Atypical schedules and cognitive aging – HAVCOG

The goal of the current project is to examine whether and how atypical schedules of work have short-term and long-term effects on cognitive functioning and whether they moderate cognitive trajectories associated with aging, in the direction of an accelerated cognitive aging in people with atypical work schedules.
A cohort of 4000 adults covering a wide age range, representative of the French population, will be followed up on 10 years, with three measurement occasions (Wave 1 data collection starts in 2018: Wave 2 data collection starts in 2023; Wave 3 data collection starts in 2028). Data will be obtained using clinical medication examinations, and self-reported data on a website created for the study. At each measurement occasion, participants will complete questionnaires regarding current and past working conditions, personal life (social life, activities), personality and coping, health and neuropsychological tests. A comprehensive assessment of neurocognitive functioning will include several measures of episodic memory, fluid abilities, flexibility, speed of processing and crystallized abilities. A measurement-burst-design will allow to overcome main shortcomings of previous studies, and to dissociate short-term fluctuations, test-retest effects, long-term changes, and measurement errors in neurocognitive measures.
The longitudinal design of the study will make it possible to investigate (1) whether atypical work schedules have short-term and long-term negative effects on neurocognition and on neurocognitive aging; (2) whether troubles associated with atypical work schedules on neurocognition and neurocognitive aging are reversible or not, by following up people who left this type of work organization; (3) possible mechanisms involved in the atypical schedules-neurocognition relations, such as quality of sleep, engagement with life, or mood (e.g., depressive symptoms, anxiety); and (4) possible moderators of atypical schedules effects on neurocognitive trends. Both individual characteristics such as personality traits and coping strategies, and contextual factors such as task parameters will be explored as possible moderators of atypical schedules effects on neurocognition.
Our main hypotheses are that working in atypical schedules - which challenge natural biological rhythms – may have deleterious effects on neurocognitive functioning, in particular on process-related cognitive abilities such as memory or flexibility, and that these aversive effects may be stronger at older ages than at younger ages. That is, because older brains have reduced cognitive reserve and lower capacities to resist to adversity, they are expected to be more vulnerable than younger ones. We therefore assume that neurocognitive decline over 10 years will be more pronounced for people who work in atypical schedules than others. Sophisticated analyses will help us determine how these atypical schedules may influence neurocognitive functioning. We suppose that reduced quality of sleep, but also smaller engagement with life (social life, activities), may explain why this work organization may influence both the level of cognitive abilities, and how they change over time.