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The Healthy Ageing Initiative: Prevention of falls and fractures
Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine. (Healthy Ageing Initiative)ORCID iD: 0000-0001-7912-5786
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The world is currently experiencing a dramatic increase in the number of older individuals, an amount that is expected to double between 2015 and 2050. This increase will likely affect the prevalence of age-related functional impairments, such as those caused by fractures. Fractures are often immobilizing events leading to increased individual suffering and vast healthcare costs. Prevention of these events and detection of underlying risk factors are hence of utmost importance. Fracture prevention strategies have traditionally focused on strengthening the skeleton by improving bone mineral density, partly through the mechanical load of increased physical activity. However, research has shown that nine out of ten hip fractures are attributed to falls. While several risk factors behind falls have been identified, there is less knowledge about how aspects such as gait patterns and postural stability predict future falls. The aim of this thesis was to expand upon the current knowledge by investigating objective measures of physical activity in relation to bone parameters, and measures of gait patterns and postural stability in relation to incident falls, in a large population-based sample of 70-year-olds.

The samples investigated in the four included studies were drawn from the Healthy Ageing Initiative (HAI) cohort. Study I examined associations between physical activity, objectively measured using accelerometers, and bone parameters, measured by Dual-energy X-ray Absorptiometry and Peripheral Quantitative Computed Tomography. Study II examined how gait variability, measured using the GAITRite electronic walkway system, predicted incident falls in men and women. Studies III and IV examined how center of pressure (COP) sway and limits of stability (LOS), measured using a force platform, predicted incident falls. Independent prediction of bone parameters and incident falls were investigated using multiple linear and logistic regression models.

Study I revealed that moderate-to-vigorous physical activity and vertical peak acceleration independently predicted parameters of bone in the weight-bearing skeleton. Study II showed that women’s increased risk of falling could be explained by increased gait variability during dual-task assignments. Study III revealed that the risk of falling was increased by 75-90% for individuals in the highest quintile of COP sway. Study IV integrated COP and LOS data, showing that fall risk was increased by 9-16% per 1-unit increase in COP-LOS ratio. In conclusion, this thesis highlighted several objective predictors of incident falls among older adults. Future studies and recommendations should emphasize strategies to improve balance, muscle strength and physical activity in order to prevent falls and fractures.

Place, publisher, year, edition, pages
Umeå: Umeå universitet , 2018. , p. 52
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 1944
Keywords [en]
prospective falls, cohort study, fall risk, gait variability, postural stability, physical activity, bone properties, objective measurements, older individuals
National Category
Public Health, Global Health, Social Medicine and Epidemiology Geriatrics
Identifiers
URN: urn:nbn:se:umu:diva-143873ISBN: 978-91-7601-830-9 (print)OAI: oai:DiVA.org:umu-143873DiVA, id: diva2:1173884
Public defence
2018-02-09, KBE303 (Stora hörsalen), KBC-huset, Umeå, 09:00 (Swedish)
Opponent
Supervisors
Funder
Swedish Research Council, 2011-2976Available from: 2018-01-19 Created: 2018-01-15 Last updated: 2018-06-09Bibliographically approved
List of papers
1. Objectively measured physical activity is associated with parameters of bone in 70-year-old men and women
Open this publication in new window or tab >>Objectively measured physical activity is associated with parameters of bone in 70-year-old men and women
2015 (English)In: Bone, ISSN 8756-3282, E-ISSN 1873-2763, Vol. 81, p. 72-79Article in journal (Refereed) Published
Abstract [en]

