Accelerometry-measured Physical Activity Research Articles

School-level intra-cluster correlation coefficients and autocorrelations for children’s accelerometer-measured physical activity in England by age and gender

BackgroundRandomised, cluster-based study designs in schools are commonly used to evaluate children’s physical activity interventions. Sample size estimation relies on accurate estimation of the intra-cluster correlation coefficient (ICC), but published estimates, especially using accelerometry-measured physical activity, are few and vary depending on physical activity outcome and participant age. Less commonly-used cluster-based designs, such as stepped wedge designs, also need to account for correlations over time, e.g. cluster autocorrelation (CAC) and individual autocorrelation (IAC), but no estimates are currently available. This paper estimates the school-level ICC, CAC and IAC for England children’s accelerometer-measured physical activity outcomes by age group and gender, to inform the design of future school-based cluster trials.MethodsData were pooled from seven large English datasets of accelerometer-measured physical activity data between 2002–18 (> 13,500 pupils, 540 primary and secondary schools). Linear mixed effect models estimated ICCs for weekday and whole week for minutes spent in moderate-to-vigorous physical activity (MVPA) and being sedentary for different age groups, stratified by gender. The CAC (1,252 schools) and IAC (34,923 pupils) were estimated by length of follow-up from pooled longitudinal data.ResultsSchool-level ICCs for weekday MVPA were higher in primary schools (from 0.07 (95% CI: 0.05, 0.10) to 0.08 (95% CI: 0.06, 0.11)) compared to secondary (from 0.04 (95% CI: 0.03, 0.07) to (95% CI: 0.04, 0.10)). Girls’ ICCs were similar for primary and secondary schools, but boys’ were lower in secondary. For all ages, combined the CAC was 0.60 (95% CI: 0.44–0.72), and the IAC was 0.46 (95% CI: 0.42–0.49), irrespective of follow-up time. Estimates were higher for MVPA vs sedentary time, and for weekdays vs the whole week.ConclusionsAdequately powered studies are important to evidence effective physical activity strategies. Our estimates of the ICC, CAC and IAC may be used to plan future school-based physical activity evaluations and were fairly consistent across a range of ages and settings, suggesting that results may be applied to other high income countries with similar school physical activity provision. It is important to use estimates appropriate to the study design, and that match the intended study population as closely as possible.

Physical Activity Volume, Intensity, and Mortality: Harmonized Meta-Analysis of Prospective Cohort Studies

IntroductionIt is unclear whether moderate-to-vigorous physical activity (MVPA) is associated with a lower mortality risk, over and above its contribution to total physical activity volume. MethodsA total of 46,682 adults (mean age: 64 years) were included in a meta-analysis of nine prospective cohort studies. Each cohort generated tertiles of accelerometry-measured physical activity volume and volume-adjusted MVPA. Hazard ratios (HR, with 95% confidence intervals [CI]) for mortality were estimated separately and in joint models combining volume and MVPA. Data was collected between 2001-2019 and analyzed in 2023. ResultsDuring a mean follow-up of nine years, 4,666 deaths were recorded. Higher physical activity volume, and a greater contribution from volume-adjusted MVPA, were each associated with lower mortality hazard in multivariable-adjusted models. Compared to the least active tertile, higher physical activity volume was associated with a lower mortality (HRs: 0.62; 95%CI, 0.58, 0.67 and 0.50; 0.42, 0.60 for ascending tertiles). Similarly, a greater contribution from MVPA was associated with a lower mortality (HRs: 0.94; 95%CI, 0.85, 1.04 and 0.88; 0.79, 0.98). In joint analysis, a lower mortality from higher volume-adjusted MVPA was only observed for the middle tertile of physical activity volume. ConclusionsThe total volume of physical activity was associated with a lower risk of mortality to a greater extent than the contribution of MVPA to physical activity volume. Integrating any intensity of physical activity into daily life may lower mortality risk in middle aged and older adults, with a small added benefit if the same amount of activity is performed with a higher intensity.

