The Sabia team concluded in their article: “Smoking was associated with greater risk of poor memory. Middle- aged smokers are more likely to be lost to follow-up by death or through nonparticipation in cognitive tests. Ex-smokers had a lower risk of poor cognition, possibly owing to improvement in other health behaviors.”

In a news release by the researchers, they stated, "Smoking in middle age is associated with memory deficit and decline in reasoning abilities.” [WebMD: “Midlife Smoking Causes Memory Problems: Lighting Up in Middle Age Linked to Cognitive Problems”]

Their results were published in the June 9, 2008 issue of Archives of Internal Medicine (June 9, 2008; vol 168: pp 1165- 1173). The authors of the study (entitled “Smoking History and Cognitive Function in Middle Age From the Whitehall II Study”) were Séverine Sabia; Michael Marmot; Carole Dufouil; and Archana Singh-Manoux. They also said, "Our results ... suggest that the association between smoking and cognition, even in late midlife, could be underestimated because of higher risk of death and non-participation in cognitive tests among smokers.” [WebMD]

Their study also found that non-smoking people or former smoking people had healthier lifestyles than smoking people, such as drinking less, being more physically active, and eating better foods such as fruits and vegetables. The Sabia team also stated that one of their most difficult problems was getting smokers to re-take their tests. More than twice as many smokers than non-smokers refused to take the memory test the second time, or could not take the test because they had already died.

It is being reported that at least one scientist is not convinced of this connection between smoking and memory loss. Please read on. Michael Siegel, a professor of social and behavioral sciences at Boston University (Massachusetts, U.S.A.), states, "There are two things that are a little concerning about the [study] results that would give us pause before definitely concluding that smoking leads to a decrease in memory.” [U.S. Department of Health and Human Services (HHS): “Smoking Tied to Memory Loss in Middle Age”]