Accelerometer data reduction: a comparison of four reduction algorithms on select outcome variables

No one accelerometer-based physical activity data collection protocol can fit all research questions

Background

Measuring physical activity and sedentary behavior accurately remains a challenge. When describing the uncertainty of mean values or when making group comparisons, minimising Standard Error of the Mean (SEM) is important. The sample size and the number of repeated observations within each subject influence the size of the SEM. In this study we have investigated how different combinations of sample sizes and repeated observations influence the magnitude of the SEM.

Methods

A convenience sample were asked to wear an accelerometer for 28 consecutive days. Based on the within and between subject variances the SEM for the different combinations of sample sizes and number of monitored days was calculated.

Results

Fifty subjects (67% women, mean ± SD age 41 ± 19 years) were included. The analyses showed, independent of which intensity level of physical activity or how measurement protocol was designed, that the largest reductions in SEM was seen as the sample size were increased. The same magnitude in reductions to SEM was not seen for increasing the number of repeated measurement days within each subject.

Conclusion

The most effective way of reducing the SEM is to have a large sample size rather than a long observation period within each individual. Even though the importance of reducing the SEM to increase the power of detecting differences between groups is well-known it is seldom considered when developing appropriate protocols for accelerometer based research. Therefore the results presented herein serves to highlight this fact and have the potential to stimulate debate and challenge current best practice recommendations of accelerometer based physical activity research.

Physical activity among patients with breast cancer receiving aromatase inhibitors is associated with bone health: a cross-sectional observational study

PURPOSE

To examine the association of physical activity (PA) with bone health among patients with breast cancer receiving adjuvant aromatase inhibitor (AI) treatment.

METHODS

In this single-center observational study, we enrolled postmenopausal women with primary hormone receptor-positive breast cancer who were receiving adjuvant AI treatment. We assessed patient bone health [bone mineral density (BMD) and biomarkers of bone turnover] as main outcomes. PA was assessed using Baecke physical activity questionnaires (BPAQ) and an accelerometer. Multiple regression analysis was performed after adjustment for age, body mass index, smoking history and duration of AI treatment. For missing data, multiple imputation analysis was adapted.

RESULTS

The mean age of the 53 enrolled patients was 67.4 ± 8.4 years. The mean duration of AI administration was 25.7 ± 18.9 months. The most frequently administered AI was anastrozole (73.6%). Although not related to BMD, PA was related to bone turnover. Serum collagen type I amino-terminal propeptide, a bone formation marker, was associated with only light PA (t =  - 2.55, p = 0.015), while tartrate-resistant acid phosphatase 5b, a bone absorption marker, was associated with work index in the BPAQ subscale and light PA (t =  - 2.28, p = 0.028, t =  - 2.26, p = 0.031, respectively). The results for all patients were similar to those observed in the multiple imputation analysis.

CONCLUSION

PA was significantly associated with bone turnover among cancer patients receiving AI treatment. Light PA and PA in the work domain were the most important factors among various PA intensities and PA domains.

Effects of Weight Loss and Weight Regain on Circulating Biomarkers in Overweight/Obese Breast Cancer Survivors Enrolled in a Weight Loss Trial in the Rural Midwest

BACKGROUND

Obesity is associated with worse breast cancer prognosis, however little is known about the level of weight loss required to improve pathway biomarkers. The effects of weight regain on biomarkers are also largely unknown.

METHODS

Overweight/obese breast cancer survivors enrolled in an 18-month behavioral weight loss trial provided weight and serum biomarkers [leptin, adiponectin, insulin, plasminogen activator inhibitor-1 (PAI-1), IL-6, TNFα, and hepatocyte growth factor HGF] at baseline, 6, and 18 months (n = 138). Change in biomarkers over time and by weight loss thresholds were examined.

RESULTS

Mean weight loss at 6 months was 13.3 ± 5.0 kg; from 6 to 18 months, mean regain was 4.0 ± 5.2 kg. Favorable biomarker modulations were observed at 6 months for leptin, adiponectin, insulin, PAI-1, IL-6, and HGF (P < 0.006 to P < 0.0001). These changes remained significant overall at 18 months despite attenuation in some. Women who lost <10% of baseline weight showed significantly smaller modulation effects for leptin (P < 0.0001), adiponectin:leptin (A/L) ratio (P < 0.0001), PAI-1 (P < 0.001), and insulin (P = 0.003) compared with women who lost >10%. Women who lost >10% observed a significant increase in adiponectin (P < 0.0001), and these women continued to show improved adiponectin from 6 to 18 months despite weight regain. Physical activity contributed additional effects on biomarker change for leptin, A/L ratio, and PAI-1.

CONCLUSIONS

These findings are consistent with a clinical target of 10% weight.

IMPACT

Sustained increases in adiponectin likely confer benefits for breast cancer prognosis even with weight regain.

Decline of physical activity in early adolescence: A 3-year cohort study

This study analyses the changes of moderate-to-vigorous physical activity (MVPA) in a cohort of boys and girls aged 11 (n = 50) and 14 (n = 50). Physical activity was assessed with Bodymedia SenseWear Pro Armband monitor for 6 days in October 2013 and October 2016, considering 90% of daily wear time (21h and 40min). The initial sample (n = 160) included the children who wore the monitors at age 11 but the final analyzed sample included only those children from the initial sample (n = 50), whose data fulfilled the inclusion criteria at age 11 and 14. Physical fitness and somatic characteristics of the final sample (n = 50) were compared to a representative sample of Slovenian schoolchildren at ages 11 (n = 385) and 14 (n = 236) to detect possible bias. Changes in MVPA were controlled for maturity using the timing of adolescent growth spurt as its indicator. The average MVPA decreased more than one quarter (34.96 min) from age 11 to age 14. Children were significantly more active at age 11 than at age 14 (p < 0.01, d = 0.39). The timing of puberty onset in girls was significantly earlier (12.01 ± 1.0 years) (p < 0.01) than in boys (13.2 ± 0.75 years) (p < 0.01, d = 1.35). There was a significant gender difference in moderate-to vigorous physical activity at age 14 (p < 0.05, η2 = 0.12) and between moderate-to vigorous physical activity at age 11 and 14 (η2 = 0.11). After controlling for the timing of adolescent growth spurt the girls at age 11 showed significantly higher level of physical activity than at age 14 (p < 0.01, η2 = 0.17). Early adolescence is crucial for the development of physical activity behaviours, which is especially pronounced in girls. The significant decline of MVPA between ages 11 and 14 in Slovenia are likely influenced by environmental changes since the timing of adolescent growth spurt did not prove as a factor underlying the decline of MVPA.

Bidirectional 10-year associations of accelerometer-measured sedentary behavior and activity categories with weight among middle-aged adults

BACKGROUND

Although higher sedentary behavior (SB) with low light intensity (LPA) and moderate-to-vigorous intensity physical activity (MVPA) are thought to increase risk for obesity, other data suggest excess weight may precede these behaviors in the causal pathway. We aimed to investigate 10-year bidirectional associations between SB and activity with weight.

METHODS

Analysis included 886 CARDIA participants (aged 38-50 years, 62% female, 38% black) with weight and accelerometry ( ≥ 4 days with ≥ 10 h/day) collected in 2005-6 (ActiGraph 7164) and 2015-6 (ActiGraph wGT3X-BT). Accelerometer data were calibrated, harmonized, and expressed as counts per minute (cpm) and time-dependent intensity categories (min/day of SB, LPA, and MVPA; SB and MVPA were also separated into long-bout and short-bout categories). Linear regression models were constructed to estimate adjusted associations of baseline activity with 10-year change in weight and vice versa. When activity categories were the independent variables, standardized regression coefficients (βstd.) estimated associations of replacing SB with a one SD increase in other categories, adjusted for accelerometer wear time.

RESULTS

Over 10-years, weight increased by a mean 2.55 ± 8.05 kg and mean total activity decreased by 50 ± 153 cpm. In adjusted models, one SD higher baseline mean total activity (βstd. = -1.4 kg, p < 0.001), LPA (βstd. = -0.80 kg, p = 0.013), total MVPA (βstd. = -1.07 kg, p = 0.001), and long-bout MVPA (βstd. = -1.20 kg, p < 0.001) were associated with attenuated 10-year weight gain. Conversely, a one SD higher baseline weight was associated with unfavorable 10-year changes in daily activity profile including increases in SB (βstd. = 12.0 min, p < 0.001) and decreases in mean total activity (βstd. = 14.9 cpm, p = 0.004), LPA (βstd. = 8.9, p = 0.002), and MVPA (βstd. = 3.5 min, p = 0.001). Associations varied by race and gender.

CONCLUSIONS

Higher SB with lower activity and body weight were bidirectionally related. Interventions that work simultaneously to replace SB with LPA and long-bout MVPA while also using other methods to address excess weight may be optimal.

Relationship of workplace exercise with work engagement and psychological distress in employees: A cross-sectional study from the MYLS study

We investigated the relationship between workplace exercise and psychological distress, and work engagement, both of which are factors related to the mental health and work productivity of employees. Data from the Meiji Yasuda Lifestyle study, collected from July 2017 through December 2017, were used. Data from an annual health checkup and questionnaire were collected from the Meiji Yasuda Shinjuku Medical Center in Tokyo, Japan. The 1321 participants (mean age: 50.8 ± 9.5 years, rate of female: 68.2%, rate of white-collar workers: 64.7%) were divided into three groups based on the frequency of performing workplace exercise: less than once, once or twice, and three or more times a week. Vigor of work engagement and psychological distress were assessed using the Utrecht Work Engagement Scale and Kessler Psychological Distress Scale (K6). Logistic regression analyses were performed to examine relationships between workplace exercise frequencies and work engagement or psychological distress. Demographic variables, health behaviors, health status, work characteristics, and objectively measured physical activity and sedentary behavior were adjusted for odds ratio (OR) and 95% confidence interval (95% CI). Participants who performed workplace exercise once or twice and three or more times a week showed a significantly higher OR (OR = 1.93, 95% CI = 1.00-3.71, p = 0.049, OR = 1.63, 95% CI = 1.23-2.15, p = 0.001, respectively) for vigor of work engagement. Neither groups of workplace exercise showed a significant OR for psychological distress even when adjusted for covariates. The practice of workplace exercise is positively and independently related to vigor of work engagements of physical activity and sedentary behavior, and the association was observed regardless of the frequency of once or twice, or three or more times a week. Workplace exercise, however, does not correlate with psychological distress. Our findings indicated that workplace exercise at least once or twice a week could have practical implications for the enhancement of vigor of work engagement, especially among white-collar workers.

