Evaluating health effects of transport interventions methodologic case study

TRIPLE C reporting principles for case study evaluations of the role of context in complex interventions

BACKGROUND

Guidance and reporting principles such as CONSORT (for randomised trials) and PRISMA (for systematic reviews) have greatly improved the reporting, discoverability, transparency and consistency of published research. We sought to develop similar guidance for case study evaluations undertaken to explore the influence of context on the processes and outcomes of complex interventions.

METHODS

A range of experts were recruited to an online Delphi panel, sampling for maximum diversity in disciplines (e.g. public health, health services research, organisational studies), settings (e.g. country), and sectors (e.g. academic, policy, third sector). To inform panel deliberations, we prepared background materials based on: [a] a systematic meta-narrative review of empirical and methodological literatures on case study, context and complex interventions; [b] the collective experience of a network of health systems and public health researchers; and [c] the established RAMESES II standards (which cover one kind of case study). We developed a list of topics and issues based on these sources and encouraged panel members to provide free text comments. Their feedback informed development of a set of items in the form of questions for potential inclusion in the reporting principles. We circulated these by email, asking panel members to rank each potential item twice (for relevance and validity) on a 7-point Likert scale. This sequence was repeated twice.

RESULTS

We recruited 51 panel members from 50 organisations across 12 countries, who brought experience of a range of case study research methods and applications. 26 completed all three Delphi rounds, reaching over 80% consensus on 16 items covering title, abstract, definitions of terms, philosophical assumptions, research question(s), rationale, how context and complexity relates to the intervention, ethical approval, empirical methods, findings, use of theory, generalisability and transferability, researcher perspective and influence, conclusions and recommendations, and funding and conflicts of interest.

CONCLUSION

The 'Triple C' (Case study, Context, Complex interventions) reporting principles recognise that case studies are undertaken in different ways for different purposes and based on different philosophical assumptions. They are designed to be enabling rather than prescriptive, and to make case study evaluation reporting on context and complex health interventions more comprehensive, accessible and useable.

Impacts of a New Supermarket on Dietary Behavior and the Local Foodscape in Kisumu, Kenya: Protocol for a Mixed Methods, Natural Experimental Study

Background

Access to healthy food is considered a key determinant of dietary behavior, and there is mixed evidence that living near a supermarket is associated with a healthier diet. In Africa, supermarkets may contribute to the nutrition transition by offering both healthy and unhealthy foods and by replacing traditional food sellers. In Kisumu, Kenya, a planned hypermarket (ie, a supermarket combined with a department store) will form the basis for a natural experimental evaluation.

Objective

The aim of this study is to explore the impacts of a new hypermarket on food shopping practices, dietary behaviors, physical activity patterns, and body composition among local residents and to identify concurrent changes in the local foodscape. We also aim to explore how impacts and associations vary by socioeconomic status.

Methods

We employ a mixed methods, longitudinal study design. Two study areas were defined: the hypermarket intervention area (ie, Kisumu) and a comparison area with no hypermarket (ie, Homabay). The study is comprised of 4 pieces of primary data collection: a quantitative household survey with local residents, a qualitative study consisting of focus group discussions with local residents and semistructured interviews with government and private sector stakeholders, an audit of the local foodscape using on-the-ground data collection, and an intercept survey of shoppers in the hypermarket. Assessments will be undertaken at baseline and approximately 1 year after the hypermarket opens.

Results

Baseline assessments were conducted from March 2019 to June 2019. From a total sampling frame of 400 households, we recruited 376 of these households, giving an overall response rate of 94.0%. The household survey was completed by 516 individuals within these households. Across the two study areas, 8 focus groups and 44 stakeholder interviews were conducted, and 1920 food outlets were geocoded.

Conclusions

This study aims to further the understanding of the relationship between food retail and dietary behaviors in Kenya. Baseline assessments for the study have been completed.

International Registered Report Identifier (IRRID)

DERR1-10.2196/17814

Case study research for better evaluations of complex interventions: rationale and challenges

BACKGROUND

The need for better methods for evaluation in health research has been widely recognised. The 'complexity turn' has drawn attention to the limitations of relying on causal inference from randomised controlled trials alone for understanding whether, and under which conditions, interventions in complex systems improve health services or the public health, and what mechanisms might link interventions and outcomes. We argue that case study research-currently denigrated as poor evidence-is an under-utilised resource for not only providing evidence about context and transferability, but also for helping strengthen causal inferences when pathways between intervention and effects are likely to be non-linear.

MAIN BODY

Case study research, as an overall approach, is based on in-depth explorations of complex phenomena in their natural, or real-life, settings. Empirical case studies typically enable dynamic understanding of complex challenges and provide evidence about causal mechanisms and the necessary and sufficient conditions (contexts) for intervention implementation and effects. This is essential evidence not just for researchers concerned about internal and external validity, but also research users in policy and practice who need to know what the likely effects of complex programmes or interventions will be in their settings. The health sciences have much to learn from scholarship on case study methodology in the social sciences. However, there are multiple challenges in fully exploiting the potential learning from case study research. First are misconceptions that case study research can only provide exploratory or descriptive evidence. Second, there is little consensus about what a case study is, and considerable diversity in how empirical case studies are conducted and reported. Finally, as case study researchers typically (and appropriately) focus on thick description (that captures contextual detail), it can be challenging to identify the key messages related to intervention evaluation from case study reports.

CONCLUSION

Whilst the diversity of published case studies in health services and public health research is rich and productive, we recommend further clarity and specific methodological guidance for those reporting case study research for evaluation audiences.

Towards better evidence-informed global action: lessons learnt from the Lancet series and recent developments in physical activity and public health

In the past few decades, the field of physical activity has grown and evolved in scope, depth, visibility and impact around the world. Global progress has been observed in research and practice in physical activity regarding surveillance, health outcomes, correlates/determinants, interventions, translation and policy. The 2012 and 2016 Lancet series on physical activity provide some of the most comprehensive global analysis on various topics within physical activity. Based on the Lancet series and other key developments in the field, literature searches, and expert group meetings and consultation, we provide a global summary on the progress of, gaps in and future directions for physical activity research in the following areas: (1) surveillance and trends, (2) correlates and determinants, (3) health outcomes and (4) interventions, programmes and policies. Besides lessons learnt within each specific area, several recommendations are shared across areas of research, including improvement in measurement, applying a global perspective with a growing emphasis on low-income and middle-income countries, improving inclusiveness and equity in research, making translation an integral part of research for real-world impact, taking an 'upstream' public health approach, and working across disciplines and sectors to co-design research and co-create solutions. We have summarised lessons learnt and recommendations for future research as 'roadmaps' in progress to encourage moving the field of physical activity towards achieving population-level impact globally.

