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"Marcus, Bess"
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Validation of Walk Score for estimating access to walkable amenities
2011
Background Proximity to walkable destinations or amenities is thought to influence physical activity behaviour. Previous efforts attempting to calculate neighbourhood walkability have relied on self-report or time-intensive and costly measures. Walk Score is a novel and publicly available website that estimates neighbourhood walkability based on proximity to 13 amenity categories (eg, grocery stores, coffee shops, restaurants, bars, movie theatres, schools, parks, libraries, book stores, fitness centres, drug stores, hardware stores, clothing/music stores). Objective The purpose of this study is to test the validity and reliability of Walk Score for estimating access to objectively measured walkable amenities. Methods Walk Scores of 379 residential/non-residential addresses in Rhode Island were manually calculated. Geographic information systems (GIS) was used to objectively measure 4194 walkable amenities in the 13 Walk Score categories. GIS data were aggregated from publicly available data sources. Sums of amenities within each category were matched to address data, and Pearson correlations were calculated between the category sums and address Walk Scores. Results Significant correlations were identified between Walk Score and all categories of aggregated walkable destinations within a 1-mile buffer of the 379 residential and non-residential addresses. Test–retest reliability correlation coefficients for a subsample of 100 addresses were 1.0. Conclusion These results support Walk Score as a reliable and valid measure of estimating access to walkable amenities. Walk Score may be a convenient and inexpensive option for researchers interested in exploring the relationship between access to walkable amenities and health behaviours such as physical activity.
Journal Article
The implications of megatrends in information and communication technology and transportation for changes in global physical activity
by
Marcus, Bess H
,
Ogilvie, David
,
Perez, Lilian G
in
Biological and medical sciences
,
Communication
,
communications technology
2012
Physical inactivity accounts for more than 3 million deaths per year, most from non-communicable diseases in low-income and middle-income countries. We used reviews of physical activity interventions and a simulation model to examine how megatrends in information and communication technology and transportation directly and indirectly affect levels of physical activity across countries of low, middle, and high income. The model suggested that the direct and potentiating effects of information and communication technology, especially mobile phones, are nearly equal in magnitude to the mean effects of planned physical activity interventions. The greatest potential to increase population physical activity might thus be in creation of synergistic policies in sectors outside health including communication and transportation. However, there remains a glaring mismatch between where studies on physical activity interventions are undertaken and where the potential lies in low-income and middle-income countries for population-level effects that will truly affect global health.
Journal Article
The impact of a randomized controlled trial of a lifestyle intervention on postpartum physical activity among at-risk hispanic women: Estudio PARTO
2020
To assess the impact of a culturally modified, motivationally targeted, individually-tailored intervention on postpartum physical activity (PA) and PA self-efficacy among Hispanic women. Estudio PARTO was a randomized controlled trial conducted in Western Massachusetts from 2013-17. Hispanic women who screened positive for gestational diabetes mellitus were randomized to a Lifestyle Intervention (LI, n = 100) or to a comparison Health and Wellness (HW, n = 104) group during late pregnancy. Exercise goals in LI were to meet American College of Obstetrician & Gynecologists guidelines for postpartum PA. The Pregnancy Physical Activity Questionnaire (PPAQ) and the Self-Efficacy for Physical Activity Questionnaire were administered at 6 weeks, 6 months, and 1 year postpartum. Compared to baseline levels, both groups had significant increases in moderate-to-vigorous PA at 6 months and one year postpartum (i.e., LI: mean change = 30.9 MET-hrs/wk, p = 0.05; HW: 27.6 MET-hrs/wk, p = 0.01), with only LI group experiencing significant increases in vigorous PA (mean change = 1.3 MET-hrs/wk, p = 0.03). Based on an intent-to-treat analysis using mixed effects models, we observed no differences in pattern of change in PA intensity and type over time between intervention groups (all p > 0.10). However, there was the suggestion of a greater decrease in sedentary activity in the LI group compared to the HW group ([beta] = -3.56, p = 0.09). In this randomized trial among high-risk Hispanic women, both groups benefitted from participation in a postpartum intervention.
Journal Article
A Framework for Bayesian Nonparametric Inference for Causal Effects of Mediation
by
Marcus, Bess H.
,
Roy, Jason A.
