The Association of Trail Features With Self-Report Trail Use by Neighborhood Residents.

BACKGROUND: Urban trails are a useful resource to promote physical activity. This study identified features of urban trails that correlated with trail use. METHODS: Multiuse urban trails were selected in Chicago, Dallas, and Los Angeles. An audit of each trail was completed using the Systematic Pedestrian and Cyclist Environmental Scan for Trails instrument, identifying built environmental features. A self-report of trail use was obtained from trailside residents (N = 331) living within 1 mile of each trail. Univariate and multivariate Poisson regressions controlled for trail time from home and motivation for physical activity. RESULTS: Positive associations with the past month's hours on the trail were observed for the presence of distance signs, vegetation height, vegetation maintenance, and trail crowding, and a negative association was observed for the presence of crossings on the trail. Positive associations with dichotomous trail use were observed for the presence of distance signs, vegetation height, and vegetation maintenance, and a negative association was observed for the presence of crossings on the trail. CONCLUSIONS: These correlates should be confirmed in other studies and, if supported, should be considered in the promotion and design of urban trails.

Safe Routes to Play? Pedestrian and Bicyclist Crashes Near Parks in Los Angeles.

BACKGROUND: Areas near parks may present active travelers with higher risks than in other areas due to the confluence of more pedestrians and bicyclists, younger travelers, and the potential for increased traffic volumes. These risks may be amplified in low-income and minority neighborhoods due to generally higher rates of active travel or lack of safety infrastructure. This paper examines active travel crashes near parks and builds on existing research around disparities in park access and extends research from the Safe Routes to School and Safe Routes to Transit movements to parks. METHODS: We utilized the Green Visions Parks coverage, encompassing Los Angeles County and several other cities in the LA Metropolitan area. We used negative bionomial regression modeling techniques and ten years of geolocated pedestrian and bicyclist crash data to assess the number of active travel injuries within a quarter mile (~400m) buffer around parks. We controlled for differential exposures to active travel using travel survey data and Bayesian smoothing models. RESULTS: Of 1,311,736 parties involved in 608,530 crashes, there were 896,359 injuries and 7317 fatalities. The number of active travel crash injuries is higher within a quarter-mile of a park, with a ratio of 1.52 per 100,000 residents, compared to areas outside that buffer. This higher rate near parks is amplified in neighborhoods with high proportions of minority and low-income residents. Higher traffic levels are highly predictive of active travel crash injuries. CONCLUSIONS: Planners should consider the higher risks of active travel near parks and the socioeconomic modification of these risks. Additional traffic calming and safety infrastructure may be needed to provide safe routes to parks.

A longitudinal cohort study of body mass index and childhood exposure to secondhand tobacco smoke and air pollution: the Southern California Children's Health Study.

BACKGROUND: Childhood body mass index (BMI) and obesity prevalence have been associated with exposure to secondhand smoke (SHS), maternal smoking during pregnancy, and vehicular air pollution. There has been little previous study of joint BMI effects of air pollution and tobacco smoke exposure. METHODS: Information on exposure to SHS and maternal smoking during pregnancy was collected on 3,318 participants at enrollment into the Southern California Children's Health Study. At study entry at average age of 10 years, residential near-roadway pollution exposure (NRP) was estimated based on a line source dispersion model accounting for traffic volume, proximity, and meteorology. Lifetime exposure to tobacco smoke was assessed by parent questionnaire. Associations with subsequent BMI growth trajectory based on annual measurements and attained BMI at 18 years of age were assessed using a multilevel modeling strategy. RESULTS: Maternal smoking during pregnancy was associated with estimated BMI growth over 8-year follow-up (0.72 kg/m2 higher; 95% CI: 0.14, 1.31) and attained BMI (1.14 kg/m2 higher; 95% CI: 0.66, 1.62). SHS exposure before enrollment was positively associated with BMI growth (0.81 kg/m2 higher; 95% CI: 0.36, 1.27) and attained BMI (1.23 kg/m2 higher; 95% CI: 0.86, 1.61). Growth and attained BMI increased with more smokers in the home. Compared with children without a history of SHS and NRP below the median, attained BMI was 0.80 kg/m2 higher (95% CI: 0.27, 1.32) with exposure to high NRP without SHS; 0.85 kg/m2 higher (95% CI: 0.43, 1.28) with low NRP and a history of SHS; and 2.15 kg/m2 higher (95% CI: 1.52, 2.77) with high NRP and a history of SHS (interaction p-value 0.007). These results suggest a synergistic effect. CONCLUSIONS: Our findings strengthen emerging evidence that exposure to tobacco smoke and NRP contribute to development of childhood obesity and suggest that combined exposures may have synergistic effects.