Application of Raw Accelerometer Data and Machine-Learning Techniques to Characterize Human Movement Behavior: A Systematic Scoping Review

BACKGROUND

Application of machine learning for classifying human behavior is increasingly common as access to raw accelerometer data improves. The aims of this scoping review are (1) to examine if machine-learning techniques can accurately identify human activity behaviors from raw accelerometer data and (2) to summarize the practical implications of these machine-learning techniques for future work.

METHODS

Keyword searches were performed in Scopus, Web of Science, and EBSCO databases in 2018. Studies that applied supervised machine-learning techniques to raw accelerometer data and estimated components of physical activity were included. Information on study characteristics, machine-learning techniques, and key study findings were extracted from included studies.

RESULTS

Of the 53 studies included in the review, 75% were published in the last 5 years. Most studies predicted postures and activity type, rather than intensity, and were conducted in controlled environments using 1 or 2 devices. The most common models were support vector machine, random forest, and artificial neural network. Overall, classification accuracy ranged from 62% to 99.8%, although nearly 80% of studies achieved an overall accuracy above 85%.

CONCLUSIONS

Machine-learning algorithms demonstrate good accuracy when predicting physical activity components; however, their application to free-living settings is currently uncertain.

Physical activity across the curriculum (PAAC3): Testing the application of technology delivered classroom physical activity breaks

Only 43% of children in the U.S., ages 6-11 yrs., meet current physical activity (PA) guidelines. To satisfy the MVPA requirement, schools have begun incorporating MVPA in the form of activity breaks or MVPA academic lessons. We completed two, 3 academic-yr. cluster randomized trials (DK61489, DK85317) called "Physical Activity Across the Curriculum" (PAAC) which involved increasing MVPA in the classroom. Across 3-yrs. teachers in PAAC schools delivered ~60 min/wk. (12 min/day) of MVPA. Although short of our MVPA goal (20 min/d), the PAAC approach substantially increased in-school MVPA. Teacher reluctance to devote additional time to develop and integrate PA lessons into their curriculum was the overwhelming barrier to meeting the MVPA goal. Therefore, to reduce barriers to delivery of classroom PA we developed a 3-academic yr. cluster randomized trial (2 yrs. active intervention, 1 yr. follow-up) to compare the effectiveness and sustainability of technology delivered (PAAC-R) and classroom teacher delivered (PAAC-T) activity breaks for increasing classroom MVPA in elementary school students in grades 2 and 3 at baseline who will progress to grades 4-5. NCT registration: NCT03493139.

Correlation between Accelerometer and Questionnaire-Based Assessment of Physical Activity in Patients with Cerebral Palsy

Background

Precise measuring and monitoring of physical activity (PA) in patients with cerebral palsy (CP) are critical for assessing their PA participation and its potential health benefits. Accelerometer-based assessment of PA has been considered valid, reliable, and practical in children with CP. Therefore, we investigated the correlation between accelerometer- and questionnaire-based assessment of PA in CP patients.

Methods

Nineteen patients with CP who were classified as Gross Motor Function Classification System level I–III and 84 normally developed participants were included in the study. Study participants wore an accelerometer for seven days, after which they visited the hospital and completed the International Physical Activity Questionnaire (IPAQ). CP patients and their caregivers completed the Pediatric Outcomes Data Collection Instrument (PODCI) and the Caregiver Priorities and Child Health Index of Life with Disabilities, respectively. The concurrent validity of the questionnaires was assessed.

Results

In the accelerometer-based assessment, time spent in PA was significantly shorter at every intensity level in CP patients than in normally developed participants. However, PA assessed by the IPAQ was significantly higher in patients with CP, indicating that they tend to exaggerate their participation in PA. On the correlation of the assessment by the accelerometer and by the PODCI, transfer/basic mobility, sports/physical function, and happiness increased significantly as the number of steps taken and the distance travelled increased.

Conclusions

In patients with CP, happiness and quality of life are associated with higher levels of PA. Thus, programs for patients with CP should focus on improving their PA.

Ambulatory sleep scoring using accelerometers-distinguishing between nonwear and sleep/wake states

Background

Differentiating nonwear time from sleep and wake times is essential for the estimation of sleep duration based on actigraphy data. To efficiently analyze large-scale data sets, an automatic method of identifying these three different states is required. Therefore, we developed a classification algorithm to determine nonwear, sleep and wake periods from accelerometer data. Our work aimed to (I) develop a new pattern recognition algorithm for identifying nonwear periods from actigraphy data based on the influence of respiration rate on the power spectrum of the acceleration signal and implement it in an automatic classification algorithm for nonwear/sleep/wake states; (II) address motion artifacts that occur during nonwear periods and are known to cause misclassification of these periods; (III) adjust the algorithm depending on the sensor position (wrist, chest); and (IV) validate the algorithm on both healthy individuals and patients with sleep disorders.

Methods

The study involved 98 participants who wore wrist and chest acceleration sensors for one day of measurements. They spent one night in the sleep laboratory and continued to wear the sensors outside of the laboratory for the remainder of the day. The results of the classification algorithm were compared to those of the reference source: polysomnography for wake/sleep and manual annotations for nonwear/wear classification.

Results

The median kappa values for the two locations were 0.83 (wrist) and 0.84 (chest). The level of agreement did not vary significantly by sleep health (good sleepers vs. subjects with sleep disorders) (p = 0.348, p = 0.118) or by sex (p = 0.442, p = 0.456). The intraclass correlation coefficients of nonwear total time between the reference and the algorithm were 0.92 and 0.97 with the outliers and 0.95 and 0.98 after the outliers were removed for the wrist and chest, respectively. There was no evidence of an association between the mean difference (and 95% limits of agreement) and the mean of the two methods for either sensor position (wrist p = 0.110, chest p = 0.164), and the mean differences (algorithm minus reference) were 5.11 [95% LoA −15.4–25.7] and 1.32 [95% LoA −9.59–12.24] min/day, respectively, after the outliers were removed.

Discussion

We studied the influence of the respiration wave on the power spectrum of the acceleration signal for the differentiation of nonwear periods from sleep and wake periods. The algorithm combined both spectral analysis of the acceleration signal and rescoring. Based on the Bland-Altman analysis, the chest-worn accelerometer showed better results than the wrist-worn accelerometer.

A Single Motivational Lecture Can Promote Modest Weight Loss: A Randomized Controlled Trial

BACKGROUND

Obesity is a public health problem worldwide. To widely disseminate weight-loss interventions across the target population, a cost-effective approach is needed.

OBJECTIVE

We aimed to test whether a single motivational lecture could promote weight loss.

METHODS

Our study was a 3-month randomized controlled trial, and we recruited participants via local newspaper advertisements in 3 cities in Ibaraki Prefecture, Japan, and randomly assigned them to a control group (no intervention) and an intervention group, who attended a single motivational lecture lasting approximately 2 h. No other lectures or textbooks were provided. The eligibility criteria included an age of 40-64 years, a body mass index (BMI) of 25-40 kg/m2, and the presence of at least 1 component of metabolic syndrome. The primary outcome was body weight change at 3 months.

RESULTS

We enrolled 145 eligible participants with a mean age of 53.8 ± 7.1 years and a BMI of 28.5 ± 3.1 kg/m2. The 3-month body weight change in the control and intervention groups was -0.65 kg (95% confidence interval [CI] -1.09 to -0.20) and -2.48 kg (95% CI -3.01 to -1.95), respectively. The between-group difference was 1.83 kg (95% CI 1.15-2.51).

CONCLUSIONS

The significant difference suggested that a single motivational lecture is an effective option to promote modest weight loss in the short term.

Impact of Activity-Based Working and Height-Adjustable Desks on Physical Activity, Sedentary Behavior, and Space Utilization among Office Workers: A Natural Experiment

It has been reported that office environment is an important determinant of physical activity (PA) and sedentary behavior (SB) in office workers. However, the effect of changes in office environment (office renovation) is unclear. The purpose of this study was to examine PA, SB, and space utilization changes among office workers in response to office renovation. This study was a natural experiment at three offices of a single company in Tokyo, Japan. The participants were, 13 workers from one office in the renovation group (mean age: 37.9 ± 10.8 years, percentage of females: 23.1%) and 29 from two offices in the control group (mean age: 42.3 ± 11.2 years, percentage of females: 31.0%). In the renovation, introduction of activity-based working (ABW) and installation of height-adjustable desks (HAD) were adopted. The ABW office was designed to provide various shared workstations, enabling the workers to choose workstations depending on their task or mood. Accelerometer measurement and object detection method using artificial intelligence (AI) technology for video images were used to assess behavior and space utilization before and after the renovation. Two weeks after the renovation, significant improvements in SB (pre- to post-renovation improvements: 346.8 ± 28.6 to 321.2 ± 17.8 min/working-hours) and PA (total PA: 173.2 ± 28.6 to 198.8 ± 17.8 min/working-hours; and light-intensity PA: 130.4 ± 27.1 to 150.7 ± 31.0 min/working-hours) were observed. In addition, the results of the object detection analysis showed that the central aisle of the office and shared HAD workstations near the entrance or window were utilized more frequently than the other spaces. This study suggested that office renovation could improve SB and PA immediately after the renovation. Moreover, utilized spaces and HAD workstations could play an important role to enhance employees’ activity in an ABW office.

