Evaluating health effects of transport interventions methodologic case study

Interventions to promote walking: systematic review

OBJECTIVE

To assess the effects of interventions to promote walking in individuals and populations.

DESIGN

Systematic review.

DATA SOURCES

Published and unpublished reports in any language identified by searching 25 electronic databases, by searching websites, reference lists, and existing systematic reviews, and by contacting experts.

REVIEW METHODS

Systematic search for and appraisal of controlled before and after studies of the effects of any type of intervention on how much people walk, the distribution of effects on walking between social groups, and any associated effects on overall physical activity, fitness, risk factors for disease, health, and wellbeing.

RESULTS

We included 19 randomised controlled trials and 29 non-randomised controlled studies. Interventions tailored to people's needs, targeted at the most sedentary or at those most motivated to change, and delivered either at the level of the individual (brief advice, supported use of pedometers, telecommunications) or household (individualised marketing) or through groups, can encourage people to walk more, although the sustainability, generalisability, and clinical benefits of many of these approaches are uncertain. Evidence for the effectiveness of interventions applied to workplaces, schools, communities, or areas typically depends on isolated studies or subgroup analysis.

CONCLUSIONS

The most successful interventions could increase walking among targeted participants by up to 30-60 minutes a week on average, at least in the short term. From a perspective of improving population health, much of the research currently provides evidence of efficacy rather than effectiveness. Nevertheless, interventions to promote walking could contribute substantially towards increasing the activity levels of the most sedentary.

The physical environment and physical activity: a critical appraisal of review articles

BACKGROUND

Over the last few years an increasing number of studies investigating the association between the physical environment and physical activity have been published. Many reviews have also summarized this emerging body of research, and such review papers are frequently used by public health policymakers and researchers themselves to inform decision making.

METHODS

This paper systematically appraises methodologic aspects of literature reviews examining the relationship between physical activity and the physical environment published in peer-reviewed journals between 2000 and 2005. Eleven reviews and their antecedent source papers were examined.

RESULTS

The majority of these reviews omitted between one third and two thirds of the studies that could have been eligible for inclusion at the time they conducted the review. Methodologic information on how the review was conducted was not always provided. Furthermore, in some cases results of a study were reported incorrectly, or physical environmental aspects were conflated with social environmental or cognitive factors. Moreover, when results were reported incorrectly, physical environmental variables were almost always reported as significantly associated with physical activity, when these associations were nonsignificant, or were not assessed as part of the primary study.

CONCLUSIONS

Users of reviews in this field should be aware that there are significant methodologic variations among them, and that some reviews may include only a sample of the relevant primary studies. However, this is difficult to determine given the frequent incompleteness of review method reporting. Greater standardization in the reporting of review methods may assist with future efforts to summarize studies of the relationship between physical environments and physical activity.