As a decaf drinker, I found myself shouting, “What about caffeine”?” as I read your article. How can any report not, at least, mention its involvement or lack thereof?

Greg Tullo
Raleigh, N.C

Researcher Pertti Happonen suspects that caffeine was responsible for the effects seen in his study, but since Finns don’t drink much decaf, he couldn’t sort out the effect of the less stimulating brew .—J. Raloff