The World Health Organization (WHO) recommends that children and adolescents should accumulate at least 60 minutes of moderate-to-vigorous-intensity physical activity (MVPA) daily.1 Engaging in regular physical activity offers substantial numerous short- and long-term health benefits to children and adolescents,2-4 including improving muscular fitness and helping to build strong bones (thereby enhancing their body composition),1,4 and improving their cardiorespiratory fitness, metabolic health, mental health, cognition and psychosocial well-being.5-10 Physical activity also reduces adiposity and stress levels in children and adolescents.11,12 Physically active children and adolescents are more likely to become physically active adults,13 which underscores the importance of physical activity during childhood and adolescence.11 Physical activity is an effective measure for preventing diseases in children and adolescents across all ethnic and socioeconomic subgroups.3 Despite the benefits accrued from being physically active, MVPA levels among children and adolescents globally are typically lower than recommended. Existing evidence from a worldwide study indicates that MVPA begins to decline from approximately five years of age in children,14 and as few as 20% of adolescents appear to meet the MVPA recommendation.14-16
The role of the built environment in physical activity in children and adolescents
The built environment refers to the surroundings created by humans and used for human activity.17 It has the potential to change the physical activity levels of a larger population of children and adolescents compared to behavioral interventions that are usually aimed at a smaller portion of a population.18 Thus, it is identified as an important driver of children's and adolescents’ physical activity levels.19,20 Built environment constructs, such as availability of and access to parks, higher street connectivity, lower levels of crime and the esthetic qualities of neighborhoods, have been positively associated with physical activity levels in children and adolescents.21-23 Parks have consistently shown significant positive associations with children's and adolescents’ engagement in physical activities. When in close proximity to the home, parks are destinations that can be reached by active travel.18
Four previous systematic reviews have assessed the association between the built environment and physical activity in children and adolescents, but these reviews have included studies conducted in high-income countries.2,20,24,25 These reviews indicate that there are variations in this association between children and adolescents. For example, the reviews demonstrate that some of the built environment constructs, such as recreation facilities, land use mix and residential density, show consistent positive associations with physical activity in adolescents but such consistency is not observed in children. A plausible explanation for the association seen in children is parental concerns about safety, which may deter parents from allowing children to play outside or actively commute even in walkable environments.20 Understanding the influence of the built environment on physical activity among children and adolescents is especially important because they have less autonomy in their behaviors and are more likely than adults to be influenced by the built environment.2,24
The situation in Africa
A comparative analysis of physical activity levels in adolescents across 16 African countries using the global school-based student health survey revealed that only about 15% of adolescents in Africa met the recommended level.26 Cross-national variations do exist between the countries—Beninese and Tanzanian adolescents were the most physically active (25.6% and 23.1%, respectively), while Sudanese and Zambians were the least physically active (8.2% and 9.7%, respectively). The possible reasons for such country differences could be urbanization, as Sudan and Zambia have a higher gross national income than Tanzania and Benin.27,28 Given the rapid urbanization occurring across Africa, physical inactivity in children and adolescents is likely to increase.29 Addressing these low physical activity levels in an increasingly urbanized world presents opportunities to encourage the key foundations of habitual physical activity, such as walking, cycling and active play in children and adolescents.30
Most of the nations in Africa are low- and middle-income countries. These nations have specific built environment features that are different from those in high-income countries, including diverse terrains, land use, infrastructures, transportation and road designs.31 It appears that urban development in Africa has often resulted in the propagation of fewer and less conducive spaces for outdoor physical activity.32 While urbanization and shaping of the built environment have provided a number of socioeconomic benefits, they have also brought negative health consequences, particularly non-communicable diseases (NCDs).33,34 Children and adolescents can be heavily affected by NCDs. For example, 1.2 million people under 20 years of age died of NCDs in 2002. Also, more than 25% of obese adolescents have signs of type 2 diabetes by 15 years of age.35 In terms of health promotion and combating NCDs globally, children and adolescents from Africa are important targets because over 360 million Africans are between 5 and 19 years of age.36 Promoting physical activity is a public health priority included in the global action plan for the prevention and control of NCDs 2013–2020.37
Rationale for a systematic review
A number of studies have been conducted in Africa to assess the association between the built environment and physical activity in children and adolescents.22,31,38-40 Findings from these studies reveal the following: physical activity in children and adolescents is associated with residential density, street connectivity and traffic safety; the association differs by gender and socioeconomic status; and parents’ perception of the built environment is associated with children's physical activity levels. A search in MEDLINE, Embase, JBI Database of Systematic Reviews and Implementation Reports and the Cochrane Library in August 2019 did not identify any systematic reviews or protocols on this topic.
