(NaturalNews) Smoking is directly correlated with a lower IQ, according to a study conducted by researchers from Tel Aviv University in Israel and published in the journal Addiction.
Researchers tested the IQs of more than 20,000 healthy men between the ages of 18 and 21 who were either serving in the Israeli military or who had recently completed their service. Twenty-eight percent of the men in the sample smoked, while 3 percent were former smokers and 68 percent had never smoked.
The average IQ of the smokers was 94, compared with 101 among the non-smokers. Men who smoked more than a pack of cigarettes a day had an average IQ of 90. Although a normal IQ falls between 84 and 116, the difference observed in the study is still considered significant.
In twin pairs where one brother smoked and the other did not, the smoker consistently tested at a lower IQ.
The study could not prove whether smoking caused a lower IQ or having a lower IQ predisposed people to smoke, but the researchers did rule out the possibility that low socioeconomic status produces both smoking and a lower IQ.
"In the health profession, we've generally thought that smokers are most likely the kind of people to have grown up in difficult neighborhoods, or who've been given less education at good schools," said researcher Mark Weiser, also of Tel Hashomer Hospital. "But because our study included subjects with diverse socioeconomic backgrounds, we've been able to rule out socioeconomics as a major factor."
Weiser noted that people with lower IQs are also more likely to suffer from other forms of drug addiction and to have health and weight problems.
"People on the lower end of the average IQ tend to display poorer overall decision-making skills when it comes to their health," he said.
"Our study may help parents and health professionals help at-risk young people make better choices."