Effective analysis of a community-based intervention during heat waves to improve knowledge, attitude and practice in a population in Licheng District, Jinan City, China

Background

Intervention strategies that focus on coping with continuous heat wave threats have been implemented in many countries. Despite these efforts, we still lack evidence concerning intervention efficacy. A Heat Wave Intervention Program (HWIP) that impacts knowledge, attitude and practice (KAP) was designed, and its effectiveness during heat waves was evaluated.

Methods

A stratified two-stage probability proportion to size sampling method was employed to analyze an intervention group and a control group. Two cross-sectional surveys, which included questions about heat waves in 2014 and 2015, were analyzed using difference-in-difference (DID) analysis.

Results

Mean KAP scores among participants with different demographic characteristics in the intervention group were higher in 2015 than those in 2014. Further analysis by DID found that implementing interventions was positively associated with knowledge (ß = 0.387, P < 0.001) and attitude (ß = 0.166, P < 0.01).

Conclusion

Intervention measures can significantly promote levels of knowledge and attitude. However, as the practice level, most of the sub-groups showed no significant differences for net values between in the intervention group and control group. A cost-benefit analysis was suggested as future work to check the effectiveness of the program. Therefore, further improvement measures should be targeted towards the populations to enable them to effectively cope with the heat waves.

Local walking and cycling by residents living near urban motorways: cross-sectional analysis

Background

Everyday activities, such as walking or cycling, may be a feasible and practical way to integrate physical activity into everyday life. Walking and cycling for transport or recreation in the area local to a person’s home may have additional benefits. However, urban planning tends to prioritise car use over active modes. We explored the cross-sectional association between living near an urban motorway and local walking and cycling.

Methods

In 2013, residents living in an area (a) near a new urban motorway (M74), (b) near a longstanding urban motorway (M8), or (c) without a motorway, in Glasgow, Scotland, were invited to complete postal surveys assessing local walking and cycling journeys and socio-demographic characteristics. Using adjusted regression models, we assessed the association between motorway proximity and self-reported local walking and cycling, as well as the count of types of destination accessed. We stratified our analyses according to study area.

Results

One thousand three hundred forty-three residents (57% female; mean age: 54 years; SD: 16 years) returned questionnaires. There was no overall association between living near an urban motorway and the likelihood of local walking or cycling, or the number of types of local destination accessed by foot or bicycle.

In stratified analyses, for those living in the area around the new M74 motorway, increasing residential proximity to the motorway was associated with lower likelihood of local recreational walking and cycling (OR 0.63, 95% CI: 0.39 to 1.00) a pattern not found in the area with the longstanding M8 motorway. In the area near the M8 motorway residential proximity was statistically significantly (p = 0.014) associated with a 12% decrease in the number of types of destination accessed, a pattern not found in the M74 study area.

Conclusions

Our findings suggest that associations between living near a motorway and local walking and cycling behaviour may vary by the characteristics of the motorway, and by whether the behaviour is for travel or recreation. The lack of associations seen in the study area with no motorway suggests a threshold effect whereby beyond a certain distance from a motorway, additional distance makes no difference.

The effects of changes to the built environment on the mental health and well-being of adults: Systematic review

There is increasing interest in the influence of place on health, and the need to distinguish between environmental and individual level factors. For environmental-level factors, current evidence tends to show associations through cross-sectional and uncontrolled longitudinal analyses rather than through more robust study designs that can provide stronger causal evidence. We restricted this systematic review to randomised (or cluster) randomised controlled trials and controlled before-and-after studies of changes to the built environment. Date of search was December 2016. We identified 14 studies. No evidence was found of an effect on mental health from 'urban regeneration' and 'improving green infrastructure' studies. Beneficial effects on quality-of-life outcomes from 'improving green infrastructure' were found in two studies. One 'improving green infrastructure' study reported an improvement in social isolation. Risk-of-bias assessment indicated robust data from only four studies. Overall, evidence for the impact of built environment interventions on mental health and quality-of-life is weak. Future research requires more robust study designs and interdisciplinary research involving public health, planning and urban design experts.

Moving from the Trial to the Real World: Improving Medication Adherence Using Insights of Implementation Science

Medication nonadherence is a serious public health concern. Although there are promising interventions that improve medication adherence, most interventions are developed and tested in tightly controlled research environments that are dissimilar from the real-world settings where the majority of patients receive health care. Implementation science methods have the potential to facilitate and accelerate the translation shift from the trial world to the real world. We demonstrate their potential by reviewing published, high-quality medication adherence studies that could potentially be translated into clinical practice yet lack essential implementation science building blocks. We further illustrate this point by describing an adherence study that demonstrates how implementation science creates a junction between research and real-world settings. This article is a call to action for researchers, clinicians, policy makers, pharmaceutical companies, and others involved in the delivery of care to adopt the implementation science paradigm in the scale-up of adherence (research) programs.

Moving to an active lifestyle? A systematic review of the effects of residential relocation on walking, physical activity and travel behaviour

OBJECTIVE

To synthesise the literature on the effects of neighbourhood environmental change through residential relocation on physical activity, walking and travel behaviour.

DESIGN

Systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PROSPERO registration number CRD42017077681).

DATA SOURCES

Electronic databases for peer-reviewed and grey literature were systematically searched to March 2017, followed by forward and backward citation tracking.

ELIGIBILITY CRITERIA

A study was eligible for inclusion if it (1) measured changes in neighbourhood built environment attributes as a result of residential relocation (either prospectively or retrospectively); (2) included a measure of physical activity, walking, cycling or travel modal change as an outcome; (3) was quantitative and (4) included an English abstract or summary.

RESULTS

A total of 23 studies was included in the review. Among the eight retrospective longitudinal studies, there was good evidence for the relationship between relocation and walking (consistency score (CS)>90%). For the 15 prospective longitudinal studies, the evidence for the effects of environmental change/relocation on physical activity or walking was weak to moderate (CS mostly <45%), even weaker for effects on other outcomes, including physical activity, cycling, public transport use and driving. Results from risk of bias analyses support the robustness of the findings.

CONCLUSION

The results are encouraging for the retrospective longitudinal relocation studies, but weaker evidence exists for the methodologically stronger prospective longitudinal relocation studies. The evidence base is currently limited, and continued longitudinal research should extend the plethora of cross-sectional studies to build higher-quality evidence.

What works to promote walking at the population level? A systematic review

OBJECTIVE

Interventions to promote walking have focused on individual or group-based approaches, often via the randomised controlled trial design. Walking can also be promoted using population health approaches. We systematically reviewed the effectiveness of population approaches to promote walking among individuals and populations.

DESIGN

A systematic review.

DATA SOURCES

10 electronic databases searched from January 1990 to March 2017.