The aim of the proposed systematic review is to summarize the following: the built environment constructs that are associated with physical activity in children and adolescents in Africa; the gender and socioeconomic differences in this association; and parental influences on this association. This systematic review will help policymakers and health professionals to take necessary actions in improving inter-sectoral policies by identifying the built environment constructs that are associated with physical activity in children and adolescents. Evidence can be presented to transportation officials, city planners and other key stakeholders on the built environment constructs that should be invested in to facilitate habitual physical activity, thereby promoting and protecting health.
What is the association between the built environment and physical activity in children and adolescents in Africa?
This review will consider studies conducted among children and adolescents (between five and 19 years of age) residing in African countries, or among people who have responsibility for these children and adolescents (such as their parents, guardians or teachers). Any setting, such as communities and schools, will be eligible. Five years of age is the lower limit because evidence suggests that MVPA begins to decline from approximately five years of age in children,14 and 19 years of age is the upper limit because it is consistent with the WHO's cut-off for adolescence.41 If a study includes children, adolescents and adults, the study will be included if the mean age of the study participants is ≤ 19 years. Also, if the study findings are stratified by age, the association between the built environment and physical activity in children and adolescents will be extracted. If it is not possible to extract these findings, the study will be excluded.
Studies will be excluded if they are conducted in children younger than five years or in adults 20 years and over, or are conducted outside of Africa.
The built environment includes variables such as, but not limited to, walkability, playground, traffic safety, residential density, land use mix, green spaces and crime-related safety.
This review will consider studies that report outcomes on physical activity in children and adolescents, measured either subjectively (reported) among them or by their parents, teachers or guardians who have responsibility for them, or objectively among children and adolescents using accelerometers or pedometers.
Types of studies
This review will consider experimental, quasi-experimental and analytical observational study designs such as randomized controlled trials, non-randomized controlled trials, prospective and retrospective cohort studies, case-control studies and analytical cross-sectional studies.
Studies published in any language will be considered, and translations will be sought where necessary. Studies published from database inception to present will be considered.
The proposed systematic review will adhere to the preferred reporting items for systematic reviews and meta-analyses (PRISMA)42 and JBI systematic review of association methodology guidelines.43-45
The search strategy will aim to locate both published and unpublished studies. An initial limited search was carried out in MEDLINE to identify relevant articles. The text words contained in the titles and abstracts of relevant articles, and the index terms used to describe the articles, were used to develop a full search strategy for MEDLINE (see Appendix I). The search strategy will be adapted for each included data source in consultation with an information specialist/librarian. The reference lists of all studies selected for inclusion and all relevant systematic reviews will be screened for additional studies.
The following databases will be searched for published studies: MEDLINE, Embase, CINAHL, Web of Science, PsycINFO, Scopus, SPORTDiscus (EBSCO). No lower date limit will be imposed. The following sources will be searched for unpublished studies: WHOLIS, EThOS, OpenGrey and ProQuest Dissertations and Theses.
