Neighborhood Environment and Physical Activity Among Youth. A Review

Transcription

1 Neighborhood Environment and Physical Activity Among Youth A Review Ding Ding, MPH, James F. Sallis, PhD, Jacqueline Kerr, PhD, Suzanna Lee, MPH, Dori E. Rosenberg, PhD, MPH Context: Research examining the association between environmental attributes and physical activity among youth is growing. An updated review of literature is needed to summarize the current evidence base, and to inform policies and environmental interventions to promote active lifestyles among young people. Evidence acquisition: A literature search was conducted using the Active Living Research (ALR) literature database, an online database that codes study characteristics and results of published papers on built/social environment and physical activity/obesity/sedentary behavior. Papers in the ALR database were identifıed through PubMed, Web of Science, and SPORTDiscus using systematically developed and expert-validated search protocols. For the current review, additional inclusion criteria were used to select observational, quantitative studies among youth aged 3 18 years. Evidence synthesis: Papers were categorized by design features, sample characteristics, and measurement mode. Relevant results were summarized, stratifıed by age (children or adolescents) and mode of measurement (objective or perceived) for environmental attributes and physical activity. Percentage of signifıcant results was calculated. Conclusions: Mode of measurement greatly influenced the consistency of associations between environmental attributes and youth physical activity. For both children and adolescents, the most consistent associations involved objectively measured environmental attributes and reported physical activity. The most supported correlates for children were walkability, traffıc speed/volume, access/proximity to recreation facilities, land-use mix, and residential density. The most supported correlates for adolescents were land-use mix and residential density. These fındings support several recommendations for policy and environmental change from such groups as the IOM and National Physical Activity Plan. (Am J Prev Med 2011;41(4): ) 2011 American Journal of Preventive Medicine Context Physical activity offers numerous health benefıts to young people. 1 It is recommended that youth participate in moderate to vigorous physical activity for at least 60 minutes daily. 2 Recent accelerometer data 2,3 indicated, however, that only 42% of children and 8% of adolescents in the U.S. met this guideline. From the Graduate School of Public Health (Ding, Lee); the Department of Psychology (Sallis), San Diego State University, San Diego; the Department of Family and Preventive Medicine, University of California San Diego (Ding, Kerr), La Jolla, California; and the Department of Rehabilitation, University of Washington (Rosenberg), Seattle, Washington Address correspondence to: Ding Ding, MPH, th Avenue, Suite 310, San Diego CA dding@projects.sdsu.edu /$17.00 doi: /j.amepre Ecologic models postulate multiple environmental influences on physical activity. 4 Growing literature from public health, transportation, urban planning, and leisure studies 5 7 has examined the association between the built environment (i.e., physical environment) and physical activity. However, these associations are less understood among young people than among adults, as reflected by fewer published studies. 8,9 Understanding environmental correlates of physical activity among young people is especially important because children and adolescents have less autonomy in their behaviors and are more likely than adults to be influenced by the environment, directly or indirectly through parents or peers Informed decision making about environmental interventions, often through policy changes, requires a comprehensive understanding of environmental correlates of 442 Am J Prev Med 2011;41(4): American Journal of Preventive Medicine Published by Elsevier Inc.

2 physical activity. 13 The preferred method of deriving lessons from scientifıc literature is to use a systematic approach to synthesize empirical fındings. 14 A recent review of reviews 8 identifıed a small number of review papers on environmental correlates of youth physical activity. Most of the identifıed reviews included a broad range of correlates, of which the built environment attributes constituted only a small percentage of variables reviewed. 15,16 Some reviews 12,17 19 were limited to a specifıc type of physical activity (e.g., active commute to school) or a specifıc activity setting (e.g., school). The most thorough review of the built environment and youth physical activity was by Davison and Lawson in 2006, 7 which included 33 papers. Because the number of studies has increased rapidly, an updated review is needed to better represent the current evidence base. To date, fındings regarding the built environment and physical activity revealed complex patterns, 8 characterized by inconsistent associations with some environmental attributes. 9,20,21 Heterogeneity across studies poses a major challenge for summarizing fındings. 21 Mode of measurement (e.g., objective or perceived) may influence environmental variables associations with physical activity. 8,9,22 Similarly, mode of measuring overall or domainspecifıc physical activity (e.g., active commute) is expected to affect associations with environmental attributes, because these associations are highly specifıc to domains of physical activity. 16,23 Completeness of literature search and accuracy of reporting studies are also concerns that may influence conclusions of a review. 