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Physical frailty and decline in general and specific cognitive abilities: the Lothian Birth Cohort 1936
  1. Catharine Gale1,2,
  2. Stuart J Ritchie3,
  3. John M Starr4,
  4. Ian J Deary1
  1. 1Psychology, The University of Edinburgh, Edinburgh, UK
  2. 2MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, United Kingdom
  3. 3Social, Genetic and Developmental Psychiatry Centre, King's College London, London, UK
  4. 4Geriatric Medicine Unit, University of Edinburgh, Edinburgh, United Kingdom
  1. Correspondence to Professor Catharine Gale, MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, United Kingdom; crg{at}mrc.soton.ac.uk

Abstract

Background Physical frailty is associated with many adverse outcomes including disability, chronic disease, hospitalisation, institutionalisation and death. It is unclear what impact it might have on the rate of normal cognitive ageing. We investigated whether physical frailty was related to initial level of, and change in, cognitive abilities from age 70 to 79 years.

Method Participants were 950 members of the Lothian Birth Cohort 1936. Physical frailty was assessed at age 70 years using the Fried criteria. Cognitive function was assessed at ages 70, 73, 76 and 79 years. We used linear regression to examine cross-sectional and prospective associations between physical frailty status at age 70 years and factor score estimates for baseline level of and change in four cognitive domains (visuospatial ability, memory, processing speed and crystallised ability) and in general cognitive ability.

Results Physical frailty, but not prefrailty, was associated with lower baseline levels of visuospatial ability, memory, processing speed and general cognitive ability after control for age, sex, education, depressive symptoms, smoking and number of chronic illnesses. Physical frailty was associated with greater decline in each cognitive domain: age-adjusted and sex-adjusted standardised regression coefficients (95% CIs) were: −0.45 (−0.70 to –0.20) for visuospatial ability, −0.32 (−0.56 to –0.07) for memory, −0.47 (−0.72 to −0.22) for processing speed, −0.43 (−0.68 to –0.18) for crystallised ability and −0.45 (−0.70 to –0.21) for general cognitive ability. These associations were only slightly attenuated after additional control for other covariates.

Conclusion Physical frailty may be an important indicator of age-related decline across multiple cognitive domains.

  • cohort studies
  • ageing
  • cognition

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Footnotes

  • Deceased John Starr died in December 2018

  • Contributors CG and ID planned the study; SR and CG carried out the statistical analysis; CG and SR drafted the manuscript; CG, SR, JS and ID revised the manuscript.

  • Funding This work was supported by the Disconnected Mind project (funded by Age UK and MRC (Mr/M01311/1 and G1001245/96077)) and undertaken within the University of Edinburgh Centre for Cognitive Ageing and Cognitive Epidemiology (funded by the BBSRC and MRC as part of the Life Long Health and Wellbeing programme (MR/K026992/1)).

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval Ethical approval was obtained from the Multi-Centre Ethics Committee for Scotland (MREC/01/0/56) and Lothian Research Ethics Committee (LREC/2003/2/29).

  • Provenance and peer review Not commissioned; internally peer reviewed.

  • Data availability statement Data are available only upon request because there are ethical restrictions on openly sharing the dataset. The consent forms for the study (approved by the Multi-Centre Research Ethics Committee for Scotland and the Lothian Research Ethics Committee) included that participants’ data, some of which is sensitive, would only be used for research. Data are available by submitting a data access form to i.deary{at}ed.ac.uk or lbc1936{at}ed.ac.uk.

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