Traffic-related air pollution and obesity formation in children: a longitudinal, multilevel analysis.

BACKGROUND: Biologically plausible mechanisms link traffic-related air pollution to metabolic disorders and potentially to obesity. Here we sought to determine whether traffic density and traffic-related air pollution were positively associated with growth in body mass index (BMI = kg/m2) in children aged 5-11 years. METHODS: Participants were drawn from a prospective cohort of children who lived in 13 communities across Southern California (N = 4550). Children were enrolled while attending kindergarten and first grade and followed for 4 years, with height and weight measured annually. Dispersion models were used to estimate exposure to traffic-related air pollution. Multilevel models were used to estimate and test traffic density and traffic pollution related to BMI growth. Data were collected between 2002-2010 and analyzed in 2011-12. RESULTS: Traffic pollution was positively associated with growth in BMI and was robust to adjustment for many confounders. The effect size in the adjusted model indicated about a 13.6% increase in annual BMI growth when comparing the lowest to the highest tenth percentile of air pollution exposure, which resulted in an increase of nearly 0.4 BMI units on attained BMI at age 10. Traffic density also had a positive association with BMI growth, but this effect was less robust in multivariate models. CONCLUSIONS: Traffic pollution was positively associated with growth in BMI in children aged 5-11 years. Traffic pollution may be controlled via emission restrictions; changes in land use that promote jobs-housing balance and use of public transit and hence reduce vehicle miles traveled; promotion of zero emissions vehicles; transit and car-sharing programs; or by limiting high pollution traffic, such as diesel trucks, from residential areas or places where children play outdoors, such as schools and parks. These measures may have beneficial effects in terms of reduced obesity formation in children.

Factors predicting the capacity of Los Angeles city-region recreation programs to promote energy expenditure.

An audit of recreation programs with moderate or higher levels of physical activity (PA) in Los Angeles area cities (N=82) was conducted using internet, telephone, and survey methods. Metabolic Equivalents (METs) were used to code programs׳ physical activity intensity. MET-hours per recreation program was associated with required age for enrollment, percent of residents >64 years of age, and fiscal capacity of cities. Capacity to promote energy expenditure may depend on targeted age groups, age of population, and municipal fiscal capacity. Cities with lower fiscal capacity might offer those higher MET-hour activities which require less specialized equipment and seek outside funding to offer higher MET programs.

Neighborhood park use by children: use of accelerometry and global positioning systems.

BACKGROUND: Although having a greater number of neighborhood parks may be associated with greater overall physical activity in children, information is lacking about the extent to which children actually use parks for physical activity. PURPOSE: This study combined accelerometer, GPS, GIS, and self-report methods to examine neighborhood park availability, perceived proximity, and use for physical activity in children. METHODS: Low- to middle-income children (aged 8-14 years) (n=135) from suburban communities in Southern California wore an Actigraph accelerometer and GlobalSat BT-335 GPS device across 7 days to measure physical activity and park use, respectively. ArcGIS identified parks within a 500-m residential buffer of children's homes. Parents reported perceptions of neighborhood park proximity through the Neighborhood Environment Walkability Survey (NEWS). Data were collected from March 2009 to December 2010, and analyzed in 2013. RESULTS: Fifty-four percent of families lived within 500 m of a park. Of these children, GPS data indicated that 16% used it more than 15 minutes and an additional 11% of children used it between 5 and 15 minutes during the 7-day study period. The odds of extended park use (>15 minutes) increased fourfold when the distance between home and the nearest neighborhood park decreased by 100 m. Additionally, the odds of any park use (>5 minutes) doubled when moving from the 25th to the 75th percentile for park greenness/vegetation density. CONCLUSIONS: Although children's use of neighborhood parks was generally low, it increased substantially when parks were closer to children's homes and had greater vegetation density.

