It’s perfectly simple – the heavier the smoker, the lower his IQ – a straightforward Israeli study finds that it’s the people with lower IQs who tend to smoke.
We generally think that people who smoke despite numerous health warnings and the increased risk of cancer do so because of social and economic reasons. Perhaps it’s a matter of irresistible peer pressure or maybe they simply don’t know any better? Not so, finds a new Israeli study that links smoking to lower IQs.
Dr. Mark Weiser from the Sheba Medical Center at Tel Hashomer Hospital in Israel found a direct correlation between the number of cigarettes a smoker inhales and his IQ. People with lower IQs are the ones who tend to be smokers and the heavier the smoker, the lower the IQ.
“It was really quite a straightforward study,” says Weiser, who compared the cognitive test scores of male adolescent smokers and non-smokers. “We looked at cross-sectional data on IQ and smoking cigarettes, and looked at people’s smoking status and their IQs,” he tells ISRAEL21c.
Some media reports distorted the findings of the study that appeared recently in the journal Addiction, and reported that smoking actually damages your IQ, but Weiser says this is not likely the case, and it’s not what he and his colleagues found in their study.
“It’s very clear that people with low IQs are the ones who choose to smoke. It’s not just a matter of socioeconomic status – if they are poor or have less education – and because of that do less well on IQ tests. And that’s really the story,” he says.
Peer pressure tactics that are smoking hot
What the study does show, however, is that there could be a new intervention approach for health specialists at schools and in institutions where young people and teens are at risk for smoking. People with lower IQs could be targeted for specialized programs, helping them to kick or avoid the habit altogether.
The results could also be used to pressure friends and colleagues to quit smoking. If smoking means you have a lower IQ, this could be information one might be unwilling to advertise. Weiser agrees that “perhaps” this may help to convince smokers to give up the habit.
As a scientist, he sees his study as something that adds another piece of the puzzle to a larger group of studies ongoing around the world. Some scientists are testing the hypothesis that on average, people with lower IQs tend to make poorer decisions regarding their health. These are people who may be overweight, will abuse drugs more often and will exercise less to improve their health status, explains Weiser, who examined a cohort of 20,000 Israeli military personnel in his study.
Weiser and his colleagues found that 18-year-old men who smoke a pack or more of cigarettes a day were likely to have an IQ score that on average is 7.5 points lower than that of young men who choose not to smoke.
Unlike other studies that correlate health and IQ, the researchers did not include people who suffer from any major health problem, since these people are weeded out during army selection. This is one of many health-related studies based on the data collected by the Israel Defense Forces before, during and after recruitment.
Family status data not relevant
In the recent smoking study, the researchers found that 28 percent of the new recruits smoked one or more cigarettes a day; about three percent admitted to being ex-smokers, while 68% of the young men had never smoked.
Even after examining socio-economic data, including the level of education of the recruits’ fathers, the researchers found that the men who smoked showed a significantly lower IQ score than their non-smoking counterparts did.
An average IQ for a smoker was found to be about 94, while non-smokers averaged around 101. Interestingly, the researchers point out that a steady drop in IQ levels corresponds to a greater number of cigarettes smoked per day. Those who smoked more than a pack a day had IQs of around 90, for example. An average intelligence IQ score is described as one in the range of 84 to 116.
Even in studies of brothers, where environmental factors growing up can be assumed to be similar, the researchers found consistent results: The non-smoking sibling achieved a higher IQ than did his smoking brother.
The researchers conclude: “The IQs of adolescents who began smoking between ages 18-21 are lower than those of non-smokers. Adolescents with poorer IQ scores might be targeted for programs designed to prevent smoking.”