Echocardiographic Measures of Left atrial function and size
A prospective cohort study of United States participants (aged 45-64 years at enrollment) who were free of dementia, atrial fibrillation (AF), and stroke at baseline. Several measures of LA size and function were derived from each subject’s baseline echocardiogram. Subjects were followed longitudinally. The outcome of interest was incident dementia. Mediation analysis was used to quantify the extent to which associations between LA measures and dementia were mediated by incident AF.

A total of 4,096 subjects composed the final cohort. Over a median follow-up of 6 years, 531 (13%) subjects were diagnosed with incident dementia. Measures of LA size were not associated with incident dementia risk. However, several measures of LA function were associated with dementia risk in the fully adjusted model, including reservoir strain, conduit strain, contractile strain, emptying fraction, and active and passive emptying fractions. Incident AF mediated <2% of the association between each of the above measures and incident dementia.

In this cohort study, several echocardiographic measures of atrial function but not size were associated with an increased risk of dementia without significant mediation from incident AF.