Understanding the physical and social contexts of children's nonschool sedentary behavior: an ecological momentary assessment study.

BACKGROUND: Research on children's sedentary behavior has relied on recall-based self-report or accelerometer methods, which do not assess the context of such behavior. PURPOSE: This study used ecological momentary assessment (EMA) to determine where and with whom children's sedentary behavior occurs during their nonschool time. METHODS: Children (N = 120) ages 9-13 years (51% male, 33% Hispanic) wore mobile phones that prompted surveys (20 total) for 4 days. Surveys measured current activity (eg, exercise, watching TV), physical location (eg, home, outdoors), and social company (eg, family, friends). RESULTS: Children engaged in a greater percentage of leisure-oriented (eg, watching TV) than productive (eg, reading, doing homework) sedentary behavior (70% vs 30%, respectively). Most of children's sedentary activity occurred at home (85%). Children's sedentary activity took place most often with family members (58%). Differences in physical context of sedentary behavior were found for older vs. younger children (P < .05). Type of sedentary behavior differed by gender, racial/ethnic group, and social context (P < .05). CONCLUSION: Children may prefer or have greater opportunities to be sedentary in some contexts than others. Research demonstrates the potential for using EMA to capture real-time information about children's sedentary behavior during their nonschool time.

Smart growth community design and physical activity in children.

BACKGROUND: Physical inactivity is a leading cause of death and disease globally. Research suggests physical inactivity might be linked to community designs that discourage active living. A "smart growth" community contains features likely to promote active living (walkability, green space, mixed land use), but objective evidence on the potential benefits of smart growth communities is limited. PURPOSE: To assess whether living in a smart growth community was associated with increased neighborhood-centered leisure-time physical activity in children aged 8-14 years, compared to residing in a conventional community (i.e., one not designed according to smart growth principles). METHODS: Participants were recruited from a smart growth community, "The Preserve," located in Chino, California, and eight conventional communities within a 30-minute drive of The Preserve. The analytic sample included 147 children. During 2009-2010, each child carried an accelerometer and a GPS for 7 days to ascertain physical activity and location information. Negative binomial models were used to assess the association between residence in the smart growth community and physical activity. Analyses were conducted in 2012. RESULTS: Smart growth community residence was associated with a 46% increase in the proportion of neighborhood moderate-to-vigorous physical activity (MVPA) as compared to conventional community residence. This analysis included neighborhood activity data collected during the school season and outside of school hours and home. Counterfactual simulations with model parameters suggested that smart growth community residence could add 10 minutes per day of neighborhood MVPA. CONCLUSIONS: Living in a smart growth community may increase local physical activity in children as compared to residence in conventionally designed communities.

Factors influencing whether children walk to school.

Few studies have simultaneously evaluated multiple levels of influence on whether children walk to school. A large cohort of 4338 subjects from 10 communities was used to identify the determinants of walking through (1) a one-level logistic regression model for individual-level variables and (2) a two-level mixed regression model for individual and school-level variables. Walking rates were positively associated with home-to-school proximity, greater age, and living in neighborhoods characterized by lower traffic density. Greater land use mix around the home was, however, associated with lower rates of walking. Rates of walking to school were also higher amongst recipients of the Free and Reduced Price Meals Program and attendees of schools with higher percentage of English language learners. Designing schools in the same neighborhood as residential districts should be an essential urban planning strategy to reduce walking distance to school. Policy interventions are needed to encourage children from higher socioeconomic status families to participate in active travel to school and to develop walking infrastructures and other measures that protect disadvantaged children.

Organized physical activity in young school children and subsequent 4-year change in body mass index.

