Comparing residence-based to actual path-based methods for defining adolescents' environmental exposures using granular spatial data

Feasibility and acceptability of mobile methods to assess home and neighborhood environments related to adolescent sleep

OBJECTIVE

A growing evidence base suggests home and neighborhood environmental exposures may influence adolescent sleep, but few studies have assessed these relationships using methods that account for time-varying, location-specific exposures, or multiple neighborhood contexts. This study aimed to assess the feasibility and acceptability of using smartphone global positioning system (GPS) tracking and ecological momentary assessment (EMA) to assess time-varying home and neighborhood environmental exposures hypothesized to be associated with adolescent sleep.

METHODS

Adolescents aged 15-17 years in Philadelphia completed 7 days of continuous smartphone GPS tracking, which was used to identify daily levels of exposure to geocoded neighborhood factors (eg, crime, green space). Four daily EMA surveys assessed home sleep environment (eg, noise, light), stress, health behaviors, and neighborhood perceptions. Feasibility and acceptability of GPS tracking and EMA were assessed, and distributions of daily environmental exposures were examined.

RESULTS

Among 25 teens (mean age 16, 56% male), there was a high level of GPS location data captured (median daily follow-up: 24 hours). Seventy-eight percent of EMA surveys were completed overall. Most participants (96%) reported no privacy concerns related to GPS tracking and minimal burden from EMA surveys. Exposures differed between participants' home neighborhoods and locations visited outside the home neighborhood (eg, higher crime away from home). Sleep environment disruptions were present on 29% of nights (most common: uncomfortable temperature) and were reported by 52% of adolescents.

CONCLUSIONS

Results demonstrate the feasibility and acceptability of mobile methods for assessing time-varying home and neighborhood exposures relevant to adolescent sleep for up to 1 week.

Multiple environmental exposures along daily mobility paths and depressive symptoms: A smartphone-based tracking study

Few studies go beyond the residential environment in assessments of the environment-mental health association, despite multiple environments being encountered in daily life. This study investigated 1) the associations between multiple environmental exposures and depressive symptoms, both in the residential environment and along the daily mobility path, 2) examined differences in the strength of associations between residential- and mobility-based models, and 3) explored sex as a moderator. Depressive symptoms of 393 randomly sampled adults aged 18-65 were assessed using the Patient Health Questionnaire (PHQ-9). Respondents were tracked via global positioning systems- (GPS) enabled smartphones for up to 7 days. Exposure to green space (normalized difference vegetation index (NDVI)), blue space, noise (Lden) and air pollution (particulate matter (PM_2.5)) within 50 m and 100 m of each residential address and GPS point was computed. Multiple linear regression analyses were conducted separately for the residential- and mobility-based exposures. Wald tests were used to assess if the coefficients differed across models. Interaction terms were entered in fully adjusted models to determine if associations varied by sex. A significant negative relationship between green space and depressive symptoms was found in the fully adjusted residential- and mobility-based models using the 50 m buffer. No significant differences were observed in coefficients across models. None of the interaction terms were significant. Our results suggest that exposure to green space in the immediate environment, both at home and along the daily mobility path, is associated with a reduction in depressive symptoms. Further research is required to establish the utility of dynamic approaches to exposure assessment in studies on the environment and mental health.

Route Choices and Adolescent-Adult Connections in Mitigating Exposure to Environmental Risk Factors During Daily Activities

While adolescent-adult connections have been shown to be protective against violence perpetration and victimization, mechanisms through which these connections confer protection from violence are poorly understood. We assessed whether adolescent-adult connections protected youth in lower resource urban neighborhoods from exposure to environmental risk factors for violence during daily activities. We overlaid on the city landscape minute-by-minute activity paths from 274 randomly sampled predominantly African American male youth, ages 10 to 24, enrolled in a population-based study of daily activities in Philadelphia, PA, to calculate environmental exposures and to compare exposures along actual versus shortest potential travel routes. Adolescent-adult connections were defined using brief survey questions and detailed family genograms. Analyses demonstrated that youth's selected travel routes resulted in significantly lower exposure to several types of crime, including vandalism, narcotics arrests, and disorderly conduct, than would have occurred on shortest potential routes. On average, youth with adolescent-adult connections spent less time outdoors than youth without connections, although these differences did not reach statistical significance (p = .06). There were no significant differences in environmental risk factors encountered by youth with versus without adolescent-adult connections. Future mixed-methods research combining qualitative and geographic information systems (GIS) approaches should investigate which factors shape travel decisions during daily activities to guide multimodal violence prevention interventions.