14 The present study summarized fındings from peerreviewed papers on the associations between neighborhood environment and physical activity among youth. The review focused on attributes that can be modifıed through policies and planning initiatives (e.g., sidewalks, traffıc). To improve on previous reviews, the current review included a larger number of studies from multiple disciplines, employed systematic literature search and data extraction methods, used a semi-quantitative approach for summarizing results, 23 and stratifıed results by age and by measurement modes of environmental attributes and physical activity. Evidence Acquisition Data Sources The present review used the Active Living Research (ALR) literature database, a publicly accessible online database that codes study characteristics and results of published papers on the relationship between built and social environment variables and physical activity, obesity, and sedentary behavior. The database can be accessed at Ding et al / Am J Prev Med 2011;41(4): Since 2002, researchers at ALR have conducted semiannual literature searches through PubMed, Web of Science, and SPORTDiscus, using a systematically developed and expert-validated search protocol. The protocol defıned comprehensive search terms, term combinations, and search limitations, which can be accessed at background. The resulting papers were screened by researchers based on inclusion and exclusion criteria. Inclusion criteria were as follows: (1) published in English language; (2) dependent variables included a measure of physical activity, weight status, or sedentary behavior; and (3) for observational studies, the environmental attributes were measured as independent variables, and for intervention studies, environmental change was an experimental condition. Papers were screened for inclusion in three steps based on reading the title, abstract, and full text. Two researchers conducted screening independently, and the fınal lists were compared to ensure completeness and accuracy of screening. Trained research assistants coded design features, methods, and results using a detailed protocol. For quality control, another research assistant and a supervisor checked each coded variable. The corresponding author of each paper was invited to approve the coding of their paper. If the corresponding author was not reachable, a second author was contacted. If corrections were requested by authors, their suggestions were compared with the database protocol, and decisions for correction were made accordingly. By October 2010, the ALR database included 648 coded papers. Inclusion and Exclusion Criteria for Review Additional inclusion criteria were applied to select papers from the ALR database for the current review. These criteria were: (1) observational study design; (2) study population was children or adolescents (aged 3 18 years); (3) sample size was 50 or larger; (4) study was published before January 2010; (5) dependent variables included total, recreational, or transport physical activity; (6) independent variables were specifıc environmental attributes of neighborhoods; (7) test statistics for associations between dependent and independent variables were provided and signifıcance could be determined. Studies were excluded if: (1) the study population included other age groups in addition to children and adolescents that could not be separated; (2) physical activity was observed in specifıc settings only (e.g., park, school); (3) the study reported only descriptive or qualitative results. Although experimental studies provide stronger evidence for causality, such studies were not included because of the small number of papers available and the diffıculty of separating effects from different components of interventions. October 2011

3 444 Ding et al / Am J Prev Med 2011;41(4): Environmental Variables Reviewed Considering the large number of environmental variables included in papers, only common neighborhood environmental attributes with at least three coded results were selected for review (Table 1). When the variable could not be categorized because of lack of specifıcity, a more general category was created (e.g., unspecifıed safety). Broad and nonmodifıable variables such as urban/rural and SES were not included. Study results were stratifıed by objective and perceived measures separately for children and adolescents. Table 1. Expected directions of associations between attributes of neighborhood environment and domains of physical activity among youth Environmental attributes Expected direction of association Domains of physical activity a Parks (access/density/proximity) Positive Leisure-time (Transport) Recreation facilities (access/density/ proximity) Positive Land-use mix/destinations Positive Transport Residential density Positive Transport Street connectivity Positive Transport Walkability Positive Transport Walking/biking facilities (e.g., sidewalks, bike paths) Positive Leisure-time (Transport) Transport Leisure-time Traffic speed/volume Inverse Transport Leisure-time Pedestrian safety structures (e.g., zebra crossing, traffic lights) Positive Transport Leisure-time Neighborhood incivilities/disorders Inverse Transport Leisure-time Crime-related safety Positive Transport Leisure-time Vegetation Positive Leisure-time (Transport) a Primary domain of physical activity expected to be associated with environmental attributes is presented without parentheses, secondary domain is presented in parentheses. Data Extraction Methods. The following information was extracted from each paper: study design, study region, total sample size, sample age, year of publication, and measures of the environment and physical activity (Table 2). Sample age was determined using reported mean or median age: Those aged 3 12 years were coded as children and those aged years were coded as adolescents. Nine studies including both children and adolescents presented separate analyses for each sample. 62,108 These studies were coded as including both children and adolescents for sample characteristics description (Table 2), and their results were summarized separately for children and adolescents (Tables 3 6). Objectively measured physical activity included overall physical activity (total or moderate-to-vigorous) captured by motion detectors such as accelerometers and pedometers. Reported physical activity included self- or parent-reports using a survey instrument. Examples of objective and perceived measures of neighborhood environmental attributes are presented in Appendix A ( Coding of results. Separate results were presented for children and adolescents because age was expected to affect the associations between neighborhood environment and physical activity. 