MADELEINE BRAND, host:
From NPR News, this is DAY TO DAY.
About 20 million Americans have asthma, but what exactly causes the illness is a mystery. It's often linked to smoking, obesity and environmental factors. And several studies point to the use of antibiotics very early in a child's life as a precursor to asthma.
Dr. Sydney Spiesel treats children nearly every day in his practice. He's a professor at the Yale Medical School. And Sid writes the Medical Examiner column for the online magazine Slate. He's our expert on all things medical.
And Sid, welcome back to DAY TO DAY.
Dr. SYDNEY SPIESEL (Yale School of Medicine): Thank you. Hi, Madeleine.
BRAND: So why is it that patients and some doctors actually think antibiotics might be behind childhood asthma?
Dr. SPIESEL: Well, there are two reasons. One is a kind of theoretical sense that we've been seeing an increase in the amount of asthma in children, the rate and the prevalence of asthma in children, and that somehow that may go along with the use of antibiotics. And then there's always that kind of suspicion that there's something unnatural, that anything that useful must be harmful. But that's just my prejudice.
(Soundbite of laughter)
BRAND: Well, there's more than just that because there's, a study actually came out recently where they looked at all those studies. And this study concluded, I believe, that there was twice the likelihood, right, of children getting asthma if they used antibiotics in their first year of life.
Dr. SPIESEL: Well, this study put together eight previous studies. The researchers here really didn't do anything themselves. They just put together a bunch of studies, kind of hoping that by increasing the numbers they'd come to more satisfying, demonstrative results. And in fact in half of the studies, they were so-called retrospective studies, where they took kids with asthma and asked the parents to remember back and see if the kids had been given antibiotics in the first year. The other half of the studies were prospective studies, in which they started tracking kids with and without the use of antibiotics, and then looked to see if they developed asthma or not.
BRAND: Well, Sid, what do you make of the results of this study?
Dr. SPIESEL: Well, the results of this study on one hand look as if there's an association. At least there's a -- when you put all the -- this was a sort of, they smushed together eight different studies. When you put them all together it looked as if there was a higher likelihood that kids who either were known to have been given antibiotics early on or where the parents remembered it were more likely to have asthma later on.
But the two questions come to mind. One of them is whether there really is a causal connection. It might look as if having been given the antibiotic led to the development of the asthma. But it's a sort of coincidental relationship. So that's one question. And the other question is a kind of funny memory question. The strongest evidence comes from people who remembered having given antibiotics to their kids with asthma. And memory is a very tricky business, I'll tell you. In my practice I'm always struck by the difference between what parents remember and what the medical record shows.
I think the final answer is far from in, I'm sorry to say. I love it when we have final answers that are solid and we can depend on.
BRAND: Dr. Sydney Spiesel of the Yale Medical School and of Slate.com, thank you.
Dr. SPIESEL: My pleasure. Take care. Transcript provided by NPR, Copyright NPR.