Literally, you're dumb if you smoke

I read the following article (http://www.foxnews.com/story/0,2933,587241,00.html) on the FOX News website and found the conclusions to be controversial. This article describes a scientific study titled "Cognitive test scores in male adolescent cigarette smokers compared to non-smokers: a population-based study" that was published this month in the journal Addiction.

This study examined whether there was a correlation between smoking habits and the intelligence quotient (IQ) of over 20,000 Israeli military recruits. This paper reported that the average IQ of non-smokers was 101, but dropped to 94 for smokers. Furthermore, they claim that the drop in the IQ score correlated with the amount of cigarettes consumed by the individual. So, the average IQ was 98 for less than five cigarettes a day, and dropped to 90 if over a pack of cigarettes were smoked per day.
In conjunction with previously published reports, the authors of this scientific study conclude that a low IQ score is a risk factor for smoking addiction. Thus, they propose that anti-smoking campaigns should target youth with low IQ scores.

I don't know why, but I can't help feeling that the conclusions made by the authors of this study are biased by the age in which we live. For starters, tobacco was a major American agricultural crop because there was an insatiable European and global desire for this product for centuries. Smoking in some form, whether by cigarette, cigar or a pipe, was common among all strata of society. Now flash forward to modern day, a time where science has shown that smoking is an addiction known to cause death from lung cancer. Given our increased understanding of tobacco cigarettes as a carcinogen, I see the temptation to say in jest that choosing to smoke is stupid. But joking and attempting to prove such a sentiment are two completely different things.

Personally, my gut says the observed correlation between IQ and smoking may have a better scientific hypothesis. Nicotine, a compound that targets neurons and influences their activity, could have profound effects on the development and long-term function of an adolescent brain. Therefore, I'm curious to see whether studies in mice have examined whether nicotine exposure induces cognitive damage that could explain this study's observation that smokers have a lower IQ.