ELIGIBILITY CRITERIA

Eligibility criteria include pre-experimental and postexperimental studies of the effects of population interventions to change walking, and the effects must have been compared with a 'no intervention', or comparison group/area/population, or variation in exposure; duration of ≥12 months of follow up; participants in free-living populations; and English-language articles.

RESULTS

12 studies were identified from mostly urban high-income countries (one focusing on using tax, incentivising the loss of parking spaces; and one using policy only, permitting off-leash dogs in city parks). Five studies used mass media with either environment (n=2) or community (n=3) approaches. Four studies used environmental changes that were combined with policies. One study had scaled up school-based approaches to promote safe routes to schools. We found mass media, community initiatives and environmental change approaches increased walking (range from 9 to 75 min/week).

Longitudinal association between change in the neighbourhood built environment and the wellbeing of local residents in deprived areas: an observational study

BACKGROUND

Features of the urban neighbourhood influence the physical, social and mental wellbeing of residents and communities. We explored the longitudinal association between change to the neighbourhood built environment and the wellbeing of local residents in deprived areas of Glasgow, Scotland.

METHODS

A cohort of residents (n = 365; mean age 50 years; 44% male; 4.1% of the 9000 mailed surveys at baseline) responded to a postal survey in 2005 and 2013. Wellbeing was assessed with the mental (MCS-8) and physical (PCS-8) components of the SF-8 scale. We developed software to aid identification of visible changes in satellite imagery occurring over time. We then used a Geographical Information System to calculate the percentage change in the built environment occurring within an 800 m buffer of each participant's home.

RESULTS

The median change in the neighbourhood built environment was 3% (interquartile range 6%). In the whole sample, physical wellbeing declined by 1.5 units on average, and mental wellbeing increased by 0.9 units, over time. In multivariable linear regression analyses, participants living in neighbourhoods with a greater amount of change in the built environment (unit change = 1%) experienced significantly reduced physical (PCS-8: -0.13, 95% CI -0.26 to 0.00) and mental (MCS-8: -0.16, 95% CI -0.31 to - 0.02) wellbeing over time compared to those living in neighbourhoods with less change. For mental wellbeing, a significant interaction by baseline perception of financial strain indicated a larger reduction in those experiencing greater financial strain (MCS-8: -0.22, 95% CI -0.39 to - 0.06). However, this relationship was reversed in those experiencing lower financial strain, whereby living in neighbourhoods with a greater amount of change was associated with significantly improved mental wellbeing over time (MCS-8: 0.38, 95% CI 0.04 to 0.72).

CONCLUSIONS

Overall, we found some evidence that living in neighbourhoods experiencing higher levels of physical change worsened wellbeing in local residents. However, we found a stronger negative relationship in those with lower financial security and a positive relationship in those with higher financial security. This is one of few studies exploring the longitudinal relationship between the environment and health.

Assessing the effect of physical activity classes in public spaces on leisure-time physical activity: "Al Ritmo de las Comunidades" A natural experiment in Bogota, Colombia

The Recreovia program provides free physical activity (PA) classes in public spaces in Bogota, Colombia. The purpose of this study was to assess the effectiveness of the Recreovia program in increasing PA among users of nine parks in Bogota. This study was a natural experiment conducted between 2013 and 2015 in Bogota. Community members and park users living nearby three groups of parks were compared: Group 1 were parks implementing new Recreovias (n=3), Group 2 were control parks (n=3) without Recreovias, and Group 3 were parks with existing Recreovías. Individuals in the "intervention" group were exposed to newly implemented Recreovia programs in parks near their homes. Measurements were collected at baseline and 6-8months after the intervention started. A total of 1533 participants were enrolled in the study: 501 for the existing Recreovias (included in a cross-sectional assessment) and 1032 participants (from the new Recreovias and control parks) included in the cross-sectional and pre-post study. Most participants were low income females. Twenty-three percent of the intervention group started participating in the program. Users of existing Recreovias were significantly more active and less likely to be overweight/obese compared to new Recreovia users at baseline. No changes on PA were found when comparing the intervention and control groups. Recreovias may have potential for increasing PA at the population level in urban areas given their rapid scalability, the higher levels of PA observed among program users, and its potential to reach women, low-income, less educated populations, and the overweight and obese.

Effects of urban motorways on physical activity and sedentary behaviour in local residents: a natural experimental study

BACKGROUND

There is little evidence on how changing the physical environment changes health-related behaviours. We studied the effects of the new M74 motorway (freeway) - opened in 2011 - and the existing M8 motorway in Glasgow, Scotland, on physical activity and sedentary behaviour among local residents.

METHODS

This natural experimental study used baseline (T1; 2005) and follow-up data (T2; 2013) from a longitudinal cohort (N = 365) and two cross-sectional samples (T1 N = 980; T2 N = 978). Adult participants were recruited from three study areas: one surrounding the new motorway, one surrounding the existing motorway, and a third, control, area without a motorway. The outcomes were self-reported time spent sitting, walking, and in moderate-to-vigorous physical activity (MVPA). Motorway exposure was defined in terms of (1) study area and (2) distance from home to the nearest motorway junction. Outcomes were regressed on exposures in two-part (walking and MVPA) or linear (sedentary behaviour) cohort and repeat cross-sectional models, adjusted for baseline behaviour and sociodemographic covariates.

RESULTS

Cohort participants living in the M8 area were less likely to participate in MVPA at follow-up than those living in the area without a motorway (OR 0.37; 95%CI 0.15, 0.91). Within the M8 area, those living closer to the motorway were also less likely to do so (OR 0.30; 95%CI 0.09, 0.97). No other statistically significant results were found.

CONCLUSIONS

We found some evidence of a negative association between exposure to an existing urban motorway and MVPA. However, the behavioural impacts of motorways are likely to be complex and evolve over time.

Questioning the application of risk of bias tools in appraising evidence from natural experimental studies: critical reflections on Benton et al., IJBNPA 2016

We recently read the article by Benton et al. which reviewed risk of bias in natural experimental studies investigating the impact of the built environment on physical activity (Benton et al., 2016; Int J Behav Nutr Phys Act 13:107). As a technical exercise in assessing risk of bias to understand study quality, we found the results of this study both interesting and potentially useful. However, it prompted a number of concerns with the use of risk of bias tools for assessing the quality of evidence from studies exploiting natural experiments. As we discuss in this commentary, the rigid application of such tools could have adverse effects on the uptake and use of natural experiments in population health research and practice.

Effects of living near an urban motorway on the wellbeing of local residents in deprived areas: Natural experimental study

BACKGROUND

Health and wellbeing are partly shaped by the neighbourhood environment. In 2011, an eight kilometre (five mile) extension to the M74 motorway was opened in Glasgow, Scotland, constructed through a predominantly urban, deprived area. We evaluated the effects of the new motorway on wellbeing in local residents.

