E-drug: Asthma associated with early antibiotic use (cont'd)
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[For all clarity, I had reservations about this research as well and
already contacted the author for more information. As soon as she
responds, I will circulate her additional information. In the mean
time I hope E-druggers would react on this certainly interesting
study. HH]
Dear E-druggers,
It's difficult to comment fully on the study highlighted in Hilbrand's
recent posting without seeing all the details, but one caveat should be
mentioned. Any observational study such as this can only
demonstrate an association and not prove causality. There is also the
possibility of reverse causality being at play - my own family is a
lovely n=2 case series - let's examine this statement from the Reuters
Health story: "The link between early antibiotic exposure and the
development of allergy and asthma was stronger in children whose
mothers had similar conditions". Is it not possible that some, but not
all, of the children of a parent with an atopic history might, by virtue of
their own atopy, be more susceptible to respiratory tract infections
and therefore present to a GP more often and receive more courses
of antibiotics (some of which would be warranted and others not)?
There would therefore be a positive association between the
presence of asthma at 7 years and earlier antibiotic use, but both
would be driven by the pre-existing allergic conditions, in part
inherited from the parent(s), hence the stronger association in
children of atopic mothers.
A quick explanation of the n=2: two children, one parent with a strong
family history of atopy - one child showed early signs of atopy and
developed asthma, but also had markedly more respiratory tract
infections (and hence antibiotics - though not without much agonising
and debate with the GP and/or paediatrician), whereas the other has
shown no signs of atopy, and has had less antibiotics (though seen
by the same practitioners and with the same approach) and also has
never presented with anything remotely like asthma. What caused the
asthma - the atopic tendency or the antibiotics?
Having said all that, if an association such as this - however
tendentious - results in lower use of antibiotics in children, where
much of their use is related to viral infections or self-limiting bacterial
infections, then that should be welcomed.
regards,
Andy
Andy Gray MSc(Pharm) FPS
Senior Lecturer
Dept of Experimental and Clinical Pharmacology
Nelson R Mandela School of Medicine
University of Natal
PBag 7 Congella 4013
South Africa
Tel: +27-31-2604334/4298 Fax: +27-31-2604338
email: graya1@nu.ac.za or andy@gray.za.net
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