Following the search, all identified citations will be collated and uploaded into EndNote X8.2 (Clarivate Analytics, PA, USA) and duplicates will be removed. Two reviewers will independently screen titles and abstracts for eligibility against the inclusion criteria. Studies identified as potentially eligible or those without an abstract will be retrieved in full and their citation details will be imported into the JBI System for the Unified Management, Assessment and Review of Information (JBI SUMARI; JBI, Adelaide, Australia). Two reviewers will independently assess in detail the full text of these studies against the inclusion criteria. Full-text studies that do not meet the inclusion criteria will be excluded, and the reasons for their exclusion will be reported. Any disagreements that arise between the two reviewers at each stage of the study selection process will be resolved through discussion or with a third reviewer if a consensus is not reached.
Assessment of methodological quality
Eligible studies will be critically appraised by two independent reviewers using the standardized critical appraisal tools incorporated within JBI SUMARI, as appropriate to the study designs.44,45 Any disagreements that arise will be resolved through discussion, or with a third reviewer if consensus is not reached. The results of the critical appraisal will be reported in a table (separately for each study design) and in narrative form. All studies, regardless of the results of their methodological quality, will undergo data extraction and synthesis (where possible).
Two independent reviewers will extract data from studies included in the review using the standardized data extraction tool incorporated within JBI SUMARI.44 In the first phase of data extraction, the following specific information regarding the study characteristics will be extracted: study period, study design, location, population characteristics (including age and gender), inclusion and exclusion criteria, sample size, recruitment method, data collection procedure and tool, data analysis technique and authors’ conclusions. In the second phase of data extraction, the following specific study findings will be extracted: association between the built environment constructs and physical activity. Any disagreement that arises between the reviewers will be resolved through discussion or with a third reviewer if consensus is not reached. Where data are missing or insufficient, the corresponding author of the paper will be contacted up to two times via email.
A narrative synthesis approach will initially be used to look systematically at the data. Depending on the type of data, effect sizes will be expressed as either odd ratios (for dichotomous data) or weighted (standardized) mean differences (for continuous data) and their 95% confidence intervals (CIs) will be calculated for analysis. Adjusted estimates will be used in preference to crude estimates. Where only raw data are presented, these will be used to estimate odd ratios for all study designs. Odd ratios and risk ratios will be pooled together and reported as pooled relative risks with 95% CI, using random-effects meta-analysis models. Studies which report other measures of effect for binary outcomes, for example hazard ratios or incidence rate ratios, will not be pooled with other measures of effect. Separate meta-analyses will be conducted for each built environment variable which assesses a different construct (e.g. walkability, residential density, land use mix, traffic safety).
Heterogeneity will be assessed by the I2 test. If data permit, reasons for heterogeneity will be explored using subgroup analyses based on age (children versus adolescents), gender, the ascertainment of physical activity (subjective versus objective), adjustment for confounders (adjusted versus crude estimates) and the built environment variables used in the study (e.g. walkability, residential density, land use mix, traffic safety). Also, where data permit, sensitivity analyses will be conducted by excluding studies of poor methodological quality to assess the robustness of the conclusions. Statistical analysis will be performed using JBI SUMARI and STATA v.16 (Stata Corp LLC, Texas, USA). Where statistical pooling is not possible, the findings will be presented in a narrative form, including tables to aid in data presentation.
A funnel plot will be generated to assess publication bias where there are at least 10 studies in a meta-analysis.
Assessing certainty in the findings
The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach for grading the quality of evidence will be used to determine the strength of evidence for each finding related to the categorization of built environment constructs.46,47
Findings will be initially ranked as low and will be downgraded to very low if there is evidence of any of the following: risk of bias, imprecision, inconsistency of evidence, indirectness, or publication bias. Findings will be upgraded based on the magnitude of association, evidence of a dose-response relationship, and where all plausible residual confounders or biases would reduce the demonstrated effect or suggest a spurious effect when the results shows no effect.
A Summary of Findings will be created using GRADEPro GDT (McMaster University, ON, Canada). The Summary of Findings will present physical activity as the outcome and the following: magnitude of the effect, number of participants and studies, quality of the evidence and reasons behind decisions made.
Three reviewers will be involved in this process.