SciKit digital health package for accelerometry-measured physical activity: comparisons to existing solutions and investigations of age effects in healthy adults

IntroductionAccelerometry has become increasingly prevalent to monitor physical activity due to its low participant burden, quantitative metrics, and ease of deployment. Physical activity metrics are ideal for extracting intuitive, continuous measures of participants’ health from multiple days or weeks of high frequency data due to their fairly straightforward computation. Previously, we released an open-source digital health python processing package, SciKit Digital Health (SKDH), with the goal of providing a unifying device-agnostic framework for multiple digital health algorithms, such as activity, gait, and sleep.MethodsIn this paper, we present the open-source SKDH implementation for the derivation of activity endpoints from accelerometer data. In this implementation, we include some non-typical features that have shown promise in providing additional context to activity patterns, and provide comparisons to existing algorithms, namely GGIR and the GENEActiv macros. Following this reference comparison, we investigate the association between age and derived physical activity metrics in a healthy adult cohort collected in the Pfizer Innovation Research Lab, comprising 7–14 days of at-home data collected from younger (18–40 years) and older (65–85 years) healthy volunteers.ResultsResults showed that activity metrics derived with SKDH had moderate to excellent ICC values (0.550 to 1.0 compared to GGIR, 0.469 to 0.697 compared to the GENEActiv macros), with high correlations for almost all compared metrics (>0.733 except vs GGIR sedentary time, 0.547). Several features show age-group differences, with Cohen’s d effect sizes >1.0 and p-values < 0.001. These features included non-threshold methods such as intensity gradient, and activity fragmentation features such as between-states transition probabilities.DiscussionThese results demonstrate the validity of the implemented SKDH physical activity algorithm, and the potential of the implemented PA metrics in assessing activity changes in free-living conditions.

Relationship Between Physical Activity and Estimated Glomerular Filtration Rate in Renal Transplant Recipients: A Cross-sectional Study Analyzing Isotemporal Substitution Model

Successful renal transplantation reduces mortality rates. However, the decline in the estimated glomerular filtration rate (eGFR) after transplantation is strongly associated with premature mortality in renal transplant recipients (RTRs). Physical activity (PA) is a modifiable lifestyle factor with the potential to maintain or improve eGFR. However, the effects of the type or intensity of PA and sedentary behavior (SB) on eGFR in RTRs remain unclear. The purpose of this study was to clarify the association between accelerometry-measured PA and SB and eGFR in RTRs using isotemporal substitution (IS) analysis. A total of 82 renal transplant outpatients participated in this cross-sectional study, among which 65 (average age, 56.9 years; average time post-transplant, 83.0 months) were finally analyzed. All RTRs wore a triaxial accelerometer to measure PA for seven consecutive days. The measured PA was classified based on intensity into light PA (LPA), moderate-to-vigorous PA (MVPA), and SB. The association of each type of PA with eGFR was examined using multi-regression analyses of single-factor, partition, and IS models. The IS model was applied to examine the estimated effects of substituting 30 min of SB with an equal amount of time of LPA or MVPA on eGFR. The partition model showed that MVPA was an independent explanatory variable for eGFR (β = 5.503, p < 0.05), and the IS model identified that the substitution of time spent in SB with MVPA led to improvements in eGFR (β = 5.902, p < 0.05). The present study suggests that MVPA has an independent and positive association with eGFR, and replacing 30 min of SB with MVPA after renal transplantation might lead to the maintenance or improvement of eGFR in RTRs.

Understanding the Patient Experience of Home-Based Pulmonary Rehabilitation with Health Coaching for COPD: A Qualitative Interview Study.

We recently reported on a randomized trial of home-based pulmonary rehabilitation (PR) for chronic obstructive pulmonary disease (COPD) that showed improvement in all domains of quality of life, accelerometry-measured physical activity, and self-management. In this current study, we used a theoretical framework to help us gain an in-depth understanding of how patients experience complex, multi-component programs to help uncover factors related to behavior change and to inform program scale-up in other populations. The parent trial was conducted with COPD patients receiving care at an academic medical center and a community health system in the upper Midwest. The 12-week PR intervention included 3 daily video-guided exercises, activity monitors, and weekly telephonic health coaching. Trial participants were eligible to participate in an individual phone interview about their experience if they completed the intervention within the prior 12 months.. Analysis of verbatim transcripts followed an inductive thematic approach followed by deductive categorization and interpretation using a theoretical model: the Capability, Opportunity, Motivation-Behavior (COM-B) model developed for linking intervention functions to aspects of behavioral change. Among 32 eligible program participants,32 were approached, and 15 completed interviews between October 19, 2021, and January 13, 2022. The COM-B model and recommendations for program improvement were observed in the primary findings. Participants' feedback highlighted how the health coaching bolstered skills and confidence among individuals with the poorest function at program enrollment and how improved physical function and mood led to motivation. It also highlighted the roles of technology and telephonic support in a home-based program. Suggestions for improvement included providing exercise variations.