METHODS

This natural experimental study involved a longitudinal cohort (n = 365) and two cross-sectional samples (baseline n = 980; follow-up n = 978) recruited in 2005 and 2013. Adults from one of three study areas-surrounding the new motorway, another existing motorway, or no motorway-completed a postal survey. Within areas, individual measures of motorway proximity were calculated. Wellbeing was assessed with the mental (MCS-8) and physical (PCS-8) components of the SF-8 scale at both time points, and the short Warwick-Edinburgh Mental Well-being Scale (SWEMWBS) at follow-up only.

RESULTS

In multivariable linear regression analyses, cohort participants living nearer to the new M74 motorway experienced significantly reduced mental wellbeing over time (MCS-8: -3.6, 95% CI -6.6 to -0.7) compared to those living further away. In cross-sectional and repeat cross-sectional analyses, an interaction was found whereby participants with a chronic condition living nearer to the established M8 motorway experienced reduced (MCS-8: -3.7, 95% CI -8.3 to 0.9) or poorer (SWEMWBS: -1.1, 95% CI -2.0 to -0.3) mental wellbeing compared to those living further away.

CONCLUSIONS

We found some evidence that living near to a new motorway worsened local residents' wellbeing. In an area with an existing motorway, negative impacts appeared to be concentrated in those with chronic conditions, which may exacerbate existing health inequalities and contribute to poorer health outcomes. Health impacts of this type of urban regeneration intervention should be more fully taken into account in future policy and planning.

Health impacts of the M74 urban motorway extension: a mixed-method natural experimental study

Background

Making travel easier can improve people’s access to opportunities, but motor transport also incurs substantial undesirable health and social impacts.

Aims

To assess how a new urban motorway affected travel and activity patterns, road accidents and well-being in local communities, and how these impacts were experienced and brought about.

Design

The Traffic and Health in Glasgow study, a mixed-method controlled before-and-after study.

Setting

Glasgow, UK.

Participants

Repeat cross-sectional survey samples of 1345 and 1343 adults, recruited in 2005 and 2013, respectively. Of these, 365 formed a longitudinal cohort, 196 took part in a quantitative substudy using accelerometers and global positioning system receivers and 30, living within 400 m of the new motorway, took part in a qualitative substudy along with 12 other informants. Complementary analyses used police STATS19 road traffic accident data (1997–2014) and Scottish Household Survey travel diaries (2009–13).

Intervention

A new 5-mile, six-lane section of the M74 motorway, opened in 2011 and running through predominantly deprived neighbourhoods in south-east Glasgow, with associated changes to the urban landscape.

Main outcome measures

Differences in self-reported travel behaviour (1-day travel record), physical activity (short International Physical Activity Questionnaire) and well-being [Short Form 8 Health Survey (SF-8) and a short version of the Warwick–Edinburgh Mental Well-being Scale], and in the incidence of road traffic accidents.

Methods

A combination of multivariable cohort, cross-sectional, repeat cross-sectional and interrupted time series regression analyses comparing residents of the ‘M74 corridor’ intervention area and two matched control areas, complemented by novel qualitative spatial methods. Graded measures of the proximity of the motorway to each participant’s home served as a further basis for controlled comparisons.

Results

Both benefits and harms were identified. Cohort participants living closer to the new motorway experienced significantly reduced mental well-being (mental component summary of the SF-8 scale) over time compared with those living further away [linear regression coefficient –3.6, 95% confidence interval (CI) –6.6 to –0.7]. In the area surrounding an existing motorway, this association was concentrated among those with chronic conditions. In repeat cross-sectional analyses, participants living closer to a new motorway junction were more likely to report using a car at follow-up than those living further away (odds ratio 3.4, 95% CI 1.1 to 10.7). We found weaker quantitative evidence of a decline in physical activity participation and no quantitative evidence of an overall change in either active travel or accidents associated with motorway exposure. Qualitative evidence suggested that, although the new motorway improved connectivity for those with dispersed social networks and access to motor vehicles, the impacts were more complex for others, some of whom found the motorway to be a cause of severance. Changes in community composition and cohesion, and perceptions of personal safety, were widely perceived as more important to local people.

Limitations

A key limitation of natural experimental studies is that the risk of residual confounding cannot be eliminated.

Conclusions

Overall, these findings highlight the potential for urban infrastructural projects of this kind to add further burdens to already disadvantaged communities, exacerbating inequalities and contributing to poorer health outcomes. The health and social impacts of such initiatives should be more fully taken into account in planning and research.

Funding

The National Institute for Health Research Public Health Research programme.

Effects of living near a new urban motorway on the travel behaviour of local residents in deprived areas: Evidence from a natural experimental study

We evaluated the effects of a new motorway built through deprived neighbourhoods on travel behaviour in residents. This natural experiment comprised a longitudinal cohort (n=365) and two cross-sectional samples (baseline n=980; follow-up n=978) recruited in 2005 and 2013. Adults from one of three study areas - surrounding the new motorway (South), an existing motorway (East), or no motorway (North) - completed a previous day travel record. Adjusted two-part regression models examined associations between exposure and outcome. Compared to the North, cohort participants in the South were more likely to undertake travel by any mode (OR 2.1, 95% CI 1.0–4.2) at follow-up. Within the South study area, cohort participants living closer to a motorway junction were more likely to travel by any mode at follow-up (OR 4.7, 95% CI 1.1–19.7), and cross-sectional participants living closer were more likely to use a car at follow-up (OR 3.4, 95% CI 1.1–10.7), compared to those living further away. Overall, the new motorway appeared to promote travel and car use in those living nearby, but did not influence active travel. This may propagate socioeconomic inequalities in non-car owners.

Opportunities for longitudinal data linkage in Scotland

Scotland has existing data resources which are competitive internationally and available to researchers from elsewhere. The Scottish Informatics and Linkage Collaboration (SILC) was recently launched, allowing data sets to be linked within and between sectors (e.g. health to non-health). The purpose of this review article is to introduce and define key terms in data linkage, to describe the emerging data linkage resources available in Scotland and to describe the opportunities available in Scotland to researchers internationally. The review is aimed at researchers internationally who are interested in data linkage using Scottish data resources. The review makes particular reference to longitudinal health data but emphasises that linkage to non-health data allows research questions to be considered that were previously not answerable. The review is focused on longitudinal data resources (e.g. cohort studies and repeated measures designs), since they are usually the focus of data linkage research. The review concludes that any intended data linkage for research should be driven by a clear research question. The infrastructure already available and the launch of SILC will accelerate research in Scotland and generate new research questions that previously could not be considered.