As the world's population ages, the occurrence of osteoporosis-related fractures is projected to increase. Low areal bone mineral density (aBMD), a well-known risk factor for fractures, may be influenced by physical activity (PA). In this cross-sectional study, we aimed to investigate potential associations between objective measures of PA and bone properties, in a population-based cohort of 1228 70-year-old men and women. We measured volumetric BMD (vBMD, mg/cm3) together with cross-sectional area (CSA, mm2) by peripheral quantitative computed tomography at sites located 4% and 66% in the distal–proximal trajectory at the tibia and radius. We also measured aBMD (g/cm2) by dual energy X-ray absorptiometry at the femoral neck, lumbar spine (L1–L4) and radius. Participants wore triaxial accelerometers for 7 consecutive days to obtain objective estimates of PA. The intensity of the objective PA was divided into light (100–1951 counts/min [CPM]), moderate (1952– 5724 cpm) and vigorous (≥5725 cpm). Maximal accelerations for the anterior–posterior (z), medio-lateral (x), and vertical (y) axes were also separately assessed. Associations were investigated using bivariate correlations and multiple linear regression, adjusted for height, weight and sex. Vigorous PA showed the strongest association with femoral neck aBMD (β = 0.09, p b 0.001), while both moderate and vigorous PAs were associated with cor- tical area and trabecular vBMD in the weight-bearing tibia (all p b 0.05). Peak vertical accelerations were associated significantly with cortical area (β = 0.09, p b 0.001) and trabecular vBMD (β = 0.09, p = 0.001) of the tibia, whereas peak anterior–posterior accelerations showed no correlation with these properties. No positive association was found between objectively measured PA and bone parameters of the radius. In conclusion, vertical accelerations and moderate to vigorous PA independently predict bone properties, especially in the weight-bearing tibia, in 70-year-old men and women. 

Place, publisher, year, edition, pages
Elsevier, 2015
Keywords
Physical activity, Aging, Peripheral quantitative computed tomography, Accelerometer, Volumetric BMD
National Category
Geriatrics
Identifiers
urn:nbn:se:umu:diva-112194 (URN)10.1016/j.bone.2015.07.001 (DOI)000365372800011 ()26151120 (PubMedID)
Funder
Swedish Research Council, 2011-2976
Available from: 2015-12-03 Created: 2015-12-03 Last updated: 2018-06-07Bibliographically approved
2. Greater Fall Risk in Elderly Women Than in Men Is Associated With Increased Gait Variability During Multitasking
Open this publication in new window or tab >>Greater Fall Risk in Elderly Women Than in Men Is Associated With Increased Gait Variability During Multitasking
2016 (English)In: Journal of the American Medical Directors Association, ISSN 1525-8610, E-ISSN 1538-9375, Vol. 17, no 6, p. 535-540Article in journal (Refereed) Published
Abstract [en]

Objective: As 90% of fractures are caused by falls, and as fractures are more common in elderly women than in elderly men, a better understanding of potential sex differences in fall rates and underlying mechanisms is needed. The purpose of this study was to determine whether women are more prone than men to falling, and to evaluate whether the risk of falling is associated with variations in gait patterns.

Design, setting, and participants: The cohort for this prospective observational study consisted of 1390 community-dwelling men and women aged 70 years, examined in a health survey between July 2012 and November 2014.

Measurements: Gait patterns were measured using a computerized walkway system during normal-speed, fast-speed, and dual-task trials. Triaxial accelerometers were used to collect objective data on physical activity, and self-reported fall data were collected by telephone 6 and 12 months after examination. Incident low-energy falls were defined as unexpected events in which participants came to rest on the ground.

Results: During the follow-up period, 148 study participants (88 women, 60 men; P = .01) reported falls. After adjusting for multiple confounders, including objective measures of physical activity, socioeconomic factors, cardiovascular disease, and cognitive function, the odds ratio for falling in women was 1.49 (95% confidence interval [CI] 1.02–2.19). Variations in gait pattern were significantly (20%–40%) increased in fallers compared with nonfallers during the dual-task trial for step width, step length, stride length, step time, stance time, stride velocity, and single support time (all P < .05). Furthermore, women showed 15% to 35% increased variability in all of these gait parameters during the dual-task trial compared with men (all P < .01).

