Investigator G.J. Reynolds writes:
Here’s a nice little set of papers on how the color of a cat affects its owners allergies.
First, a 2000 abstract in the Journal of Allergy and Clinical Immunologyestablishing that owners of lighter-colored cats have fewer symptoms than owners of darker-colored cats [one of the authors, Clifford Bassett, is pictured here in lieu of a cat]. And then, a 2001 paper in the same journal establishing that levels of cat allergen are in fact the same, regardless of cat color.
I would note that the conclusion drawn by the first article is a nice case of assuming causation when you only have correlation. The cats in question were not randomly assigned to owners, so it could be that people with severe allergies are drawn to darker-colored cats, or that people without allergies are more likely to choose light-colored cats.
BONUS: A 2010 NY Times look at the same question.