Implications of reduced sleep duration and sleep disturbances on neuromuscular strength and walking speed in the elderly: evidence from the ELSA Study

• Grant number: 23/02140-6
• Support Opportunities: Scholarships in Brazil - Master
• Start date: June 01, 2023
• End date: May 31, 2024
• Field of knowledge: Health Sciences - Collective Health - Epidemiology
• Principal Investigator: Tiago da Silva Alexandre
• Grantee: Leticia Coelho Silveira
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Concomitantly with the aging process, changes in sleep patterns occur. Decreased efficiency and total sleep time, increased time to fall asleep, comorbidities and use of drugs increase the chances of developing sleep disorders. Thus, reduced sleep duration and the presence of sleep disorders may be associated with reduced neuromuscular strength and walking speed in elderly people of both sexes due to changes in protein synthesis and the process of muscle protein degradation that may be influenced by time and quality of sleep. However, the results of these associations are scarce and predominantly from cross-sectional studies. Therefore, the aim of the present project will be to analyze whether the sleep duration and/or the presence of sleep disorders impair neuromuscular strength and walking speed trajectories in people over 50 years old participating in the English Longitudinal Study of Aging (ELSA Study) over an eight-year follow-up period. The sample will consist of 9,886 individuals who participated in the ELSA Study in 2008, aged over 60 years. The exposures analyzed will be sleep duration and the presence of sleep disorders. Sleep duration was assessed in the ELSA Study by self-report and will be classified as short (< 5 hours), ideal (5-8 hours) and long (> 8 hours). The presence of sleep disorders was assessed by the Sleep Problems Scale in which participants were asked about the presence, in the last month, of difficulty falling asleep, staying asleep, waking up feeling tired and about their general sleep quality. The total score of the scale ranges from 1 to 16 points with higher scores indicating a greater occurrence of sleep disorders. The outcomes evaluated will be neuromuscular strength and walking speed, measured by the handgrip strength test and walking speed, respectively. To analyze the trajectories of neuromuscular strength and walking speed, generalized linear mixed models controlled by socioeconomic, behavioral and clinical variables will be used. All measures were evaluated in the ELSA Study at baseline (2008) and at four (2012) and eight (2016) years of follow-up. Therefore, it is expected that the decline in neuromuscular strength and walking speed will be more accelerated in the elderly with total sleep time < 5 hours, as well as in those with higher sleep disorders scores.