Ten-year change in sedentary behaviour, moderate-to-vigorous physical activity, cardiorespiratory fitness and cardiometabolic risk: independent associations and mediation analysis.

BACKGROUND: We aimed to study the independent associations of 10-year change in sedentary behaviour (SB), moderate-to-vigorous physical activity (MVPA) and objectively measured cardiorespiratory fitness (CRF), with concurrent change in clustered cardiometabolic risk and its individual components (waist circumference, fasting glucose, high-density lipoprotein (HDL) cholesterol, triglycerides and blood pressure). We also determined whether associations were mediated by change in CRF (for SB and MVPA), waist circumference (for SB, MVPA and CRF) and dietary intake (for SB). METHODS: A population-based sample of 425 adults (age (mean±SD) 55.83±9.40; 65% men) was followed prospectively for 9.62±0.52 years. Participants self-reported SB and MVPA and performed a maximal cycle ergometer test to estimate peak oxygen uptake at baseline (2002-2004) and follow-up (2012-2014). Multiple linear regression and the product of coefficients method were used to examine independent associations and mediation effects, respectively. RESULTS: Greater increase in SB was associated with more detrimental change in clustered cardiometabolic risk, waist circumference, HDL cholesterol and triglycerides, independently of change in MVPA. Greater decrease in MVPA was associated with greater decrease in HDL cholesterol and increase in clustered cardiometabolic risk, waist circumference and fasting glucose, independent of change in SB. Greater decrease in CRF was associated with more detrimental change in clustered cardiometabolic risk and all individual components. Change in CRF mediated the associations of change in SB and MVPA with change in clustered cardiometabolic risk, waist circumference and, only for MVPA, HDL cholesterol. Change in waist circumference mediated the associations between change in CRF and change in clustered cardiometabolic risk, fasting glucose, HDL cholesterol and triglycerides. CONCLUSIONS: A combination of decreasing SB and increasing MVPA, resulting in positive change in CRF, is likely to be most beneficial towards cardiometabolic health.This work was supported by a British Heart Foundation Intermediate Basic Science Research Fellowship to KW (grant number FS/12/58/29709), the UK Medical Research Council (grant number MC_UU_12015/3) to KW, the Research Foundation Flanders (grant number G.0194.11N) and the Flemish Policy Research Centre Sport

Impact of sit-stand desks at work on energy expenditure and sedentary time: protocol for a feasibility study.

BACKGROUND: Prolonged sitting, an independent risk factor for disease development and premature mortality, is increasing in prevalence in high- and middle-income countries, with no signs of abating. Adults in such countries spend the largest proportion of their day in sedentary behaviour, most of which is accumulated at work. One promising method for reducing workplace sitting is the use of sit-stand desks. However, key uncertainties remain about this intervention, related to the quality of existing studies and a lack of focus on key outcomes, including energy expenditure. We are planning a randomised controlled trial to assess the impact of sit-stand desks at work on energy expenditure and sitting time in the short and longer term. To reduce the uncertainties related to the design of this trial, we propose a preliminary study to assess the feasibility and acceptability of the recruitment, allocation, measurement, retention and intervention procedures. METHODS: Five hundred office-based employees from two companies in Cambridge, UK, will complete a survey to assess their interest in participating in a trial on the use of sit-stand desks at work. The workspaces of 100 of those interested in participating will be assessed for sit-stand desk installation suitability, and 20 participants will be randomised to either the use of sit-stand desks at work for 3 months or a waiting list control group. Energy expenditure and sitting time, measured via Actiheart and activPAL monitors, respectively, as well as cardio-metabolic and anthropometric outcomes and other outcomes relating to health and work performance, will be assessed in 10 randomly selected participants. All participants will also be interviewed about their experience of using the desks and participating in the study. DISCUSSION: The findings are expected to inform the design of a trial assessing the impact of sit-stand desks at work on short and longer term workplace sitting, taking into account their impact on energy expenditure and the extent to which their use has compensation effects outside the workplace. The findings from such a trial are expected to inform discussions regarding the potential of sit-stand desks at work to alleviate the harm to cardio-metabolic health arising from prolonged sitting. TRIAL REGISTRATION: ISRCTN44827407.This work was supported by a grant from the Department of Health Policy Research Program (Policy Research Unit in Behaviour and Health [PR-UN-0409-10109]), the Medical Research Council (Unit Programme number MC_UU_12015/3) and the British Heart Foundation (Intermediate Basic Science Research Fellowship grant FS/12/58/29709 to KW)

The descriptive epidemiology of accelerometer-measured physical activity in older adults.

