The online version of this article (https://doi.org/10.1186/s12888-018-1851-3) contains supplementary material, which is available to authorized users.
Previous studies have demonstrated that individual measures of fitness – such as reduced pulmonary function, slow walking speed and weak handgrip – are associated with an increased risk of dementia. Only a minority of participants included in these studies were aged over 80. The aim of this study was therefore to investigate the association between physical fitness and dementia in the oldest old.
Subjects (n = 488) were enrolled in the Lothian Birth Cohort 1921 and aged 79 at baseline. Dementia cases arising after enrolment were determined using data from death certificates, electronic patient records and clinical reviews. Fitness measures included grip strength, forced expiratory volume in 1 s (FEV1) and walking speed over 6 m, measured at 79 years. Dementia risk associated with each fitness variable was initially determined by logistic regression analysis, followed by Cox regression analysis, where death was considered as a competing risk. APOE ε4 status, age, sex, height, childhood IQ, smoking, history of cardiovascular or cerebrovascular disease, hypertension and diabetes were included as additional variables. Cumulative incidence graphs were calculated using Aalen-Johansen Estimator.
Although initial results indicated that greater FEV1 was associated with an increased risk of dementia (OR (odds ratio per unit increase) 1.93, p = 0.03, n = 416), taking into account the competing risk of mortality, none of the fitness measures were found to be associated with dementia; FEV1 (HR (hazard ratio per unit increase) 1.30, p = 0.37, n = 416), grip strength (HR 0.98, p = 0.35, n = 416), walking speed (HR 0.99, p = 0.90, n = 416). The presence of an APOE ɛ4 allele was however an important predictor for dementia (HR 2.85, p < 0.001, n = 416). Cumulative incidence graphs supported these findings, with an increased risk of dementia for APOE ɛ4 carriers compared with non-carriers. While increased FEV1 was associated with reduced risk of death, there was no reduction in risk for dementia.
In contrast to previous studies, this study found that lower fitness beyond age 79 was not a risk factor for subsequent dementia. This finding is not explained by those with poorer physical fitness, who would have been more likely to develop dementia, having died before onset of dementia symptoms.
Additional file 1: Table S1. Group Comparison: Deceased and Living. (DOCX 14 kb)12888_2018_1851_MOESM1_ESM.docx
Schaub RT, Münzberg H, Borchelt M, Nieczaj R, Hillen T, Reischies FM, Schlattmann P, Geiselmann B, Steinhagen-Thiessen E. Ventilatory capacity and risk for dementia. J Gerontol Series A. 2000;55(11):M677–83. CrossRef
Russ TC, Kivimaki M, Batty GD. Pulmonary function and risk of dementia: a systematic review with meta-analysis [poster abstract]. Alzheimer’s & Dementia In Press, 7(Suppl.)(Suppl.).
Dumurgier J, Artaud F, Touraine C, Rouaud O, Tavernier B, Dufouil C, Singh-Manoux A, Tzourio C, Elbaz A. Gait speed and decline in gait speed as predictors of incident dementia. J Gerontol Series A. 2017;72(5):655–61.
Welmer A-K, Rizzuto D, Qiu C, Caracciolo B, Laukka EJ. Walking speed, processing speed, and dementia: a population-based longitudinal study. J Gerontol Series A. 2014;69(12):1503–10. CrossRef
Abellan van Kan G, Rolland Y, Gillette-Guyonnet S, Gardette V, Annweiler C, Beauchet O, Andrieu S, Vellas B. Gait speed, body composition, and dementia. The EPIDOS-Toulouse cohort. J Gerontol Series A. 2012;67A(4):425–32. CrossRef
Hörder H, Johansson L, Guo X, Grimby G, Kern S, Östling S, Skoog I. Midlife cardiovascular fitness and dementia: a 44-year longitudinal population study in women. Neurology. 2018;14:10–212.
Deckers K, van Boxtel MP, Schiepers OJ, de Vugt M, Munoz Sanchez JL, Anstey KJ, Brayne C, Dartigues JF, Engedal K, Kivipelto M, et al. Target risk factors for dementia prevention: a systematic review and Delphi consensus study on the evidence from observational studies. Int J Geriatr Psychiatry. 2015;30:234–46. CrossRefPubMed
Office for National Statistics. Population estimates for UK, England and Wales, Scotland and Northern Ireland: mid-2017. https://www.ons.gov.uk/peoplepopulationandcommunity/populationandmigration/populationestimates/bulletins/annualmidyearpopulationestimates/mid2017. Accessed 5 July 2018.
Cooper R, Kuh D, Hardy R, Mortality Review Group. Objectively measured physical capability levels and mortality: systematic review and meta-analysis. BMJ. 2010;341:c4467.
Scottish Council For Research In Education. The intelligence of Scottish children: a national survey of an age-group. London; University of London Press: 1933.
Bellamy, D. Spirometry in practice: a practical guide to using spirometry in primary care: 2 nd edition . British Thoracic Society 2005. https://www.brit-thoracic.org.uk/document-library/delivery-of-respiratory-care/spirometry/spirometry-in-practice-a-practical-guide-(2005)/. Accessed 5 July 2018.
R-project. A language and environment for statistical computing. https://www.R-project.org/. Accessed 5 July 2018.
Aalen OO, Johansen S. An empirical transition matrix for non-homogeneous Markov chains based on censored observations. Scand J Stat. 1978;5(3):141–50.
Wain LV, Shrine N, Artigas MS, Erzurumluoglu AM, Noyvert B, Bossini-Castillo L, Me O, Henry AP, Portelli MA, Hall RJ, et al. Genome-wide association analyses for lung function and chronic obstructive pulmonary disease identify new loci and potential druggable targets. Nat Genet. 2017;49:416. CrossRefPubMedPubMedCentral
Wain LV, Shrine N, Miller S, Jackson VE, Ntalla I, Artigas MS, Billington CK, Kheirallah AK, Allen R, Cook JP, et al. Novel insights into the genetics of smoking behaviour, lung function, and chronic obstructive pulmonary disease (UK BiLEVE): a genetic association study in UK biobank. Lancet Respir Med. 2015;3(10):769–81. CrossRefPubMedPubMedCentral
Biobank UK. Genetic study targets lung disease and smoking behaviour. Sept 2015. http://www.ukbiobank.ac.uk/2015/09/genetic-study-targets-lung-disease-and-smoking-behaviour/. Accessed 5 July 2018.
Li G, Rhew IC, Shofer JB, Kukull WA, Breitner JCS, Peskind E, Bowen JD, McCormick W, Teri L, Crane PK, et al. Age-varying association between blood pressure and risk of dementia in those aged 65 and older: a community-based prospective cohort study. J Am Geriatr Soc. 2007;55(8):1161–7. CrossRefPubMed
- Physical fitness and dementia risk in the very old: a study of the Lothian Birth Cohort 1921
Ruth A. Sibbett
Tom C. Russ
Ian J. Deary
John M. Starr
- BioMed Central