Neighborhood segregation and cancer prevention guideline adherence in US Hispanic/Latino adults: Results from the HCHS/SOL.

Adherence to the American Cancer Society (ACS) guidelines for cancer prevention is associated with a lower risk of cancer and mortality. The role of neighborhood segregation on adherence to the guidelines among Hispanic/Latino adults is relatively unexplored. The Hispanic Community Health Study/Study of Latinos is a community-based prospective cohort of 16,462 Hispanic/Latino adults, ages 18-74 years enrolled in 2008-2011 from the Bronx, Chicago, Miami and San Diego. Dimensions of neighborhood segregation were measured using 2010 United States' census tracts:-evenness (the physical separation of a group), exposure (the propensity for contact between groups), and their joint effect (hypersegregation). ACS guideline adherence levels - low, moderate, high - were created from accelerometry-measured physical activity, dietary intake, alcohol intake, and body mass index. Weighted multinominal logistic regressions estimated relative risk ratios (RRR) and 95% confidence intervals (CI) for guideline adherence levels and its components. Hispanic/Latino adults were classified as low (13.7%), moderate (58.8%) or highly (27.5%) adherent to ACS guidelines. We found no evidence of an association between segregation and overall guideline adherence. Exposure segregation associated with lower likelihood of moderate adherence to alcohol recommendations (RRRmoderate vs. low:0.86, 95%CI:0.75-0.98) but higher likelihood for diet recommendations (RRRmoderate vs. low:1.07, 95%CI:1.01-1.14). Evenness segregation associated with lower likelihood of high adherence to the physical activity recommendations (RRRhigh vs. low:0.73, 95%CI:0.57-0.94). Hypersegregation was associated with individual guideline components. We found evidence of a cross-sectional relationship between neighborhood segregation and ACS cancer prevention guideline components, but not with overall ACS guideline adherence.

The Association Between Objectively-Measured Physical Activity and Cognitive Functioning in Middle-Aged and Older People Living with HIV.

Middle-aged and older people living with HIV (PWH) are at higher risk for cognitive impairment and engage in lower levels of physical activity (PA) than seronegative counterparts. Research examining the association between objectively-measured PA and cognitive function in this population is scarce. This cross-sectional study examined the association between accelerometry-measured PA and cognitive functioning among 75 PWH (mean age 55.63). Light PA was the PA variable with the most consistent associations with cognition, with more minutes per week of light PA (performed in bouts of ≥ 10min) being associated with better executive function, working memory/attention, and speed of processing performance, adjusted for age and current CD4 count. Findings suggest that although middle-aged and older PWH engage in more light than moderate-to-vigorous PA, light PA may be beneficial to cognition. Longitudinal studies are needed to understand PA dose-response associations with cognitive trajectories, cognitive domain specificity of PA effects, and underlying neural mechanisms of PA.

P05-06 Composition of physical behaviors at work and risk of sick leave due to musculoskeletal pain

BackgroundSick leave due to musculoskeletal pain is common in the workforce. Time use in physical behaviors at work such as sitting, standing, low- (LIPA) and moderate-to-vigorous physical activity (MVPA) may impact on sick leave due to pain. However, studies addressing this relationship using technical measures of physical behaviors are scarce. The aim was to investigate the association between time-use compositions of physical behavior at work and sick leave trajectories due to musculoskeletal pain over one year.MethodsWe analyzed data of 981 workers in a Danish cohort (DPHACTO 2012-2014). We assessed physical behaviors at work at baseline using thigh-worn accelerometers, and classified behaviors at work as sitting, standing, LIPA, and MVPA. Over 1 year follow-up, workers reported sick leave days due to musculoskeletal pain using text messages at 4-week intervals (14 waves). We used Latent class growth analysis to distinguish sub-groups with different trajectories of sick leave. We analyzed associations between time-use in physical behaviors and sick leave trajectories using multinomial regression analysis with adjustment for age, gender, BMI, smoking, and accelerometry-measured physical activity during leisure. Compositional data analysis was used to account for the co-dependency of different behaviors.ResultsWe identified four distinct trajectories of sick leave due to pain over one year as follows: no sick days (prevalence 76%), few days-increasing trajectory (19%), some days-decreasing trajectory (3%), and some days-increasing trajectory (2%). Spending more time in sitting relative to the other behaviors was negatively associated with few days-increasing trajectory of sick leave (p > 0.001), while time in LIPA was positively associated with some days-increasing trajectory of sick leave (p = 0.001). Reallocating 60 min/day from sitting to other behaviors at work predicted a 22% increased likelihood of few days-increasing trajectory of sick-leave. In contrast, reallocating 30 min/day from LIPA to other behaviors at work predicted a 57% decreased likelihood for some days-increasing trajectory.ConclusionWe found that compositions with more sitting relative to the other behaviors had lower odds for the trajectory with increasing sick leave due to pain, while compositions with more LIPA had higher odds. This may have implications for prevention of pain-related sick leave in workers.