12 In each paper, all results (adjusted and unadjusted) regarding statistical tests of associations between environmental variables and physical activity were considered for the review. Multiple entries for an association might be reported from one study as a result of different statistical tests, participant subgroups, and covariates adjusted. Associations of environmental attributes with conceptually mismatched domains of physical activity (Table 1) were excluded. Direction of each association was coded as,,or0: indicated a signifıcant association in the hypothesized direction; signifıed a signifıcant association not in the hypothesized direction; and 0 stood for a nonsignifıcant association. Hypothesized directions of associations were based on theories and previous literature, 4,5, and are presented in Table 1. The signifıcance and direction of each result were tallied separately for children and adolescents and stratifıed by measurement mode of environmental attributes and physical activity. The total number of associations is presented for each code (,, or 0), and the number of studies from which the results were abstracted is presented in parentheses. A percentage ( %) was calculated to represent the proportion of comparisons supporting the hypothesized association (i.e., those coded as ) over the total number of comparisons for each environmental variable. When interpreting the percentages, rules used by a previous review 23 were adopted to classify variables based on strength of evidence for associations with physical ac-

4 Table 2. Characteristics of papers reviewed (n 103) Characteristics of paper Paper counts Reference no. Total sample size Ding et al / Am J Prev Med 2011;41(4): tivity (0% 33%, little evidence/no association; 34% 59%, intermediate evidence/inconsistent association; 60% 100%, strong evidence/association) Not reported Study design Cross-sectional , 31 54, 56 77, , Longitudinal 4 30, 55, 78, 116 Sample age (years) Children 56 24, 26, 28, 29, 31 34, 40 42, 45 48, 50 52, 54 56, 58, 60, 65, 69, 70, 72, 75, 77, 78, 80 83, 85, 86, 94, 95, 97, 99, 101, 104, 106, 107, 109, 110, 112, , 120, 121, Adolescents 38 25, 27, 30, 36 39, 43, 44, 49, 57, 59, 61, 63, 66, 68, 71, 73, 74, 76, 84, 87 93, 96, 98, 100, 102, 103, 105, 113, 117, 119, 122 Both 9 35, 53, 62, 64, 67, 79, 108, 111, 118 Geographic origin Asia 1 88 Australia/New Zealand 11 41, 42, 49, 54, 55, 64, 67, 99, 112, 113, 125 Europe 18 44, 46, 50, 56, 58, 59, 66, 71, 73, 75, 76, 81, 86, 87, 90, 96, 107, 118 North America , 43, 47, 48, 51 53, 57, 60 63, 65, 68 70, 72, 74, 77 80, 82 85, 89, 91 95, 97, 98, , , , , 126 Year of publication , 78, 100, , 25, 41, 58, 68, 77, 79, 89, 104, , 30 40, 42 57, 59 67, 69 76, 80 88, 90 99, , 105, 106, , Environmental measures Objective 25 26, 30 33, 38, 39, 48, 50, 61, 64, 67, 70, 74, 80, 82, 83, 104, 105, 108, 109, 111, 117, 122, 124 Perceived 58 24, 27, 29, 34, 35, 40 44, 46, 47, 49, 52, 53, 55 60, 62, 65, 66, 68, 71, 73, 75, 77 79, 86 92, 94 96, , 106, 107, 109, , 118, 119, 123 Both 20 25, 28, 36, 37, 45, 51, 54, 63, 69, 72, 76, 81, 84, 85, 93, 97, 120, 121, 125, 126 Physical activity measures Objective 18 24, 26, 28 30, 32, 33, 38, 39, 42, 48, 51, 60, 64, 74, 82, 83, 85 Report 77 25, 27, 31, 34 36, 40, 41, 43 47, 49, 50, 52, 53, 55, 56 59, 62, 63, 65, 66, 68, 69 73, 75 77, 80, 81, 84, 86 94, 96, Both 8 37, 54, 61, 67, 78, 79, 95, 97 Evidence Synthesis General Characteristics of Papers Reviewed A total of 103 papers were reviewed. Most studies were cross-sectional and conducted in North America (fıve in Canada, 68 in the U.S.). There has been a dramatic growth in the number of papers in the last few years, with 86% of papers published between 2005 and Sample sizes ranged from 52 to 68,288, with a median of 781. There were more studies of children than adolescents. A large majority of papers used only reported measures for neighborhood environment and for physical activity. For comparisons involving reported physical activity, domain-specifıc results are summarized in the text to aid interpretation, but results in tables are not domain-specifıc. Neighborhood Environment and Physical Activity Among Children A total of 878 comparisons were reviewed from 65 papers, including 317 using objective measures of neighborhood environment and 561 using perceived measures. More than two thirds of the comparisons involved re- October 2011

5 446 Ding et al / Am J Prev Med 2011;41(4): Table 3. Summary of associations between objectively measured environmental attributes and physical activity of children (aged 3 12 years) Objectively measured physical activity outcomes a Reported physical activity outcome a Objectively measured environmental variables References Result counts (paper counts) a Result counts (paper counts) a 0 % 0 % Total % Recreation environment Parks (access/density/ proximity) 28, 31 33, 80, 83, (4) 30 (4) 0 (0) 43 4 (1) 8 (2) 0 (0) Recreation facilities (access/density/ proximity) Neighborhood design 28, 31, 32, 51, 64, 80, 82, (3) 10 (4) 0 (0) (2) 0 (0) 0 (0) Land-use mix destinations 69, 70, 108, 110, (4) 13 (2) 0 (0) Residential density 31, 33, 69, 70, 72, 108, 110, 111, 120, 121 Street connectivity 31, 33, 67, 69, 70, 83, 104, 108, (1) 5 (1) 0 (0) (8) 8 (4) 3 (1) (1) 12 (4) 5 (1) 19 5 (3) 10 (4) 0 (0) Walkability 45, 69 3 (2) 0 (0) 0 (0) Transportation environment Walking/biking facilities 26, 28, 64, 67, 70, 83, (3) 13 (4) 3 (1) 33 4 (1) 1 (1) 0 (0) Traffic speed/volume 50, 67, (2) 7 (2) 0 (0) Pedestrian safety structures 50, 67 0 (0) 2 (1) 4 (1) 0 8 (1) 1 (1) 0 (0) Social environment Crime-related safety 28, 32, 64 3 (2) 13 (4) 0 (0) Incivilities/disorders 26, 28, 50 0 (0) 5 (2) 0 (0) 0 4 (1) 2 (1) 0 (0) Other Vegetation 26, 50, 64, 70, 83 3 (2) 5 (2) 0 (0) 38 4 (1) 0 (0) 0 (0) Total results a, significant association in the expected direction; 0, nonsignificant association;, significant association in the unexpected direction; %, number of results coded as /total number of results. ported physical activity (n 609), and less than one third used objective measures of physical activity (n 269). Results Based on Objective Measures of Neighborhood Environment Among Children When neighborhood environmental attributes were measured objectively (Table 3), 50% of the results showed significant associations in the expected direction. The percentage of signifıcant associations ( %) was higher when physical activity was measured by reports (66%) compared with objectively measured overall physical activity (33%). Several environmental variables had inconsistent associations with objectively measured physical activity, including residential density (44%); parks (43%); recreation facilities (41%); and vegetation (38%). No environmental attribute was associated with objectively measured physical activity in more than 60% of the results. Stronger evidence existed for associations between neighborhood environmental attributes and reported physical activity; nine of 11 variables had % 60%. Walkability, access to recreation facilities/open space, and vegetation (i.e., presence of street trees) were associated with domain-specifıc physical activity in all comparisons. Pedestrian safety structures (89%) and social incivilities (67%) were associated with several reported physical activity outcomes, such as active commute and