BACKGROUND: Objectively measured physical activity between older individuals and between populations has been poorly described. We aimed to describe and compare the variation in accelerometry data in older UK (EPIC-Norfolk) and American (NHANES) adults. METHODS: Physical activity was measured by uniaxial accelerometry in 4,052 UK (49-91 years) and 3459 US older adults (49-85 years). We summarized physical activity as volume (average counts/minute), its underlying intensity distribution, and as time spent 809 counts/minute is used 18.7% of people reached the 30 min/day threshold. By comparison, 2.5% and 9.5% of American older adults accumulated activity at these levels, respectively. CONCLUSION: As assessed by objectively measured physical activity, the majority of older adults in this UK study did not meet current activity guidelines. Older adults in the UK were more active overall, but also spent more time being sedentary than US adults.This work was supported by programme grants from the Medical Research Council [G9502233; G0401527] and Cancer Research UK [C864/A8257]. A grant from Research into Ageing [262] funded the 3rd health check clinic. KW is supported by a British Heart Foundation Intermediate Basic Science Research Fellowship [FS/12/58/29709], and AJMC, SJG, NJW, and SB are supported by MRC programme grants [MC_UU_12015/3 and MC_UU_12015/4].This is the final version of the article. It was first available from BioMed Central via http://dx.doi.org/10.1186/s12966-015-0316-

Objectively measured physical activity and longitudinal changes in adolescent body fatness: an observational cohort study.

BACKGROUND: The data regarding prospective associations between physical activity (PA) and adiposity in youth are inconsistent. OBJECTIVE: The objective of this study was to investigate associations between baseline levels of objectively measured PA and changes in adiposity over 2.5 years from mid-to-late adolescence. METHODS: This was an observational cohort study in 728 school students (43% boys) from Cambridgeshire, United Kingdom. Fat mass index (FMI, kg m(-2) ) was estimated at baseline (mean ± standard deviation age: 15 ± 0.3 years) and follow-up (17.5 ± 0.3 years) by anthropometry and bioelectrical impedance. Habitual PA was assessed at baseline by ≥3 d combined heart rate and movement sensing. Average daily PA energy expenditure (PAEE) and the time (min d(-1) ) spent in light, moderate and vigorous intensity PA (LPA, MPA and VPA, respectively) was estimated. Multilevel models were used to investigate associations between baseline PA and change in FMI (ΔFMI). Adjustment for baseline age, sex, follow-up duration, area-level socioeconomic status, season of PA assessment, sedentary time, energy intake and sleep duration was made; baseline FMI was also added in a second model. RESULTS: FMI increased significantly over follow-up (0.6 ± 1.2 kg m(-2) , P < 0.001). Baseline PAEE and LPA positively predicted ΔFMI in overfat participants (P ≤ 0.030), as did VPA in initially normal fat participants (P ≤ 0.044). There were further positive associations between PAEE and ΔFMI in normal fat participants, and between MPA and ΔFMI in both fat groups, when adjusted for baseline FMI (P ≤ 0.024). CONCLUSIONS: Baseline PAEE and its subcomponents were positively associated with small and unlikely clinically relevant increases in ΔFMI. These counter-intuitive findings may be explained by behavioural changes during the course of study follow-up.This work was supported by the Medical Research Council (Unit Programme number MC_UU_12015/3), the Wellcome Trust (grant 074296/Z/04/Z) and the British Heart Foundation (grant FS/12/58/29709 to KW).This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1111/ijpo.1203

Sedentary Time and Physical Activity Surveillance Through Accelerometer Pooling in Four European Countries.

