Describing habitual levels of physical activity (PA) in older people in terms of impact loads and how this relates to bone and other systems

Lead Research Organisation: University of Bristol
Department Name: Faculty of Medicine and Dentistry

Abstract

Context
Accelerometers have been widely used to record physical activity (PA) in studies evalauting effects of exercise on human health. Traditionally, these devices provide a measure related to energy consumption which is ideally suited to studying obesity-related outcomes. More recently, accelerometers have been developed which provide information about exposure to forces of different magnitudes. This may represent a more accurate approach to evaluating PA in the case of physiological systems such as the skeleton, which responds to brief high impacts as opposed to sustained loading.

Aims
1. To characterise the extent to which older people are exposed to impact loading of varying magnitudes.
2. To determine whether higher levels of impact loads resulting from everyday PA in older people are related to properties of bone, such as its density and size, whereas little relationship is observed with lower levels of impact.
3. To identify lifestyle, social, psychological and health related factors which affect the exposure of older people to impact loads of different magnitudes.
4. To characterise how relationships between PA and other physiological systems differ according to level of impact load.
5. To explore barriers to participation of older people in PA associated with higher levels of impact.

Methods
Setting: Relationships between PA and bone will be studied in two well characterised population cohorts of older people, namely the MRC National Survey for Health and Development (NSHD; age 68) and the Hertfordshire Cohort Study (HCS; age 74-82) (n=2000 under active follow up in both cohorts). A cohort of 500 elite athletes over 65 will also be recruited.
Study design: Participants from the three cohorts will be asked to wear an accelerometer for seven days, and information about exposure to different levels of impact subsequently extracted using methods developed in our previous studies. A questionnaire asking about factors related to PA will be completed at the same time. Bone measures will include bone density at the hip as measured by a widely used low dose radiation method (DXA), and more detailed measurements of bone size and shape derived from cross sectional images of the lower leg using a different low radiation imaging device (pQCT).
Analysis: PA data will be analysed in relation to bone parameters (i) currently being measured in a subgroup of HCS, and (ii) due to be measured in a subgroup of NSHD and elite athletes as part of this project. We also aim to extrapolate information about exposure to impacts from a previous NSHD data collection involving the whole cohort, relating this to hip bone density obtained at the same time. NSHD and HCS provide detailed information for other systems (eg muscle, obesity, metabolic, cardiovascular, respiratory, cognitive), which will also be analysed in relation to different impacts.

Potential application
Osteoporosis is a common condition predominantly affecting older people, in which weakening of bone leading to an increased risk of fracture. Since decreased PA is thought to contribute to this process, there is a strong need to develop PA interventions to preserve bone strength and reduce fracture risk in older people, particularly in light of emerging safety concerns over conventional pharmacological approaches. However, if successful PA interventions are to be developed for preserving bone, the relationship between PA and bone strength needs to be clearly understood, particularly if only impacts of a certain magnitude are effective in maintaining bone. Likewise, the types of activities which produce desired levels of impact, and the barriers to carrying out these activities, need to be understood if interventions are to be developed which bring about sustained alterations in behaviour required to prevent bone loss in older people.

Technical Summary

We will use a combination of data previously or currently being collected in NSHD and HCS, future data collections funded separately, and data funded via this project comprising (i) accelerometers offered to all participants including a further cohort of Master Athletes, and (ii) and a bone study performed in a subgroup of NSHD and Master Athletes.

Objective 1. Describe habitual PA according to level of impact load in older people
The GCDC X16-1c tri-axial accelerometer will be posted out to participants, worn for 7 days, and number of counts derived within 0.3-0.9g (low eg normal walking), 1-1.5g (medium eg brisk walking), 1.6-2g (high eg aerobics class activities), >2g (very high eg jogging).

Objective 2. Associations between impact loads and bone in older people
Linear regression (adjusted for confounders - see objective 3) will be used to analyse counts within different impact bands in relation to: DXA and tibial pQCT as measured in the bone study; DXA, tibial pQCT and HRpQCT currently being measured in a subgroup of HCS; DXA obtained in the same HCS subgroup 12 months after accelerometry. Additionally, impact data will be extrapolated from previous from Actiheart data, and analysed in relation to hip BMD.

Objective 3: Determinants of exposure to different impact loads
Exposure to different impacts will be related to information about social, economic and psychological influences on PA from a questionnaire sent out with accelerometers, and information on physical performance and other health related factors obtained from face to face assessments.