6 Ding et al / Am J Prev Med 2011;41(4): Table 4. Summary of associations between perceived environmental attributes and physical activity of children (aged 3 12 years) Objectively measured physical activity outcomes Reported physical activity outcomes Perceived environmental variables References Result counts (paper counts) a Result counts (paper counts) a 0 % 0 % Total % Recreation environment Parks (access/density/ proximity) Recreation facilities (access/density/ proximity) Neighborhood design 24, 35, 47, 50, 52, 62, 79, 80, 85, 109, , 35, 47, 50, 52, 62, 79, 80, 85, 109, (1) 6 (2) 0 (0) 25 4 (2) 15 (6) 0 (0) (1) 17 (4) 1 (1) (7) 37 (7) 2 (1) Land-use mix/destinations 42, 50, 52, 62, 69, 85, (1) 18 (2) 1 (1) 5 9 (4) 23 (5) 6 (1) Residential density 50, 62, 69, (2) 17 (5) 0 (0) Street connectivity 62, 69, (3) 5 (2) 0 (0) Transportation environment Walking/biking facilities 34, 35, 40, 50, 52, 56, 62, 69, 85, 86, 94, 95, 101, 114 Traffic speed/volume 46, 52, 54, 85, 95, 101, 112, 114, 125, 126 Pedestrian safety structures 3 (1) 8 (1) 1 (1) (6) 21 (6) 1 (1) (0) 4 (1) 2 (1) 0 35 (10) 61 (10) 1 (1) , (2) 1 (1) 0 (0) Traffic safety (unspecified) 40, 41, 46, 54, 56, 62, 69, 86, 107, 114, 125 Social environment Crime-related safety 40, 41, 46, 52, 60, 62, 69, 79, 85, 86, 95, 114, 125, 126 Unspecified safety 34, 52 54, 58, 65, 79, 81, 86, 95, 99, 102, 106, 109, 114, 115, 123, (6) 13 (6) 0 (0) (1) 19 (3) 2 (1) 9 14 (8) 25 (8) 2 (1) (1) 18 (5) 0 (0) 5 17 (12) 44 (14) 1 (1) Incivilities/disorders 52, 54, 77 7 (3) 8 (3) 0 (0) Other Vegetation 52, 54, 58, 62, 114, (4) 13 (5) 1 (1) Total results a, significant association in the expected direction; 0, nonsignificant association;, significant association in the unexpected direction; %, number of results coded as /total number of results. playing outdoors. Land-use mix (66%); residential density (68%); walking facilities (e.g., sidewalk; 80%); and traffıc speed/volume (67%) were consistently associated with transport physical activity or walking. Results Based on Perceived Measures of Neighborhood Environment Among Children Neighborhood environment physical activity associations were much weaker when environmental attributes were measured by participants perceptions (Table 4). Only 30% of all comparisons were signifıcant. When the perceived environment objective physical activity combination was used, none of the environmental attributes had consistent associations with overall physical activity (all % 33%). The consistency of associations was higher when physical activity was measured by reports. The most supported association involved pedestrian safety October 2011

7 448 Ding et al / Am J Prev Med 2011;41(4): Table 5. Summary of associations between objectively measured environmental attributes and physical activity of adolescents (aged years) Objectively measured physical activity outcomes Reported physical activity outcomes Objectively measured environmental variables References Result counts (paper counts) a Result counts (paper counts) a 0 % 0 % Total % Recreation environment Parks (access/density/ proximity) Recreation facilities (access/density/ proximity) Neighborhood design Land-use mix/destinations 25, 37, 61, 74, 76, , 117, 64, 76, 80, 93 2 (2) 8 (3) 0 (0) 20 9 (4) 10 (5) 0 (0) (2) 9 (2) 0 (0) (3) 21 (2) 0 (0) , 39, 74, (3) 3 (1) 0 (0) 57 5 (1) 3 (1) 0 (0) Residential density 30, 74, 108, (0) 3 (2) 0 (0) 0 4 (2) 1 (1) 0 (0) Street connectivity 63, 67, 74, 105, (1) 19 (2) 2 (1) (4) 15 (2) 0 (0) Walkability 39, 74 1 (1) 4 (2) 0 (0) Transportation environment Walking/biking facilities 64, 67, 76 0 (0) 11 (2) 0 (0) 0 0 (0) 4 (1) 0 (0) 0 0 Traffic speed/volume 67 0 (0) 5 (1) 0 (0) 0 0 Pedestrian safety structures Social environment 67 3 (1) 13 (1) 2 (1) 17 5 (1) 14 (1) 2 (1) Crime-related safety 25, 37, 61, 64 0 (0) 10 (3) 0 (0) 0 1 (1) 5 (3) 0 (0) 17 6 Other Vegetation 64 1 (1) 3 (1) 0 (0) Total results a, significant association in the expected direction; 0, nonsignificant association;, significant association in the unexpected direction; %, number of results coded as /total number of results. structures (e.g., traffıc lights, crosswalks) and reported physical activity (83%). Several environmental attributes showed inconsistent associations with reported physical activity, including street connectivity (55%); incivilities (47%); residential density (43%); unspecifıed traffıc safety (43%); walking/biking facilities (35%); traffıc speed/volume (36%); and crime-related safety (34%). Neighborhood Environment and Physical Activity Among Adolescents A total of 843 comparisons from 47 studies were reviewed. More results involved perceived environmental measures (n 602) than objective measures (n 241). Similarly, more results were based on reported physical activity (n 702) than objective measures (n 141). Results Based on Objective Measures of Neighborhood Environment Among Adolescents When objective measures were employed for neighborhood environmental attributes (Table 5), 31% of all associations were signifıcant in expected directions. Similar to patterns found among children, results were more likely to be significant when objective environmental measures were matched with reported physical activity measures than with objective physical activity (19% vs 40%). None of the environmental attributes was signifıcantly associated with objective physical activity in more than 60% of the comparisons. However, land-use mix was signifıcant in 57% of comparisons, providing intermediate evidence. When physical activity was measured by reports, evidence supported associations of land-use mix (63%) and residential density (80%) with reported physical activity.

