A review of tobacco, alcohol, adiposity, and activity as predictors of cognitive change

The global population is now aging rapidly, and cognitive impairment and dementia will be associated with increased disease burden worldwide. Recent research efforts have been directed at identifying risk and protective factors in both middle and late life in order to identify potential preventive interventions. Evidence from recent reviews indicates that modifiable risk factors such as tobacco smoking, alcohol consumption, adiposity, and activities have significant impacts on cognitive function and dementia. However, it is not clear how these risk factors might influence within-person cognitive changes or rates of cognitive decline. We searched Medline and PsycINFO for prospective studies examining the effects of baseline and within-person changes in drinking, smoking, activity level, and adiposity on either cognitive functioning or cognitive changes. Because of the heterogeneity in methodology, a narrative review was used to summarize the findings. Forty-nine studies were found to be relevant to the current review-10 on smoking, 5 on adiposity, 12 on drinking, and 22 on activity level. This review found that smoking in general increased the rate of memory decline but not decline in language or visuospatial reasoning abilities. No consistent relationship between adiposity and change in global cognitive functioning could be found, regardless of whether adiposity was measured in mid-life or late life. Moderate alcohol consumption was shown to slow down decline in global cognitive functioning but not in specific domains. Finally, an active lifestyle physically, cognitively, and socially appeared to offer the most promise of slowing decline in global cognitive functioning, memory, and perceptual speed. Intervention programs targeted at modifying these lifestyle factors may have the potential of improving physical, mental, and cognitive health of our aging population, as well as enhancing overall quality of life