Elizabeth Doney, senior research librarian at the University of Nottingham (UK), for her contribution to the search strategy.
BA is a PhD student, funded by the University of Nottingham Vice Chancellor Scholarship for Research Excellence. This systematic review is part of her PhD project.
Appendix I: Search strategy for Ovid MEDLINE
1. exp Physical Fitness/
2. exp Running/
3. exp Walking/
4. exp Exercise/
5. exp Gardening/
6. exp Sports/
7. exp “Sports and Recreational Facilities”/
8. exp Dancing/
9. exp “Physical Education and Training”/
10. exp Motor Activity/
11. exp Yoga/
12. exp Fitness Centers/
13. exp “play and playthings”/
14. exp Recreation/
15. exp Sedentary Behavior/
16. (physical adj5 (fit* or train* or activit* or inactivit* or endur* or exercis*)).mp.
17. ((leisure or fitness) adj5 (centre* or center* or facilit*)).mp.
18. (swim*1 or swimming).mp.
19. (exercis*3 adj5 aerobic).mp.
20. (active adj (travel*4 or transport* or commut*)).mp.
21. (exercise* or sport* or sedentariness).mp.
22. (sedentary adj (lifestyle or behavio$r)).mp.
23. (“use” adj3 stair*).ti,ab.
25. exp Child/
26. exp Adolescent/
27. exp Students/
28. exp Pupil/
29. exp Youth Sports/
30. exp Minors/
31. (boy or boys or boyhood).mp.
33. (child* or adolescen* or student* or minor* or kid* or teen* or preteen* or youth* or young* or juvenil*).mp.
35. exp Environment/
36. exp Built Environment/
37. exp Environment Design/
39. exp Residence Characteristics/
41. exp Crime/
42. street connectivity.mp.
43. exp Parks, Recreational/
44. exp Public Facilities/
45. exp Bicycling/
46. exp Social Environment/
47. exp “Conservation of Natural Resources”/
48. exp City Planning/
51. exp Urban Health/
52. exp Cities/
53. (neighbourhood* or neighborhood*).ti,ab.
60. land us*.ti,ab.
61. (aesthetic* or esthetic*).ti,ab.
62. (pavement* or sidewalk*).ti,ab.
66. (city or cities).mp.
67. (park or parks or parkland or parklands).mp.
68. playing field*.mp.
69. open space*.mp.
72. motor vehicle*.mp.
74. Automobile Driving/
77. (motoring or motorist*1).ti,ab.
78. road us*.ti,ab.
82. (speed hump*1 or speed bump*1).ti,ab.
85. exp Africa/
86. exp Africa, Central/
87. exp Africa, Eastern/
88. exp Africa, Northern/
89. exp “Africa South of the Sahara”/
90. exp Africa, Southern/
91. exp Africa, Western/
92. exp South Africa/
93. sub-saharan africa.mp.
94. (Algeria or Angola or Benin or Botswana or Burkina Faso or Burkina Fasso or Upper Volta or Burundi or Urundi or Cameroon or Cameroons or Cameron or Camerons or Cabo Verde or Central African Republic or Chad or Comoros or Comoro Islands or Comores or Mayotte or Congo or Zaire or Cote d’Ivoire or Ivory Coast or Djibouti or Egypt or United Arab Republic or Equatorial Guinea or Eritrea or Ethiopia or Gabon or Gabonese Republic or Gambia or Ghana or Guinea or Guinea-Bissau or Kenya or Liberia or Madagascar or Malawi or Nyasaland or Mali or Mauritania or Mauritius or Agalega Islands or Morocco or Ifni or Mozambique or Namibia or Niger or Nigeria or Rwanda or Ruanda or Sao Tome or Seychelles or Sierra Leone or Somalia or South Africa or Sudan or Swaziland or Tanzania or Togo or Togolese Republic or Tunisia or Uganda or Zambia or Zimbabwe or Rhodesia).hw,kf,ti,ab,cp.
96. 24 and 34 and 83 and 95
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