Background
The three US authors - who hail, respectively, from the David Geffen School of Medicine at the University of California at Los Angeles, Harvard Medical School, and Brigham and Women's Hospital in Boston -- say "there is concern that climate change may affect hay fever and other allergic conditions by impacting pollen amount, pollen allergenicity, pollen season, and plant and pollen distribution," because "allergy and atopic disease rates are rising, and global warming has been implicated as a possible cause." However, they state that "concomitant with climate change over the time course of many of these studies are changes in air pollution levels, economic factors, and lifestyle," and these potentially confounding factors led them to conduct a study that they hoped would clarify this situation.

What was done
According to Miller et al., annual prevalence data for frequent otitis media (defined as three or more ear infections per year), respiratory allergy, and non-respiratory seizures in children were extracted from the US National Health Interview Survey for 1998 to 2006, while average annual temperatures for the same period were obtained from the US Environmental Protection Agency, after which "complex samples logistic regression analyses" were performed to identify possible correlations between annual temperature and each of the three different disease conditions, while controlling for age and sex.

What was learned
The three researchers report that regression analysis found that (1) "annual temperature did not influence the prevalence of frequent otitis media," (2) "annual temperature did not influence prevalence of respiratory allergy," and (3) "annual temperature and sex did not influence seizure prevalence."

What it means
Miller et al. conclude that their negative findings "may demonstrate that average temperature is not likely to be the dominant cause of the increase in allergy burden or that larger changes in temperatures over a longer period are needed to observe this association." Therefore, their final words on the subject are that "in the absence of more dramatic annual temperature changes, we do not expect prevalence of otitis media to change significantly as global warming may continue to affect our environment."