Effects of new motorway infrastructure on active travel in the local population: a retrospective repeat cross-sectional study in Glasgow, Scotland

Background

Promoting active travel is an important part of increasing population physical activity, which has both physical and mental health benefits. A key benefit described by the then Scottish Government of the five-mile M74 motorway extension, which opened during June 2011 in the south of Glasgow, was that the forecast reduction in motor traffic on local streets would make these streets safer for walking and cycling, thus increasing active travel by the local population. The aim of the study was to evaluate the impact of new motorway infrastructure on the proportion of journey stages made actively (cycling or on foot) by individuals travelling in and out of the local area.

Methods

Data for the periods 2009–10 and 2012–13 were extracted from the Scottish Household Survey (SHS) travel diaries, which record each journey stage made during the previous day by a representative sample of the Scottish population aged 16 and over. Each individual journey stage was assigned to one of the following study areas surrounding existing and new transport infrastructure: (1) an area surrounding the new M74 motorway extension (n = 435 (2009–10), 543 (2012–13)), (2) a comparator area surrounding an existing motorway (n = 477 (2009–10), 560 (2012–13)), and (3) a control area containing no comparable motorway infrastructure (n = 541 (2009–10), 593 (2012–13)). Multivariable, multi-level regression analysis was performed to determine any between-area differences in change in active travel over time, which might indicate an intervention effect. Reference populations were defined using two alternative definitions, (1) Glasgow City and (2) Glasgow and surrounding local authorities.

Results

The results showed an increase in the proportion of journey stages using active travel in all study areas compared to both reference populations. However, there were no significant between-area differences to suggest an effect attributable the M74 motorway extension.

Conclusions

There was no clear evidence that the M74 motorway extension either increased or decreased active travel in the local area. The anticipation by policy makers that reduced motorised traffic on local streets might increase journeys walked or cycled appears to have been unfounded.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-016-0403-9) contains supplementary material, which is available to authorized users.

Effects of new urban motorway infrastructure on road traffic accidents in the local area: a retrospective longitudinal study in Scotland

BACKGROUND

The M74 motorway extension, Glasgow, opened in June 2011. One justification for construction was an expectation that it would reduce road traffic accidents (RTAs) on local non-motorway roads. This study evaluated the impact of the extension on the number of RTAs, stratifying by accident severity.

METHODS

Data for the period 1997-2014 were extracted from a UK database of reported RTAs involving a personal injury. RTA severity was defined by the level of injury: minor, severe or fatal. RTAs were assigned to (1) the local area surrounding the motorway extension, (2) a comparator area surrounding an existing motorway or (3) a control area elsewhere in the conurbation. Interrupted time-series regression with autoregressive integrated moving average (ARIMA) errors was used to determine longitudinal between-area differences in change in the number of RTAs, which might indicate an intervention effect.

RESULTS

Glasgow and surrounding local authorities saw a 50.6% reduction in annual RTAs (n: 5901 to 2914) between 1997 and 2014. In the intervention area, the number of recorded RTAs decreased by 50.7% (n: 758 to 374), and that of fatal/severe RTAs by 57.4% (n: 129 to 55), with similar reductions in the comparator/control areas. The interrupted time-series analysis showed no significant between-area differences in temporal trends. The reduction of pedestrian casualties was attenuated in the intervention area relative to Glasgow and surrounding authorities.

CONCLUSIONS

Reduction in RTAs was not associated with the motorway extension. Our findings suggest that in planning future investment, it should not be taken for granted that new road infrastructure alone will reduce RTAs in local areas. Urbanisation is proceeding rapidly worldwide, and evidence of infrastructure changes is lacking; this novel study provides important findings for future developments.

Changing the environment to improve population health: a framework for considering exposure in natural experimental studies

There is renewed optimism regarding the use of natural experimental studies to generate evidence as to the effectiveness of population health interventions. Natural experimental studies capitalise on environmental and policy events that alter exposure to certain social, economic or environmental factors that influence health. Natural experimental studies can be useful for examining the impact of changes to ‘upstream’ determinants, which may not be amenable to controlled experiments. However, while natural experiments provide opportunities to generate evidence, they often present certain conceptual and methodological obstacles. Population health interventions that alter the physical or social environment are usually administered broadly across populations and communities. The breadth of these interventions means that variation in exposure, uptake and impact may be complex. Yet many evaluations of natural experiments focus narrowly on identifying suitable ‘exposed’ and ‘unexposed’ populations for comparison. In this paper, we discuss conceptual and analytical issues relating to defining and measuring exposure to interventions in this context, including how recent advances in technology may enable researchers to better understand the nature of population exposure to changes in the built environment. We argue that when it is unclear whether populations are exposed to an intervention, it may be advantageous to supplement traditional impact assessments with observational approaches that investigate differing levels of exposure. We suggest that an improved understanding of changes in exposure will assist the investigation of the impact of complex natural experiments in population health.

[Same words, different meanings: How epidemiological terminology struggles with population health intervention research]

Public health research differs from clinical epidemiological research in that its focus is primarily on the population level social and structural determinants of individual health and the interventions that might ameliorate them, rather than having a primary focus on individual-level risks. It is typically concerned with the proximal and distal causes of health problems, and their location within complex systems, more than with single exposures. Thus, epidemiological terms and concepts may have very different implications when used in the context of population health. This paper considers some key differences in relation to terms like 'population', 'baseline', 'control group' 'outcome' and 'adverse effects'. Even the concept of an 'intervention' often needs careful handling. The paper concludes that there is a need for an expanded, and more realistic use of these terms in the population health intervention research context.

Improving current practice in reviews of the built environment and physical activity

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.

From the concrete to the intangible: understanding the diverse experiences and impacts of new transport infrastructure

BACKGROUND

Changes to the environment that support active travel have the potential to increase population physical activity. The Cambridgeshire Guided Busway is an example of such an intervention that provides new traffic-free infrastructure for walking, cycling and public transport. This qualitative investigation explored the diverse experiences of new transport infrastructure and its impacts on active travel behaviours.

METHODS

Thirty-eight adult participants from the Commuting and Health in Cambridge natural experimental study were purposively selected according to their demographic and travel behaviour change characteristics and invited to participate in semi-structured interviews between February and June 2013. A mixed-method, following-a-thread approach was used to construct two contrasting vignettes (stories) to which the participants were asked to respond as part of the interviews. Inductive thematic qualitative analysis of the interview data was performed with the aid of QSR NVivo8.

