How many percentage points of reduction in manual grip strength determine the decline in walking speed in people aged 60 or older?

• Grant number: 23/14294-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2024
• End date: October 31, 2024
• Field of knowledge: Health Sciences - Physiotherapy and Occupational Therapy
• Principal Investigator: Tiago da Silva Alexandre
• Grantee: Yasmin Oliveira Machado
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Several studies have established different cutoff points for manual grip strength as an indicator of mobility decline risk. However, we still lack longitudinal studies that have explored how much reduction in manual grip strength, in percentage terms, would be able to predict a decline in walking speed over time, as well as in different age groups. In light of this scenario, the present study aims to determine how much proportional reduction in manual grip strength would indicate a decline in walking speed in different age groups over twelve years of follow-up. To address this research question, we will use data from the English Longitudinal Study of Ageing (ELSA). These data are made available to the Epidemiology and Aging Studies Group (GEPEN) thanks to the International Collaboration of Longitudinal Studies of Ageing (InterCoLAging), a consortium of Longitudinal Studies led by the supervisor of this proposal, funded by CNPQ, and based in the Department of Gerontology where this study will be conducted. Therefore, a longitudinal study will be conducted involving 7,666 individuals aged 60 years or older, followed for twelve years. At baseline, those with mobility limitations, i.e., walking speed d 0.8 m/s, will be excluded. The exposure of interest will be the proportional decline in manual grip strength over the follow-up period. The outcome of interest will be walking speed in meters per second. Three generalized linear mixed models (GLMM) will be performed: 1) for participants aged 60 to 69 at baseline; 2) for participants aged 70 to 79; 3) for participants aged 80 and older at baseline. All models will be controlled for sociodemographic, behavioral, and clinical characteristics. It is expected that there will be a difference in the percentage of manual grip strength loss that can influence the decline in walking speed among different age groups. It is believed that greater losses may be necessary to compromise walking speed in younger age strata, while smaller losses may already affect walking speed in older age strata. This study aims to provide information about the rate of strength decline that leads to mobility decline, enabling healthcare professionals to identify individuals at risk of mobility decline in clinical follow-up appointments.