OBJECTIVE: To determine whether participation in organized outdoor team sports and structured indoor nonschool activity programs in kindergarten and first grade predicted subsequent 4-year change in body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) during the adiposity rebound period of childhood. DESIGN: Longitudinal cohort study. SETTING: Forty-five schools in 13 communities across Southern California. PARTICIPANTS: Largely Hispanic and non-Hispanic white children (N = 4550) with a mean (SD) age at study entry of 6.60 (0.65) years. MAIN EXPOSURES: Parents completed questionnaires assessing physical activity, demographic characteristics, and other relevant covariates at baseline. Data on built and social environmental variables were linked to the neighborhood around children's homes using geographical information systems. MAIN OUTCOME MEASURES: Each child's height and weight were measured annually during 4 years of follow-up. RESULTS: After adjusting for several confounders, BMI increased at a rate 0.05 unit/year slower for children who participated in outdoor organized team sports at least twice per week compared with children who did not. For participation in each additional indoor nonschool structured activity class, lesson, and program, BMI increased at a rate 0.05 unit/year slower, and the attained BMI level at age 10 years was 0.48 units lower. CONCLUSION: Engagement in organized sports and activity programs as early as kindergarten and the first grade may result in smaller increases in BMI during the adiposity rebound period of childhood.

Children's perceptions of physical activity environments captured through ecological momentary assessment: a validation study.

OBJECTIVE: This study used ecological momentary assessment (EMA) to investigate whether children's perceptions of physical activity (PA) settings correspond with (1) parents' perceptions of neighborhood characteristics (convergent construct validity) and (2) children's level of PA in those settings (concurrent criterion validity). METHODS: Low-to-middle income, ethnically-diverse children (N=108) (ages 9-13) living in Southern California participated in 8 days of EMA during non-school time. EMA measured current activity type (e.g., sports/exercise, TV watching) and perceptions of the current setting (i.e., vegetation, traffic, safety). The Neighborhood Environment Walkability Survey (NEWS) assessed parents' perceptions of neighborhood characteristics. EMA responses were time-matched to moderate-to-vigorous physical activity (MVPA) (measured by accelerometer) in the 30 min before and after each EMA survey. Data were collected in 2009-2010. RESULTS: Children's perceptions of vegetation and traffic in PA settings corresponded with parents' perceptions of the aesthetics (OR=2.21, 95% CI=1.04-4.73) and traffic (OR=2.64, 95% CI=1.31-5.30) in neighborhood environment, respectively. MVPA minutes were higher in settings perceived by children to have less traffic (ß=3.47, p<.05). CONCLUSIONS: This work provides initial support for the construct and criterion validity of EMA-based measures of children's perceptions of their PA environments.

Investigating the impact of a smart growth community on the contexts of children's physical activity using Ecological Momentary Assessment.

This quasi-experimental research used Ecological Momentary Assessment with electronic surveys delivered through mobile phones to determine whether children change the type of contexts (i.e., settings) where they engage in physical activity after a recent move to a smart growth (SG) community in the U.S. as compared to children living in conventional low-to-medium density U.S. suburban communities (controls). SG vs. control children engaged in a greater proportion of physical activity bouts with friends, a few blocks from home, and at locations to which they walked. Over six months, the proportion of physical activity bouts reported at home (indoors) and in high traffic locations decreased among SG but not control children. Six-month increases in daily moderate-to-vigorous physical activity did not significantly differ by group. Children might have altered the type of contexts where they engage in physical activity after moving to SG communities, yet more time may be necessary for these changes to impact overall physical activity.

Assessing the social and physical contexts of children's leisure-time physical activity: an ecological momentary assessment study.

PURPOSE: To use Ecological Momentary Assessment with mobile phones to describe where and with whom children's leisure-time physical activity occurs. DESIGN: Repeated assessments across 4 days (Friday-Monday) during nonschool time (20 total). SETTING: Chino, California, and surrounding communities. SUBJECTS: Primarily low to middle income children (N =121; aged 9-13 years; x¯=11.0 years, SD =1.2 years; 52% male, 38% Hispanic/Latino). MEASURES: Electronic surveys measured current activity (e.g., active play/sports/exercise, watching TV/movies), social company (e.g., family, friends, alone), physical location (e.g., home, outdoors, school), and other perceived contextual features (e.g., safety, traffic, vegetation, distance from home). Analysis . Multilevel linear and multinomial logistic regression. RESULTS: Most of children's physical activity occurred outdoors (away from home) (42%), followed by at home (indoors) (30%), front/backyard (at home) (8%), someone else's house (8%), at a gym/recreation center (3%), and other locations (9%). Children's physical activity took place most often with multiple categories of people together (e.g., friends and family) (39%), followed by family members only (32%), alone (15%), and with friends only (13%). Age, weight status, income, and racial/ethnic differences in physical activity contexts were observed. CONCLUSIONS: The most frequently reported contexts for children's leisure time physical activity were outdoors and with family members and friends together.

