Saturday, November 30, 2013

Chronic smoking accelerates atrophy of the hippocampus, a key memory structure in the brain.

Most people are aware that our memory abilities decline with aging, but a recent paper in the journal Drug and Alcohol Dependence reported that chronic cigarette smoking seems to strikingly accelerate shrinkage of a key memory structure in the brain, the hippocampus (Figure (MRI image), red circles).

The study also reported that hippocampus shrinkage in smokers is associated with smoking severity, as measured in pack-years, and that certain types of memory decline, including auditory-verbal memory (the ability to remember sounds and words) and visuospatial learning and visuospatial memory (the ability to learn and remember spatial relationships among elements in view, required to navigate through one’s environment), are associated with hippocampal volumes in smokers and nonsmokers. Thus, chronic smokers likely experience greater deficits in these key memory capabilities than nonsmokers.

Over the age range studied (20-70 years old), hippocampus volume declined by ~12% in nonsmokers and by ~30% in smokers, meaning that chronic smoking more than doubled the rate of hippocampal volume loss occurring as a consequence of normal aging.

The study authors noted that the severity of hippocampal volume loss among older smokers in their study was on par with the severity of volume loss found in people with mild cognitive impairment, which could in part explain the increased risk among chronic smokers for developing dementias such as Alzheimer’s Disease.

Many smokers resolve to quit smoking as a New Year’s resolution. If you smoke, the findings from this study provide yet another reason to seriously consider trying to quit smoking during this holiday season.

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