Physical activity measured by accelerometry in paediatric and young adult patients with inflammatory bowel disease

ObjectivesPhysical activity in paediatric and young adult patients suffering from inflammatory bowel disease (IBD) may play an important role in the overall health status. However, physical activity in these patients has not been reported using objective methods. We aimed to describe accelerometry-measured physical activity levels in paediatric and young adult IBD patients with either ulcerative colitis (UC) or Crohn’s disease (CD).MethodsWe recruited Danish patients with IBD aged 10–20 years in clinical remission and with a faecal calprotectin below 200 µg/mg. Physical activity was assessed using tri-axial wrist accelerometry over seven days and quantified using the activity-related acceleration derived as the conventional Euclidian Norm Minus One (ENMO) metric expressed in milli-gravity units (mg). Time spent in Moderate-to-Vigorous Physical Activity (MVPA) was classified as ENMO > 210 mg in 5 s epoch resolution (unbouted).ResultsWe included 61 patients with a median age of 17 years [Inter Quartile Range, IQR 14–19]. The total volume of activity expressed as average acceleration (ENMO) per day was 31.5 mg (95% CI 29.1–33.9). Time spent in unbouted MVPA was 32 min per day (95% CI 26–37). There was no significant difference in activity volume between patients with UC to patients with CD, the adjusted linear regression coefficient was − 1.7 mg (95% CI –6.2–2.7). Activity volume was higher for males (36.2 mg, 95% CI 31.9–40.5) than for females (27.8 mg, 95% CI 25.6–30.0), and younger patients were more active than older patients; Activity volume in 10–13 year olds was 37.2 mg (95% CI 28.6–45.7), whereas it was 28.5 mg (95% CI 25.2–31.7) for those aged 18–20 years.ConclusionsWe collected tri-axial accelerometry in young patients with IBD in clinical remission, and described their level of physical activity by the conventional ENMO measure. We found no statistically significant difference in patients with UC compared to patients with CD. The volume of physical activity was higher in males compared to females, and inversely associated with age.

The feasibility and acceptability of a home-based, virtual exercise intervention for older patients with hepatocellular carcinoma: protocol for a non-randomised feasibility study (TELEX-Liver Cancer)

BackgroundThe number of incident cases and deaths from primary liver cancer, predominantly hepatocellular carcinoma (HCC), has increased markedly in the last two decades. HCC is generally diagnosed at an advanced stage, and most new cases are in people aged over 70 years with age-related comorbidities. Treatment options are often limited, with most patients receiving palliative treatment or supportive care only. As a consequence, maintaining quality of life (QoL) through symptom management is critically important and is a core objective of clinical care. Strong evidence supports the efficacy of supervised exercise training for addressing certain cancer-related symptoms, including QoL, physical function, and fatigue. However, there are many barriers to implementing supervised exercise programmes within cancer care pathways, including economic pressures on healthcare systems and personal barriers for patients. Recent advances in technology allow patients to exercise at home under the ‘virtual’ supervision of an exercise professional through videoconferencing software (termed ‘telehealth exercise’). Despite its potential, there are uncertainties relating to the feasibility, acceptability, and safety of telehealth exercise in people living with HCC.MethodsThis is a protocol for a prospective, single-centre, single-arm, pretest-posttest feasibility trial. We aim to recruit 20 patients aged 60 years or older who have received treatment for HCC and are undergoing routine clinical monitoring. Patients will be invited to take part in two online, home-based, group exercise sessions per week for 10 consecutive weeks. The ‘virtual’ exercise sessions will be delivered in real time by an exercise professional through videoconferencing software. Each session will comprise 30 min of aerobic and resistance exercise performed at a moderate intensity, as guided by the 10-point Borg rating of perceived exertion scale. Feasibility outcomes include recruitment, retention, adherence, intervention fidelity, and safety. Acceptability of the intervention will be assessed using a mixed-methods approach via monthly online surveys and an exit telephone interview. Physical function, accelerometry-measured physical activity, mid-upper arm circumference, and patient-reported outcome measures (PROMS) will be assessed before and after the intervention to determine the feasibility of assessing outcome measures. Physical function outcomes include the short physical performance battery and Liver Frailty Index. PROMS include the Functional Assessment of Cancer Therapy-Hepatobiliary questionnaire, Functional Assessment of Chronic Illness Therapy-Fatigue questionnaire, Activities-specific Balance Confidence scale, Hospital Anxiety and Depression Scale, and the Godin Leisure-Time Exercise Questionnaire.DiscussionThis mixed-methods study will address uncertainties relating to the feasibility and acceptability of delivering live, online, home-based, group exercise sessions to patients with HCC. The findings will inform whether any modifications are required to refine and optimise the intervention, and the assessment of outcome measures will provide information on the likely size and variability of intervention effects. Collectively, the data generated will inform the design of a subsequent, adequately powered, randomised controlled trial to evaluate the efficacy of the telehealth exercise intervention.Trial registrationISRCTN14411809