8 Ding et al / Am J Prev Med 2011;41(4): Table 6. Summary of associations between perceived environmental attributes and physical activity of adolescents (aged years) Objectively measured physical activity outcomes Reported physical activity outcomes Perceived environmental variables Recreation environment References Result counts (paper counts) a Result counts (paper counts) a 0 % 0 % Total % Parks (access/density/proximity) Recreation facilities (access/density/proximity) Neighborhood design 35 37, 44, 61, 71, 76, 79, 93, 102, , 35 37, 44, 49, 57, 59, 62, 66, 68, 71, 76, 79, 84, 87, 88, 90 92, 96, 98, 100, 113, 122 Land-use mix/destinations 35, 44, 49, 59, 62, 71, 88, 90, 96 1 (1) 6 (2) 0 (0) 14 9 (7) 25 (7) 0 (0) (0) 6 (2) 0 (0) 0 64 (17) 120 (18) 1 (1) (6) 36 (8) 2 (1) Residential density 62, 96 3 (1) 11 (2) 0 (0) Street connectivity 35, 44, 59, 62, 71, 90, 96 5 (3) 19 (7) 0 (0) Transportation environment Walking/biking facilities 35, 44, 59, 62, 71, 76, 87, 88, 90, 96, (1) 8 (1) 1 (1) (7) 24 (8) 0 (0) Traffic speed/volume 49, 71, 90, (2) 24 (3) 0 (0) Traffic safety (unspecified) 35, 59, 62 7 (3) 12 (3) 0 (0) Social environment Crime-related safety 27, 35, 43, 49, 59, 61, 62, 79, 89, 90, 96, 98 Unspecified safety 25, 27, 37, 44, 49, 53, 57, 79, 88, 91, 92, 100, 103, 113, (0) 3 (2) 0 (0) 0 11 (4) 60 (10) 1 (1) (0) 6 (2) 0 (0) 0 13 (8) 52 (13) 0 (0) Incivilities/disorders 27, 89 4 (2) 4 (2) 0 (0) Other Vegetation 44, 62, 87, (1) 11 (4) 0 (0) 8 8 Total results a, significant association in the expected direction; 0, nonsignificant association;, significant association in the unexpected direction; %, number of results coded as /total number of results. Access to parks (47%); recreation facilities (43%); and street connectivity (48%) had inconsistent relationships with reported physical activity. Results Based on Perceived Measures of Neighborhood Environment Among Adolescents As Table 6 shows, when perceived measures of environmental attributes were matched with objective measures of overall physical activity, none of the environmental attributes showed a consistent association (all % 33%), and the overall percentage of signifıcant associations was only 12%. When perceived measures of neighborhood environment were matched with reported physical activity, 29% of all comparisons were signifıcant, and no environmental attribute was strongly related (all % 60%) to physical activity. However, a few variables had inconsistent associations with domainspecifıc physical activity measures. These variables included social incivilities (50%); walking/biking facilities (47%); traffıc speed/volume (38%); unspecifıed traffıc safety (37%); and access to recreation facilities (35%). Results Summary Table 7 summarizes the consistency of neighborhood environment physical activity associations. Consis- October 2011

9 450 Ding et al / Am J Prev Med 2011;41(4): tency of associations was generally higher among children than adolescents except for the perceived environment objective physical activity combination, for which the level of consistency of associations was low among both age groups. For both children and adolescents, associations were the most consistent when comparisons involved the objective environment reported physical activity combination, and the least consistent was the perceived environment objective physical activity combination. Discussion This review extracted 1721 results from 103 papers. A key fınding was that mode of measurement influenced observed associations between neighborhood environment and youth physical activity (Table 7). Objectively measured environmental attributes were much more consistently related to physical activity. This pattern may be explained by less measurement error in objective measures. In contrast, reported physical activity was much more consistently related to neighborhood environment than was objectively measured physical activity. This may be because reported measures captured specifıc domains of physical activity (e.g., active transport, leisure-time physical activity), which provided a more precise test of association. This fınding is consistent with theory and literature 127,129,130 indicating that environmental influence on physical activity is domain-specifıc and context-specifıc. Based on present results, conclusions based on objectively measured environmental variables seem more credible. For children, evidence supports associations of reported physical activity with objective measures of access to recreation facilities, land-use mix, residential density, walkability, walking/biking facilities, traffıc speed/ volume, pedestrian safety structures, incivilities/ disorders, and vegetation. Inconsistent evidence exists for park access and street connectivity. For adolescents, evidence supported the associations of reported PA with objective measures of residential density and land-use mix, and inconsistent evidence existed for parks, recreation facilities, and street connectivity. All reported physical activity measures pertained to a specifıc domain (e.g., transportation) or a specifıc type (e.g., walking). Such domain-specifıc and behaviorspecifıc fındings are well documented among adults, 5,14 so the present review provides evidence that such associations generalize to youth as well. There is suffıcient evidence to recommend policy changes to enhance access to parks and recreation facilities and to encourage mixeduse developments to promote physical activity across a wide age range. Crime and general measures of safety were extensively studied, but there was very limited support for associations with youth physical activity. There are two caveats for this literature. First, one paper 49 contributed a large proportion of results on reported crime-related safety, mostly nonsignifıcant, possibly skewing the results. Second, measures of safety, especially reported measures, were often crude and rarely validated. Studies often did not distinguish crime from traffıc safety, or combined different domains of safety in one scale, which might obscure associations with physical activity. 131 The current review revealed that associations between physical activity and traffıc safety were more consistently supported than those with crime-related safety, suggesting differential effects from different domains of safety. Given high levels of safety concerns among parents as a barrier to youth physical activity, further studies, including more-sophisticated and specifıc measures, are warranted. 