OBJECTIVE: The objective of this study was to pool, harmonise and re-analyse national accelerometer data from adults in four European countries in order to describe population levels of sedentary time and physical inactivity. METHODS: Five cross-sectional studies were included from England, Portugal, Norway and Sweden. ActiGraph accelerometer count data were centrally processed using the same algorithms. Multivariable logistic regression analyses were conducted to study the associations of sedentary time and physical inactivity with sex, age, weight status and educational level, in both the pooled sample and the separate study samples. RESULTS: Data from 9509 participants were used. On average, participants were sedentary for 530 min/day, and accumulated 36 min/day of moderate to vigorous intensity physical activity. Twenty-three percent accumulated more than 10 h of sedentary time/day, and 72% did not meet the physical activity recommendations. Nine percent of all participants were classified as high sedentary and low active. Participants from Norway showed the highest levels of sedentary time, while participants from England were the least physically active. Age and weight status were positively associated with sedentary time and not meeting the physical activity recommendations. Men and higher-educated people were more likely to be highly sedentary, while women and lower-educated people were more likely to be inactive. CONCLUSIONS: We found high levels of sedentary time and physical inactivity in four European countries. Older people and obese people were most likely to display these behaviours and thus deserve special attention in interventions and policy planning. In order to monitor these behaviours, accelerometer-based cross-European surveillance is recommended.The original studies were funded by the Norwegian Directorate of Health and the Norwegian School of Sport Sciences; the Portuguese Institute of Sport; a grant from the Stockholm County Council; and grants from the Swedish Council for Working Life and Social Research, and The Swedish Research Council for Environment, Agricultural Sciences, and Spatial Planning. AL, JL, JB and HvdP were supported by the Netherlands Organisation for Health Research and Development (Grant no. 200.600.001). KS was supported by the National Heart, Lung, And Blood Institute of the National Institutes of Health (award no. R01HL116381). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. KW was supported by the British Heart Foundation (Grant FS/12/58/29709). KW and SB were supported by the UK Medical Research Council (Grant MC_UU_12015/3)

Reliability and validity of three questionnaires measuring context-specific sedentary behaviour and associated correlates in adolescents, adults and older adults

BACKGROUND: Reliable and valid measures of total sedentary time, context-specific sedentary behaviour (SB) and its potential correlates are useful for the development of future interventions. The purpose was to examine test-retest reliability and criterion validity of three newly developed questionnaires on total sedentary time, context-specific SB and its potential correlates in adolescents, adults and older adults. METHODS: Reliability and validity was tested in six different samples of Flemish (Belgium) residents. For the reliability study, 20 adolescents, 22 adults and 20 older adults filled out the age-specific SB questionnaire twice. Test-retest reliability was analysed using Kappa coefficients, Intraclass Correlation Coefficients and/or percentage agreement, separately for the three age groups. For the validity study, data were retrieved from 62 adolescents, 33 adults and 33 older adults, with activPAL as criterion measure. Spearman correlations and Bland-Altman plots (or non-parametric approach) were used to analyse criterion validity, separately for the three age groups and for weekday, weekend day and average day. RESULTS: The test-retest reliability for self-reported total sedentary time indicated following values: ICC = 0.37-0.67 in adolescents; ICC = 0.73-0.77 in adults; ICC = 0.68-0.80 in older adults. Item-specific reliability results (e.g. context-specific SB and its potential correlates) showed good-to-excellent reliability in 67.94%, 68.90% and 66.38% of the items in adolescents, adults and older adults respectively. All items belonging to sedentary-related equipment and simultaneous SB showed good reliability. The sections of the questionnaire with lowest reliability were: context-specific SB (adolescents), potential correlates of computer use (adults) and potential correlates of motorized transport (older adults). Spearman correlations between self-reported total sedentary time and the activPAL were different for each age group: rho = 0.02-0.42 (adolescents), rho = 0.06-0.52 (adults), rho = 0.38-0.50 (older adults). Participants over-reported total sedentary time (except for weekend day in older adults) compared to the activPAL, for weekday, weekend day and average day respectively by +57.05%, +46.29%, +53.34% in adolescents; +40.40%, +19.15%, +32.89% in adults; +10.10%, -6.24%, +4.11% in older adults. CONCLUSIONS: The questionnaires showed acceptable test-retest reliability and criterion validity. However, over-reporting of total SB was noticeable in adolescents and adults. Nevertheless, these questionnaires will be useful in getting context-specific information on SB

Feasibility of incorporating objective measures of physical activity in the STEPS program. A pilot study in Malawi