RESULTS

Perceptions of the busway's attributes were important in shaping responses to it. Some participants rarely considered the new transport infrastructure or described it as unappealing because of its inaccessibility or inconvenient routing. Others located more conveniently for access points experienced the new infrastructure as an attractive travel option. Likewise, the guided buses and adjacent path presented ambiguous spaces which were received in different ways, depending on travel preferences. While new features such as on board internet access or off-road cycling were appreciated, shortcomings such as overcrowded buses or a lack of path lighting were barriers to use. The process of adapting to the environmental change was discussed in terms of planning and trialling new behaviours. The establishment of the busway in commuting patterns appeared to be influenced by whether the anticipated benefits of change were realised.

CONCLUSIONS

This study examined the diverse responses to an environmental intervention that may help to explain small or conflicting aggregate effects in quantitative outcome evaluation studies. Place and space features, including accessibility, convenience, pleasantness and safety relative to the alternative options were important for the acceptance of the busway. Our findings show how environmental change supporting active travel and public transport can encourage behaviour change for some people in certain circumstances.

Increasing active travel: results of a quasi-experimental study of an intervention to encourage walking and cycling

BACKGROUND

There is increased interest in the effectiveness and co-benefits of measures to promote walking and cycling, including health gains from increased physical activity and reductions in fossil fuel use and vehicle emissions. This paper analyses the changes in walking and cycling in two New Zealand cities that accompanied public investment in infrastructure married with programmes to encourage active travel.

METHOD

Using a quasi-experimental two-group pre-post study design, we estimated changes in travel behaviour from baseline in 2011 to mid-programme in 2012, and postprogramme in 2013. The intervention and control cities were matched in terms of sociodemographic variables and baseline levels of walking and cycling. A face-to-face survey obtained information on walking and cycling. We also drew from the New Zealand Travel Survey, a national ongoing survey of travel behaviour, which was conducted in the study areas. Estimates from the two surveys were combined using meta-analysis techniques.

RESULTS

The trips and physical activity were evaluated. Relative to the control cities, the odds of trips being by active modes (walking or cycling) increased by 37% (95% CI 8% to 73%) in the intervention cities between baseline and postintervention. The net proportion of trips made by active modes increased by about 30%. In terms of physical activity levels, there was little evidence of an overall change.

DISCUSSION

Comparing the intervention cities with the matched controls, we found substantial changes in walking and cycling, and conclude that the improvements in infrastructure and associated programmes appear to have successfully arrested the general decline in active mode use evident in recent years.

Increasing active travel: aims, methods and baseline measures of a quasi-experimental study

BACKGROUND

Policy advisers are seeking robust evidence on the effectiveness of measures, such as promoting walking and cycling, that potentially offer multiple benefits, including enhanced health through physical activity, alongside reductions in energy use, traffic congestion and carbon emissions. This paper outlines the 'ACTIVE' study, designed to test whether the Model Communities Programme in two New Zealand cities is increasing walking and cycling. The intervention consists of the introduction of cycle and walkway infrastructure, along with measures to encourage active travel. This paper focuses on the rationale for our chosen study design and methods.

METHOD

The study design is multi-level and quasi-experimental, with two intervention and two control cities. Baseline measures were taken in 2011 and follow-up measures in 2012 and 2013. Our face-to-face surveys measured walking and cycling, but also awareness, attitudes and habits. We measured explanatory and confounding factors for mode choice, including socio-demographic and well-being variables. Data collected from the same households on either two or three occasions will be analysed using multi-level models that take account of clustering at the household and individual levels. A cost-benefit analysis will also be undertaken, using our estimates of carbon savings from mode shifts. The matching of the intervention and control cities was quite close in terms of socio-demographic variables, including ethnicity, and baseline levels of walking and cycling.

DISCUSSION

This multidisciplinary study provides a strong design for evaluating an intervention to increase walking and cycling in a developed country with relatively low baseline levels of active travel. Its strengths include the use of data from control cities as well as intervention cities, an extended evaluation period with a reasonable response rate from a random community survey and the availability of instrumental variables for sensitivity analyses.

The contribution of media analysis to the evaluation of environmental interventions: the commuting and health in Cambridge study

Background

Media content can increase awareness of, and shape interactions with, public health interventions. As part of a natural experimental evaluation of the travel, physical activity and health impacts of the Cambridgeshire Guided Busway, we analysed print and social media discourse and interview data to understand the nature of new transport infrastructure and how it was experienced.

Methods

Newspaper articles were systematically retrieved from the LexisNexis database and tweets were identified from an online archive. Interviews were conducted as part of the larger evaluation study with 38 adults. Inductive thematic analysis was performed and comparisons were drawn between datasets.

Results

The findings are discussed in relation to five themes. First, an understanding of the intervention context and how the intervention was experienced was developed through accounts of events occurring pre and post the busway’s opening. Second, the media captured the dynamic nature of the intervention. Third, the media constructed idealised portrayals of the anticipated busway which in some cases were contradicted by the impact of the busway on the existing context and people’s lived experiences. Fourth, differential media coverage of the intervention components suggested that a lesser value was placed on promoting active travel compared with public transport. Lastly, interview data provided support for the hypothesis that the media increased awareness of the busway and served as a frame of reference for constructing expectations and comparing experiences.

Conclusions

This analysis has contributed to the wider evaluation of the busway, helping to understand its nature and implementation and informing hypotheses about how the local population interact with the infrastructure by attending to the significance of representations in the media.

On the buses: a mixed-method evaluation of the impact of free bus travel for young people on the public health

Background

In September 2005 London introduced a policy granting young people aged < 17 years access to free bus and tram travel. A year later this policy was extended to people aged < 18 years in education, work or training. This intervention was part of a broader environmental strategy in London to reduce private car use, but its primary aim was to decrease ‘transport exclusion’, and ensure that access to goods, services, education and training opportunities were not denied to some young people because of transport poverty. However, there were also likely to be positive and negative health implications, which were difficult to assess in the absence of a robust evidence base on the impact of transport policies on health and well-being.

Objectives

To evaluate the impact of free bus travel for young people in London on the public health. Specifically, to provide empirical evidence for the impact of this ‘natural experiment’ on health outcomes and behaviours (e.g. injuries, active travel) for young people; explore the effects on the determinants of health; identify the effects on older citizens of increased access to bus travel for young people and to identify whether or not the intervention represented value for money.

Design

Quasi-experimental design, using secondary analysis of routine data, primary qualitative data and literature reviews.

Setting

London, UK.

Participants

Young people aged 12–17 years and older citizens aged ≥ 60 years.

Intervention

The introduction of free bus travel for those aged < 17 years living in London in 2005, extended to those aged < 18 years in 2006.

Main outcome measures

Quantitative: number of journeys to school or work; frequency and distance of active travel (i.e. walking and/or cycling), bus travel, car travel; incidence of road traffic injuries and assaults and socioeconomic gradients in travel patterns. Qualitative: how free bus travel affected young people and older citizens’ travel and well-being.

