Mild cognitive impairment is associated with poor physical function but not bone structure or density in late adulthood: findings from the Hertfordshire cohort study
Archives of Osteoporosis
Mild cognitive impairment is associated with poor physical function but not bone structure or density in late adulthood: findings from the Hertfordshire cohort study
A. Patel 0 1 2 4 5
K. A. Jameson 0 1 2 4 5
M. H. Edwards 0 1 2 4 5
K. Ward 0 1 2 4 5
C. R. Gale 0 1 2 4 5
C. Cooper 0 1 2 4 5
Elaine M. Dennison 0 1 2 4 5
0 Centre for Cognitive Ageing and Cognitive Epidemiology, Department of Psychology, University of Edinburgh , Edinburgh , UK
1 MRC Lifecourse Epidemiology Unit, Southampton General Hospital, University of Southampton , Southampton SO16 6YD , UK
2 University Hospital Southampton NHS Foundation Trust , Southampton , UK
3 Elaine M. Dennison
4 Victoria University , Wellington , New Zealand
5 NIHR Musculoskeletal Biomedical Research Unit, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford , Oxford , UK
Summary This study investigated the association between mild cognitive impairment (MCI) and physical function and bone health in older adults. MCI was associated with poor physical performance but not bone mineral density or bone microarchitecture. Purpose Cross-sectional study to investigate the association between mild cognitive impairment (MCI) and physical performance, and bone health, in a community-dwelling cohort of older adults. Methods Cognitive function of 222 men and 221 women (mean age 75.5 and 75.8 years in men and women, respectively) was assessed by the Strawbridge questionnaire and Mini Mental State Exam (MMSE). Participants underwent dual-energy X-ray absorptiometry (DXA), peripheral-quantitative computed tomography (pQCT) and high-resolution peripheral-quantitative computed tomography (HR-pQCT) scans to assess their bone density, strength and microarchitecture. Their physical function was assessed and a physical performance (PP) score was recorded. Results In the study, 11.8% of women and 8.1% of men were cognitively impaired on the MMSE (score < 24). On the Strawbridge questionnaire, 24% of women were deemed cognitively impaired compared to 22.3% of men. Cognitive impairment on the Strawbridge questionnaire was associated with poorer physical performance score in men but not in women in the unadjusted analysis. MMSE < 24 was strongly associated with the risk of low physical performance in men (OR 12.9, 95% CI 1.67, 99.8, p = 0.01). Higher MMSE score was associated with better physical performance in both sexes. Poorer cognitive function, whether assessed by the Strawbridge questionnaire, or by MMSE score, was not associated with bone density, shape or microarchitecture, in either sex. Conclusion MCI in older adults was associated with poor physical performance, but not bone density, shape or microarchitecture.
Mild cognitive impairment; Physical performance; Bone parameters; Epidemiology
A. Patel is first author.
C. Cooper and E.M. Dennison are joint senior authors.
Introduction
Mild cognitive impairment (MCI) is a heterogeneous state
between normal ageing and early dementia [
1
]. The
prevalence of MCI is rising as the population ages. It has been
estimated to affect 19% of individuals aged 65 and over [
2
].
While cognitive decline is a well-documented clinical
hallmark of MCI, changes in physical health are also apparent
during the course of MCI and include increased physical
fragility and reduced physical performance [
3–6
], resulting in
individuals being at increased risk of injuries [7].
Emerging data suggest bone mineral density (BMD) is
reduced in severely cognitively impaired individuals, compared
to cognitively normal individuals of a similar age [
8
].
Although it has been suggested that there may be a link
between cognitive impairment and BMD [9], little is known
about bone loss rates in MCI subjects.
The majority of evidence to date has been derived from
studies set in long-term care/nursing homes and hospitals [
7,
10–12
] where individuals are frail and severely cognitively
impaired. The purpose of this study was to further investigate
whether an association exists between MCI and both bone
health and physical performance status in a well-established
community-dwelling cohort of older adults. If MCI was
associated with reduced bone density, this might be considered an
important risk factor for fracture that could be addressed in
treatment algorithms that included anti-osteoporosis therapy.
Methods
The Hertfordshire Cohort Study (HCS) is a population-based
UK cohort of older adults. Study design and recruitment have
been described in detail previously [
13
]. In brief, we traced
men and women bo rn b etween 19 31 a nd 1 939 in
Hertfordshire and who still lived there in 1998–2003. A
nurse-administered questionnaire, which included details of
socioeconomic status and dietary calcium intake, was
conducted at this time. In 2011–2012, 443 participants consented
to a home visit by a trained research nurse. At this visit, a
nurse-administered questionnaire was again administer (...truncated)