,
Kim, Chanmin
in
Bayes Theorem
,
Bayesian analysis
,
BIOMETRIC METHODOLOGY
2017
We propose a Bayesian non-parametric (BNP) framework for estimating causal effects of mediation, the natural direct, and indirect, effects. The strategy is to do this in two parts. Part 1 is a flexible model (using BNP) for the observed data distribution. Part 2 is a set of uncheckable assumptions with sensitivity parameters that in conjunction with Part 1 allows identification and estimation of the causal parameters and allows for uncertainty about these assumptions via priors on the sensitivity parameters. For Part 1, we specify a Dirichlet process mixture of multivariate normals as a prior on the joint distribution of the outcome, mediator, and covariates. This approach allows us to obtain a (simple) closed form of each marginal distribution. For Part 2, we consider two sets of assumptions: (a) the standard sequential ignorability (Imai et al., 2010) and (b) weakened set of the conditional independence type assumptions introduced in Daniels et al. (2012) and propose sensitivity analyses for both. We use this approach to assess mediation in a physical activity promotion trial.
Journal Article
Does Affective Valence During and Immediately Following a 10-Min Walk Predict Concurrent and Future Physical Activity?
by
Dunsiger, Shira
,
Marcus, Bess H.
,
Williams, David M.
in
Adolescent
,
Adult
,
Affect - physiology
2012
Background
Affect may be important for understanding physical activity behavior.
Purpose
To examine whether affective valence (i.e., good/bad feelings) during and immediately following a brief walk predicts concurrent and future physical activity.
Methods
At months 6 and 12 of a 12-month physical activity promotion trial, healthy low-active adults (
N
= 146) reported affective valence during and immediately following a 10-min treadmill walk. Dependent variables were self-reported minutes/week of lifestyle physical activity at months 6 and 12.
Results
Affect reported during the treadmill walk was cross-sectionally (month 6:
β
= 28.6,
p
= 0.008; month 12:
β
= 26.6,
p
= 0.021) and longitudinally (
β
= 14.8,
p
= 0.030) associated with minutes/week of physical activity. Affect reported during a 2-min cool down was cross-sectionally (month 6:
β
= 21.1,
p
= 0.034; month 12:
β
= 30.3,
p
< 0.001), but not longitudinally associated with minutes/week of physical activity. Affect reported during a postcool-down seated rest was not associated with physical activity.
Conclusions
During-behavior affect is predictive of concurrent and future physical activity behavior.
Journal Article
The Hombres Saludables Physical Activity Web-Based and Mobile Phone Intervention: Pilot Randomized Controlled Trial With Latino Men
2023
Owing to structural-level, interpersonal-level, and individual-level barriers, Latino men have disproportionately high rates of physical inactivity and experience related chronic diseases. Despite these disparities, few physical activity (PA) interventions are culturally targeted for Latino men.
This study reported the feasibility and acceptability of Hombres Saludables PA intervention for Latino men. We also reported the preliminary efficacy of the intervention on PA change and provided the results of the exploratory moderator and mediator analysis.
We completed a 6-month, single-blind, pilot randomized controlled trial of Hombres Saludables with Latino men aged between 18 and 65 years. Men were randomized to either (1) a theory-driven, individually tailored, internet-based and SMS text message-based, Spanish-language PA intervention arm or (2) a nutrition and wellness attention contact control arm that was also delivered via the web and SMS text message. We assessed the primary study outcomes of feasibility using participant retention and acceptability using postintervention survey and open-ended interview questions. We measured the preliminary efficacy via change in minutes of moderate to vigorous PA per week using ActiGraph wGT3X-BT accelerometry (primary measure) and self-reported minutes per week using 7-day Physical Activity Recall. Participants completed the assessments at study enrollment and after 6 months.
The 38 participants were predominantly Dominican (n=8, 21%) or Guatemalan (n=5, 13%), and the mean age was 38.6 (SD 12.43) years. Retention rates were 91% (21/23) for the PA intervention arm and 100% (15/15) for the control arm. Overall, 95% (19/20) of the intervention arm participants reported that the Hombres study was somewhat to very helpful in getting them to be more physically active. Accelerometry results indicated that participants in the intervention group increased their PA from a median of 13 minutes per week at study enrollment to 34 minutes per week at 6 months, whereas the control group participants showed no increases. On the basis of self-reports, the intervention group was more likely to meet the US PA guidelines of 150 minutes per week of moderate to vigorous PA at 6-month follow-up, with 42% (8/19) of the intervention participants meeting the PA guidelines versus 27% (4/15) of the control participants (odds ratio 3.22, 95% CI 0.95-13.69). Exploratory analyses suggested conditional effects on PA outcomes based on baseline stage of motivational readiness, employment, and neighborhood safety.
