Rygere har lavere IQ
The smokers had significantly lower intelligence test scores than non-smokers, and this remained true even after the researchers accounted for socioeconomic status as measured by how many years of formal education a recruit's father had completed.
Det er dog ikke rygningen der gør at intelligensen er lavere, men den lavere intelligens der gør at de ryger:
The findings suggest that lower IQ individuals are more likely to choose to smoke, rather than that smoking makes people less intelligent, Weiser and his team conclude. Læs artikel