How many days of global positioning system (GPS) monitoring do you need to measure activity space environments in health research?

Activity space metrics not associated with sociodemographic variables, diet or health outcomes in the Seattle Obesity Study II

BACKGROUND

Activity spaces (AS), captured using GPS tracking devices, are measures of dynamic exposure to the built environment (BE).

METHODS

Seven days of Global Positioning Systems (GPS) tracking data were obtained for 433 adult participants in the Seattle Obesity Study (SOS II). Heights and weights were measured. Dietary intakes from a food frequency questionnaire were used to calculate Healthy Eating Index (HEI 2010) scores. Linear regression analyses examined associations between AS measures: daily route length, convex hull, and radius of gyration, and diet quality and health outcomes, adjusting for covariates.

RESULTS

AS measures did not vary by age, gender, race/ethnicity, or socioeconomic status. AS measures were not associated with diet quality or with self-reported obesity or diabetes. One AS measure, route length (in miles), was associated with being employed, living in the suburbs, and with distance and time commuting to work.

CONCLUSION

Spatial mobility studies based on GPS tracking of environmental exposure need to demonstrate a link to relevant health outcomes.

Assessing Individuals' Exposure to Environmental Conditions Using Residence-based Measures, Activity Location-based Measures, and Activity Path-based Measures

BACKGROUND

Many approaches are available to researchers who wish to measure individuals' exposure to environmental conditions. Different approaches may yield different estimates of associations with health outcomes. Taking adolescents' exposure to alcohol outlets as an example, we aimed to (1) compare exposure measures and (2) assess whether exposure measures were differentially associated with alcohol consumption.

METHODS

We tracked 231 adolescents 14-16 years of age from the San Francisco Bay Area for 4 weeks in 2015/2016 using global positioning systems (GPS). Participants were texted ecologic momentary assessment surveys six times per week, including assessment of alcohol consumption. We used GPS data to calculate exposure to alcohol outlets using three approach types: residence-based (e.g., within the home census tract), activity location-based (e.g., within buffer distances of frequently attended places), and activity path-based (e.g., average outlets per hour within buffer distances of GPS route lines). Spearman correlations compared exposure measures, and separate Tobit models assessed associations with the proportion of ecologic momentary assessment responses positive for alcohol consumption.

RESULTS

Measures were mostly strongly correlated within approach types (ρ ≥ 0.7), but weakly (ρ < 0.3) to moderately (0.3 ≤ ρ < 0.7) correlated between approach types. Associations with alcohol consumption were mostly inconsistent within and between approach types. Some of the residence-based measures (e.g., census tract: β = 8.3, 95% CI = 2.8, 13.8), none of the activity location-based approaches, and most of the activity path-based approaches (e.g., outlet-hours per hour, 100 m buffer: β = 8.3, 95% CI = 3.3, 13.3) were associated with alcohol consumption.

CONCLUSIONS

Methodologic decisions regarding measurement of exposure to environmental conditions may affect study results.

Neighborhood Social Environment and Cardiovascular Disease Risk

Purpose of review

Limited physical activity (PA) and obesity are two primary risk factors for cardiovascular disease (CVD). Within a socio-ecological framework, neighborhood social environment may play a key role in influencing PA and obesity. However, the mechanisms underlying this relationship remain ambiguous. Our goals in this review are: (1) to summarize findings from the recent studies on neighborhood social environment in relation to PA and obesity as CVD risk factors, and (2) to briefly describe several innovative approaches to assessing neighborhood social environment.

Recent findings

Almost all recent studies assessed neighborhood social environment around residential areas. There were consistent associations between neighborhood social environment and PA and obesity, with some exceptions (indicating null associations or paradoxical associations). However, a focus on residential social environment may limit results because these studies did not account for any exposures occurring away from individuals' homes. Additionally, the majority of studies utilized a cross-sectional design, which limits our ability to make inferences regarding the causality of the association between social environment and PA or obesity as CV risk factors.

Summary

The majority of the studies on neighborhood social environment characterized factors around residential areas and assessed participant activity via self-reported surveys. Future research should leverage tools to account for the spatial mismatch between environmental exposures and outcomes by using global positioning systems, ecological momentary assessments, virtual neighborhood audits, and simulation modeling. These approaches can overcome major limitations by tracking individuals' daily activity and real-time perceptions of neighborhood social environments linked to CVD events.