Non-wear or sleep? Evaluation of five non-wear detection algorithms for raw accelerometer data

Detection of non-wear periods is an important step in accelerometer data processing. This study evaluated five non-wear detection algorithms for wrist accelerometer data and two rules for non-wear detection when non-wear and sleep algorithms are implemented in parallel. Non-wear algorithms were based on the standard deviation (SD), the high-pass filtered acceleration, or tilt angle. Rules for differentiating sleep from non-wear consisted of an override rule in which any overlap between non-wear and sleep was deemed non-wear; and a 75% rule in which non-wear periods were deemed sleep if the duration was < 75% of the sleep period. Non-wear algorithms were evaluated in 47 children who wore an ActiGraph GT3X+ accelerometer during school hours for 5 days. Rules for differentiating sleep from non-wear were evaluated in 15 adults who wore a GeneActiv Original accelerometer continuously for 24 hours. Classification accuracy for the non-wear algorithms ranged between 0.86-0.95, with the SD of the vector magnitude providing the best performance. The override rule misclassified 37.1 minutes of sleep as non-wear, while the 75% rule resulted in no misclassification. Non-wear algorithms based on the SD of the acceleration signal can effectively detect non-wear periods, while application of the 75% rule can effectively differentiate sleep from non-wear when examined concurrently.

Influence of Health Literacy on the Physical Activity of Working Adults: A Cross-Sectional Analysis of the TRISEARCH Trial

Studies show that high health literacy (HL) can support the promotion and maintenance of healthy behavior such as physical activity (PA). However, most studies rely on subjective data. The aim of the present study is to investigate the relationship between HL and PA, not only with subjectively but also with objectively measured PA data. The present study is a pooled analysis of baseline data from the research association TRISEARCH (2015-2018), which focused on the HL of working adults. HL was measured by Lenartz' questionnaire, and PA by the Global Physical Activity Questionnaire (GPAQ; n = 1056). A subsample (n = 124) also received accelerometers (Actigraph GT3X+) to provide more objective PA data. Partial correlations and regression models were used to investigate the relationship between HL and questionnaire- and accelerometer-derived PA. Very low and medium partial correlations could be found for HL subscales and daily PA by questionnaire (r = -0.06, p < 0.05) and accelerometer (r = 0.26, p < 0.01). No subscale of HL made a significant contribution to the amount of daily PA (all p > 0.05). Not all subscales of HL seem to have an influence on the occurrence of healthy behavior, such as PA. This should be considered when HL-based interventions are designed. Further investigation of the relationship between HL and PA is needed. Objective assessments of both HL and PA can provide additional information for this task.

Influence of Health Literacy on the Physical Activity of Working Adults: A Cross-Sectional Analysis of the TRISEARCH Trial

Studies show that high health literacy (HL) can support the promotion and maintenance of healthy behavior such as physical activity (PA). However, most studies rely on subjective data. The aim of the present study is to investigate the relationship between HL and PA, not only with subjectively but also with objectively measured PA data. The present study is a pooled analysis of baseline data from the research association TRISEARCH (2015–2018), which focused on the HL of working adults. HL was measured by Lenartz’ questionnaire, and PA by the Global Physical Activity Questionnaire (GPAQ; n = 1056). A subsample (n = 124) also received accelerometers (Actigraph GT3X+) to provide more objective PA data. Partial correlations and regression models were used to investigate the relationship between HL and questionnaire- and accelerometer-derived PA. Very low and medium partial correlations could be found for HL subscales and daily PA by questionnaire (r = −0.06, p < 0.05) and accelerometer (r = 0.26, p < 0.01). No subscale of HL made a significant contribution to the amount of daily PA (all p > 0.05). Not all subscales of HL seem to have an influence on the occurrence of healthy behavior, such as PA. This should be considered when HL-based interventions are designed. Further investigation of the relationship between HL and PA is needed. Objective assessments of both HL and PA can provide additional information for this task.

Physical activity levels in adults and elderly from triaxial and uniaxial accelerometry. The Tromsø Study

Introduction

Surveillance of physical activity at the population level increases the knowledge on levels and trends of physical activity, which may support public health initiatives to promote physical activity. Physical activity assessed by accelerometry is challenged by varying data processing procedures, which influences the outcome. We aimed to describe the levels and prevalence estimates of physical activity, and to examine how triaxial and uniaxial accelerometry data influences these estimates, in a large population-based cohort of Norwegian adults.

Methods

This cross-sectional study included 5918 women and men aged 40–84 years who participated in the seventh wave of the Tromsø Study (2015–16). The participants wore an ActiGraph wGT3X-BT accelerometer attached to the hip for 24 hours per day over seven consecutive days. Accelerometry variables were expressed as volume (counts·minute^-1 and steps·day^-1) and as minutes per day in sedentary, light physical activity and moderate and vigorous physical activity (MVPA).

Results

From triaxial accelerometry data, 22% (95% confidence interval (CI): 21–23%) of the participants fulfilled the current global recommendations for physical activity (≥150 minutes of MVPA per week in ≥10-minute bouts), while 70% (95% CI: 69–71%) accumulated ≥150 minutes of non-bouted MVPA per week. When analysing uniaxial data, 18% fulfilled the current recommendations (i.e. 20% difference compared with triaxial data), and 55% (95% CI: 53–56%) accumulated ≥150 minutes of non-bouted MVPA per week. We observed approximately 100 less minutes of sedentary time and 90 minutes more of light physical activity from triaxial data compared with uniaxial data (p<0.001).

Conclusion

The prevalence estimates of sufficiently active adults and elderly are more than three times higher (22% vs. 70%) when comparing triaxial bouted and non-bouted MVPA. Physical activity estimates are highly dependent on accelerometry data processing criteria and on different definitions of physical activity recommendations, which may influence prevalence estimates and tracking of physical activity patterns over time.

Physical activity and work activities in Florida agricultural workers

BACKGROUND

Laboring in hot and humid conditions is a risk factor for heat-related illnesses. Little is known about the amount of physical activity performed in the field setting by agricultural workers, a population that is among those at highest risk for heat-related mortality in the United States.

METHODS

We measured accelerometer-based physical activity and work activities performed in 244 Florida agricultural workers, 18 to 54 years of age, employed in the fernery, nursery, and crop operations during the summer work seasons of 2015-2017. Environmental temperature data during the participant's workdays were collected from the Florida Automated Weather Network and used to calculate wet bulb globe temperature (WBGT). Generalized linear mixed model regression was used to examine the association between WBGT on physical activity, stratified by the agricultural sector.

RESULTS

Fernery workers had the highest overall volume of physical activity, spending nearly 4 hours in moderate to vigorous activity per workday. Activity over the course of the workday also differed by the agricultural sector. A reduction on average physical activity with increasing environmental temperature was observed only among crop workers.

CONCLUSIONS

The quantity and patterns of physical activity varied by the agricultural sector, sex, and age, indicating that interventions that aim to reduce heat-related morbidity and mortality should be tailored to specific subpopulations. Some workers did not reduce overall physical activity under dangerously hot environmental conditions, which has implications for policies protecting worker health. Future research is needed to determine how physical activity and climatic conditions impact the development of heat-related disorders in this population.

Physical Activity and Sedentary Behavior at the End of the Human Lifespan

To objectively assess physical activity levels and sedentary behavior in a cohort of Spanish centenarians and their nonagenarian peers. Physical activity and sedentary behavior patterns were objectively measured by an ActiGraph GT3X accelerometer in centenarians (n = 18; 83% women; 100.8 ± 0.8 [100-103] years) and nonagenarians (n = 11; 91% women; 93.3 ± 2.5 [90-98] years). Centenarians showed less counts per minute (17.6 ± 7.1 vs. 46.1 ± 23.7, p = .003, d = 1.851) and steps per day (455 ± 237 vs. 1,249 ± 776, p = .007, d = 1.587) than nonagenarians. The daily number of sedentary breaks was also lower in the former (5.0 ± 1.5 vs. 6.7 ± 2.0, p = .019, d = 0.971). When observing time distribution, the most active day period in both groups was the morning, with a peak between 10:00 and 11:59. This data suggest that the decline in physical activity levels continues to worsen until the end of the human lifespan.

Enhanced motivational interviewing for reducing weight and increasing physical activity in adults with high cardiovascular risk: the MOVE IT three-arm RCT

BACKGROUND

Motivational interviewing (MI) enhanced with behaviour change techniques (BCTs) and deployed by health trainers targeting multiple risk factors for cardiovascular disease (CVD) may be more effective than interventions targeting a single risk factor.

OBJECTIVES

The clinical effectiveness and cost-effectiveness of an enhanced lifestyle motivational interviewing intervention for patients at high risk of CVD in group settings versus individual settings and usual care (UC) in reducing weight and increasing physical activity (PA) were tested.

DESIGN

This was a three-arm, single-blind, parallel randomised controlled trial.

SETTING

A total of 135 general practices across all 12 South London Clinical Commissioning Groups were recruited.

PARTICIPANTS

A total of 1742 participants aged 40-74 years with a ≥ 20.0% risk of a CVD event in the following 10 years were randomised.

INTERVENTIONS

The intervention was designed to integrate MI and cognitive-behavioural therapy (CBT), delivered by trained healthy lifestyle facilitators in 10 sessions over 1 year, in group or individual format. The control group received UC.