Daily activity spaces and drug use among female sex workers living with HIV in the Dominican Republic

The purpose of this study was to explore the daily activity spaces of female sex workers living with HIV in the Dominican Republic and assess the relationship between activity path and location-based risk exposure measures and daily drug use. The study employed a micro-longitudinal observational study design using an innovative 7-day travel diary to capture daily activity routes and a 7-day mobile health (mHealth) daily diary to collect daily substance use behaviors among 51 female sex workers. To estimate between-subject variability, a series of crude and adjusted modified log-Poisson repeated measures regression models with generalized estimating equations, clustering by individual with a compound symmetry working correlation structure were fit to estimate the relative risks and 95% confidence intervals. Controlling for individual level factors, findings showed that female sex workers exposed to a higher number of risk outlets (e.g., liquor stores, bars, hotels, nightclubs, brothels, etc.) within 200 and 100-meters of sex work locations were at an increased risk of daily drug use (RRadj: 1.03, 95%CI: 1.01, 1.05, RRadj: 1.05, 95%CI: 1.01, 1.09). No association was detected between activity path exposure and daily drug use. These findings illustrate the importance of moving beyond static residential neighborhood boundaries for measuring risk exposures and highlight the significant role that daily work environments have on drug harms among a highly stigmatized and vulnerable population.

Beyond survival: the broader consequences of prehospital transport by police for penetrating trauma

Background

Time to definitive hemorrhage control is a primary driver of survival after penetrating injury. For these injuries, mortality outcomes after prehospital transport by police and emergency medical service (EMS) providers are comparable. In this study we identify patient and geographic predictors of police transport relative to EMS transport and describe perceptions of police transport elicited from key stakeholders.

Methods

This mixed methods study was conducted in Philadelphia, Pennsylvania, which has the highest rate of police transport nationally. Patient data were drawn from Pennsylvania’s trauma registry and geographic data from the US Census and American Community Survey. For all 7500 adults who presented to Philadelphia trauma centers with penetrating injuries, 2006–2015, we compared how individual and geospatial characteristics predicted the odds of police versus EMS transport. Concurrently, we conducted qualitative interviews with patients, police officers and trauma clinicians to describe their perceptions of police transport in practice.

Results

Patients who were Black (OR 1.50; 1.20–1.88) and Hispanic (OR 1.38; 1.05–1.82), injured by a firearm (OR 1.58; 1.19–2.10) and at night (OR 1.48; 1.30–1.69) and who presented with decreased levels of consciousness (OR 1.18; 1.02–1.37) had higher odds of police transport. Neighborhood characteristics predicting police transport included: percent of Black population (OR 1.18; 1.05–1.32), vacant housing (OR 1.40; 1.20–1.64) and fire stations (OR 1.32; 1.20–1.44). All stakeholders perceived speed as police transport’s primary advantage. For patients, disadvantages included pain and insecurity while in transport. Police identified occupational health risks. Clinicians identified occupational safety risks and the potential for police transport to complicate the workflow.

Conclusions

Police transport may improve prompt access to trauma care but should be implemented with consideration of the equity of access and broad stakeholder perspectives in efforts to improve outcomes, safety, and efficiency.

Level of evidence

Epidemiological study, level III.

Coupling mobile phone data with machine learning: How misclassification errors in ambient PM2.5 exposure estimates are produced?

BACKGROUND

Most studies relying on time-activity diary or traditional air pollution modelling approach are insufficient to suggest the impacts of ignoring individual mobility and air pollution variations on misclassification errors in exposure estimates. Moreover, very few studies have examined whether such impacts differ across socioeconomic groups.

OBJECTIVES

We aim to examine how ignoring individual mobility and PM2.5 variations produces misclassification errors in ambient PM2.5 exposure estimates.

METHODS

We developed a geo-informed backward propagation neural network model to estimate hourly PM2.5 concentrations in terms of remote sensing and geospatial big data. Combining the estimated PM2.5 concentrations and individual trajectories derived from 755,468 mobile phone users on a weekday in Shenzhen, China, we estimated four types of individual total PM2.5 exposures during weekdays at multi-temporal scales. The estimate ignoring individual mobility, PM2.5 variations or both was compared with the hypothetical error-free estimate using paired sample t-test. We then quantified the exposure misclassification error using Pearson correlation analysis. Moreover, we examined whether the misclassification error differs across different socioeconomic groups. Taking findings of ignoring individual mobility as an example, we further investigated whether such findings are robust to the different selections of time.

RESULTS

We found that the estimate ignoring PM2.5 variations, individual mobility or both was statistically different from the hypothetical error-free estimate. Ignoring both factors produced the largest exposure misclassification error. The misclassification error was larger in the estimate ignoring PM2.5 variations than that ignoring individual mobility. People with high economic status suffered from a larger exposure misclassification error. The findings were robust to the different selections of time.