Background Physical activity is an important determinant of human health but it is inherently difficult to measure. Global surveillance systems for physical activity have so far only included self-report measures, which capture only a small subset of daily activity and are limited due to issues of recall bias. Wrist-worn accelerometry offers a reasonably cost-effective objective method of measuring physical activity during free-living with proven feasibility in large-scale population studies. The key objective of this project was to pilot wrist-worn accelerometry within a surveillance setting in order to inform the implementation of this methodology into the global WHO STEPS programme. Method development and implementation Accelerometry protocols were developed and deployed within an existing STEPS survey in two regions of Malawi (Dowa and Lilongwe). This also included developing training for local staff. Survey information was collected on tablets. Accelerometers could only be set up on PCs, so the protocol was adapted to do this in advance of recruiting participants. For this, an alternative Participant ID linkage system was developed to enable linking accelerometer files to the rest of the survey data. On the whole, the implementation was successful. During the process evaluation, some issues were identified. For example, black wrist straps were culturally associated with the Devil by some participants. A total of 499 participants were recruited for Step 1 and 2, of whom 446 returned for Step 3 measurements which included accelerometry. The accelerometry data collection was well accepted by both fieldwork team members and study participants, with only four participants (<1% of those eligible) declining to wear the device. There were no major technical issues with devices, although a small number of wrist straps were damaged and 13 monitors were lost (3% of deployed). Of 456 accelerometer files retrieved, 410 files (90%) could be linked to survey participants. All but two accelerometer files could be processed with standard techniques to produce participant-level summary results. Sufficient valid data (defined as at least 48 hours of monitor wear time with reasonable diurnal representation) were available for 386 survey participants (87% of eligible). Results Objective levels of physical activity in Malawi from this pilot study were about 50% higher than levels observed in the UK using similar methodology. Rural dwellers were more active than urban dwellers, particularly in the morning hours of the day. Men had higher activity levels compared to women, and there were decreasing trends with advancing age. Conclusion and recommendations This pilot demonstrated that it is feasible to implement wrist-worn accelerometry within the STEPS program in settings such as Malawi. Detailed description of objectively measured physical activity patterns could be produced from nearly all accelerometer files retrieved, including behavioural indicators known to be important for human health. In future surveys, culturally specific issues that could impact data collection should be identified early in the fieldwork planning stage and changes to the protocol made. Experiences from this pilot have led to development of software platforms that allow accelerometers to be set up from Android tablets at the point of issuing the device to the participant, which would simplify future fieldwork training and reduce risk of data linkage error

Patterns of impact resulting from a 'sit less, move more' web-based program in sedentary office employees.

PURPOSE: Encouraging office workers to 'sit less and move more' encompasses two public health priorities. However, there is little evidence on the effectiveness of workplace interventions for reducing sitting, even less about the longer term effects of such interventions and still less on dual-focused interventions. This study assessed the short and mid-term impacts of a workplace web-based intervention (Walk@WorkSpain, W@WS; 2010-11) on self-reported sitting time, step counts and physical risk factors (waist circumference, BMI, blood pressure) for chronic disease. METHODS: Employees at six Spanish university campuses (n=264; 42±10 years; 171 female) were randomly assigned by worksite and campus to an Intervention (used W@WS; n=129; 87 female) or a Comparison group (maintained normal behavior; n=135; 84 female). This phased, 19-week program aimed to decrease occupational sitting time through increased incidental movement and short walks. A linear mixed model assessed changes in outcome measures between the baseline, ramping (8 weeks), maintenance (11 weeks) and follow-up (two months) phases for Intervention versus Comparison groups. RESULTS: A significant 2 (group) × 2 (program phases) interaction was found for self-reported occupational sitting (F[3]=7.97, p=0.046), daily step counts (F[3]=15.68, p=0.0013) and waist circumference (F[3]=11.67, p=0.0086). The Intervention group decreased minutes of daily occupational sitting while also increasing step counts from baseline (446±126; 8,862±2,475) through ramping (+425±120; 9,345±2,435), maintenance (+422±123; 9,638±3,131) and follow-up (+414±129; 9,786±3,205). In the Comparison group, compared to baseline (404±106), sitting time remained unchanged through ramping and maintenance, but decreased at follow-up (-388±120), while step counts diminished across all phases. The Intervention group significantly reduced waist circumference by 2.1cms from baseline to follow-up while the Comparison group reduced waist circumference by 1.3cms over the same period. CONCLUSIONS: W@WS is a feasible and effective evidence-based intervention that can be successfully deployed with sedentary employees to elicit sustained changes on "sitting less and moving more"

