Cecil did a column last year entitled, “Does a mattress double its weight due to dust mites and their debris? (07-Apr-2000).” If you distill the column down to one word, that word would be, “no.”
However, just today I ran across this interview with John Maunder, head of Britain’s Medical Entomology Centre (which sounds official to me). Amongst other things, he says,
Now, pillow <> mattress and 1/2 <> 1/10, but this little factoid seems to be mighty close to the one Cecil discusses.
Problem is, I see no cites in the linked article, and I also wonder about the “Medical Entomology Centre.” Is it legit? Any discussion?