A comprehensive assessment of neurocognition in middle-aged chronic cigarette smokers

Background: The majority of studies investigating the neurocognitive consequences of chronic smoking have been conducted with adults 60 years and older. Therefore, the scope of neurocognitive dysfunction associated with chronic cigarette smoking in middle age (i.e., 30-60 age range) has not been fully delineated. Methods: Twenty-seven (44 +/- 9 years of age; 4 females) non-smoking and 30 smoking (49 +/- 8 years of age; 4 females) participants completed a comprehensive neurocognitive battery and measures of fine motor dexterity and postural stability. All participants were free of biomedical or psychiatric conditions that may have influenced neurocognitive and motor function. Results: Smokers performed significantly worse than non-smokers on the following domains: auditory-verbal and visuospatial learning, visuospatial memory, cognitive efficiency, executive skills, general intelligence, processing speed, fine motor dexterity and postural stability. The differences between smokers and non-smokers evidenced moderate to strong effect sizes and were not mediated by age, education, vocational level, estimated verbal intelligence or alcohol consumption. In smokers, a greater number of lifetime years of smoking was related to poorer performance on measures of cognitive efficiency, processing speed and visuospatial skills. Conclusions: Results from this middle-aged cohort replicated previous research and provides novel findings indicating that chronic smoking was associated with inferior performance on measures of general intelligence, visuospatial learning and memory and fine motor dexterity. Research that relates measures of neurobiological function/integrity to neurocognition is needed to better understand the mechanisms contributing to the poorer performance across multiple domains demonstrated by smokers. Published by Elsevier Ireland Ltd.