Diurnal Profiles of Physical Activity and Postures Derived From Wrist-Worn Accelerometry in UK Adults

Background: Wrist-worn accelerometry is the commonest objective method for measuring physical activity in large-scale epidemiological studies. Research-grade devices capture raw triaxial acceleration which, in addition to quantifying movement, facilitates assessment of orientation relative to gravity. No population-based study has yet described the interrelationship and variation of these features by time and personal characteristics. Methods: 2,043 United Kingdom adults (35–65 years) wore an accelerometer on the non-dominant wrist and a chest-mounted combined heart-rate-and-movement sensor for 7 days free-living. From raw (60 Hz) wrist acceleration, we derived movement (non-gravity acceleration) and pitch and roll (forearm) angles relative to gravity. We inferred physical activity energy expenditure (PAEE) from combined sensing and sedentary time from approximate horizontal arm angle coupled with low movement. Results: Movement differences by time-of-day and day-of-week were associated with forearm angles; more movement in downward forearm positions. Mean (SD) movement was similar between sexes ∼31 (42) mg, despite higher PAEE in men. Women spent longer with the forearm pitched &gt;0°, above horizontal (53% vs 36%), and less time at &lt;0° (37% vs 53%). Diurnal pitch was 2.5–5° above and 0–7.5°below horizontal during night and daytime, respectively; corresponding roll angles were ∼0° (hand flat) and ∼20° (thumb-up). Differences were more pronounced in younger participants. All diurnal profiles indicated later wake-times on weekends. Daytime pitch was closer to horizontal on weekdays; roll was similar. Sedentary time was higher (17 vs 15 hours/day) in obese vs normal-weight individuals. Conclusions: More movement occurred in forearm positions below horizontal, commensurate with activities including walking. Findings suggest time-specific population differences in behaviors by age, sex, and BMI.The authors were supported by the UK Medical Research Council (MC_UU_12015/3) and the NIHR Biomedical Research Centre in Cambridge (IS-BRC-1215-20014). We would also like to thank EPSRC and GlaxoSmithKline for their support through graduate fellowships (iCase 17100053)

Using alternatives to the car and risk of all-cause, cardiovascular and cancer mortality

Abstract: Objective: To investigate the associations between using alternatives to the car which are more active for commuting and non-commuting purposes and morbidity and mortality Methods: We conducted a prospective study using 358799 participants aged 37-73 from UK Biobank. Commute and non-commute travel were assessed at baseline in 2006-2010. We classified participants according to whether they relied exclusively on the car, or used alternative modes of transport that were more active at least some of the time. Main outcome measures were incident CVD and cancer, and CVD, cancer and all-cause mortality. We excluded events in the first two years and conducted analyses separately for those who regularly commuted and those who did not. Results: In maximally-adjusted models, regular commuters with more active patterns of travel on the commute had a lower risk of incident (HR 0.89, 95% CI 0.79 to 1.00) and fatal CVD (HR 0.70, 95% CI 0.51 to 0.95). Those regular commuters who also had more active patterns of non-commute travel had an even lower risk of fatal CVD (HR 0.57, 95% CI 0.39 to 0.85). Among those who were not regular commuters, more active patterns of travel were associated with a lower risk of all-cause mortality (HR 0.92, 95% CI 0.86 to 0.99). Conclusions: More active patterns of travel are associated with a reduced risk of incident and fatal CVD and all-cause mortality in adults. This is an important message for clinicians advising people about how to be physically active and reduce their risk of disease.JP, DO, SB and SS are supported by the Medical Research Council (Unit Programme Nos MC_UU_12015/1, MC_UU_12015/3 and MC_UU_12015/6) and KW is also supported by the British Heart Foundation (Intermediate Basic Science Research Fellowship grant No FS/12/58/29709). AAL is funded by the NIHR (RP 014-04-032), and the Public Health Policy Evaluation Unit are grateful for the support of the NIHR School of Public Health Research. This research was conducted using the UK Biobank resource (application No 20684). The work was also supported under the auspices of the Centre for Diet and Activity Research (CEDAR), a UKCRC Public Health Research Centre of Excellence at the University of Cambridge, for which funding from the British Heart Foundation, Economic and Social Research Council, Medical Research Council, National Institute for Health Research and the Wellcome Trust, under the auspices of the United Kingdom Clinical Research Collaboration, is gratefully acknowledged