Does exposure to air pollution in urban parks have socioeconomic, racial or ethnic gradients?

Little is known about the levels of air pollution at public parks where regular exercise takes place or in park-adjacent neighborhoods where people have easy access to parks. In this study we investigated the ambient concentrations of criteria pollutants nitrogen dioxide (NO(2)), fine particulate (PM(2.5)) and ozone (O(3)) at public parks and in park-adjacent neighborhoods for metropolitan Los Angeles. Socioeconomic and racial-ethnic inequalities in exposure to the three criteria pollutants were also investigated using multiple linear regression models. In addition, differences in inhalation doses from breathing the three +criteria pollutants were investigated for the top and bottom quartile racial composition in the parks and neighborhoods. Our research showed that although public parks had on average the lowest pollutant concentrations of NO(2) and PM(2.5), they had relatively high O(3) concentrations. Park-adjacent neighborhoods, by contrast, had the highest NO(2) and PM(2.5) concentrations, but the lowest O(3) concentrations. Higher exposures to NO(2) and PM(2.5) were systematically identified for the lower socioeconomic position or higher minority population neighborhoods. For children and adolescents aged 6-15 engaging in high and moderate intensity activities in and around public parks, those from the top quartile of primarily Hispanic neighborhoods had much higher (63%) inhaled doses of NO(2) compared to the bottom quartile counterpart. PM(2.5) showed a similar but less pronounced pattern of inhalation doses. Evidence of socioeconomic and racial-ethnic gradients was found in air pollution exposure and inhalation doses in and around the urban parks in Los Angeles. This suggests that patterns of exposure inequality found in other environmental justice research are present in exposures in and around urban parks.

Physical and social contextual influences on children's leisure-time physical activity: an ecological momentary assessment study.

BACKGROUND: This study used real-time electronic surveys delivered through mobile phones, known as Ecological Momentary Assessment (EMA), to determine whether level and experience of leisure-time physical activity differ across children's physical and social contexts. METHODS: Children (N = 121; ages 9 to 13 years; 52% male, 32% Hispanic/Latino) participated in 4 days (Fri.-Mon.) of EMA during nonschool time. Electronic surveys (20 total) assessed primary activity (eg, active play/sports/exercise), physical location (eg, home, outdoors), social context (eg, friends, alone), current mood (positive and negative affect), and enjoyment. Responses were time-matched to the number of steps and minutes of moderate-to-vigorous physical activity (MVPA; measured by accelerometer) in the 30 minutes before each survey. RESULTS: Mean steps and MVPA were greater outdoors than at home or at someone else's house (all P < .05). Steps were greater with multiple categories of company (eg, friends and family together) than with family members only or alone (all P < .05). Enjoyment was greater outdoors than at home or someone else's house (all P < .05). Negative affect was greater when alone and with family only than friends only (all P < .05). CONCLUSION: Results describing the value of outdoor and social settings could inform context-specific interventions in this age group.

Childhood obesity and proximity to urban parks and recreational resources: a longitudinal cohort study.

The objective of the research was to assess how proximity to parks and recreational resources affects the development of childhood obesity through a longitudinal study. Data were collected on 3173 children aged 9-10 from 12 communities in Southern California in 1993 and 1996. Children were followed for eight years to collect longitudinal information, including objectively measured body mass index (BMI). Multilevel growth curve models were used to assess associations between attained BMI growth at age 18 and numerous environmental variables, including park space and recreational program access. For park acres within a 500 m distance of children's homes, there were significant inverse associations with attained BMI at age 18. Effect sizes were larger for boys than for girls. Recreation programs within a 10 km buffer of children's homes were significantly and inversely associated with achieved levels in BMI at age 18, with effect sizes for boys also larger than those for girls. We conclude that children with better access to parks and recreational resources are less likely to experience significant increases in attained BMI.