Conclusion: In the present cohort, 70-year-old women were at greater risk of falls compared with their male counterparts. This increased risk was associated with increased variation in gait pattern during dual-task activities, and may contribute to women's greater fracture risk compared with men.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Incident falls, gait variability, dual-task, elderly, physical activity
National Category
Geriatrics
Identifiers
urn:nbn:se:umu:diva-123443 (URN)10.1016/j.jamda.2016.02.009 (DOI)000377400500013 ()27006336 (PubMedID)
Funder
Swedish Research Council
Available from: 2016-07-20 Created: 2016-07-04 Last updated: 2018-06-07Bibliographically approved
3. Increased postural sway during quiet stance as a risk factor for prospective falls in community-dwelling elderly individuals
Open this publication in new window or tab >>Increased postural sway during quiet stance as a risk factor for prospective falls in community-dwelling elderly individuals
Show others...
2017 (English)In: Age and Ageing, ISSN 0002-0729, E-ISSN 1468-2834, Vol. 46, no 6, p. 964-970Article in journal (Refereed) Published
Abstract [en]

Objective: fall-related injuries constitute major health risks in older individuals, and these risks are projected to increase in parallel with increasing human longevity. Impaired postural stability is a potential risk factor related to falls, although the evidence is inconclusive, partly due to the lack of prospective studies. This study aimed to investigate how objective measures of postural sway predict incident falls.

Design, setting and participants: this prospectively observational study included 1,877 community-dwelling individuals aged 70 years who participated in the Healthy Ageing Initiative between June 2012 and December 2015.

Measurements: postural sway was measured during eyes-open (EO) and eyes-closed (EC) trials using the Wii Balance Board. Functional mobility, muscle strength, objective physical activity and cognitive performance were also measured. Participants reported incident falls 6 and 12 months after the examination.

Results: during follow-up, 255 (14%) prospective fallers were identified. Division of centre of pressure (COP) sway lengths into quintiles revealed a nonlinear distribution of falls for EO trial data, but not EC trial data. After adjustment for multiple confounders, fall risk was increased by 75% for participants with COP sway lengths ≥400 mm during the EO trial (odds ratio [OR] 1.75, 95% confidence interval [CI] 1.09-2.79), and approximately doubled for sway lengths ≥920 mm during the EC trial (OR 1.90, 95% CI 1.12-3.22).

Conclusion: objective measures of postural sway independently predict incident falls in older community-dwelling men and women. Further studies are needed to evaluate whether postural sway length is of interest for the prediction of incident falls in clinical settings.

Place, publisher, year, edition, pages
Oxford University Press, 2017
Keywords
incident fall, postural sway, older people, cohort study, posturography
National Category
Physiotherapy Geriatrics
Identifiers
urn:nbn:se:umu:diva-135433 (URN)10.1093/ageing/afx083 (DOI)000413549300016 ()28531243 (PubMedID)
Available from: 2017-05-29 Created: 2017-05-29 Last updated: 2018-06-09Bibliographically approved
4. Predicting incident falls: relationship between postural sway and functional limits of stability in older adults
Open this publication in new window or tab >>Predicting incident falls: relationship between postural sway and functional limits of stability in older adults
Show others...
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Background: We have previously shown that objective measurements of postural sway predicts fall risk, although it is currently unknown how functional limits of stability (LOS) might influence these results.

Research question: How integrated postural sway and LOS measurements predict the risk of incident falls in a population-based sample of older adults.

Methods: The sample for this prospective observational study was drawn from the Healthy Ageing Initiative cohort and included data collected between June 2012 and December 2016 for 2396 men and women, all 70 years of age. LOS was compared to postural sway with measurements during eyes-open (EO) and eyes-closed (EC) trials, using the previously validated Wii Force Plate. Fall history was assessed during baseline examination and incident falls were collected during follow-up at 6 and 12 months. Independent predictors of incident falls and additional covariates were investigated using multiple logistic regression models.

Results: During follow-up, 337 (14%) fallers were identified. Unadjusted regression models from the EO trial revealed increased fall risk by 6% (OR 1.06, 95% CI 1.02 – 1.11) per each centimeter squared increase in sway area and by 16 % (OR 1.16, 95% CI 1.07 – 1.25) per 1-unit increase in Sway-Area-to-LOS ratio. Odds ratios were generally lower when analyzing EC trials and only slightly attenuated in fully adjusted models.

Significance: Integrating postural sway and LOS parameters provides valid fall risk prediction and a holistic analysis of postural stability. Future work should establish normative values and evaluate clinical utility of these measures.

National Category
Public Health, Global Health, Social Medicine and Epidemiology
Identifiers
urn:nbn:se:umu:diva-143872 (URN)
Available from: 2018-01-11 Created: 2018-01-11 Last updated: 2018-06-09Bibliographically approved

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