Supervisory experience at work is linked to low rate of hippocampal atrophy in late life

Abstract

Cultivation of an active cognitive lifestyle, including diverse and challenging educational, occupational and cognitively-loaded leisure activities may be protective against development of dementia but the mechanisms underlying this link are not clear. We used the Lifetime Experiences Questionnaire (LEQ) to assess the structural brain correlates of cognitive lifestyle in the Sydney Memory and Aging Study, a large population-based cohort of originally 1037 non-demented elderly aged over 70 years of age. After excluding those without structural Magnetic Resonance Image data or Mild Cognitive Impairment at their most recent assessment, 151 cognitively intact subjects were studied. Whole-brain voxel based morphometric analysis found that higher total Lifetime Experiences Questionnaire scores are linked with increased grey matter volume in the medial temporal lobe, especially in the hippocampus. Through a series of more specific analyses, we found that supervisory and managerial experience in midlife was the dominant contributor to this effect. Furthermore, in those with longitudinal neuroimaging data (N=91), we measured hippocampal structural changes over a 2-3 year period by gold-standard manual tracing. The rate of hippocampal atrophy in late-life in those with high level supervisory experience in midlife was five-times slower than those with no midlife supervisory experience (p<0.001). Individual differences in intracranial volume, age, gender, physical activity, depressive symptoms, or apolipoprotein ε4 genetic status could not explain these findings, nor could specific lifestyle patterns in late life. For the first time, we reveal that managerial and supervisory experience during our working life is connected to hippocampal integrity after retirement, some 20-30 years later. Our results stimulate several questions about the nature of work-related effects on longterm behaviour, structural neuroplasticity and neuroprotection, and may help explain differences in dementia-risk based on cognitive lifestyle.