesting finding, it
would have been published in a significant journal," she said. "You know,
like Journal of Asthma, Pulmonary Journal, Pediatrics, JAMA. I mean, if it
was sort of a light bulb going off (study). The problem is, just because
they had changes in lung proteins because they swam in a pool doesn't mean
that makes you have asthma or makes your asthma worse or anything else. I'm
surprised it got published anywhere."

The study authors, Dr. A. Bernard of the Unit of Toxicology, Catholic
University of Louvain, Brussels, Belgium, and colleagues, examined the
relationship between pool attendance and asthma prevalence in 1,881
children. They reported that "changes in serum levels of lung proteins were
reproduced in children and adults attending an indoor pool." The researchers
conclusion said, "Regular attendance at chlorinated pools by young children
is associated with an exposure dependent increase in lung epithelium
permeability and increase in the risk of developing asthma, especially in
association with other risk factors. We therefore postulate that the
increasing exposure of children to chlorination products in indoor pools
might be an important cause of the rising incidence of childhood asthma and
allergic diseases in industrialised countries."

Pool chlorine could cause an allergic or asthmatic reaction in some
children, Dr. Smith said.

"Every child who has asthma has different triggers," she said. "For some
kids, it's their pet. For some kids, it's pollen in the fall or spring. I'm
sure there are kids out there in whom chlorine from a pool will irritate
their lungs and cause their asthma to act up. Will it make a child who's not
going to have asthma suddenly develop a disease? I don't think so. At least
their data doesn't support that.

"They did show that kids who spend a lot of time, or even a short time, near
an indoor pool with a fair amount of chlorine have changes in their lung
proteins," Dr. Smith said. "The problem is they don't tell you how those
changes compare to someone who's not near the pool. They don't have a
control group. Their work is sort of interesting. It's like the first step
in trying to figure out if there is a connection. And they took that little
first step and just blew it out of the water."

Still, any study that focuses attention on asthma triggers has some merit.
The Children's Hospital ER treats 3,000 to 4,000 children with asthma per
year, each of them different, Dr. Smith said.

"Every child's triggers are unique to that child, and they can change over
time, too," she said.

Pets are a common trigger, as is second-hand tobacco smoke.

"One of the more common ones that we have trouble controlling is cigarette
smoke," Dr. Smith said. "Kids are around people who smoke, or go in areas
where people have been smoking - that triggers asthma in many children, and
adults with asthma as well."

Roaches and mites are also triggers. To keep mites from moving in, children
with asthma shouldn't have carpet in their bedrooms, Dr. Smith said. As
added protection, mattresses and pillows should be covered with plastic
before sheets and pillowcases are added.

"Not all children need that," she said. "But there are some whose asthma is
just so sensitive, they really need to take extra precautions."

Pollen is another "huge trigger," she said.

"We have kids that we see who will only come in once a year or twice a year,
when the pollen counts are high," Dr. Smith said.

The most important thing for parents to do is determine what a child's
asthma triggers are and avoid them if possible, Dr. Smith said.

"Cigarette smoke - don't sit in the smoking section of the restaurant when
you go out to dinner with your family. Sort of common sense things," she
said. "Some things you can't avoid. You can't not let the trees bloom in the
spring time. But if you know that's a trigger for your child, either
starting the allergy medicine before the trees start to bloom or increasing
the controller medicines right around that time of year, can help prevent
those kids from having bad asthma attacks."

A bad asthma attack lands a child in the ER.

"We see them when things get out of control," Dr. Smith said.

The Children's Hospital ER has a standard treatment procedure for asthma
cases.

"We want to find out how sick they are," Dr. Smith said. "So, kids who are
having a mild asthma attack, we treat a little differently than kids who are
having a severe asthma attack. All our kids, ... we give them what we call
rescue medicine, or albuterol. That helps open their lungs up and get their
lungs to function better. All kids (with asthma problems) get that
automatically."

More severe cases will require longer treatment.

"Almost all of our kids get an oral steroid," Dr. Smith said. "Prednisone or
something called Orapred. That really helps. That's a drug that doesn't
really kick in until about an hour after they take it, and peaks somewhere
between four and six hours later. That's the medicine that really helps get
that exacerbation under control and helps those kids, if they're lucky
enough to go home, not come back a couple hours later, or the next day."

Most children suffering asthma attacks bad enough to end up in the ER don't
have a good asthma plan in place, Dr. Smith said.

"They didn't know what to do when the asthma started acting up. They didn't
have the right medications," she said. "Or something about their asthma has
changed. Or the parents weren't sure what to do. We feel very strongly that
all kids who are sick enough to be in the emergency department need to see
their (family) doctor within a couple of days after they see us, to find out
what went wrong and fix it."

Families need "a new action plan," Dr. Smith said, so parents know what
warning signs to look for, have all the medicines they need and know when to
use them.

"We're great at taking care of that initial problem when they first get
really sick with it," she said. "We'll get them through the next couple of
days, the next week. And after that, the parents are sort of like, 'Well,
what do we do now?' Most parents, if they don't see their doctor, go back to
doing whatever they were doing before. That obviously wasn't working for
them, or they wouldn't have been to see us in the first place."

Follow up with the regular family doctor was one of the key recommendations
in a National Institutes of Health report concerning emergency pediatric
asthma attacks, Dr. Smith said.

"Kids have asthma all the time, not just when they're wheezing or coughing
or having symptoms," she said. "A lot of parents don't stop to think, 'Just
because they're not needing medicine right now, doesn't mean their asthma
isn't there.' It's just not a problem for them at the moment."

Inhaled steroids, whether through an inhaler or a nebulizer, are very
effective with "virtually no side effects," Dr. Smith said. Montelukast, the
key ingredient in the once-daily, chewable form of Singulair, is another
good controller medicine for children.

"Even little kids - five or six - can take that drug," she said. "It really
does keep their asthma under control."

As an emergency room physician, Dr. Smith wants to see all children with
asthma under control.

"It may take a little time to find the right combination of controller meds,
... but most kids with asthma should have no symptoms," she said. "They
should be able to run around and play with their friends and participate in
sports and not have any real problems from their asthma. I don't think a lot
of parents realize that."

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