Do Physical Activity and Sleep Correlate with Patient-Reported Outcomes in Total Hip Arthroplasty?

AbstractPatients have increasingly high expectations of return to activity following total hip arthroplasty (THA). The current literature demonstrates marked improvements in subjective patient-reported satisfaction, and pain and functional outcomes following THA. However, there is limited evidence showing objective improvement in gait and sleep measures. The purpose of this study was to compare accelerometry-measured physical activity and sleep to patient-reported outcomes following THA.A nonrandomized, prospective cohort study was performed at a single institution from 2017 to 2019. Patients were included in the study if they were ≥ 18 years old, had a primary diagnosis of osteoarthritis of the hip, and were undergoing primary, elective THA. Eligible patients received a tracker device upon enrollment which recorded the average number of daily steps and minutes slept at baseline, 1 to 2 weeks, 1 month, and 3 months postoperatively. Hip disability and osteoarthritis outcome score for joint replacement (HOOS Jr) scores were recorded at the same intervals. Paired two-tailed t-tests and chi-squared analyses were performed to compare means. Pearson correlation tests were utilized to determine the correlation between objective measurements and HOOS Jr.Fifty subjects were enrolled, however, only 41 had sufficient data for analysis at 3-month follow-up. Patients demonstrated improved HOOS Jr scores from preoperatively to 2 weeks (p &lt; 0.001) and 3 months (p &lt; 0.001) postoperatively. Average daily steps ambulated and minutes slept preoperatively were statistically similar to average daily steps and minutes slept 3 months postoperatively (p = 0.67 and p = 0.24, respectively). Pearson correlation models only detected a weak negative correlation between average steps preop and preop HOOS Jr (r = –0.401, p = 0.013).Patients returned to similar ambulation distances and sleep time by 3 months postoperatively. Changes in accelerometry-measured activity level and sleep may not correlate with functional outcomes in early follow-ups after THA. While patients report improvements in subjective clinical outcomes, our findings suggest a return to preoperative levels in objective measures at 3 months post-THA.

Cross-sectional associations between accelerometry-measured physical activity, left atrial size, and indices of left ventricular diastolic dysfunction: The Tromsø Study.

Whereas left atrial (LA) enlargement is an independent predictor for adverse cardiovascular events and all-cause mortality, this is regarded a physiological adaption of exercise. Paradoxically, LA size in athletes may overlap the enlargement observed in patients with cardiac pathology. Current knowledge is mainly derived from studies of athletes, and little is known about cardiac adaptations to physical activity (PA) in the general population. We explored the association between objectively measured PA and LA volume index (LAVi), and between LAVi enlargement and indices of diastolic dysfunction stratified by PA-level. Our study included 1573 participants from the population-based Tromsø Study (2015-16). PA was assessed with an ActiGraph wGT3X-BT accelerometer. Echocardiography was performed according to current guidelines. The associations between PA and LAVi, and between LAVi enlargement and indices of diastolic dysfunction were estimated by univariable and multivariable linear regression analyses, adjusted for sex, age, and cardiovascular risk factors. Our multiple adjusted analyses showed significant linear associations between PA and LAVi in ages < 70years, and between PA and LAVi in participants with normal diastolic function. No associations were seen in ages≥70years or for participants with abnormal diastolic function. In those 40-54years, the most active participants had larger LAVi (4.45mL/m2, p=0.016) than the least active. LAVi enlargement was only associated with indices of diastolic dysfunction in the most inactive participants. In conclusion, higher levels of PA associate with greater LAVi in participants < 70years with normal diastolic function. LAVi enlargement is only associated with diastolic dysfunction in the most inactive participants.