Methods

Quantitative component: change-on-change analysis comparing pre–post change in the target age group (12–17 years) against that seen in ‘non-exposed’ groups [for travel mode, road traffic injury (RTI) and assaults]. Qualitative component: interviews analysed using both deductive and inductive methods. Economic evaluation: cost–benefit analysis (CBA).

Data sources

London Area Transport Survey (LATS) and London Travel Demand Survey (LTDS) (travel mode); STATS19 Road Accident data set (RTI); Hospital Episode Statistics (HES) (assaults); interviews with young people and older citizens; and cost data from providers and literature reviews.

Results

The introduction of free bus travel for young people was associated with higher use of bus travel by adults and young people [31% increase, 95% confidence interval (CI) 19% to 42%; and 26% increase, 95% CI 13% to 41%, respectively], especially for short journeys, and lower car distances relative to adults (relative change 0.73, 95% CI 0.55 to 0.94); no significant overall reduction in ‘active travel’ [reduction in number of walking trips but no evidence of change in distance walked (relative change 0.99, 95% CI 0.92 to 1.07)]; significant reduction in cycling relative to adults (but from a very low base); a reduction in road traffic injuries for car occupants (relative change 0.89, 95% CI 0.84 to 0.95) and cyclists (relative change 0.60, 95% CI 0.55 to 0.66), but not pedestrians; an overall modest increase in journeys to work or school (relative change 1.09, 95% CI 1.06 to 1.14); equivocal evidence of impact on socioeconomic gradients in travel behaviour and no evidence of adverse impact on travel of older people aged > 60 years. An increase in assaults largely preceded the scheme. Qualitative data suggested that the scheme increased opportunities for independent travel, social inclusion, and a sense of belonging and that it ‘normalised’ bus travel. The monetised benefits of the scheme substantially outweighed the costs, providing what the Department for Transport (DfT) considers ‘high’ value for money.

Conclusion

The free bus travel scheme for young people appears to have encouraged their greater use of bus transport for short trips without significant impact on their overall active travel. There was qualitative evidence for benefits on social determinants of health, such as normalisation of bus travel, greater social inclusion and opportunities for independent travel. In the context of a good bus service, universal free bus travel for young people appears to be a cost-effective contributor to social inclusion and, potentially, to increasing sustainable transport in the long term. Further research is needed on the effects of both active and other travel modes on the determinants of health; the factors that influence maintenance of travel mode change; travel as ‘social practice’; the impact of driving license changes on injury rates for young adults and the value of a statistical life for young people.

Funding

The National Institute for Health Research Public Health Research programme.

A new urban planning code's impact on walking: the residential environments project

OBJECTIVES

We examined whether people moving into a housing development designed according to a state government livable neighborhoods subdivision code engage in more walking than do people who move to other types of developments.

METHODS

In a natural experiment of 1813 people building homes in 73 new housing developments in Perth, Western Australia, we surveyed participants before and then 12 and 36 months after moving. We measured self-reported walking using the Neighborhood Physical Activity Questionnaire and collected perceptions of the environment and self-selection factors. We calculated objective measures of the built environment using a Geographic Information System.

RESULTS

After relocation, participants in livable versus conventional developments had greater street connectivity, residential density, land use mix, and access to destinations and more positive perceptions of their neighborhood (all P < .05). However, there were no significant differences in walking over time by type of development (P > .05).

CONCLUSIONS

Implementation of the Livable Neighborhoods Guidelines produced more supportive environments; however, the level of intervention was insufficient to encourage more walking. Evaluations of new urban planning policies need to incorporate longer term follow-up to allow time for new neighborhoods to develop.

Using natural experiments to evaluate population health interventions: new Medical Research Council guidance

Natural experimental studies are often recommended as a way of understanding the health impact of policies and other large scale interventions. Although they have certain advantages over planned experiments, and may be the only option when it is impossible to manipulate exposure to the intervention, natural experimental studies are more susceptible to bias. This paper introduces new guidance from the Medical Research Council to help researchers and users, funders and publishers of research evidence make the best use of natural experimental approaches to evaluating population health interventions. The guidance emphasises that natural experiments can provide convincing evidence of impact even when effects are small or take time to appear. However, a good understanding is needed of the process determining exposure to the intervention, and careful choice and combination of methods, testing of assumptions and transparent reporting is vital. More could be learnt from natural experiments in future as experience of promising but lesser used methods accumulates.

The feasibility of rapid baseline objective physical activity measurement in a natural experimental study of a commuting population

Background

Studies of the effects of environmental interventions on physical activity should include valid measures of physical activity before and after the intervention. Baseline data collection can be difficult when the timetable for introduction of an intervention is outside researchers’ control. This paper reports and reflects on the practical issues, challenges and results of rapid baseline objective physical activity measurement using accelerometers distributed by post in a natural experimental study.

Methods

A sample of working adults enrolling for the Commuting and Health in Cambridge study and expressing willingness to wear an activity monitor was selected to undertake baseline accelerometer assessment. Each selected participant received a study pack by post containing the core study questionnaire and an accelerometer to wear for seven consecutive days, and was asked to return their accelerometer and completed questionnaire in person or by post using the prepaid special delivery envelope provided. If a pack was not returned within two weeks of issue, a reminder was sent to the participant. Each participant received up to five reminders by various methods including letter, email, telephone and letter sent by recorded delivery.

Results

95% of participants registering for the study were willing in principle to undertake accelerometer assessment. Using a pool of 221 accelerometers, we achieved a total of 714 issues of accelerometers to participants during a six month period. 116 (16%) participants declined to use the accelerometer after receiving it. Three accelerometers failed, 45 (6% of 714) were lost and many were returned with insufficient data recorded, resulted in 109 (15%) participants re-wearing their accelerometer for a second week of measurement. 550 (77%) participants completed data collection, 478 (87% of 550) to the required standard. A total of 694 reminders were issued to retrieve unreturned accelerometers. More than 90% of accelerometers were retrieved after a maximum of two reminders.

Conclusions

It is feasible to use accelerometers to collect baseline objective physical activity data by post from a large number of participants in a limited time period. However, a substantial pool of devices is required and researchers need to be prepared to make significant efforts to recover some of the devices.

[Cycling to achieve healthy and sustainable alternatives]

The quest for healthier cities and citizens has contributed to the strengthening of public policies championing the bicycle as a means of transportation and offering benefits to individual wellbeing in various countries, however there is also an increased risk of accidents. The scope of this review is to analyze scientific output dealing with the relationship between cycling as a means of transportation and public health. PubMed, LILACS and SciELO were the chosen databases used in the research and 66 complete articles were selected. The results show that concern about this theme is recent, especially in developing countries. The most recurrent topics raised by the researchers were: traffic safety, public policies and the effects of cycling on health. We concluded that the decision to use the bicycle as a means of transportation occurs in a very heterogeneous manner, albeit with potentially greater impacts in developing countries where the inclusion of this theme in the research agendas related to the promotion of active transport, health and traffic safety is a matter of urgency.

