Do High Mental Demands at Work Protect Cognitive Health in Old Age via Hippocampal Volume? Results From a Community Sample.

Francisca S Rodriguez,Joachim Thiery,Steffi G Riedel-Heller,Ralph Burkhardt,Markus Löffler,Maria P Aranda,Matthias L Schroeter,A Veronica Witte,Arno Villringer,Ronny Baber,Tobias Luck,Christoph Engel,Sebastian Huhn,William A Vega

doi:10.3389/fnagi.2020.622321

Abstract

As higher mental demands at work are associated with lower dementia risk and a key symptom of dementia is hippocampal atrophy, the study aimed at investigating the association between mental demands at work and hippocampal volume. We analyzed data from the population-based LIFE-Adult-Study in Leipzig, Germany (n = 1,409, age 40–80). Hippocampal volumes were measured via three-dimensional Magnetic resonance imaging (MRI; 3D MP-RAGE) and mental demands at work were classified via the O*NET database. Linear regression analyses adjusted for gender, age, education, APOE e4-allele, hypertension, and diabetes revealed associations between higher demands in “language and knowledge,” “information processing,” and “creativity” at work on larger white and gray matter volume and better cognitive functioning with “creativity” having stronger effects for people not yet retired. Among retired individuals, higher demands in “pattern detection” were associated with larger white matter volume as well as larger hippocampal subfields CA2/CA3, suggesting a retention effect later in life. There were no other relevant associations with hippocampal volume. Our findings do not support the idea that mental demands at work protect cognitive health via hippocampal volume or brain volume. Further research may clarify through what mechanism mentally demanding activities influence specifically dementia pathology in the brain.

Highlights

Demanding activities at work seem to delay cognitive decline and lower dementia risk (Valenzuela and Sachdev, 2006a,b), as longitudinal studies (Smyth et al, 2004; Karp et al, 2009), as well as twin studies (Andel et al, 2005; Potter et al, 2007), have shown
A smaller hippocampal volume was associated with poorer performance in the Word List Test and the Trail Making Test (TMT), and less gray matter was associated with poorer performance in all cognitive tests
Since previous studies have shown that high levels of mental demands at work (MDW) are associated with lower dementia risk, this study aimed to investigate whether higher Mental demands at work (MDW) protects cognitive health by preserving hippocampal volume

Summary

Introduction

Demanding activities at work seem to delay cognitive decline and lower dementia risk (Valenzuela and Sachdev, 2006a,b), as longitudinal studies (Smyth et al, 2004; Karp et al, 2009), as well as twin studies (Andel et al, 2005; Potter et al, 2007), have shown. Therein, it seems that the effect depends on the type of mental demand at work (MDW). The evidence is still sparse and it remains unclear whether long-lasting mental stimulation preserves hippocampus plasticity

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