Accelerometry-Measured Physical Activity in Amateur Footballers. Is It Enough to Obtain Health Benefits?

Amateur football is played by millions of individuals worldwide, but it has been scarcely researched (almost no studies have targeted this sport). There seems to be a need to fill this gap, because it has an impact in these individuals’ health status. The aim of our research was to uncover amateur football players’ physical and psychological traits to understand the impact of this sport in their health (physical, mental, and social well-being). Two-hundred footballers (17–40 years) from four regions in Spain (north, central, southwest, southeast), enrolled in 16 different football teams participated. They completed a questionnaire to assess their motives for sport participation, their intention to continue playing football, and their exercise addiction. To objectively measure their physical activity levels, accelerometers were used during practice sessions. Ratings of perceived exertion (RPE) were obtained from coaches prior to and after every practice session and players at the end of every practice. Results showed a mean 140.1 moderate-to-vigorous physical activity (MVPA)/minutes/week. Players’ RPE scores were similar in the “fairly light” range (6–20 scale) at pre (11.38 ± 1.64) and post training (11.83 ± 1.39), and it was not different between players and coaches (11.50 ± 1.52). Enjoyment was the highest-ranked motive to practice amateur football (6.34 ± 0.67; 1–7 range), followed by fitness (5.68 ± 0.97; 1–7 range), social (4.80 ± 0.85; 1–7 range), and appearance (4.04 ± 1.21; 1–7 range). Players had some symptoms of exercise addiction (21.09 ± 4.53; 1–30 range) and their intentions to continue playing were very high (4.31 ± 1.08; 1–5 range). Moreover, enjoyment was the strongest predictor of these intentions (R2 = 0.260). In conclusion, a weekly amateur football practice almost allows players to meet international MVPA recommendations for health benefits. Enjoyment was their strongest motive to practice, and the players showed some symptoms of exercise addiction. These two variables were the strongest predictors of the participants’ intention to continue playing amateur football. This sport could be considered adequate to help adults maintain an active, healthy lifestyle.

Associations of accelerometer-measured physical activity and physical activity-related cancer incidence in older women: results from the WHI OPACH Study

BackgroundWe examined the associations between accelerometry-measured physical activity (PA) and incidence of 13 cancers among a cohort of postmenopausal women.MethodsIn this prospective study, 6382 women wore ActiGraph GT3X+ accelerometers at the hip for up to 7 days during 2012–2013, and were followed over a median of 4.7 years for diagnosis of 13 invasive cancers. Calibrated intensity cut points were used to define minutes per day of total, light and moderate-to-vigorous PA. We used multivariable Cox regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for tertiles, and one-standard deviation (SD) unit increments of PA exposures in relation to cancer incidence. We examined effect measure modification by age, race/ethnicity, body mass index and smoking history.ResultsThe highest (vs. lowest) tertiles of total, light and moderate-to-vigorous PA were associated with covariate-adjusted HRs of 0.72 (95% CI = 0.53–0.97), 0.81 (95% CI = 0.60–1.09) and 0.66 (95% CI = 0.48–0.91), respectively. In age-stratified analyses, HRs for total PA were lower among women <80 years (HRper one-SD = 0.75, 95% CI = 0.63–0.90) than among women ≥80 years (HRper one-SD = 0.99, 95% CI = 0.82–1.18) (PInteraction = 0.03). Race/ethnicity, BMI and smoking did not strongly modify these associations.ConclusionsEngaging in physical activity may play a beneficial role in the prevention of certain cancers in older women.

Neighborhood Recreation Facilities and Facility Membership Are Jointly Associated with Objectively Measured Physical Activity.