Objective 4: Associations between impacts and other systems in older people
Exposure to different impacts will be related to variables relating to fat, muscle, cardiovascular, respiratory, and cognition.

Objective 5: Acceptability, barriers and facilitators of activities of different impacts
30 individuals will be purposively selected from the bone study sample and interviewed face to face.

Planned Impact

Public: This research is anticipated to improve the health of older people. For example, those at increased risk of osteoporotic fracture will benefit from the greater understanding of relationships between PA impacts and bone provided by this research, since this information is expected to lead to the development of more effective PA interventions for preserving bone and reducing fracture risk. These benefits are expected to be realised over the relatively short term (ie five years following completion of the grant). Over the longer term, hypotheses concerning relationships between PA and other physiological systems arising from this project, may translate into PA interventions intended to reduce adverse effects of ageing in other patient groups.

Public sector organisations: In the short term, knowledge gained about barriers to participation in higher impact PA will help to inform public policies in the UK eg by promoting the provision of supervised aerobics classes targeted to older people, and improving the availability of exercise friendly neighbourhood spaces. This project will also benefit the public sector by identifying cultural and socio-economic influences on PA which public services need to overcome if PA participation is to be taken up widely. Other beneficiaries include agencies such as NICE, whose recommendations for PA will be modified to ensure these are optimised for preventing osteoporosis. In the longer term, knowledge gained from the research may impact advice and recommendations on PA from international organisations, such as the WHO.

Third Sector: In the short term, this project is expected to benefit patient-based charities such as the National Osteoporosis Society, and those involved in older people such as AgeUK. These charities are expected to play an important role in communicating recommendations arising from this project to the wider public through publicity campaigns, and production of information leaflets aimed at patients found to be at increased risk of osteoporosis, such as those attending hospital after sustaining a low trauma fracture. In the longer term, this research is expected to benefit international charities such as the International Osteoporosis Foundation. Charities funding research in this area, such as The British Society for Research into Ageing, and Arthritis Research UK, may also benefit in the longer term by providing a basis for targeting future research of PA interventions. Depending on the wider clinical applicability of our findings, in the longer term, charities representing other patient groups may also benefit, such as those representing patients with heart disease and dementia.

Business/Industry: This research may also provide opportunities for improving wealth, since the novel approach to PA developed through this project may attract investment from overseas charitable and commercial organisations, to support the development of novel PA interventions and accelerometer device technology. Over the short term, this research will benefit manufacturers of accelerometer devices by identifying further outputs that can be derived from raw accelerometry data, which are likely to be clinically useful, such as number of counts within pre-specified impact bands, and acceleration slopes. Our findings will provide an incentive for developing software which automatically derives these novel variables, thereby increasing the applicability of these devices. It may also be possible to develop versions of accelerometers aimed at older people, as a means of improving adherence to PA regimens, based on attainment of a target number of impacts within a pre-specified acceleration band, as exemplified by the Newtest device aimed at premenopausal women .

Publications

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Elhakeem A (2018) Correlates of high-impact physical activity measured objectively in older British adults. in Journal of public health (Oxford, England)

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Elhakeem A (2019) Lean mass and lower limb muscle function in relation to hip strength, geometry and fracture risk indices in community-dwelling older women. in Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA

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Hannam K (2017) A novel accelerometer-based method to describe day-to-day exposure to potentially osteogenic vertical impacts in older adults: findings from a multi-cohort study. in Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA

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Hannam K (2017) Habitual levels of higher, but not medium or low, impact physical activity are positively related to lower limb bone strength in older women: findings from a population-based study using accelerometers to classify impact magnitude. in Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA

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Hannam K (2015) Maternal Preeclampsia Is Associated With Reduced Adolescent Offspring Hip BMD in a UK Population-Based Birth Cohort. in Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research

 
Description National osteoporosis society guidance on physical activity and osteoporosis (to be launched end of 2018)
Geographic Reach National 
Policy Influence Type Influenced training of practitioners or researchers
 
Description Bone Research Society 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Public engagement event held in conjunction with the Bone Research Society conference in Bristol, in collaboration with the national osteoporosis society, on the importance of exercise for preventing osteoporosis
Year(s) Of Engagement Activity 2017
 