11 When both street connectivity and physical activity were measured objectively, there were about as many associations as. This was especially the case for children. This pattern is contrary to that from adult studies, 20,132 in which street connectivity has consistent and positive associations with physical activity. This pattern among youth could be a result of different functions of streets across age groups. For adults, better-connected streets provide more direct routes for active transport. 128,133 For children, however, streets may offer opportunities for both active transport and leisure-time physical activity. Previous studies 74,134 suggested that neighborhoods with low street connectivity had cul-desacs or low-traffıc areas that provided locations for children s safe outdoor play. These possibilities are worthy of more detailed study. Neighborhood Physical Activity Associations: What Are Appropriate Standards? Using an arbitrary criterion adopted by a previous review, 23 it was found that no environmental variable was supported as a consistent correlate of physical activity across all four combinations of measurement modes. Thus, there is no clear conclusion that one or more environmental variables are unambiguously supported as physical activity correlates. This fınding was similar to those from several reviews, 8,16,17 in which very few features of the neighborhood environment were identifıed as consistently being associated with physical activity. The level of consistency of fındings from the present review is lower than that from an earlier review 23 of mainly psychosocial correlates of physical activity that used a similar approach to coding results. However, the previous review did not code every fınding as was done in

10 Table 7. Summary of associations between the neighborhood environment and physical activity among children and adolescents stratified by measurement modes Physical activity measure Objective Objective Result counts (paper counts) Environmental measures % the present review. Given the present inclusion of adjusted and unadjusted tests and multiple outcome measures in multiple subgroups, it is unclear how the consistency of associations should be judged. A more-selective review of studies with the strongest methodology taking a more quantitative meta-analytic approach may be more defınitive. In a recent review of environmental correlates of physical activity among adults, Wendel-Vos et al. 20 found a large proportion of null associations and suggested that studies might have defıned or measured [environmental attributes] in a wrong way. Because the area of the built environment and physical activity is still young, 135 more studies with improved conceptualization and measures are needed to expand the current knowledge base, from which more-consistent and convincing conclusions can be drawn. Recommendation for Future Studies One major area of improvement for future studies is measurement. The current review found that consistency of associations varied greatly by measurement modes. Future studies should include both objective and perceived measures in one study, whenever possible, to compare and contrast the impact of measurement mode, 136 on total and domain-specifıc physical activity. Future studies should also improve perceived measures by using specifıc defınitions and validated instruments. Future papers should provide methodologic details regarding the operationalization of environmental constructs to facilitate the synthesis of fındings. Longitudinal study designs are encouraged to improve the rigor of research. More studies outside the U.S. can help understand generalizability of fındings. Several understudied environmental attributes, such as vegetation, neighborhood incivilities, and pedestrian safety structures are high Perceived Result counts (paper counts) Children 159 (13) (12) 12 Adolescents 107 (8) (3) 12 Reported Children 158 (20) (41) 34 Adolescents 134 (14) (35) 29 %, number of results coded as /total number of results. Ding et al / Am J Prev Med 2011;41(4): priorities for further research. Subgroup-specifıc analyses could help understand for whom built and social environments are most influential. % Strengths The large number of studies and fındings included in this review provided a useful update. Studies were searched systematically from several search engines using a comprehensive list of search terms. Review and data extraction were conducted systematically, and coding was checked by at least two researchers. Results were based on all associations reported in a paper, not selected fındings. Stratifıcations of results by age and by mode of measurement were informative. Limitations First, the present review considered only the signifıcance and direction of each association, not effect size. Therefore, no comparison could be made about the magnitude of associations across variables or measurement modes. Second, although expert-validated protocols were used to classify environmental variables, some variables could not be precisely classifıed because of lack of information. Third, this review employed a vote count review method, which disregarded sample size and gave results from the same study and those from different studies the same weight. Therefore, conclusions may be heavily influenced by a large number of studies with small sample sizes or a few studies that reported many results. 137 Fourth, some individual fındings could be considered over-adjusted because variables in the causal pathways (e.g., other built environment variables) were controlled for, possibly leading to fewer signifıcant fındings. Fifth, environment physical activity associations may vary by subgroup. However, because of a small number of gender- or location-specifıc studies, no subgroup-specifıc summaries could be reported. Finally, the current analyses did not formally stratify counts by types or domains of reported physical activity measures. This was because the review aimed to summarize overall associations of neighborhood environment with physical activity, instead of with a specifıc type of physical activity. Acknowledging that the environment October 2011