Efforts to increase physical activity have traditionally included either individual-level interventions (e.g., educational campaigns) or neighborhood-level interventions (e.g., additional recreational facilities). Little work has addressed the interaction between spatial proximity and individual characteristics related to facility use. We aimed to better understand the synergistic impact of both physical activity environments and recreational facility membership on objectively measured physical activity. Using the New York City Physical Activity and Transit (PAT) survey (n = 644), we evaluated associations between counts of commercial physical activity facilities within 1km of participants' home addresses with both facility membership and accelerometry-measured physical activity. Individuals living near more facilities were more likely to report membership (adjusted odds ratio for top versus bottom quartile of facility count: 3.77 (95% CI 1.54-9.20). Additionally, while amount of facilities within a neighborhood was associated with more physical activity, this association was stronger for individuals reporting gym membership. Interventions aiming to increase physical activity should consider both neighborhood amenities and potential barriers, including the financial and social barriers of membership. Evaluation of neighborhood opportunities must expand beyond physical presence to consider multiple dimensions of accessibility.

Accelerometry-measured physical activity and sedentary behaviour of preschoolers in Nova Scotia, Canada.

The objective of this study was to describe the levels and bouts of physical activity (PA) and sedentary behaviour (SB) among preschoolers in Nova Scotia, Canada, and the proportion meeting PA and step guidelines. Children (75 boys, 49 girls; mean age = 4.2 (range = 3-5 years)) participating in the Physical Literacy in the Early Years (PLEY) study provided data. Average time (minutes, % of day) spent sedentary, in light PA (LPA), moderate-to-vigorous PA (MVPA), and total PA; average frequency; and duration of bouts of MVPA (≥5 min, ≥10 min) and sedentary bouts (≥10 min) per day were determined using published cut-points, using 15-s epochs. The proportion of children meeting PA and step guidelines was determined, and differences by sex explored. Children spent the majority (70.8%) of their day active; nearly all (≥97%) met PA guidelines. Most children met step guidelines on a weekly basis, but not daily. Only LPA differed by sex (greater in girls; p = 0.001). Little time was spent in sustained SB (bouts ≥10 min). Boys had greater and longer bouts of MVPA and spent more of their day in these (p < 0.05). Girls spent less time in sustained SB (p = 0.009). This is the first study to describe the PA and SB of Nova Scotia preschoolers using accelerometry. Findings suggest preschoolers spend the majority of their day active, and that there are sex-related differences in PA and SB, warranting further examination.

Multilevel Matrix-Variate Analysis and its Application to Accelerometry-Measured Physical Activity in Clinical Populations

ABSTRACT The number of studies where the primary measurement is a matrix is exploding. In response to this, we propose a statistical framework for modeling populations of repeatedly observed matrix-variate measurements. The 2D structure is handled via a matrix-variate distribution with decomposable row/column-specific covariance matrices and a linear mixed effect framework is used to model the multilevel design. The proposed framework flexibly expands to accommodate many common crossed and nested designs and introduces two important concepts: the between-subject distance and intraclass correlation coefficient, both defined for matrix-variate data. The computational feasibility and performance of the approach is shown in extensive simulation studies. The method is motivated by and applied to a study that monitored physical activity of individuals diagnosed with congestive heart failure (CHF) over a 4- to 9-month period. The long-term patterns of physical activity are studied and compared in two CHF subgroups: with and without adverse clinical events. Supplementary materials for this article, that include de-identified accelerometry and clinical data, are available online.

Social capital predicts accelerometry-measured physical activity among older adults in the U.S.: a cross-sectional study in the National Social Life, Health, and Aging Project

BackgroundOlder adults receive important health benefits from more robust social capital. Yet, the mechanisms behind these associations are not fully understood. Some evidence suggests that higher levels of social capital ultimately affect health through alterations in physical activity (PA), but most of this research has relied on self-reported levels of PA. The aim of this study was to determine whether components of social capital, including social network size and composition as well as the frequency of participation in various social and community activities, were associated with accelerometry-measured PA levels in a nationally representative sample of community-dwelling older adults (≥ 62 years).MethodsWe conducted a cross-sectional analysis using data from the wrist accelerometry sub-study (n = 738) within Wave 2 of the National Social, Health, and Aging Project (NSHAP), a population-based longitudinal study that collects extensive survey data on the physical, cognitive, and social health of older adults. Participants’ physical activity was measured with a wrist accelerometer worn for 72 consecutive hours. We related seven, self-reported social relationship variables (network size, network proportion friends, and frequencies of socializing with friends and family, visiting with neighbors, attending organized group meetings, attending religious services, and volunteering) to accelerometer-measured PA (mean counts-per-minute) using multivariate linear regression analysis, while adjusting for potential confounders.ResultsLarger social networks (p = 0.042), higher network proportion friends (p = 0.013), more frequent visiting with neighbors (p = 0.009), and more frequent attendance at organized group meetings (p = 0.035) were associated with higher PA levels after controlling for demographic and health covariates. Volunteering was significant prior to adjusting for covariates. No significant associations were found between frequencies of socializing with friends and relatives or attendance at religious services and PA.ConclusionsThis study suggests social capital is significantly related to objectively measured PA levels among older adults, and that friendships as well as social participation in groups and with neighbors may be particularly pertinent to PA. These findings expand our understanding of and offer a potential mechanism linking social relationships and overall health among older adults. They also have implications for how we might motivate older adults to be more physically active.