Description Collaboration with the University of the Basque Country (Spain) utilising a method developed by the VIBE study 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact A collaboration with the Sports Science department at the University of the Basque country was initiated and fostered through a visiting PhD student attending the University of Bristol to learn and utilise accelerometer techniques developed for the VIBE study.
Year(s) Of Engagement Activity 2016
 
Description Engagement with New York Times magazine 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact The article in New York Times feature our publication in Frontiers in Endocrinology led to multiple views (over 7000 since it was published in March 2014), and one of the highest ever Altmetrics scores of the journal (22)

Multiple responses from the public discussing means, pros and cons of high impact physical activity
Year(s) Of Engagement Activity 2014
URL http://well.blogs.nytimes.com/2014/03/07/why-high-impact-exercise-is-good-for-your-bones/?_php=true&...
 
Description Invited research seminar 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Postgraduate students
Results and Impact Invited to give a presentation at the Mellanby reasearch centre research day in Sheffield.
Year(s) Of Engagement Activity 2016
URL http://www.mellanbycentre.org/seminars/7thresearchday.pdf
 
Description Oral presentation to the National Osteoporosis Society Conference (Birmingham) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Oral presentation at the 2016 National Osteoporosis Society conference titled 'Day-to-day levels of high impact physical activity are positively related to lower limb bone strength in older women: findings from a population based study using accelerometers to classify impact magnitude'. The abstract for the talk received a young investigator award.
Year(s) Of Engagement Activity 2016
 
Description Poster presentation at the American Society of Bone and Mineral Research (Atlanta) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Poster presentation titled 'Use of Jumping Mechanography to predict physical function in older women' to a large International conference.
Year(s) Of Engagement Activity 2016
 
Description Poster presentation at the Bone Research Society (Liverpool) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Poster presentation to the 2016 Bone Research Society Conference titled: 'Body composition and bone mineral density Comparison between life-long runners, later life runners and recreationally active men and women'.
The poster was presented with an award in the Muscle and Bone Workshop.
Year(s) Of Engagement Activity 2016
 
Description Poster presentation to the National Osteoporosis Society conference (Birmingham) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Poster presentation to a National conference titled 'Validation of a novel accelerometer-based method for measuring day-to-day high impact physical activity in older individuals'.
Year(s) Of Engagement Activity 2016
 
Description Presentation for Institute of advanced studies workshop series 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact A presentation was given at the Institute of advanced studies workshop series which was attended by researchers, policy makers and PhD students. The VIBE study presentation stimulated lots of questions and follow on discussions. This was an opportunity to publicise the work of VIBE and network with a range of people in cognate fields.
Year(s) Of Engagement Activity 2015
 
Description Public engagement event for the Hertfordshire Cohort Study- VIBE study stall 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Participants in your research and patient groups
Results and Impact Over 300 Hertfordshire Cohort study (HCS) participants attended a public engagement meeting on 8th July 2014 at the Hertford Theatre. During the day, the VIBE study had a stall with posters and information sheets. Two members of the VIBE research team (study co-ordinator and HCS Research Assistant) were in attendance and spent the day meeting HCS participants, providing more information about the VIBE study, listening to feedback from individuals who had already participated in the study and collecting participant details of particularly interested individuals.

The researchers representing VIBE spoke to a large proportion of the attendees and following the event there was a noticeable rise in VIBE participation rates.
The feedback received from participants was utilised to improve some aspects of the study e.g. feedback relating to confusion about which way round the accelerometer belt should be worn was addressed by providing additional verbal instructions about this over the phone to participants when they receive their study pack.
Year(s) Of Engagement Activity 2014
URL http://www.mrc.soton.ac.uk/herts/2014/08/22/hertfordshire-cohort-study-public-meeting-day/
 
Description VIBE study presentation at UK-RiME showcase (UK Research in Musculoskeletal Epidemiology) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Around 80 researchers attended the UK-RiME showcase in Manchester. The study co-ordinator presented a 'pitch presentation' providing an overview of the VIBE study and future plans for each of the cohorts involved in the study.
This informed MSK Epidemiologists across the country about the study and stimulated further discussion relating to the study after the presentation.

Networking and early collaborative links made with other MSK Epidmeiologists with a specific interest in physical activity in relation to MSK health.
Year(s) Of Engagement Activity 2014
 
Description Working group 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact As a result of this research, I have been invited to participate in the National Osteoporosis Society Exercise Expert Working Group, which aims to develop advice for exercise practioners working with patients with osteoporosis
Year(s) Of Engagement Activity 2016,2017