11 452 Ding et al / Am J Prev Med 2011;41(4): physical activity associations are context- and domainspecifıc, 129 only specifıc types or domains of physical activity outcomes that were conceptually matched with the environmental variables were selected. The domainspecifıcity of associations is not always clear, because at least one study 35 found that proximity to recreation facilities was related to active transport because children could walk or bike to a park to do recreational physical activity. Variables like crime, traffıc safety, and sidewalks are expected to be relevant for more than one physical activity domain. Conclusion The best use of the present review may be to identify the neighborhood environmental attributes that are most strongly supported, because such fındings can inform environment and policy change priorities being pursued for chronic disease prevention. More confıdence can be placed in studies in which environmental variables were measured objectively. The most supported correlates for children were traffıc speed/ volume, access/proximity to recreation facilities, mixed land use, residential density, and walkability. The most supported correlates for adolescents were land-use mix and residential density. Because these associations have been supported for both youth and adults, there is growing empirical support for policies that target these environmental conditions Policies to enhance access to parks could include development regulations for new or redeveloped neighborhoods, joint use agreements that lead to schools opening their facilities for community use, and incentives for private recreation facilities to locate in underserved neighborhoods. Zoning reform is needed in many cities to allow or require mixed-use development as the default. New road design standards and complete streets policies would need to be adopted to create roadways that are more pedestrian-friendly and safer automobile traffıc patterns. Present results provide additional evidence that generally supports childhood physical activity promotion and obesity prevention policy recommendations from the IOM, 138 The U.S. Surgeon General, 139 The White House Task Force on Childhood Obesity Prevention, 140 and the U.S. National Physical Activity Plan. 141 This study was funded by Active Living Research, a national program of the Robert Wood Johnson Foundation. The authors thank all graduate assistants who contributed to the Active Living Research Literature Database: Holly Forman, Ashley Withers, Anna Stachel, Jordan Carlson, Erin Merz, Courtney Corle, and Kalisha McIntosh. Special thanks to Carmen Cutter, Deputy Director of Active Living Research. No fınancial disclosures were reported by the authors of this paper. References 1. Salmon J, Timperio A. Prevalence, trends and environmental influences on child and youth physical activity. Med Sport Sci 2007; 50: Strong WB, Malina RM, Blimkie CJ, et al. Evidence based physical activity for school-age youth. J Pediatr 2005;146(6): Troiano RP, Berrigan D, Dodd KW, Masse LC, Tilert T, McDowell M. Physical activity in the U.S. measured by accelerometer. Med Sci Sports Exerc 2008;40(1): Sallis JF, Cervero RB, Ascher W, Henderson KA, Kraft MK, Kerr J. An ecological approach to creating active living communities. Annu Rev Public Health 2006;27: Sallis JF, Adams MA, Ding D. Physical activity and the built environment. In: Cawley J, ed. The Oxford handbook of the social science of obesity. Oxford, UK: Oxford University Press, Sallis JF, Glanz K. Physical activity and food environments: solutions to the obesity epidemic. Milbank Q 2009;87(1): Sallis JF, Kerr J. Physical activity and the built environment. President s Council on Physical Fitness and Sports. Res Digest 2006; 7(4): de Vet E, de Ridder DT, de Wit JB. Environmental correlates of physical activity and dietary behaviours among young people: a systematic review of reviews. Obes Rev 2011;12(5):e Davison KK, Lawson CT. Do attributes in the physical environment influence children s physical activity? A review of the literature. Int J Behav Nutr Phys Act 2006;3: McMillan TE. Urban form and a child s trip to school: the current literature and a framework for future research. J Plann Lit 2005; 19(4): Ding D, Bracy N, Sallis JF, et al. Is fear of strangers related to physical activity among youth? Am J Health Promot:In press. 12. Panter JR, Jones AP, van Sluijs EM. Environmental determinants of active travel in youth: a review and framework for future research. Int J Behav Nutr Phys Act 2008;5: Transportation Research Board and IOM. Does the built environment influence physical activity? Examining the evidence. Washington DC: Transportation Research Board, Gebel K, Bauman AE, Petticrew M. The physical environment and physical activity: a critical appraisal of review articles. Am J Prev Med 2007;32(5): Hanson MD, Chen E. Socioeconomic status and health behaviors in adolescence: a review of the literature. J Behav Med 2007;30(3): Ferreira I, van der Horst K, Wendel-Vos W, Kremers S, van Lenthe FJ, Brug J. Environmental correlates of physical activity in youth a review and update. Obes Rev 2007;8(2): Pont K, Ziviani J, Wadley D, Bennett S, Abbott R. Environmental correlates of children s active transportation: a systematic literature review. Health Place 2009;15(3): Davison KK, Werder JL, Lawson CT. Children s active commuting to school: current knowledge and future directions. Prev Chronic Dis 2008;5(3):A Ridgers ND, Stratton G, Fairclough SJ. Physical activity levels of children during school playtime. Sports Med 2006;36(4): Wendel-Vos W, Droomers M, Kremers S, Brug J, van Lenthe F. Potential environmental determinants of physical activity in adults: a systematic review. Obes Rev 2007;8(5):