Role of parental and environmental characteristics in toddlers\u2019 physical activity and screen time: Bayesian analysis of structural equation models

BackgroundGuided by the Socialization Model of Child Behavior (SMCB), this cross-sectional study examined direct and indirect associations of parental cognitions and behavior, the home and neighborhood environment, and toddlers’ personal attributes with toddlers’ physical activity and screen time.MethodsParticipants included 193 toddlers (1.6 ± 0.2 years) from the Parents’ Role in Establishing healthy Physical activity and Sedentary behavior habits (PREPS) project. Toddlers’ screen time and personal attributes, physical activity- or screen time-specific parental cognitions and behaviors, and the home and neighborhood environment were measured via parental-report using the PREPS questionnaire. Accelerometry-measured physical activity was available in 123 toddlers. Bayesian estimation in structural equation modeling (SEM) using the Markov Chain Monte Carlo algorithm was performed to test an SMCB hypothesized model. Covariates included toddlers’ age, sex, race/ethnicity, main type of childcare, and family household income.ResultsIn the SMCB hypothesized screen time model, higher parental barrier self-efficacy for limiting toddlers’ screen time was associated with higher parental screen time limiting practices (β = 0.451), while higher parental negative outcome expectations for limiting toddlers’ screen time was associated with lower parental screen time limiting practices (β = − 0.147). In turn, higher parental screen time limiting practices was associated with lower screen time among toddlers (β = − 0.179). Parental modeling of higher screen time was associated with higher screen time among toddlers directly (β = 0.212) and indirectly through the home environment. Specifically, higher screen time among parents was associated with having at least one electronic device in toddlers’ bedrooms (β = 0.146) and, in turn, having electronics in the bedroom, compared to none, was associated with higher screen time among toddlers (β = 0.250). Neighborhood safety was not associated with toddlers’ screen time in the SEM analysis. No significant correlations were observed between the SMCB variables and toddlers’ physical activity; thus, no further analyses were performed for physical activity.ConclusionsParents and their interactions with the home environment may play an important role in shaping toddlers’ screen time. Findings can inform family-based interventions aiming to minimize toddlers’ screen time. Future research is needed to identify correlates of toddlers’ physical activity.

Cardiovascular Stress During Inpatient Spinal Cord Injury Rehabilitation

Objectives(1) To measure the amount of cardiovascular stress, self-reported physical activity, and accelerometry-measured physical activity by individuals with spinal cord injury (SCI) during physical therapy (PT) and occupational therapy (OT); and (2) to investigate the relations between these measures. DesignObservational study. SettingTwo inpatient SCI rehabilitation centers. ParticipantsPatients with SCI (N=87) were recruited from consecutive admissions to rehabilitation. InterventionsNot applicable. Main Outcome MeasuresHeart rate was recorded by a Holter monitor, whereas physical activity was captured by self-report (Physical Activity Recall Assessment for People with SCI questionnaire) and real-time wrist accelerometry during a total of 334 PT and OT inpatient sessions. Differences between individuals with paraplegia and tetraplegia were assessed via Mann-Whitney U tests. Spearman correlations were used to explore the relation between measurements of physical activity and heart rate. ResultsTime spent at a heart rate within a cardiovascular training zone (≥40% heart rate reserve) was low and did not exceed a median of 5 minutes. In contrast, individuals reported at least 60 minutes of higher-intensity time during therapy. There was a low but statistically significant correlation between all measures. ConclusionsThe cardiovascular stress incurred by individuals with SCI during inpatient PT and OT sessions is low and not sufficient to obtain a cardiovascular training effect to optimize their neurologic, cardiovascular, or musculoskeletal health; this represents a lost opportunity to maximize rehabilitation. Self-reported minutes of higher-intensity physical activity do not reflect actual time spent at a higher intensity measured objectively via a heart rate monitor.