Intitulé du sujet: Sleep trajectories and physical functioning durig aging: a lifecourse approach.

Sujet

Codirection: S?verine Sabia et Cl?mence Cavailles

Nombre de mois: 36 mois

Ecole Doctorale: ED 393 - ED Pierre Louis de Santé Publique à Paris

Unité de recherche et équipe:

Unit : CRESS, Centre of Research in Epidemiology and StatisticS, U1153

Team : EpiAgeing

Coordonnées de l’équipe:

Universite paris cité, 10 avenue de verdun, 75010 paris

Secteur: Sciences de la vie / Life Sciences

Langue attendue: Anglais

Niveau de langue attendu: B2

Description

Description du sujet:

Background

Sleep is a critical determinant of health, influencing a wide range of physiological and cognitive processes throughout life (1). Growing evidence has linked insufficient or fragmented sleep to negative health outcomes, including frailty, disability, and premature mortality (2–4). However, most prior research has focused on sleep at a single time, neglecting its dynamic nature and the potential long-term effects of poor sleep on health. Additionally, while sleep is recognized as a risk factor for various chronic conditions, such as cardiometabolic disorders, as well as mortality (5), it remains unclear whether sleep and its changes continue to predict mortality once chronic conditions are present. Addressing these gaps through a life-course approach is crucial for both primary and secondary prevention of health outcomes during aging.

Research questions

This project aims to explore the critical role of sleep across the life course, focusing on its long-term impact on frailty, disability, and mortality. The project will provide novel insights into the long-term role of sleep across various stages of life and health contexts, offering evidence for its significance in primary and secondary prevention strategies.

The objectives of this project are:

• To investigate how trajectories of sleep duration and quality over 30 years are associated with the development of frailty and limitations in activity of daily living.
• To examine whether sleep duration and quality trajectories in individuals with chronic conditions (e.g., musculoskeletal disorders, cardiometabolic disorders, respiratory disorders, mental health and neurological disorders, cancers) are predictive of mortality.

Data

Participants were drawn from the Whitehall II study, which included 10,308 men and women aged 35-55 years at baseline (1985-1988) (6). Sleep duration and quality were assessed by questionnaire seven times between 1985-1988 and 2018-2022 (age range: 64-93 years), the Fried frailty index five times between 2002-2004 and 2018-2022, and limitations in activity of daily living (ADL) five times between 2005-2006 and 2018-2022. Mortality data were obtained through linkage to electronic health records up to 2023. Chronic conditions were identified using both clinical examinations and electronic health records and classified as: musculoskeletal disorders (e.g., frailty, ADL dependence, arthritis), cardiometabolic disorders (e.g., diabetes, coronary heart disease, stroke), respiratory disorders (e.g., asthma, chronic obstructive pulmonary disease), mental health and neurological disorders (e.g., depression, dementia, Parkinson’s disease), cancers, and multimorbidity (at least two of previous conditions).

Methods

1. In order to identify sleep duration and quality trajectories, group-based trajectory modelling will be used.

1. In order to investigate the association between sleep duration and quality trajectories from 1985-88 to 2002-2004 and subsequent development of frailty and ADL dependence, Cox models will be used as well as multi-state models to assess transitions across health stages (e.g., healthy to frailty; healthy to ADL dependence; frailty to ADL dependence).

1. In order to examine the association between sleep duration and quality before and after chronic condition diagnosis and mortality among individuals with chronic conditions, Cox models will be used.

All models will be sequentially adjusted for a large set of sociodemographic, behavioural, and health related factors.

Power

Data availability on 10,000 older individuals ensure statistical power. Moreover, objective 2 will be replicated in the UK Biobank dataset.

Calendar

Papers planned

Paper 1: Long-term sleep duration and quality trajectories and their associations with risk of frailty and disability.

Paper 2: Sleep duration and quality in chronic conditions and their predictive value for mortality risk.

Compétences requises:

Master in biostatistics, public health, epidemiology, with a good background in statistics

Interest in ageing population

First experience in epidemiology and statistical analyses, awarded by a published paper

Experience in data management of large cohort databases

Références bibliographiques:

1) Baranwal N, Yu PK, Siegel NS. Sleep physiology, pathophysiology, and sleep hygiene. Progress in Cardiovascular Diseases. 2023 Mar 1;77:59–69.

2) Guida JL, Alfini AJ, Gallicchio L, Spira AP, Caporaso NE, Green PA. Association of objectively measured sleep with frailty and 5-year mortality in community-dwelling older adults. Sleep. 2021 Jul 1;44(7):zsab003.

3) Nakakubo S, Makizako H, Doi T, Tsutsumimoto K, Hotta R, Lee S, et al. Long and Short Sleep Duration and Physical Frailty in Community-Dwelling Older Adults. J Nutr Health Aging. 2018 Nov 1;22(9):1066–71.

4) Park M, Buchman AS, Lim ASP, Leurgans SE, Bennett DA. Sleep complaints and incident disability in a community-based cohort study of older persons. Am J Geriatr Psychiatry. 2014 Jul;22(7):718–26.

5) Gao C, Guo J, Gong TT, Lv JL, Li XY, Liu FH, et al. Sleep Duration/Quality With Health Outcomes: An Umbrella Review of Meta-Analyses of Prospective Studies. Front Med (Lausanne). 2022;8:813943.

6) Marmot MG, Smith GD, Stansfeld S, Patel C, North F, Head J, et al. Health inequalities among British civil servants: the Whitehall II study. Lancet. 1991 Jun 8;337(8754):1387–93.