The PA intervention demonstrated feasibility and acceptability. Results of this pilot study indicate that the Hombres Saludables intervention is promising for increasing PA in Latino men and suggest that a fully powered trial is warranted. Our technology-based PA intervention provides a potentially scalable approach that can improve health in a population that is disproportionately affected by low PA and related chronic disease.
ClinicalTrials.gov NCT03196570; https://classic.clinicaltrials.gov/ct2/show/NCT03196570.
RR2-10.2196/23690.
Journal Article
Egocentric networks and physical activity outcomes in Latinas
2018
Despite data linking the social environment to physical inactivity in Latinas, research on social network predictors of physical activity (PA) is limited. This study examined social network predictors of PA change in Latinas.
Egocentric network data were collected from 102 adult Latinas (egos) participating in a randomized controlled PA intervention trial for underactive women. Moderate-to-vigorous PA (MVPA) was measured in minutes per week using the 7-Day PA Recall Interview and accelerometers at baseline and 12 months. Analyses characterized social network structure, composition, tie strength, homogeneity, and support for PA and determined the relationship between network characteristics and PA outcomes.
Networks had an average of four social ties (alters). Networks were high in density and transitivity and low in components, indicating high cohesion. Networks were primarily composed of females, Latinos, Spanish-speakers, and family members. Relationship ties were strong as evidenced by close living proximity, in-person contact, high emotional closeness, and long relationship duration. There was high homogeneity in demographics and PA behaviors. Multivariate analyses revealed that network size, familial ties, contact frequency, and ego-alter dissimilarities in age and running but similarities in walking, were associated with increased MVPA. Networks high in support for PA in the form of complimenting ego on exercise, taking over chores to allow ego to exercise, and co-participating with ego in exercise were also associated with greater MVPA.
These findings contribute to better understanding interpersonal processes that may influence behavior change in a group with especially low levels of PA.
Journal Article
Costs and Cost-Effectiveness at 12 and 24 Months of an Enhanced Web-Based Physical Activity Intervention for Latina Adults: Secondary Analysis of a Randomized Controlled Trial
2025
We previously established the efficacy and cost-effectiveness of a web-based physical activity (PA) intervention for Latina adults, which increased PA, but few participants met PA guidelines, and long-term maintenance was not examined. A new version with enhanced intervention features was found to outperform the original intervention in long-term guideline adherence.
This study aimed to determine the costs and cost-effectiveness of the enhanced multitechnology PA intervention compared to the original web-based intervention in increasing minutes of activity and adherence to guidelines.
Latina adults (N=195) were randomly assigned to receive a Spanish-language, individually tailored web-based PA intervention (original) or the same intervention with additional phone calls and interactive SMS text messaging (enhanced). PA was measured at baseline, 12 months (end of active intervention), and 24 months (end of tapered maintenance) using self-report (7-day PA recall interview) and ActiGraph accelerometers. Costs were estimated from a payer perspective and included all features needed to deliver the intervention, including staff, materials, and technology. Cost-effectiveness was calculated as the cost per additional minute of PA added over the intervention and the incremental cost-effectiveness ratios of each additional person meeting guidelines.
At 12 months, the costs of delivering the interventions were US $16 per person per month in the enhanced arm and US $13 per person per month in the original arm. These costs decreased to US $14 and US $8 at 24 months, respectively. At 12 months, each additional minute of self-reported activity in the enhanced group cost US $0.09 compared to US $0.11 in the original group (US $0.19 vs US $0.16 for ActiGraph), with incremental costs of US $0.05 per additional minute in the enhanced group beyond the original group. At the end of the maintenance period (24 mo), costs per additional minute decreased to US $0.06 and US $0.05 (US $0.12 vs US $0.10 for ActiGraph), with incremental costs of US $0.08 per additional minute in the enhanced group (US $0.20 for ActiGraph). Costs of meeting PA guidelines at 12 months were US $705 in the enhanced group compared to US $503 in the original group and increased to US $812 and US $601 at 24 months, respectively. The incremental cost-effectiveness ratio for meeting guidelines at 24 months was US $1837 (95% CI US $730.89-US $2673.89) per additional person in the enhanced group compared to the original group.