CONCLUSIONS

Ignoring individual mobility, PM2.5 variations or both leads to misclassification errors in ambient PM2.5 exposure estimates. A larger misclassification error occurs in the estimate neglecting PM2.5 variations than that ignoring individual mobility, which is seldom reported before.

As Violence Unfolds: A Space-Time Study of Situational Triggers of Violent Victimization among Urban Youth

OBJECTIVES

This study clarifies three important issues regarding situational or opportunity theories of victimization: 1) whether engaging in risk activities triggers violent assault during specific, often fleeting moments, 2) how environmental settings along individuals' daily paths affect their risk of violent assault, and 3) whether situational triggers have differential effects on violent assault during the day versus night.

METHODS

Using an innovative GIS-assisted interview technique, 298 young male violent assault victims in Philadelphia, PA described their activity paths over the course of the day of being assaulted. Case-crossover analyses compared each subject's exposure status at the time of assault with his own statuses earlier in the day (stratified by daytime and nighttime).

RESULTS

Being at an outdoor/public space, conducting unstructured activities, and absence of guardians increase the likelihood of violent victimization at a fine spatial-temporal scale at both daytime and nighttime. Yet, the presence of friends and environmental characteristics have differential effects on violent victimization at daytime versus nighttime. Moreover, individual risk activities appeared to exhibit better predictive performance than did environmental characteristics in our space-time situational analyses.

CONCLUSIONS

This study demonstrates the value of documenting how individuals navigate their daily activity space, and ultimately advances our understanding of youth violence from a real-time, real-life standpoint.

Effects of short- and long-term exposures to particulate matter on inflammatory marker levels in the general population

The effect of particulate matter (PM) on health increases with exposure duration but the change from short to longer term is not well studied. We examined the exposure to PM smaller 10 μm (PM₁₀) from short to longer duration and their associations with levels of inflammatory markers in the population-based CoLaus cohort in Lausanne, Switzerland. Baseline and follow-up CoLaus data were used to study the associations between PM₁₀ exposure and inflammatory markers, including the high-sensitivity C-reactive protein (CRP), as well as interleukin 1-beta (IL-1β), interleukin 6 (IL-6), and tumor-necrosis-factor alpha (TNF-α) using mixed models. Exposure was determined for each participant's home address from hourly air quality simulations at a 5-m resolution. Short-term exposure intervals were 1 day, 1 week, and 1 month prior to the hospital visit (blood withdrawal); long-term exposure intervals were 3 and 6 months prior to the visit. In most time windows, IL-6, IL-1β, and TNF-α were positively associated with PM₁₀. No significant associations were identified for CRP. Adjusted associations with long-term exposures were stronger and more significant than those for short-term exposures. In stratified models, gender, age, smoking status, and hypertension only led to small modifications in effect estimates, though a few of the estimates for IL-6 and TNF-α became non-significant. In this general adult cohort exposed to relatively low average PM₁₀ levels, clear associations with markers of systemic inflammation were observed. Longer duration of elevated exposure was associated with an exacerbated inflammatory response. This may partially explain the elevated disease risk observed with chronic PM₁₀ exposure. It also suggests that reducing prolonged episodes of high PM exposure may be a strategy to reduce inflammatory risk.

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.

Firearm assault injuries by residence and injury occurrence location

Research on spatial injury patterns is limited by a lack of precise injury occurrence location data. Using linked hospital and death records, we examined residence and injury locations for firearm assaults and homicides in or among residents of King County, Washington, USA from 1 January 2010 to 31 December 2014. In total, 670 injuries were identified, 586 with geocoded residence and injury locations. Three-quarters of injuries occurred outside the census tract where the victim resided. Median distance between locations was 3.9 miles, with victims 18-34 having the greatest distances between residence and injury location. 40 of 398 tracts had a ratio of injury incidents to injured residents of >1. Routine collection of injury location data and homelessness status could decrease misclassification and bias. Researchers should consider whether residential address is an appropriate proxy for injury location, based on data quality and their specific research question.

Does spending time outdoors reduce stress? A review of real-time stress response to outdoor environments

Everyday environmental conditions impact human health. One mechanism underlying this relationship is the experience of stress. Through systematic review of published literature, we explore how stress has been measured in real-time non-laboratory studies of stress responses to deliberate exposure to outdoor environments. The types of exposures evaluated in this review include: nature viewing, outdoor walks, outdoor exercise and gardening. We characterize study design, modalities of stress measurements, and statistical estimates of effect and significance. Heart rate, blood pressure, and self-report measures provide the most convincing evidence that spending time in outdoor environments, particularly those with green space, may reduce the experience of stress, and ultimately improve health. More work is needed to understand effects of in situ modifications to outdoor environments on residents' stress response.