Development, reliability, and validity of an urban trail use survey.

PURPOSE: To evaluate the psychometric characteristics of the Research on Urban Trail Environments (ROUTES) Trail Use Questionnaire. DESIGN: Test-retest reliability was assessed by repeated measures (study 1); validity was assessed by comparing reported trail use to self-reported and objectively measured physical activity (PA) levels (study 2). SETTING: Study 1: a religious institution situated near a Los Angeles trail. Study 2: 1-mile buffer zones surrounding three urban trails (Chicago, Dallas, and Los Angeles). SUBJECTS: Thirty-four adults between 40 and 60 years of age (10 men and 24 women) completed the ROUTES questionnaire twice (study 1). Study 2 participants were 490 adults (48% female and 73% white), mean age 48 years. MEASURES: Trail use for recreation and transportation purposes, time and distance spent on trails, and characteristics of the trail and other trail users. PA was measured using the International Physical Activity Questionnaire and accelerometry. ANALYSES: Pearson correlation coefficients and kappa statistics were used for test-retest reliability for continuous and categorical variables, respectively. Generalized linear models were used to evaluate hypotheses on PA comparing trail users and nonusers. RESULTS: Test-retest statistics were acceptable (kappa = .57, r = .66). Validity was supported by correlations between indices of trail use with self-reported PA and accelerometry, and significant group differences between trail users and nonusers in PA levels. CONCLUSIONS: The ROUTES Trail Use Questionnaire demonstrated good reliability and validity.

Reliability of an audit tool for systematic assessment of urban alleyways.

BACKGROUND: Reliable audit tools are needed to examine the potential of built environment features for physical activity. METHODS: An audit tool for alley environments was developed with land use, substrate, and use, condition, and safety items. Two audit teams independently audited 29 Los Angeles alleys, and interteam reliability was calculated with Cohen's and prevalence-adjusted, bias-adjusted kappa (PABAK) statistics; intraclass correlation coefficients; and percent observed agreement. RESULTS: Forty-two of 47 dichotomous items analyzed for reliability had PABAK values > or = 0.61 ("substantial agreement"). Sixteen of 23 ordinal and continuous response items analyzed had ICCs > or = 0.61, and an additional 6 with lower ICC values had observed agreement > or = 79%. Items concerning the presence or absence of use-related alley features demonstrated the lowest reliability. CONCLUSIONS: The instrument has acceptable reliability for most of its items and appears to be a promising tool for use by other researchers and professionals in the measurement of alley environments.

The active city? Disparities in provision of urban public recreation resources.

Recreation is critical to active living yet few studies have focused on disparities in the provision of recreational programs. We investigate the spatial distribution of public recreational programs in southern California. Findings indicate that more than half of all recreation programs take place away from a formal park site. Multivariate modeling results suggest that cities characterized by low household incomes, low fiscal capacity, minority populations, and multi-family housing are disadvantaged with respect to recreation provisions. Such disparities may increase health risks among populations in such communities. Urban planners and public health advocates should enhance recreation programs in lower-income non-white communities.

Automobile traffic around the home and attained body mass index: a longitudinal cohort study of children aged 10-18 years.

OBJECTIVES: The objective of this study is to examine the relationship between measured traffic density near the homes of children and attained body mass index (BMI) over an eight-year follow up. METHODS: Children aged 9-10 years were enrolled across multiple communities in Southern California in 1993 and 1996 (n=3318). Children were followed until age 18 or high school graduation to collect longitudinal information, including annual height and weight measurements. Multilevel growth curve models were used to assess the association between BMI levels at age 18 and traffic around the home. RESULTS: For traffic within 150 m around the child's home, there were significant positive associations with attained BMI for both sexes at age 18. With the 300 m traffic buffer, associations for both male and female growth in BMI were positive, but significantly elevated only in females. These associations persisted even after controlling for numerous potential confounding variables. CONCLUSIONS: This analysis yields the first evidence of significant effects from traffic density on BMI levels at age 18 in a large cohort of children. Traffic is a pervasive exposure in most cities, and our results identify traffic as a major risk factor for the development of obesity in children.