Improving Current Practice in Reviews of the Built Environment and Physical Activity
Klaus Gebel
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Ding Ding
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Charlie Foster
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Adrian E. Bauman
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James F. Sallis
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C. Foster British Heart Foundation Health Promotion Research Group, Department of Public Health, University of Oxford
,
Oxford, UK
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K. Gebel D. Ding A. E. Bauman Prevention Research Collaboration, Sydney School of Public Health, University of Sydney
,
Sydney, NSW, Australia
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K. Gebel (&) Centre for Chronic Disease Prevention, College of Public Health, Medical and Veterinary Sciences, James Cook University
, Cairns,
QLD, Australia
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J. F. Sallis Active Living Research, Department of Family and Preventive Medicine, University of California San Diego
,
La Jolla, CA, USA
Over the last decade, there has been a marked increase in studies about built environments and physical activity. As the number of publications is growing rapidly, literature reviews play an important role in identifying primary studies and in synthesizing their findings. However, many of the reviews of effectiveness in this field demonstrate methodological limitations that might lead to inaccurate portrayals of the evidence. Some literature reviews a priori excluded intervention studies even though they provide the strongest level of evidence. The label 'systematic review' has mostly been used inappropriately. One of the major criteria of a systematic review that is hardly ever met is that the quality of the primary studies needs to be assessed and this should be reflected in the synthesis, presentation and interpretation of results. With few exceptions, 'systematic' reviews about environments and physical activity did not refer to or follow the QUORUM or PRISMA statements. This commentary points out the usefulness of the PRISMA statement to standardize the reporting of methodology of reviews and provides additional guidance to limit sources of bias in them. The findings and recommendations from this article can help in moving forward the synthesis of evidence of effectiveness not only in built environments and physical activity, but also more broadly in exercise science and public health.
1 Introduction
Over the last decade there has been a marked increase in
publications about built environments and physical activity
[1]. There has also been a substantial policy response with
governmental and non-governmental agencies
recommending environmental strategies to counter the epidemics
of low physical activity, sedentariness and obesity while
addressing common cross-sectoral goals including traffic
congestion and safety, air pollution and climate change
[25]. As the number of publications in this field is
growing rapidly, it is becoming increasingly challenging for
researchers and policy makers to keep track of the evidence
base. Literature reviews play an important role in identifying
primary studies and in summarizing and synthesizing their
findings. Moreover, the rapidly growing evidence base
requires that reviews be regularly updated [6].
Just as the quality of primary studies can vary, the
methodological quality of review articles can vary
substantially and affect their conclusions [7, 8]. A 2007 article
critically appraised methodological aspects of literature
reviews about built environments and physical activity.
The main findings were that reviews inappropriately
claimed to be systematic, did not provide important
methodological information, omitted large numbers of
relevant studies, and reported some study results
incorrectly [9]. Since then, hundreds of primary studies and
dozens of literature reviews about environments and
physical activity have been published [1016]. Many of the
new literature reviews continue to demonstrate
methodological limitations that might lead to an inaccurate
summary of the evidence. This commentary re-emphasizes the
importance of methodological rigor in literature reviews of
effectiveness by (i) describing common problems in recent
literature reviews, and (ii) providing guidance for future
reviews on environments and physical activity.
2 Strength of Evidence
It is increasingly accepted that reviews of the effectiveness
of public health interventions should start with a
categorization of the evidence, ranking studies based on the
strength of the evidence, starting with the strongest
research designs and studies that minimized selection,
measurement and confounding bias [17]. So far, only a few
studies on the health effects of built environments managed
to randomly assign individuals [1820] or settings [21]. As
randomization is virtually impossible to achieve in this
research field, there have been calls for more opportunistic
evaluations of environmental interventions [22, 23]. In a
framework for evidence-based public health regarding built
environments and physical activity, controlled prospective
evaluations of environmental interventions and evaluations
of peoples activity level before and after they relocate
between neighborhoods of different urban forms provide
the highest level of evid (...truncated)