The enhanced intervention was more expensive but yielded better long-term maintenance of activity, costing US $1837 per extra person meeting guidelines beyond those in the original group. Both conditions were low cost relative to other medical interventions. The enhanced intervention may be preferable in populations at high risk, where more investment in meeting guidelines could yield more cost savings.
ClinicalTrials.gov NCT03491592; https://clinicaltrials.gov/study/NCT03491592.
RR2-10.1186/s13063-022-06575-4.
Journal Article
Setting larger session duration goals is associated with greater future physical activity
2018
Many national (US) and International guidelines for physical activity provide guidance that under-active and sedentary adults can begin by accumulating moderate-to-vigorous physical activity (MVPA) in bouts as brief as 10 minutes. This guidance fits well with Goal Setting theory in that goals should be realistic and achievable, and is also consistent with Social Cognitive theory since achieving small goals should boost self-efficacy and thus, encourage continued physical activity. In contrast, Behavioral Economics might suggest that fewer, longer bouts would be more conducive to the adoption of physical activity due to the costs incurred with each separate bout of MVPA. This paper examines patterns of MVPA adoption among a sample of under-active adults from the perspective of goal setting theory and behavioral economics to explore specific strategies to help people who are in the early stages of PA activity adoption. Under-active men and women (N = 225; mean age = 46 ± 10; mean BMI = 28 ± 4.48) who enrolled in a PA intervention participated in a single goal setting session at enrollment. Participants were encouraged to set realistic goals and to increase their activity to meet national recommendations (150 minutes/week of moderate to vigorous physical activity [MVPA]) by the 6-month follow up. This process included identifying a specific frequency goal (days/week) and session duration goal (minutes/day). At baseline, participants reported average weekly MVPA of 14.59 min (± 24), which increased to an average of 140.52 (± 143.55) at 6 months. MVPA goals at baseline averaged 33.24 min/day (± 18.08) and 3.85 days/week (± 1.31). Analyses showed that longer session duration goals set at baseline were associated with more weekly minutes of MVPA at 6 months (b = 1.26, SE = 0.58, t = 2.17, p = 0.03). There was no significant association between goals for number of days per week (frequency) or total minutes of weekly MVPA (minutes x frequency) and MVPA at 6 months. Widely promoted guidelines for uptake of physical activity recommend accumulating physical activity in bouts as short as 10 minutes. This recommendation may ultimately hinder the adoption of physical activity among under-active and sedentary individuals. For the purposes of behavioral adoption of MVPA, more ambitious session duration goals appear to result in higher levels of physical activity participation.
Journal Article
Psychometrics of the self-efficacy for physical activity scale among a Latina women sample
by
Marcus, Bess H.
,
Benitez, Tanya J.
,
Mendoza-Vasconez, Andrea S.
in
Accelerometers
,
Adult
,
Behavior
2018
Background
Even though Latinos have become a priority population for the promotion of physical activity in the United States, several widely used scales in physical activity promotion research have not been validated among this population, particularly in Spanish. This study aims to assess the validity and other psychometrics of the Self-Efficacy for Physical Activity scale among a sample of Spanish-speaking Latina women who participated in the Pasos Hacia La Salud intervention. We also explored alternatives for scale simplification.
Methods
Data from 205 women corresponding to baseline, 6-month, and 12-month time points were analyzed. Internal consistency was assessed. A series of Spearman correlations, t-tests, linear regressions, and logistic regressions were used to assess the concurrent and predictive validity of the Self Efficacy for Physical Activity scale against both self-report and accelerometer-measured physical activity, using both continuous and categorical outcome data. Item Response Theory and factor analysis methods were used to explore alternatives to simplify the scale. Psychometric tests were repeated with the simplified scale.
Results
Cronbach’s alpha for the original scale was .72, .76, and .78 for baseline, 6-month, and 12-month data respectively. All concurrent validity tests conducted with 6-month and 12-month data, but not with baseline data, were statistically significant. Self-efficacy at 6 months was also predictive of physical activity at 12 months for all tests except one. Based on plots of Option Characteristic Curves, a modified version of the scale was created. Psychometric results of the modified scale were similar to those of the original scale.
Conclusions
This study confirmed the scale’s reliability and validity, and revealed that the scale’s accuracy improves when some response items are collapsed, which is an important finding for future research among populations with low literacy levels.
Journal Article