12 Ding et al / Am J Prev Med 2011;41(4): Feng J, Glass TA, Curriero FC, Stewart WF, Schwartz BS. The built environment and obesity: a systematic review of the epidemiologic evidence. Health Place 2010;16(2): Brownson RC, Hoehner CM, Day K, Forsyth A, Sallis JF. Measuring the built environment for physical activity state of the science. Am J Prev Med 2009;36(4S):S e Sallis JF, Prochaska JJ, Taylor WC. A review of correlates of physical activity of children and adolescents. Med Sci Sports Exerc 2000;32(5): Adkins S, Sherwood NE, Story M, Davis M. Physical activity among African-American girls: the role of parents and the home environment. Obes Res 2004;12(S):38S 45S. 25. Gómez JE, Johnson BA, Selva M, Sallis JF. Violent crime and outdoor physical activity among inner-city youth. Prev Med 2004;39(5): Jago R, Baranowski T, Zakeri I, Harris M. Observed environmental features and the physical activity of adolescent males. Am J Prev Med 2005;29(2): Romero AJ. Low-income neighborhood barriers and resources for adolescents physical activity. J Adolesc Health 2005;36(3): Jago R, Baranowski T, Baranowski JC. Observed, GIS, and self-reported environmental features and adolescent physical activity. Am J Health Promot 2006;20(6): Trost SG, Pate RR, Ward DS, Saunders R, Riner W. Determinants of physical activity in active and low-active, sixth grade African-American youth. J Sch Health 1999;69(1): Epstein LH, Raja S, Gold SS, Paluch RA, Pak Y, Roemmich JN. Reducing sedentary behavior: the relationship between park area and the physical activity of youth. Psychol Sci 2006;17(8): Roemmich JN, Epstein LH, Raja S, Yin L, Robinson J, Winiewicz D. Association of access to parks and recreational facilities with the physical activity of young children. Prev Med 2006;43: Jago R, Baranowski T, Harris M. Relationships between GIS environmental features and adolescent male physical activity: GIS coding differences. J Phys Act Health 2006;3(2): Roemmich JN, Epstein LH, Raja S, Yin L. The neighborhood and home environments: disparate relationships with physical activity and sedentary behaviors in youth. Ann Behav Med 2007;33(1): Davison KK. School performance, lack of facilities, and safety concerns: barriers to parents support of their children s physical activity. Am J Health Promot 2009;23(5): Grow HM, Saelens BE, Kerr J, Durant NH, Norman GJ, Sallis JF. Where are youth active? Roles of proximity, active transport, and built environment. Med Sci Sports Exerc 2008;40(12): Durant N, Harris SK, Doyle S, et al. Relation of school environment and policy to adolescent physical activity. J Sch Health 2009; 79(4): Wenthe PJ, Janz KF, Levy SM. Gender similarities and differences in factors associated with adolescent moderate-vigorous physical activity. Pediatr Exerc Sci 2009;21(3): Cradock AL, Melly SJ, Allen JG, Morris JS, Gortmaker SL. Youth destinations associated with objective measures of physical activity in adolescents. J Adolesc Health 2009;45(3S):S Kligerman M, Sallis JF, Ryan S, Frank LD, Nader PR. Association of neighborhood design and recreation environment variables with physical activity and body mass index in adolescents. Am J Health Promot 2007;21: Oreskovic NM, Sawicki GS, Kinane TB, Winickoff JP, Perrin JM. Travel patterns to school among children with asthma. Clin Pediatr 2009;48(6): Ziviani J, Scott J, Wadley D. Walking to school: incidental physical activity in the daily occupations of Australian children. Occup Ther Int 2004;11(1): Hume C, Salmon J, Ball K. Children s perceptions of their home and neighborhood environments, and their association with objectively measured physical activity: a qualitative and quantitative study. Health Educ Res 2005;20(1): Kuo J, Voorhees CC, Haythornthwaite JA, Young DR. Associations between family support, family intimacy, and neighborhood violence and physical activity in urban adolescent girls. Am J Public Health 2007;97(1): Mota J, Ribeiro JC, Santos MP. Obese girls differences in neighbourhood perceptions, screen time and socioeconomic status according to level of physical activity. Health Educ Res 2009;24(1): Holt NL, Spence JC, Sehn ZL, Cutumisu N. Neighborhood and developmental differences in children s perceptions of opportunities for play and physical activity. Health Place 2008;14(1): Alton D, Adab P, Roberts L, Barrett T. Relationship between walking levels and perceptions of the local neighbourhood environment. Arch Dis Child 2007;92(1): Barnett TA, O Loughlin J, Gauvin L, Paradis G, Hanley J. Opportunities for student physical activity in elementary schools: a cross-sectional survey of frequency and correlates. Health Educ Behav 2006;33(2): Brown WH, Pfeiffer KA, McIver KL, Dowda M, Addy CL, Pate RR. Social and environmental factors associated with preschoolers nonsedentary physical activity. Child Dev 2009;80(1): Carver A, Salmon J, Campbell K, Baur L, Garnett S, Crawford D. How do perceptions of local neighborhood relate to adolescents walking and cycling? Am J Health Promot 2005;20(2): de Vries SI, Bakker I, van Mechelen W, Hopman-Rock M. Determinants of activity-friendly neighborhoods for children: results from the SPACE study. Am J Health Promot 2007;21(4S): Dowda M, Brown WH, McIver KL, et al. Policies and characteristics of the preschool environment and physical activity of young children. Pediatrics 2009;123(2): Evenson KR, Birnbaum AS, Bedimo-Rung AL, et al. Girls perception of physical environmental factors and transportation: reliability and association with physical activity and active transport to school. Int J Behav Nutr Phys Act 2006;3:28. doi: / Forman H, Kerr J, Norman GJ, et al. Reliability and validity of destination-specifıc barriers to walking and cycling for youth. Prev Med 2008;46(4): Hume C, Salmon J, Ball K. Associations of children s perceived neighborhood environments with walking and physical activity. Am J Health Promot 2007;21(3): Hume C, Timperio A, Salmon J, Carver A, Giles-Corti B, Crawford D. Walking and cycling to school: predictors of increases among children and adolescents. Am J Prev Med 2009;36(3): Johansson M. Environment and parental factors as determinants of mode for children s leisure travel. J Environ Psychol 2006; 26(2): Kerr J, Rosenberg D, Sallis JF, Saelens BE, Frank LD, Conway TL. Active commuting to school: associations with environment and parental concerns. Med Sci Sports Exerc 2006;38(4): Loucaides CA, Chedzoy S, Bennett N, Walshe K. Correlates of physical activity in a Cypriot sample of sixth-grade children. Pediatr Exerc Sci 2004;16(1): Mota J, Almeida M, Santos R, Ribeiro JC, Santos MP. Association of perceived environmental characteristics and participation in organized and non-organized physical activities of adolescents. Pediatr Exerc Sci 2009;21(2): Pfeiffer KA, Dowda M, McIver KL, Pate RR. Factors related to objectively measured physical activity in preschool children. Pediatr Exerc Sci 2009;21(2): Ries AV, Voorhees CC, Roche KM, Gittelsohn J, Yan AF, Astone NM. A quantitative examination of park characteristics related to park use and physical activity among urban youth. J Adolesc Health 2009;45(3S):S October 2011