RANDOMISATION

Simple randomisation was used with computer-generated randomisation blocks. In each block, 10 participants were randomised to the group, individual or UC arm in a 4 : 3 : 3 ratio. Researchers were blind to the allocation.

MAIN OUTCOME MEASURES

The primary outcomes are change in weight (kg) from baseline and change in PA (average number of steps per day over 1 week) from baseline at the 24-month follow-up, with an interim follow-up at 12 months. An economic evaluation estimates the relative cost-effectiveness of each intervention. Secondary outcomes include changes in low-density lipoprotein cholesterol and CVD risk score.

RESULTS

The mean age of participants was 69.75 years (standard deviation 4.11 years), 85.5% were male and 89.4% were white. At the 24-month follow-up, the group and individual intervention arms were not more effective than UC in increasing PA [mean 70.05 steps, 95% confidence interval (CI) -288 to 147.9 steps, and mean 7.24 steps, 95% CI -224.01 to 238.5 steps, respectively] or in reducing weight (mean -0.03 kg, 95% CI -0.49 to 0.44 kg, and mean -0.42 kg, 95% CI -0.93 to 0.09 kg, respectively). At the 12-month follow-up, the group and individual intervention arms were not more effective than UC in increasing PA (mean 131.1 steps, 95% CI -85.28 to 347.48 steps, and mean 210.22 steps, 95% CI -19.46 to 439.91 steps, respectively), but there were reductions in weight for the group and individual intervention arms compared with UC (mean -0.52 kg, 95% CI -0.90 to -0.13 kg, and mean -0.55 kg, 95% CI -0.95 to -0.14 kg, respectively). The group intervention arm was not more effective than the individual intervention arm in improving outcomes at either follow-up point. The group and individual interventions were not cost-effective.

CONCLUSIONS

Enhanced MI, in group or individual formats, targeted at members of the general population with high CVD risk is not effective in reducing weight or increasing PA compared with UC. Future work should focus on ensuring objective evidence of high competency in BCTs, identifying those with modifiable factors for CVD risk and improving engagement of patients and primary care.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN84864870.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 69. See the NIHR Journals Library website for further project information. This research was part-funded by the NIHR Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King's College London.

The Feasibility and Efficacy of a Behavioral Intervention to Promote Appropriate Gestational Weight Gain

INTRODUCTION

Nearly half of all women gain above gestational weight gain (GWG) recommendations. This study assessed the feasibility and efficacy of a pilot behavioral intervention on GWG and physical activity behaviors.

METHODS

Women (n = 45) 14-20 weeks gestation enrolled in a behavioral intervention. Physicians 'prescribed' the intervention to low risk patients. The intervention included self-monitoring, support, and optional walking groups. Process evaluation measures regarding usage and acceptability of study components were obtained. Physical activity was objectively measured at baseline and 35 weeks. The percentage of participants with appropriate GWG was calculated. Control data was obtained from the same clinic where participants were recruited.

RESULTS

Overall, the intervention was acceptable to participants; attrition was low (6.7%), weekly contact was high (87%), and self-monitoring was high (Fitbit worn on 82% of intervention weeks; weekly weighing on 81%). Facebook (40% of weeks) and study website use (19%) was low, as was walking group attendance (7% attended a single group). Participants reported a lack of discussions about the study with their physician. Results showed no significant difference between intervention and control participants in the percentage who gained excess weight (p = 0.37). There was a significant decrease in moderate-to-vigorous physical activity in intervention participants (p < 0.0001).

DISCUSSION

Continued efforts for promoting physical activity and appropriate GWG are needed. Although acceptable, the intervention was not efficacious. Trainings for, or input from prenatal healthcare providers on how to best encourage and support patients' engagement in healthy behaviors, such as PA, are warranted.

Metal ion concentrations after metal-on-metal hip arthroplasty are not correlated with habitual physical activity levels

INTRODUCTION

Metal-on-metal (MoM) hip arthroplasties have shown high clinical failure rates with many patients at risk for a revision and under surveillance for high metal ion concentrations. Implant wear releasing such ions is assumed to be a function of use, i.e. the patient's physical activity. This study aimed to assess whether habitual physical activity levels of MoM patients are correlated with metal ion concentrations and are higher in patients with high (at risk) than in patients with low (safe) metal ion concentrations.

METHODS

A cohort study was conducted of patients with any type of MoM hip prosthesis. Metal ion concentrations were determined using ICP-MS. Habitual physical activity of subjects was measured in daily living using an acceleration-based activity monitor. Outcome consisted of quantitative and qualitative activity parameters.

RESULTS

In total, 62 patients were included. Mean age at surgery was 60.8 ± 9.3 years and follow-up was 6.3 ± 1.4 years. Cobalt concentrations were highly elevated overall (112.4 ± 137.9 nmol/L) and significantly more in bilateral (184.8 ± 106.5 nmol/L) than in unilateral cases (87.8 ± 139.4 nmol/L). No correlations were found between physical activity parameters and metal ion concentrations. Subgroup analysis of patients with low versus high cobalt concentration showed no significant differences in habitual physical activity.

DISCUSSION

No correlation was found between physical activity levels and metal ion concentrations. Implant use by normal habitual activities of daily living seems not to influence metal ion concentrations.

Effects of sedentary behavior and physical activity on sleep quality in older people: A cross-sectional study

The aim of this cross-sectional study was to investigate the influence of replacing sedentary time with time engaged in one of two levels of physical activity on sleep quality using an isotemporal substitution model. The participants were 70 community-dwelling older Japanese adults (approximately 70% female). Physical activity types were measured using a triaxial accelerometer and categorized based on intensity as sedentary, light-intensity, and vigorous-intensity. The Pittsburgh Sleep Quality Index assessed subjective sleep quality. Objective sleep parameters were assessed using an actigraph. A series of multi-linear regression models analyzed the statistical relationships. Our findings showed that replacing 30 min of sedentary activity per day with an equal period of light-intensity physical activity significantly influenced sleep quality parameters. However, there was no significant difference in sleep quality when light-intensity activity was replaced with vigorous-intensity activity. Engaging in one activity type means less available time for other types of activity; habitual replacement of sedentary activity with light-intensity physical activity might have long-term benefits on the sleep quality of older people.

Outcome Measures of Free-Living Activity in Spinal Cord Injury Rehabilitation

PURPOSE OF REVIEW

The purpose of this article was to describe the utilization of body worn activity monitors in the SCI population and discuss the challenges of using body worn sensors in rehabilitation research.

RECENT FINDINGS

Many activity monitor-based measures have been used and validated in the SCI population including stroke number, push frequency, upper limb activity counts and wheelchair propulsion distance measured from a sensor attached to the wheelchair.

SUMMARY

The ability to accurately measure physical activity in the free-living environment using body-worn sensors has the potential to enhance the understanding of barriers to adequate activity and identify possible effective interventions. As the use of activity monitors used in SCI rehabilitation research continues to grow, care must be taken to overcome challenges related to participant adherence and data quality.

Daily and per-meal animal and plant protein intake in relation to muscle mass in healthy older adults without functional limitations: an enable study

OBJECTIVE

Animal protein sources are considered to be of higher quality than plant protein sources in terms of stimulating muscle metabolism. Our objective was to investigate whether protein intake from animal and plant sources on a daily and per-meal basis differs between healthy older adults with normal and with low muscle mass.

METHODS

In this cross-sectional study including 100 healthy, community-dwelling adults (51 women) aged 75-85 years without functional limitations dietary intake was assessed using 7-day food records. Protein intake was classified by six animal and six plant protein sources. Skeletal muscle index (SMI) was determined based on bioelectrical impedance analysis and categorized into 'normal' or 'low' (men ≤ 8.50, women ≤ 5.75 kg/m²). The absolute animal and plant protein intake and their proportion of total protein intake were compared between these groups using Mann-Whitney U test.

RESULTS

Daily protein intake was 0.96 ± 0.27 g/kg body weight (BW), 61 ± 10% hereof were from animal origin with no difference between men and women. SMI was low in 39% of men and 35% of women. No differences in absolute daily animal and plant protein intake between participants with normal vs. low SMI were observed. The proportion of animal protein was not different on neither a daily nor a per-meal basis between those with normal and those with low SMI. Women with low SMI consumed less animal protein (in g) for breakfast (4.8 ± 4.1 g vs. 8.5 ± 6.9 g, p = 0.031) and fewer meals per day with at least 50% animal protein (2.2 ± 0.9 vs. 2.7 ± 1.0, p = 0.046) compared to those with normal SMI.

CONCLUSION

On a daily basis, the absolute and relative animal protein intake does not differ between healthy older adults without functional limitations with normal vs. low SMI. However, our results indicate that in women animal protein intake on a per-meal basis might be of relevance for the maintenance of muscle mass.

Maternal BMI Change Linked to Child Activity Change in Family-Based Behavioral Interventions for Pediatric Weight Management

Background: This study investigated whether change in maternal BMI was associated with change in child's moderate-to-vigorous physical activity (MVPA) and prolonged sedentary time during the course of family-based behavioral interventions (FBBIs) for pediatric weight management. Methods: Children (n = 120) ages 5-12 [mean age = 9.04 ± 1.7) years with a baseline BMI ≥85th percentile (mean BMIz = 1.8 ± 0.5) and families were enrolled in one of three similar FBBIs for pediatric weight management and followed over 6-12 months. Activity data were collected through accelerometers. Mixed effects regression models assessed the relationship of maternal change in BMI to child change in (1) minutes/d of MVPA and (2) proportion of time spent in sedentary bouts lasting ≥10 minutes (termed prolonged sedentary time), and whether the effect of maternal BMI change was moderated by child age, sex, and race/ethnicity. Results: A decrease in maternal BMI was associated with both an increase in child MVPA, B = -2.77, t = -2.03, p = 0.048, and a decrease in proportion/d of prolonged sedentary time, B = 0.02, t = 2.40, p = 0.020, from baseline to follow-up. Child age moderated the association between maternal BMI change and change in child prolonged sedentary time (p = 0.095), whereby the association was limited to 5- to 10-year-olds and became stronger as age decreased. Conclusions: Improvement in maternal BMI showed important positive associations with child MVPA and prolonged sedentary time over the course of FBBIs for pediatric weight management. Targeting parent weight loss could improve child outcomes in FBBIs, particularly in younger children.

Increasing physical activity and healthy diet in outpatients with mental disorders: a randomized-controlled evaluation of two psychological interventions

INTRODUCTION

While physical activity (PA) can play an important role in the treatment of mental disorders (MD), large proportions of patients with MD do not meet PA recommendations. The aim of this trial was to evaluate whether structured psychological intervention (MoVo-LISA) is effective in helping outpatients with MD to increase their level of PA. As active control group (CG) we modified MoVo-LISA to target healthy diet behavior.

METHODS

N = 83 outpatients with MD (F1-F4) were randomized to the two conditions. PA (self-report and accelerometry), dietary behavior, social-cognitive determinants of health behavior change, psychiatric symptoms and health-related quality of life were assessed at baseline, 1 and 12 weeks after the intervention.

RESULTS

Significant time*group interaction effects for objectively measured PA, dietary behavior and fruit and vegetable consumption indicated differential effects of the interventions on these outcomes. PA increased in the MoVo-LISA group (IG) from baseline to follow-up while it decreased in CG. IG showed a significant higher level of objectively measured PA at follow-up compared to CG. Dietary behavior and fruit and vegetable consumption significantly increased from baseline to follow-up in CG, but not IG. IG showed a significant increase in some, but not all social cognitive determinants of health behavior change.

CONCLUSIONS

MoVo-LISA is effective in helping outpatients with MD to increase their level of PA in short- and mid-term. The used intervention strategies are effective for the promotion of healthy diet in patients with MD as well.

Familial Environment and Overweight/Obese Adolescents' Physical Activity

(1) Background: Family environments can impact obesity risk among adolescents. Little is known about the mechanisms by which parents can influence obesity-related adolescent health behaviours and specifically how parenting practices (e.g., rules or routines) and/or their own health behaviours relate to their adolescent’s behaviours. The primary aim of the study explored, in a sample of overweight/obese adolescents, how parenting practices and/or parental modeling of physical activity (PA) behaviours relate to adolescents’ PA while examining the moderating role of parenting styles and family functioning. (2) Methods: A total of 172 parent-adolescent dyads completed surveys about their PA and wore an accelerometer for eight days to objectively measure PA. Parents completed questionnaires about their family functioning, parenting practices, and styles (authoritative and permissive). Path analysis was used for the analyses. (3) Results: More healthful PA parenting practices and parental modeling of PA were both associated with higher levels of adolescents’ self-reported moderate-vigorous physical activity (MVPA). For accelerometer PA, more healthful PA parenting practices were associated with adolescents’ increased MVPA when parents used a more permissive parenting style. (4) Conclusions: This study suggests that parenting practices and parental modeling play a role in adolescent’s PA. The family’s emotional/relational context also warrants consideration since parenting style moderated these effects. This study emphasizes the importance of incorporating parenting styles into current familial interventions to improve their efficacy.

Race Differences in Physical Activity Uptake Within a Workplace Wellness Program: A Comparison of Black and White Employees

PURPOSE

To examine differences in physical activity (PA) uptake between black and white employees during a financial incentive-based workplace intervention.

DESIGN

Prospective cohort study from July 2014 to June 2015 (NCT02850094).

SETTING

Tertiary academic medical center.

PARTICIPANTS

Forty-three black and 182 white nonclinical employees.

INTERVENTION

Participants self-selected or were assigned to teams. Participants completed a 24-week intervention receiving rewards for meeting weekly PA goals (increasing moderate-to-vigorous PA [MVPA] by 10% from previous week or meeting Guidelines threshold of 150 minutes of MVPA).

MEASURES

Outcomes included weekly MVPA in minutes, average daily step counts, number of weeks meeting personal goals and the Guidelines, and Fitbit adherence in days and weeks.

ANALYSIS

We performed an analysis of covariance for each outcome, with race as the primary independent variable of interest, adjusting for demographic and health-related covariates.

RESULTS

During the intervention, blacks walked 9128 steps per day while whites walked 7826 steps per day, a difference of approximately 1300 steps (P < .05). Blacks also demonstrated a greater uptake in both steps and MVPA from baseline than did whites, resulting in similar MVPA throughout the intervention.

CONCLUSIONS

Findings suggest that workplace PA interventions using financial incentives may result in similar engagement in MVPA among white and black employees, while black employees walk more steps during the intervention. Limitations include a primarily white female sample which may not generalize.

Individual variations in steps per day for meeting physical activity guidelines in young adult women

Cross-sectional studies have found a correlation between the duration or volume of moderate-to-vigorous physical activity (MVPA) and steps per day (STEP), but there is little information on why this relationship varies among individuals. No previous research has established whether STEP can be used to estimate the duration of physical activity (PA) at or above lactate threshold (≥LT), such as for maintaining cardiorespiratory fitness. This study explored the association among STEP, MVPA indices, and ≥LT under free-living conditions. Seventy young adult women measured their PA for 7 days using a validated accelerometer. The mean LT measured by an exercise test was 5.8 ± 1.0 METs. STEP, MVPA, METs×h, and ≥LT were 9324 ± 2677 steps/day, 231.9 ± 101.5 min/week, 16.6 ± 7.4 METs×h/week and 24.0 ± 22.2 min/week, respectively. Significant correlations were found between STEP and MVPA duration and between STEP and METs×h/week (r = 0.81 and r = 0.81); however, approximately 1600 steps/day of the standard error of estimates in the regression equations were found. Multiple stepwise regression analysis revealed that the percentage of total time spent at light-intensity PA (LPA) and MVPA were significant determinants of the percent deviation of STEP from the linear relationships between STEP and MVPA indices. No significant relationship was observed between ≥LT and STEP. The association between STEP and MVPA fluctuated depending on individual daily LPA and MVPA. Thus, consideration of both STEP and the PA at specific intensities are necessary to ensure the PA guidelines are met and the health benefits gained. STEP alone would be not a sufficient indicator for assessing the ≥LT.

Efficacy of risk stratification protocols and clinical, physical, and biochemical parameters to previse signals and symptoms during cardiovascular rehabilitation programs: Protocol for an observational trial

INTRODUCTION

Despite the benefits, cardiovascular rehabilitation programs (CRPs) have been related to the appearance of signals and symptoms. Risk stratification protocols are commonly used to identify risks during the physical exercise; however, studies that investigate their efficacy to previse signals and symptoms are inconclusive. Furthermore, clinical, physical, and biochemical parameters have been used as risk markers for the appearance of adverse events, and to investigate their efficacy to previse signals and symptoms during the CRP sessions that could better guide the strategies adopted on these programs.

OBJECTIVES

The aim of this study was to evaluate the correlations between risk stratification protocols and clinical, physical, and biochemical parameters with the appearance of signals/symptoms during CRP, as well as to evaluate if modifications on clinical, physical, and biochemical parameters could influence in the appearance of signals/symptoms during CRP.

MATERIALS AND METHODS

The study was prospectively registered at ClinicalTrials.gov (NCT03446742). Forty-four patient participants of a CRP will be evaluated. First, their risk stratification is going to be performed by 2 evaluators and their clinical, physical, and biochemical parameters are going to be measured. Then, the patients are going to be followed during 24 sessions during their CRP routines in order to identify appearance of their signals/symptoms. So, the patients are going to perform their cardiovascular rehabilitation routines for 6 months and then, their clinical, physical, and biochemical parameters are going to be measured again and they are going to be followed during 24 sessions during their CRP routines in order to identify the appearance of their signals/symptoms.

Classroom Standing Desks and Time-Series Variation in Sedentary Behavior and Physical Activity among Primary School Children

The purpose of the present study was to examine the effects of height-adjustable standing desks on time-series variation in sedentary behavior (SB) among primary school children. Thirty-eight children aged 11–12 years (22 boys and 16 girls) from two classes at a primary school in Nagano, Japan, participated in this study. One class was allocated as the intervention group and provided with individual standing desks for 6 months, and the other was allocated as the control group. Time spent in SB, light-intensity physical activity (LPA), and moderate-to-vigorous-intensity physical activity (MVPA) was measured using accelerometers (ActiGraph) at baseline and follow-up. Time spent in SB was significantly lower by 18.3 min/day on average in the intervention class at follow-up (interaction effects: F_{(1, 36)} = 4.95, p = 0.035, η² = 0.082). This was accompanied by a significant increase in time spent in MVPA (+19.9 min/day on average). Our time-series analysis showed significant decreases in SB during school time, while no change in SB was found during non-school time. This result indicates that the use of standing desks promotes an overall reduction in SB with no compensatory increase during non-school time.

Comparison and validation of accelerometer wear time and non-wear time algorithms for assessing physical activity levels in children and adolescents

Background

Accelerometers are widely used to measure sedentary time and daily physical activity (PA). However, data collection and processing criteria, such as non-wear time rules might affect the assessment of total PA and sedentary time and the associations with health variables. The study aimed to investigate whether the choice of different non-wear time definitions would affect the outcomes of PA levels in youth.

Methods

Seventy-seven healthy youngsters (44 boys), aged 10–17 years, wore an accelerometer and kept a non-wear log diary during 4 consecutives days. We compared 7 published algorithms (10, 15, 20, 30, 60 min of continuous zeros, Choi, and Troiano algorithms). Agreements of each algorithm with the log diary method were assessed using Bland-Altmans plots and by calculating the concordance correlation coefficient for repeated measures.

Results

Variations in time spent in sedentary and moderate to vigorous PA (MVPA) were 30 and 3.7%. Compared with the log diary method, greater discrepancies were found for the algorithm 10 min (p < 0.001). For the time assessed in sedentary, the agreement with diary was excellent for the 4 algorithms (Choi, r = 0.79; Troiano, r = 0.81; 30 min, r = 0.79; 60 min, r = 0.81). Concordance for each method was excellent for the assessment of time spent in MVPA (> 0.86). The agreement for the wear time assessment was excellent for 5 algorithms (Choi r = 0.79; Troiano r = 0.79; 20 min r = 0.77; 30 min r = 0.80; 60 min r = 0.80).

Conclusions

The choice of non-wear time rules may considerably affect the sedentary time assessment in youth. Using of appropriate data reduction decision in youth is needed to limit differences in associations between health outcomes and sedentary behaviors and may improve comparability for future studies. Based on our results, we recommend the use of the algorithm of 30 min of continuous zeros for defining non-wear time to improve the accuracy in assessing PA levels in youth.

Trial registration

NCT02844101 (retrospectively registered at July 13th 2016).

Electronic supplementary material

The online version of this article (10.1186/s12874-019-0712-1) contains supplementary material, which is available to authorized users.

A semiparametric model for wearable sensor-based physical activity monitoring data with informative device wear

Wearable sensors provide an exceptional opportunity in collecting real-time behavioral data in free living conditions. However, wearable sensor data from observational studies often suffer from information bias, since participants' willingness to wear the monitoring devices may be associated with the underlying behavior of interest. The aim of this study was to introduce a semiparametric statistical approach for modeling wearable sensor-based physical activity monitoring data with informative device wear. Our simulation study indicated that estimates from the generalized estimating equations showed ignorable bias when device wear patterns were independent of the participants physical activity process, but incrementally more biased when the patterns of device non-wear times were increasingly associated with the physical activity process. The estimates from the proposed semiparametric modeling approach were unbiased both when the device wear patterns were (i) independent or (ii) dependent to the underlying physical activity process. We demonstrate an application of this method using data from the 2003-2004 National Health and Nutrition Examination Survey ($N=4518$), to examine gender differences in physical activity measured using accelerometers. The semiparametric model can be implemented using our R package acc, free software developed for reading, processing, simulating, visualizing, and analyzing accelerometer data, publicly available at the Comprehensive R Archive Network.

Web-based intervention to promote weight-loss maintenance using an activity monitor: A randomized controlled trial

The present study examined whether a web-based intervention could promote weight-loss maintenance, after weight loss. The study was a two-phase, 27-month, randomized controlled trial conducted in Ibaraki, Japan, from 2014 to 2017; 133 participants were recruited through local newspaper advertisements. The eligibility criteria were as follows: age of 40–64 years, body mass index of 25–40 kg/m², and having at least one metabolic syndrome component. In phase 1, a 3-month, group-based weight-loss program was provided to all eligible participants (n = 119). We then randomly assigned (1:1) participants who had lost 5% or more of their weight during phase 1 (n = 95) to either the self-help (mean 3-month weight loss 7.30 kg) or the web-support group (7.00 kg). Participants in the web-support group regularly reported their body weight and physical activity through a web-based system. They received monthly personalized feedback from a study staff for 24 months. The primary outcome, 27-month body-weight change (mean ± standard deviation), in the self-help and web-support groups were − 5.3 ± 5.0 kg and −4.5 ± 4.9 kg, respectively. There was no significant difference. An exploratory secondary analysis demonstrated that those with greater 27-month increases in their step count, assessed with an accelerometer, lost more weight with no difference in changes in energy intake. The mean 27-month body-weight change in the 4th quartile of changes in step count was −7.78 kg. Although web-based intervention using an activity monitor failed to promote weight-loss maintenance, increased physical activity was associated with successful weight-loss maintenance.

•

Web-based intervention using an activity monitor delivered no benefit on weight.

•

Participants with larger increases in step count lost more weight.

•

Increased physical activity was associated with successful weight loss maintenance.

Data management and wearables in older adults: A systematic review

BACKGROUND

Wearable trackers as research or clinical tools are increasingly used to support the care of older adults, due to their practicality in self-monitoring and potential to promote healthy lifestyle behaviours. However, there is limited understanding of appropriate data collection and analysis methods in different contexts.

AIM

To summarise evidence on wearable data generation and management in older adults, focusing on physical activity (PA), electrocardiogram (ECG), and vital signs monitoring. In addition to examine the accuracy and utility of wearable trackers in the care of older people.

METHODS

A systematic search of CINAHL, MEDLINE, PubMed and a manual search were conducted. Twenty studies on the use of wearable trackers by older adults met the inclusion criteria.

RESULTS

Methodological designs for data collection and analysis were heterogeneous, with diverse definitions of wear and no-wear time, the number and type of valid days, and proprietary algorithms. Wearable trackers had adequate accuracy for measuring step counts, moderate to vigorous physical activity (MVPA), ECG and heart rate (HR), but not for respiratory rate. Participants reported ease of use and had high-level adherence over daily long-term use. Moreover, wearable trackers encouraged users to increase their daily level of physical activity and decrease waist circumference, facilitating atrial fibrillation (AF) diagnoses and predicting length of stay.

CONCLUSION

Wearable trackers are multi-dimensional technologies offering a viable and promising approach for sustained and scaled monitoring of older people's health. Frameworks and/or guidelines, including standards for the design, data management and application of use specifically for older adults, are required to enhance validity and reliability.

Physical Activity Questionnaires for Pregnancy: A Systematic Review of Measurement Properties

Background

In order to assess physical activity (PA) during pregnancy, it is important to choose the instrument with the best measurement properties.

Objectives

To systematically summarize, appraise, and compare the measurement properties of all self-administered questionnaires assessing PA in pregnancy.

Methods

We searched PubMed, Embase, and SPORTDiscus with the following inclusion criteria: (i) the study reported at least one measurement property (reliability, criterion validity, construct validity, responsiveness) of a self-administered questionnaire; (ii) the questionnaire intended to measure PA; (iii) the questionnaire was evaluated in healthy pregnant women; and (iv) the study was published in English. We evaluated results, quality of individual studies, and quality of evidence using a standardized checklist (Quality Assessment of Physical Activity Questionnaires [QAPAQ]) and the GRADE (Grading of Recommendation, Assessment, Development, and Evaluation) approach.

Results

Seventeen articles, reporting 18 studies of 11 different PA questionnaires (17 versions), were included. Most questionnaire versions showed insufficient measurement properties. Only the French and Turkish versions of the Pregnancy Physical Activity Questionnaire (PPAQ) showed both sufficient reliability and construct validity. However, all versions of the PPAQ pooled together showed insufficient construct validity. The quality of individual studies was usually high for reliability but varied considerably for construct validity. Overall, the quality of evidence was very low to moderate.

Conclusions

We recommend the PPAQ to assess PA in pregnancy, although the pooled results revealed insufficient construct validity. The lack of appropriate standards in data collection and processing criteria for objective devices in measuring PA during pregnancy attenuates the quality of evidence. Therefore, research on the validity of comparison instruments in pregnancy followed by consensus on validation reference criteria and standards of PA measurement is needed.

Electronic supplementary material

The online version of this article (10.1007/s40279-018-0961-x) contains supplementary material, which is available to authorized users.

Actigraphy-measured nocturnal wrist movements and assessment of sleep quality in patients with bullous pemphigoid: a pilot case-control study

BACKGROUND

Bullous pemphigoid (BP) is a distressing autoimmune bullous disease strongly associated with severe pruritus; however, data concerning pruritus in BP are still scarce. No clinical research evaluating the effect of BP on sleep quality has been conducted.

AIM

To evaluate the intensity of pruritus measured by nocturnal wrist movements (NWMs) and the sleep quality in patients with BP using actigraphy in comparison with nonpruritic healthy controls (HCs) with subsequent correlations with an itch visual analogue scale (VAS) as a subjective measure, disease severity [Bullous Pemphigoid Disease Area Index (BPDAI), urticaria/erythema, erosions/blisters] and serum total IgE level.

METHODS

In total, 31 patients with newly diagnosed BP (mean ± SD age 75.4 ± 12.3 years) and 40 nonpruritic HCs (age 73.5 ± 11.7 years) were recruited. All participants wore a sleep monitor (ActiSleep+) on the dominant wrist.

RESULTS

For patients with BP, median VAS score was 5.5 and median BPDAI was 43 (urticaria/erythema BPDAI was 16, erosions/blisters BPDAI was 29). Scratching, defined as bouts of NWMs, was significantly (P < 0.001) more intensive in patients with BP than in controls. Characteristic of BP was that scratching bouts corresponded with the slowest wrist movements. There were no correlations with VAS, BPDAI or total IgE level. Compared with HCs, patients with BP presented significant (P < 0.001) sleep disturbances, as determined by sleep efficiency, waking after sleep onset and average duration of awakening, and these were strongly correlated with urticaria/erythema BPDAI.

CONCLUSION

Nocturnal wrist movements measured by actigraphy are more intensive in patients with BP than in nonpruritic HCs, and characteristically slow movements. Actigraphy method showed very low sleep quality in patients with BP, thus severity of BP has a negative impact on sleep.

Feasibility of smart wristbands for continuous monitoring during pregnancy and one month after birth

Background

Smart wristbands enable the continuous monitoring of health parameters, for example, in maternity care. Understanding the feasibility and acceptability of these devices in an authentic context is essential. The aim of this study was to evaluate the feasibility of using a smart wristband to collect continuous activity, sleep and heart rate data from the beginning of the second trimester until one month postpartum.

Methods

The feasibility of a smart wristband was tested prospectively through pregnancy in nulliparous women (n = 20). The outcomes measured were the wear time of the device and the participants’ experiences with the smart wristband. The data were collected from the wristbands, phone interviews, questionnaires, and electronic patient records. The quantitative data were analyzed with hierarchical linear mixed models for repeated measures, and qualitative data were analyzed using content analysis.

Results

Participants (n = 20) were recruited at a median of 12.9 weeks of gestation. They used the smart wristbands for an average of 182 days during the seven-month study period. The daily use of the devices was similar during the second (17.9 h, 95% CI 15.2 to 20.7) and third trimesters (16.7 h, 95% CI 13.8 to 19.5) but decreased during the postpartum period (14.4 h, 95% CI 11.4 to 17.4, p = 0.0079). Participants who could not wear smart wristbands at work used the device 300 min less per day than did those with no use limitations. Eight of the participants did not wear the devices or wore them only occasionally after giving birth. Nineteen participants reported that the smart wristband did not have any permanent effects on their behavior. Problems with charging and synchronizing the devices, perceiving the devices as uncomfortable, or viewing the data as unreliable, and the fear of scratching their babies with the devices were the main reasons for not using the smart wristbands.

Conclusions

A smart wristband is a feasible tool for continuous monitoring during pregnancy. However, the daily use decreased after birth. The results of this study may support the planning of future studies and help with overcoming barriers related to the use of smart wristbands on pregnant women.

Electronic supplementary material

The online version of this article (10.1186/s12884-019-2187-9) contains supplementary material, which is available to authorized users.

The association between park facilities and the occurrence of physical activity during park visits

Prior research has found a positive relationship between the variety of park facilities and park-based physical activity (PA), but has not provided an estimate of the effect that additional different PA facilities have on whether an individual is active during a park visit. Using objective measures of park visits and PA from an urban sample of 225 adults in King County, Washington, we compared the variety of PA facilities in parks visited where an individual was active to PA facilities in parks where the same individual was sedentary. Each additional different PA facility at a park was associated with a 6% increased probability of being active during a visit. Adding additional different PA facilities to a park appears to have a moderate effect on whether an individual is active during a park visit, which could translate into large community health impacts when scaled up to multiple park visitors.

Physical activity levels of allied health professionals working in a large Australian metropolitan health district - an observational study

PURPOSE

The aim of this observational cross-sectional study was to determine if allied health professionals working in a large metropolitan health district were meeting the minimal physical activity (PA) recommendations and the proportion that occupational PA contributed to the recommended PA levels. A secondary aim was to determine possible relationships between self-report questionnaire measures of PA and PA measured by accelerometry.

MATERIALS AND METHODS

Allied health professionals, working in the Sydney Local Health District (SLHD) in 2016-2017, completed the Active Australia Survey (AAS), Occupational Sitting and Physical Activity Questionnaire (OSPAQ), International Physical Activity Questionnaire Long form (IPAQ-L), and wore the ActiGraph GT1M accelerometer for 7 days consecutively.

RESULTS

Based on accelerometry results, allied health professionals (N=126) spent a mean (SD) of 51 (23) minutes in moderate-to-vigorous physical activity (MVPA)/day, representing 171% of the total recommended MVPA/day, with work contributing 76% to this recommendation. Participants walked a mean of 10,077 (2,766) steps/day, meeting 100% of the recommended 10,000 steps/day, with work contributing 54% to this recommendation. Sedentary behaviors were predominant throughout the entire day and work day. Compared with the ActiGraph MVPA time measurements, AAS MVPA time showed a fair level of agreement [intraclass correlation coefficient (ICC)=0.44, P<0.01], while OSPAQ and IPAQ-L MVPA time showed no agreement (ICC=0.05, P=0.27; ICC=0.13, P=0.10, respectively).

CONCLUSION

Allied health professionals working in a large metropolitan health district met the daily PA recommendations based on accelerometry measures but tended to overreport their MVPA on self-report questionnaires.

The Impact of Step Recommendations on Body Composition and Physical Activity Patterns in College Freshman Women: A Randomized Trial

PURPOSE

Transitioning from high school to college generally results in reduced physical activity and weight gain at a rate that is higher than the general population. The purpose of this study was to examine the effects of three progressively higher step recommendations over 24 weeks on changes in body weight and body composition.

METHODS

Ninety-two freshmen college women wore a multifunction pedometer for 24 weeks after being randomly assigned to a daily step level: 10,000, 12,500, or 15,000. Pedometer data were downloaded every two weeks and participants were counseled on meeting their step recommendation. Body weight and body composition were assessed at baseline and 24 weeks. Body composition was assessed by dual X-ray absorptiometry.

RESULTS

On average, women took 10,786 ± 1501, 12,650 ± 2001, and 13,762 ± 2098 steps per day for the 10,000-, 12,500-, and 15,000-step groups, respectively (F = 15.48, P < 0.0001). Participants gained 1.4 ± 2.6, 1.8 ± 2.1, and 1.4 ± 2.1 kg for the 10,000-, 12,500-, and 15,000-step groups, respectively (F = 37.74, P < 0.0001). Weight gain was not significantly different between groups (F = 0.18, P=0.8385). There was also no difference in fat weight gain (F = 0.41, P=0.7954).

DISCUSSION

A step recommendation beyond 10,000 does not prevent weight or fat gain over the first year of college. Future research should focus on either intensity of physical activity or the addition of dietary interventions to prevent weight gain during the first year of college.

Differences in physical activity between seasons with and without snowfall among elderly individuals residing in areas that receive snowfall

[Purpose] This study aimed to examine the influence of climatic conditions on the daily physical activities of elderly individuals by comparing the physical activity during seasons with and without snowfall. [Participants and Methods] In total, 35 participants attending the Health Promotion Program conducted by Chitose City Office participated in this study. The survey for the seasons with snowfall was conducted in February 2016, while the survey for the seasons without snowfall was conducted in September 2015. The physical activity of the participants was measured using a Kenz Lifecorder GS accelerometer. [Results] Physical activity was found to be significantly lower during seasons with snowfall than in seasons without snowfall. Multivariate analysis revealed that physical activity significantly increased with lower temperature during the seasons with snowfall, and it significantly increased with higher temperature and decreased with larger amounts of precipitation during the seasons without snowfall. [Conclusion] It was found that the climatic conditions affect the level of physical activity during seasons with and without snowfall. A lower level of physical activity was observed in areas that received snowfall than in areas that did not receive snowfall.

Reliability of Wearable-Sensor-Derived Measures of Physical Activity in Wheelchair-Dependent Spinal Cord Injured Patients

Physical activity (PA) has been shown to have a positive influence on functional recovery in patients after a spinal cord injury (SCI). Hence, it can act as a confounder in clinical intervention studies. Wearable sensors are used to quantify PA in various neurological conditions. However, there is a lack of knowledge about the inter-day reliability of PA measures. The objective of this study was to investigate the single-day reliability of various PA measures in patients with a SCI and to propose recommendations on how many days of PA measurements are required to obtain reliable results. For this, PA of 63 wheelchair-dependent patients with a SCI were measured using wearable sensors. Patients of all age ranges (49.3 ± 16.6 years) and levels of injury (from C1 to L2, ASIA A-D) were included for this study and assessed at three to four different time periods during inpatient rehabilitation (2 weeks, 1 month, 3 months, and if applicable 6 months after injury) and after in-patient rehabilitation in their home-environment (at least 6 months after injury). The metrics of interest were total activity counts, PA intensity levels, metrics of wheeling quantity and metrics of movement quality. Activity counts showed consistently high single-day reliabilities, while measures of PA intensity levels considerably varied depending on the rehabilitation progress. Single-day reliabilities of metrics of movement quantity decreased with rehabilitation progress, while metrics of movement quality increased. To achieve a mean reliability of 0.8, we found that three continuous recording days are required for out-patients, and 2 days for in-patients. Furthermore, the results show similar weekday and weekend wheeling activity for in- and out-patients. To our knowledge, this is the first study to investigate the reliability of an extended set of sensor-based measures of PA in both acute and chronic wheelchair-dependent SCI patients. The results provide recommendations for sensor-based assessments of PA in clinical SCI studies.

Antidepressant effects of direct-acting antivirals against hepatitis C virus-Results from a pilot study

BACKGROUND AND AIMS

The new direct-acting antiviral agents (DAA) have revolutionized the treatment of patients with chronic hepatitis C virus (HCV) infection. This study investigates to which extent DAA affect fatigue and mood and, if so, whether this results from changes to tryptophan (TRP) metabolism, as reflected by two critical biosynthetic pathways, serotonin (SRT) generation from TRP and TRP degradation through kynurenines (KYN) via indoleamine 2,3-dioxygenase (IDO).

METHODS

This study assessed 24 patients with chronic HCV infection, before (T1), during (T2: at 4 weeks) and 12 weeks post-treatment with DAA (T3) with respect to viral load, fatigue and depressive symptoms (BDI-II questionnaire), physical activity (actigraph) and plasma serotonin-tryptophan metabolites (LC/MS). The KYN:TRP ratio reflected IDO activity.

RESULTS

All participants achieved sustained virological response (SVR12) with DAA treatment (79% sofosbuvir-based). Fatigue (scores at T1:0.83 ± 0.70, T2:0.48 ± 0.70, T3:0.30 ± 0.50; P = 0.023) and depressive symptoms (scores at T1:9.8 ± 10.2, T2:6.0 ± 7.3, T3:5.0 ± 7.6; P = 0.005) improved significantly on therapy, whereas no changes were noted in five untreated controls. TRP plasma concentrations markedly decreased (T1:306 ± 179 mg/L, T2:283 ± 84 mg/L), whereas 5-HTP levels increased (T1:0.08 ± 0.01 mg/L, T2:0.10 ± 0.06 mg/L). KYN concentrations (T1:2.4 ± 2.0 mg/L, T2:3.7 ± 1.4 mg/L, P = 0.003) increased significantly during treatment, as did IDO activity (T1:0.008 ± 0.006 mg/L, T2:0.014 ± 0.004 mg/L; P < 0.001).

CONCLUSIONS

In this study, DAA exert positive and persistent effects on both fatigue and mood in patients with chronic HCV infection. These extrahepatic benefits are, at least in part, related to the modulation of TRP metabolism. The robust elevation of KYN concentrations challenges the current paradigm of low KYN levels as prerequisite for mental health.

The Association Between Park Facilities and Duration of Physical Activity During Active Park Visits

Public parks provide places for urban residents to obtain physical activity (PA), which is associated with numerous health benefits. Adding facilities to existing parks could be a cost-effective approach to increase the duration of PA that occurs during park visits. Using objectively measured PA and comprehensively measured park visit data among an urban community-dwelling sample of adults, we tested the association between the variety of park facilities that directly support PA and the duration of PA during park visits where any PA occurred. Cross-classified multilevel models were used to account for the clustering of park visits (n = 1553) within individuals (n = 372) and parks (n = 233). Each additional different PA facility at a park was independently associated with a 6.8% longer duration of PA bouts that included light-intensity activity, and an 8.7% longer duration of moderate to vigorous PA time. Findings from this study are consistent with the hypothesis that more PA facilities increase the amount of PA that visitors obtain while already active at a park.

Accelerometer Data Collection and Processing Criteria to Assess Physical Activity and Other Outcomes: A Systematic Review and Practical Considerations

BACKGROUND

Accelerometers are widely used to measure sedentary time, physical activity, physical activity energy expenditure (PAEE), and sleep-related behaviors, with the ActiGraph being the most frequently used brand by researchers. However, data collection and processing criteria have evolved in a myriad of ways out of the need to answer unique research questions; as a result there is no consensus.

OBJECTIVES

The purpose of this review was to: (1) compile and classify existing studies assessing sedentary time, physical activity, energy expenditure, or sleep using the ActiGraph GT3X/+ through data collection and processing criteria to improve data comparability and (2) review data collection and processing criteria when using GT3X/+ and provide age-specific practical considerations based on the validation/calibration studies identified.

METHODS

Two independent researchers conducted the search in PubMed and Web of Science. We included all original studies in which the GT3X/+ was used in laboratory, controlled, or free-living conditions published from 1 January 2010 to the 31 December 2015.

RESULTS

The present systematic review provides key information about the following data collection and processing criteria: placement, sampling frequency, filter, epoch length, non-wear-time, what constitutes a valid day and a valid week, cut-points for sedentary time and physical activity intensity classification, and algorithms to estimate PAEE and sleep-related behaviors. The information is organized by age group, since criteria are usually age-specific.

CONCLUSION

This review will help researchers and practitioners to make better decisions before (i.e., device placement and sampling frequency) and after (i.e., data processing criteria) data collection using the GT3X/+ accelerometer, in order to obtain more valid and comparable data.

PROSPERO REGISTRATION NUMBER

CRD42016039991.

Reliability and validity of a self-administered Arabic version of the Global Physical Activity Questionnaire (GPAQ-A)

BACKGROUND

The primary objective of this study was to assess the test-retest reliability of the Arabic language version of the Global Physical Activity Questionnaire (GPAQ-A). Additionally, the study assessed criterion validity of the instrument.

METHODS

Emirati university students (N.=93) were asked to complete the GPAQ-A on two occasions (7 days apart). A subset of 48 participants wore an accelerometer for 7 days after which they completed the GPAQ-A.

RESULTS

Test-retest reliability of the GPAQ-A was acceptable for moderate to vigorous physical activity (MVPA) (ρ=0.78; 95% CI: 0.69 to 0.86), moderate physical activity (MPA) (ρ=0.73; 95% CI: 0.61 to 0.82) and vigorous physical activity (VPA) (ρ=0.62; 95% CI: 0.44 to 0.76). Test-retest reliability of the single item sedentary behavior (SB) measure was less promising (ρ=0.44; 95% CI: 0.22 to 0.64). Criterion validity of the MVPA measure was fair (ρ=0.23; 95% CI: -0.13 to 0.57).

CONCLUSIONS

Test-retest reliability for the GPAQ-A was acceptable to assess physical activity (PA) but less promising for SB. Criterion validity of the PA measures was fair. Additional work is needed to develop robust measures of PA and SB in this population.

Do moderate- to vigorous-intensity accelerometer count thresholds correspond to relative moderate- to vigorous-intensity physical activity?

We aimed to predict % maximal oxygen consumption at absolute accelerometer thresholds and to estimate and compare durations of objective physical activity (PA) among body mass index (BMI) categories using thresholds that account for cardiorespiratory fitness. Eight hundred twenty-eight adults (53.5% male; age, 33.9 ± 0.3 years) from the National Health and Nutrition Examination Survey 2003-2004 were analyzed. Metabolic equivalent values at absolute thresholds were converted to percentage of maximal oxygen consumption, and accelerometer counts corresponding to 40% or 60% maximal oxygen consumption were determined using 4 energy expenditure prediction equations. Absolute thresholds underestimated PA intensity for all adults; however, because of lower fitness, individuals with overweight and obesity work at significantly higher percentage of maximal oxygen consumption at the absolute thresholds and require significantly lower accelerometer counts to reach relative moderate and vigorous PA intensities compared with those with normal weight (P < 0.05). However, moderate-to-vigorous physical activity (MVPA) durations were shorter when using relative thresholds compared with absolute thresholds (in all BMI groups, P < 0.05), and they were shorter among individuals with obesity compared with those with normal weight when using relative thresholds (P < 0.05). Regardless of the thresholds used, a greater proportion of individuals with normal weight met the PA guideline of 150 min·week^-1 of MVPA compared with individuals with obesity (absolute: 21.3% vs 6.7%; Yngve: 4.0% vs 0.2%; Swartz: 10.7% vs 3.9%; Hendelman: 4.7% vs 0.2%; Freedson: 6.4% vs 0.5%; P < 0.05). Current absolute thresholds of accelerometry-derived PA may overestimate MVPA for all BMI categories when compared with relative thresholds that account for cardiorespiratory fitness. Given the large variability in our results, more work is needed to better understand how to use accelerometers for evaluating PA at the population level.

Associations of device-measured physical activity across adolescence with metabolic traits: Prospective cohort study

BACKGROUND

Multiple occasions of device-measured physical activity have not been previously examined in relation to metabolic traits. We described associations of total activity, moderate-to-vigorous physical activity (MVPA), and sedentary time from three accelerometry measures taken across adolescence with detailed traits related to systemic metabolism.

METHODS AND FINDINGS

There were 1,826 male and female participants recruited at birth in 1991-1992 via mothers into the Avon Longitudinal Study of Parents and Children offspring cohort who attended clinics in 2003-2005, 2005-2006, and 2006-2008 who were included in ≥1 analysis. Waist-worn uniaxial accelerometers measured total activity (counts/min), MVPA (min/d), and sedentary time (min/d) over ≥3 d at mean age 12y, 14y, and 15y. Current activity (at age 15y), mean activity across occasions, interaction by previous activity, and change in activity were examined in relation to systolic and diastolic blood pressure, insulin, C-reactive protein, and 230 traits from targeted metabolomics (nuclear magnetic resonance spectroscopy), including lipoprotein cholesterol and triglycerides, amino and fatty acids, glycoprotein acetyls, and others, at age 15y. Mean current total activity was 477.5 counts/min (SD = 164.0) while mean MVPA and sedentary time durations were 23.6 min/d (SD = 17.9) and 522.1 min/d (SD = 66.0), respectively. Mean body mass index at age 15y was 21.4 kg/m2 (SD = 3.5). Correlations between first and last activity measurement occasions were low (e.g., r = 0.40 for counts/min). Current activity was most strongly associated with cholesterol and triglycerides in high-density lipoprotein (HDL) and very low-density lipoprotein (VLDL) particles (e.g., -0.002 mmol/l or -0.18 SD units; 95% CI -0.24--0.11 for triglycerides in chylomicrons and extremely large very low-density lipoprotein [XL VLDL]) and with glycoprotein acetyls (-0.02 mmol/l or -0.16 SD units; 95% CI -0.22--0.10), among others. Associations were similar for mean activity across 3 occasions. Attenuations were modest with adjustment for fat mass index based on dual-energy X-ray absorptiometry (DXA). In mutually adjusted models, higher MVPA and sedentary time were oppositely associated with cholesterol and triglycerides in VLDL and HDL particles (MVPA more strongly with glycoprotein acetyls and sedentary time more strongly with amino acids). Associations appeared less consistent for sedentary time than for MVPA based on longer-term measures and were weak for change in all activity types from age 12y-15y. Evidence was also weak for interaction between activity types at age 15y and previous activity measures in relation to most traits (minimum P = 0.003; median P = 0.26 for counts/min) with interaction coefficients mostly positive. Study limitations include modest sample sizes and relatively short durations of accelerometry measurement on each occasion (3-7 d) and of time lengths between first and last accelerometry occasions (<4 years), which can obscure patterns from chance variation and limit description of activity trajectories. Activity was also recorded using uniaxial accelerometers which predated more sensitive triaxial devices.

CONCLUSIONS

Our results support associations of physical activity with metabolic traits that are small in magnitude and more robust for higher MVPA than lower sedentary time. Activity fluctuates over time, but associations of current activity with most metabolic traits do not differ by previous activity. This suggests that the metabolic effects of physical activity, if causal, depend on most recent engagement.