Objectives: To examine the mediating role between educational attainment and risk for incidence delirium of activity participation and to examine the contribution of participation in specific activities to the development of delirium.
Design: Prospective cohort study.
Setting: Urban teaching hospital in New Haven, Connecticut.
Participants: Participants were drawn from two prospective cohort studies of 779 newly hospitalized patients aged 70 and older without dementia.
Measurements: The main outcome was delirium, measured using the full Confusion Assessment Method (CAM) algorithm, which consisted of acute onset and fluctuating course, inattention, and disorganized thinking or altered level of consciousness, as rated by trained clinical interviewers.
Results: Bivariable results indicated a significant relationship between education and the development of delirium (odds ratio (OR)=0.92, 95% confidence interval (CI)=0.88-0.97) and between activity and delirium (OR= 0.60, 95% CI=0.46-0.79). In multivariable analysis, activity mediated the relationship between education and risk for delirium. Considering each activity separately, multivariable logistic regression analysis showed that regular exercise significantly lowered the risk for developing delirium (OR=0.76, 95% CI=0.60-0.96).
Conclusion: In older persons without dementia, activity participation before hospitalization is a mediator between education and incidence of delirium. Specifically, it was found that participation in regular exercise was found to be significantly protective against delirium.