Children's mobility and environmental exposures in urban landscapes: A cross-sectional study of 10-11 year old Scottish children

Research into how the environment affects health and related behaviour is typically limited in at least two ways: it represents the environment to which people are exposed using fixed areal units, and, it focuses on one or two environmental characteristics only. This study developed a methodology for describing children's mobility and the complexity of their environmental exposure across a 1934 km2 study area, including urban, suburban and rural zones. It conceptualised and modelled this area as a landscape, comprised of spatially discrete amenities, infrastructure features, differing land covers/use and broader environmental contexts. The model used a 25 m2 grid system (∼3 million cells). For each cell, there was detailed built-environment information. We joined data for 100 10/11-year-old children who had worn GPS trackers to provide individual-level mobility information for one week during 2015/16 to our model. Using negative binomial regression, we explored which landscape features were associated with a child visiting that space and time spent there. We examined whether relationships between the features across our study area and children's use of the space differed by their sociodemographic characteristics. We found that children often used specific amenities outside their home neighbourhood, even if they were also available close to home. They spent more time in cells containing roads/transportation stops, food/drink retail (Incidence rate ratio (IRR):4.02, 95%CI 2.33 to 6.94), places of worship (IRR:5.98, 95%CI 3.33 to 10.72) and libraries (IRR:7.40, 95%CI 2.13 to 25.68), independently of proximity to home. This has importance for the optimal location of place-based health interventions. If we want to target children, we need to understand that using fixed neighbourhood boundaries may not be the best way to do it. The variations we found in time spent in certain areas by sex and socio-economic position also raise the possibility that interventions which ignore these differences may exacerbate inequalities.

Evidence synthesis - Where are children and adults physically active and sedentary? - a rapid review of location-based studies

INTRODUCTION

Geographical positioning systems (GPS) have the capacity to provide further context around where physical activity (PA) and sedentary time (ST) are accrued especially when overlaid onto objectively measured movement. The objective of this rapid review was to summarize evidence from location-based studies which employed the simultaneous use of GPS and objective measures of PA and/or ST.

METHODS

Six databases were searched to identify studies that employed the simultaneous use of GPS and objective measures of PA or ST to quantify location of movement. Risk of bias was assessed, and a qualitative synthesis completed.

RESULTS

Searching identified 3446 articles; 59 were included in the review. A total of 22 studies in children, 17 in youth and 20 in adults were captured. The active transportation environment emerged as an important location for moderate-to-vigorous intensity physical activity (MVPA) in children, youth and adults. In children and youth, the school is an important location for MVPA, especially the schoolyard for children. Indoor locations (e.g., schools, homes) appear to be greater sources of lighter intensities of PA and ST. The review was limited by a lack of standardization in the nomenclature used to describe the locations and methods, as well as measures of variance.

CONCLUSION

Evidence suggests that the active transportation environment is a potentially important contributor of MVPA across an individual's lifespan. There is a need for future location-based studies to report on locations of all intensity of movement (including minutes and proportion) using a whole-day approach in larger representative samples.

Convergent validity of an activity-space survey for use in health research

We explored the validity of a survey measuring activity spaces for use in health research in a racially/ethnically diverse adult sample (n = 86) living in four Chicago neighborhoods. Participants reported on the location and visit frequency of 64 activities and wore a GPS data logger. We assessed the spatial congruence of survey- and GPS-derived convex hull measures and the number of GPS points within 100 m and 1000 m of survey locations. The survey-derived convex hull measures captured a small percentage (median = 35.9%) of the GPS-derived convex hull area. However, most GPS points were located within 100 m or 1000 m of home or reported survey locations (median = 73.4% and 92.6%, respectively).

Contextual correlates of energy-dense snack food and sweetened beverage intake across the day in African American women: An application of ecological momentary assessment

This study examined relationships between contextual factors and within-person variations in snack food and sweetened beverage intake in African American women (n = 79), aged 25-65 years living in metropolitan Chicago. For seven days, participants wore a global positioning system (GPS) logger and were signaled five times per day to complete an ecological momentary assessment (EMA) survey assessing behaviors and environmental, social, and other contextual factors via smartphones. Within-person associations between snack food and beverage intake and contextual factors were analyzed using three-level logistic regressions. Participants reported consuming a snack food at 38.4% of signals and a sweetened beverage at 17.9% of signals. Fast food restaurant and convenience store density within the daily activity space was not associated with either snack food or sweetened beverage intake. However, perceptions of close proximity to fast food restaurants and convenience stores making it easier to eat/drink, while accounting for one's usual proximity, were associated with increased odds of snack intake (O.R. 2.1; 95% C.I. 1.4, 3.0) but not sweetened beverage. We also found engaging in activities such as watching television (O.R. 1.8; 95% C.I. 1.2, 2.7) and talking (O.R. 1.7; 95% C.I. 1.1, 2.6) while eating were associated with higher snack intake. These factors were not related to sweetened beverage intake. Public health interventions addressing fast food restaurant and convenience store accessibility and food offerings and marketing within these outlets may help reduce snack food intake. Additionally, to reduce concurrent activities while eating, real-time interventions using smart technology could be used to enhance attentive eating in this population.