Dogs and asthma
One News says “The family dog or growing up on a farm could be the keys to reducing the chances of a young person suffering from asthma.”
This is pretty good research. It’s obviously not a randomised experiment, but it uses the population administrative and medical data of Sweden to get a reasonable estimate of associations, and it is consistent with other population studies and has a reasonable explanation in immunology. One News gave all the relevant numbers, and got Dr Collin Brooks from Massey in as an expert. So that’s all good.
But (you knew there was a ‘but’), the population impact is smaller than the news story suggests. That has to be the case: New Zealand, with very high asthma rates by international standards, already has fairly high dog ownership rates. In fact, as often happens, this new study has found less benefit than earlier, smaller studies.
At current NZ asthma rates, for every extra 100 little kids who live with dogs, the research would predict that you’d prevent one or two cases of asthma. And that’s without worrying about, say, reduced housing options for households with pets.
Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »