Daily self-weighing compared with an active control causes greater negative affective lability in emerging adult women: A randomized trial

Age-related weight gain prevention may reduce population overweight/obesity. Emerging adulthood is a crucial time to act, as rate of gain accelerates and health habits develop. Evidence supports self-weighing (SW) for preventing weight gain; however, how SW impacts psychological states and behaviors in vulnerable groups is unclear. This study assessed daily SW effects on affective lability, stress, weight-related stress, body satisfaction, and weight-control behaviors. Sixty-nine university females (aged 18-22) were randomized to daily SW or temperature-taking (TT) control. Over 2 weeks, participants completed five daily ecological momentary assessments with their intervention behavior. A graph of their data with a trendline was emailed daily, with no other intervention components. Multilevel mixed models with random effect for day assessed variability in positive/negative affect. Generalized linear mixed models assessed outcomes pre- and post-SW or TT and generalized estimating equations assessed weight-control behaviors. Negative affective lability was significantly greater for SW versus TT. While general stress did not differ between groups, weight-related stress was significantly higher and body satisfaction was significantly lower post-behavior for SW but not TT. Groups did not significantly differ in the number or probability of weight-control behaviors. Caution is advised when recommending self-weighing to prevent weight gain for emerging adults.

Multi Agent Architecture for Automated Health Coaching

For software applications in health coaching domains to be effective, it is vital that they address issues of privacy, modularity, scalability, individualization, data integration, transferability, coordination and flexibility. In this paper, we propose a novel generic multi-agent architecture which serves as a template for health coaching applications involving wearable sensors. Analyzer and communication modules allow different functionalities like goal formation, planning, scheduling, event detection, learning, inter-agent + human communication and long-term data collection, based on the capabilities of the underlying sensor platforms. To show the flexibility of our proposed architecture, we have successfully built two different health coaching systems with the proposed architecture: (1) a static system based on the Fitbit platform where the coaching is done at specific preset times to encourage increased physical activity, and (2) a dynamic system based on the Apple Watch platform where the smart coach adapts and learns when to intervene to encourage physical activity and reduce sedentary behavior.

Does meeting physical activity recommendations ameliorate association between television viewing with cardiovascular disease risk? A cross-sectional, population-based analysis

OBJECTIVES

As a common form of sedentary behaviour, television viewing is associated with an increase in body mass index (BMI) as well as overall cardiovascular disease (CVD) risk. This study examined the extent to which meeting the recommended volume of weekly physical activity (PA) reduced the association between television viewing with the outcomes of BMI and CVD risk. A second aim was to determine the number of hours (ie, cut-point) of daily television viewing that conferred a higher BMI and CVD risk for a large population-based sample of adults.

DESIGN

Population-based, cross-sectional study.

SETTING

UK Biobank recruited across 35 centres in the UK between 2006 and 2010.

PRIMARY OUTCOME

CVD risk, as measured by the 30-year Framingham risk score.

RESULTS

Linear regression models indicated that every additional hour of television viewing per day was associated with a 3% increase in CVD risk (aCoeff=0.03, d=0.16, p<0.0001); the interaction between television viewing with meeting PA guidelines was marginally associated with CVD risk (aCoeff=0.0010, d=0.01, p=0.014). Each additional hour of television viewing per day was associated with a 0.54 increase in BMI (aCoeff=0.54, d=0.13, p<0.0001); the interaction between television viewing with meeting PA guidelines was not significantly associated with BMI. Regression tree models of the study outcomes revealed that 2.5 hours of television viewing was associated with pronounced increases in BMI and CVD risk.

CONCLUSIONS

These data underscore the independent association between television viewing with cardiovascular risk and suggest that reducing television viewing to less than 2.5 hours per day, even in physically active adults, is a clinical and public health priority.

Assessing Physical Activities Occurring on Sidewalks and Streets: Protocol for a Cross-Sectional Study

Background

A considerable proportion of outdoor physical activity (PA) is done on sidewalks and streets, necessitating the development of a reliable measure of PA performed in these settings. The Block Walk Method (BWM) is one of the more common approaches for this purpose. Although it utilizes reliable observation techniques and displays criterion validity, it remains relatively unchanged since its introduction in 2006. It is a nontechnical, labor-intensive, first generation method. Advancing the BWM would contribute significantly to our understanding of PA behavior.

Objective

This study will develop and test a new BWM that utilizes a wearable video device (WVD) and computer video analysis to assess PAs performed on sidewalks and streets. The specific aims are to improve the BWM by incorporating a WVD (eyeglasses with a high-definition video camera in the frame) into the methodology and advance this WVD-enhanced BWM by applying machine learning and recognition software to automatically extract information on PAs occurring on the sidewalks and streets from the videos.

Methods

Trained observers (1 wearing and 1 not wearing the WVD) will walk together at a set pace along predetermined 1000 ft sidewalk and street observation routes representing low, medium, and high walkable areas. During the walks, the non-WVD observer will use the traditional BWM to record the numbers of individuals standing, sitting, walking, biking, and running in observation fields along the routes. The WVD observer will continuously video the observation fields. Later, 2 investigators will view the videos to determine the number of individuals performing PAs in the observation fields. The video data will then be analyzed automatically using multiple deep convolutional neural networks (CNNs) to determine the number of humans in the observation fields and the type of PAs performed. Bland Altman methods and intraclass correlation coefficients (ICCs) will be used to assess agreement. Potential sources of error such as occlusions (eg, trees) will be assessed using moderator analyses.

Results

Outcomes from this study are pending; however, preliminary studies supporting the research protocol indicate that the BWM is reliable for determining the PA mode (Cramer V=.89; P<.001), the address where the PA occurred (Cohen kappa=.85; P<.001), and the number engaged in an observed PA (ICC=.85; P<.001). The number of individuals seen walking along routes was correlated with several environmental characteristics such as sidewalk quality (r=.39; P=.02) and neighborhood aesthetics (r=.49; P<.001). Furthermore, we have used CNNs to detect cars, bikes, and pedestrians as well as individuals using park facilities.

Conclusions

We expect the new approach will enhance measurement accuracy while reducing the burden of data collection. In the future, the capabilities of the WVD-CNN system will be expanded to allow for the determination of other characteristics captured in videos such as caloric expenditure and environmental conditions.

International Registered Report Identifier (IRRID)

PRR1-10.2196/12976

Modeling Clinically Validated Physical Activity Assessments Using Commodity Hardware

Consumer-grade wearable activity devices such as Fitbits are increasingly being used in research settings to promote physical activity (PA) due to their low-cost and widespread popularity. However, Fitbit-derived measures of activity intensity are consistently reported to be less accurate than intensity estimates obtained from research-grade accelerometers (i.e., ActiGraph). As such, the potential for using a Fitbit to measure PA intensity within research contexts remains limited. This study aims to model ActiGraph-based intensity estimates from the validated Freedson vector magnitude (VM3) algorithm using measures of steps, metabolic equivalents, and intensity levels obtained from Fitbit. Minute-level data collected from 19 subjects, who concurrently wore the ActiGraph GT3X and Fitbit Flex devices for an average of 1.8 weeks, were used to generate the model. After testing several modeling methods, a naïve Bayes classifier was chosen based on the lowest achieved error rate. Overall, the model reduced Fitbit to ActiGraph errors from 19.97% to 16.32%. Moreover, the model reduced misclassification of Fitbit-based estimates of moderate-to-vigorous physical activity (MVPA) by 40%, eliminating a statistically significant difference between MVPA estimates derived from ActiGraph and Fitbit. Study findings support the general utility of the model for measuring MVPA with the Fitbit Flex in place of the more costly ActiGraph GT3X accelerometer for young healthy adults.

Randomized controlled trial testing an internet physical activity intervention for sedentary adults

OBJECTIVE

Internet-based physical activity (PA) interventions have shown promise, although findings remain equivocal. We used formative research to enhance a previously demonstrated program (Step into Motion) with the goal of developing an Internet program poised for dissemination.

METHODS

We conducted focus groups to identify Internet features targeted to theoretical constructs (social cognitive theory) predictive of PA behavior and rated as "useful for increasing PA." We identified 5 theory-targeted Internet features as useful for increasing PA: (1) a PA tracking/logging calendar targeting self-monitoring and goal setting; (2) geographic mapping tools targeting perceived environment; (3) a discussion forum targeting social support; (4) exercise videos targeting observational learning; and (5) regular updates of peer PA progress targeting situation. We then tested the efficacy of the enhanced program (enhanced Internet, EI; N = 25) in relation to publicly available PA Websites (standard Internet, SI; N = 28) among 53 participants in a randomized controlled trial.

RESULTS

The EI arm increased PA in relation to the SI arm at 3 months (18.4 to 186.0 min/wk vs. 20.9 to 57.3 min/wk; p = .03) but between-groups differences were not observed at 6 months (176.8 vs. 133.5 min/wk; p = .44). EI participants maintained PA from 3 to 6 months (186.0 to 176.8 min/wk), and the SI group increased PA (57.3 to 133.5 min/wk).

CONCLUSION

The EI program was efficacious at improving PA levels in relation to publicly available Websites initially, but differences in PA levels were not maintained at 6 months. Future research should identify Internet features that promote long-term maintenance.

Using Cognitive Interviewing and Behavioral Coding to Determine Measurement Equivalence across Linguistic and Cultural Groups: An Example from the International Tobacco Control Policy Evaluation Project

The present study aimed to examine and compare results from two questionnaire pretesting methods (i.e., behavioral coding and cognitive interviewing) in order to assess systematic measurement bias in survey questions for adult smokers across six countries (USA, Australia, Uruguay, Mexico, Malaysia and Thailand). Protocol development and translation involved multiple bilingual partners in each linguistic/cultural group. The study was conducted with convenience samples of 20 adult smokers in each country. Behavioral coding and cognitive interviewing methods produced similar conclusions regarding measurement bias for some questions; however, cognitive interviewing was more likely to identify potential response errors than behavioral coding. Coordinated survey qualitative pretesting (or post-survey evaluation) is feasible across cultural groups, and can provide important information on comprehension and comparability. Cognitive interviewing appears a more robust technique than behavioral coding, although combinations of the two might be even better.

Investigations in generalized osteoarthritis. Part 2: special histological features in generalized osteoarthritis (histological investigations in Heberden's nodes using a histological score)

OBJECTIVE

In accordance with the literature, our previous epidemiological, clinical and genetical investigations have confirmed a correlation between generalized osteoarthritis (GOA) and Heberden's nodes. Heberden's nodes can be considered as genetic markers for the existence of a generalized osteoarthritic predisposition. The present study's concern was to establish whether there are special histological features in this disease.

METHODS

Layered sections of 218 distal finger joints from 56 deceased persons were investigated using a histological-histochemical score modified by Mankin.

RESULTS

In Heberden's nodes, we found all the typical degradative sequences of the osteoarthritic process but also some specific modifications. The osteoarthritis (OA) starts with a subchondral ossification and manifests a reactive tidemark flaking. At this time, the surface of the cartilage is not yet destroyed. Later on, there is progression of general degradation. Significant differentiation from the control group is possible using a histological score.

CONCLUSIONS

In patients with Heberden's nodes, the OA starts with the subchondral ossification. Heberden's nodes are the specific manifestation of GOA in the distal finger joints. Further studies are therefore required to assess whether the same pathogenetic mechanism can be seen in OA of the large joints in GOA.

[Examination of Heberden arthrosis with a histological-histochemical score]

QUESTIONS

In case of Heberden's nodes the osteoarthritis starts with a so called tidemark flaking as a reaction to a subchondral ossification. The question was, if a differentiation in relation to a control group by an objective score is possible.

METHODS

218 finger joints from 56 cadavers were investigated morphologically (score).

RESULTS

The osteoarthritis starts with a subchondral ossification. At this time the surface of the cartilage is not destroyed yet. Reactive tidemark flaking is the beginning of the general degradation. In relation to a control group a significant differentiation by a histological score is possible.

CONCLUSIONS

In case of Heberden's nodes the osteoarthritis starts with the subchondral ossification. Because Heberden's nodes are the specific manifestation of the Generalized Osteoarthritis on the distal finger joints, further studies have to assess, if the same pathogenetic mechanism can be seen in osteoarthritis of the large joints.