Evaluating the travel, physical activity and carbon impacts of a 'natural experiment' in the provision of new walking and cycling infrastructure: methods for the core module of the iConnect study

INTRODUCTION

Improving infrastructure to support walking and cycling is often regarded as fundamental to encouraging their widespread uptake. However, there is little evidence that specific provision of this kind has led to a significant increase in walking or cycling in practice, let alone wider impacts such as changes in overall physical activity or carbon emissions. Connect2 is a major new project that aims to promote walking and cycling in the UK by improving local pedestrian and cycle routes. It therefore provides a useful opportunity to contribute new evidence in this field by means of a natural experimental study.

METHODS AND ANALYSIS

iConnect is an independent study that aims to integrate the perspectives of public health and transport research on the measurement and evaluation of the travel, physical activity and carbon impacts of the Connect2 programme. In this paper, the authors report the study design and methods for the iConnect core module. This comprised a cohort study of residents living within 5 km of three case study Connect2 projects in Cardiff, Kenilworth and Southampton, supported by a programme of qualitative interviews with key informants about the projects. Participants were asked to complete postal questionnaires, repeated before and after the opening of the new infrastructure, which collected data on demographic and socioeconomic characteristics, travel, car fuel purchasing and physical activity, and potential psychosocial and environmental correlates and mediators of those behaviours. In the absence of suitable no-intervention control groups, the study design drew on heterogeneity in exposure both within and between case study samples to provide for a counterfactual.

ETHICS AND DISSEMINATION

The study was approved by the University of Southampton Research Ethics Committee. The findings will be disseminated through academic presentations, peer-reviewed publications and the study website (http://www.iconnect.ac.uk) and by means of a national seminar at the end of the study.

The effectiveness of a community playground intervention

This study assessed whether an upgrade of playgrounds in a community was associated with changes in the physical activity of local children. The study used a natural experiment design with a local authority project to upgrade two community playgrounds as the intervention and a matched control community. Children's physical activity was measured by an Actigraph GT1M accelerometer worn for 8 days, enabling up to 6 days of data to be analyzed. A self-administered parent/guardian questionnaire was used to collect additional data, including perceptions of the neighborhood, school-travel modes, days involved in extracurricular activities, ethnicity, caregiver age, caregiver sex, household vehicle access, and household income. At baseline, 184 children (5-10 years old) participated. Of these, 156 completed the 1-year follow-up assessment (20% lost to follow-up). There was statistically significant evidence that change in mean total daily physical activity was associated with on an interaction between participant's body mass index (BMI) z-score and her or his community of residence (p = 0.006), with the intervention being associated with higher levels of activity for children with lower BMIs but lower levels for children with higher BMIs. Physical activity is not the only focus of local authority playground provision as playgrounds also have benefits for social development and fundamental movement skills. However, making sure that physical activity is always included in the design rationale and that playgrounds are designed to encourage and sustain physical activity could be a useful population health intervention. The effects of such interventions on different subgroups are of importance, especially if the effects differ over levels of BMI.

Residents' diverse perspectives of the impact of neighbourhood renewal on quality of life and physical activity engagement: improvements but unresolved issues

Few studies have been published on the reactions of residents to modifications of their residential landscape. We explored residents' experiences of home zone remodelling and construction of a new cycle-walkway in a deprived neighbourhood with a particular focus on aspects of quality of life and physical activity participation. Focus groups (n=5 groups, 21 individuals) were used to investigate residents' perceptions of the effects of neighbourhood change on their lives. Consultation by planners was received positively. Several aspects of the neighbourhood were perceived to have improved, including spatial aesthetics, lighting and streetscape planting. However, influence on physical activity was minimal. Car-focused behaviour and ownership remained dominant, and safety related concerns limited behavioural choices. Residents highlighted many socio-environmental challenges that remained such as sense of neighbourhood safety, poor public transport provision, people's parking behaviour locally, and problem neighbours, and these tended to dominate conversations. Infrastructural intervention may be one important part of multi-layered solutions to improved neighbourhood life.

Challenges in evaluating Welfare to Work policy interventions: would an RCT design have been the answer to all our problems?

Background

UK policy direction for recipients of unemployment and sickness benefits is to support these people into employment by increasing 'into work' interventions. Although the main aim of associated interventions is to increase levels of employment, improved health is stated as a benefit, and a driver of these interventions. This is therefore a potentially important policy intervention with respect to health and health inequalities, and needs to be validated through rigorous impact evaluation.

We attempted to evaluate the Pathways Advisory Service intervention which aims to provide employment support for Incapacity Benefit recipients, but encountered a number of challenges and barriers to evaluation. This paper explores the issues that arose in designing a suitable evaluation of the Pathways Advisory Service.

Discussion

The main issues that arose were that characteristics of the intervention lead to difficulties in defining a suitable comparison group; and governance restrictions such as uncertainty regarding ethical consent processes and data sharing between agencies for research. Some of these challenges threatened fundamentally to limit the validity of any experimental or quasi-experimental evaluation we could design - restricting recruitment, data collection and identification of an appropriate comparison group. Although a cluster randomised controlled trial design was ethically justified to evaluate the Pathways Advisory Service, this was not possible because the intervention was already being widely implemented. However, this would not have solved other barriers to evaluation. There is no obvious method to perform a controlled evaluation for interventions where only a small proportion of those eligible are exposed. Improved communication between policymakers and researchers, clarification of data sharing protocols and improved guidelines for ethics committees are tangible ways which may reduce the current obstacles to this and other similar evaluations of policy interventions which tackle key determinants of health.

Summary

The evaluation of social interventions is hampered by more than their suitability to randomisation. Data sharing, participant identification and recruitment problems are common to randomised and non-randomised evaluation designs. These issues require further attention if we are to learn from current social policy.

Shoe leather epidemiology: active travel and transport infrastructure in the urban landscape

Background

Building new transport infrastructure could help to promote changes in patterns of mobility, physical activity, and other determinants of population health such as economic development. However, local residents may not share planners' goals or assumptions about the benefits of such interventions. A particularly contentious example is the construction of major roads close to deprived residential areas. We report the qualitative findings of the baseline phase of a longitudinal mixed-method study of a new urban section of the M74 motorway in Glasgow, Scotland, that aims to combine quantitative epidemiological and spatial data with qualitative interview data from local residents.

Methods

We interviewed 12 residents purposively sampled from a larger study cohort of 1322 to include men and women, different age groups, and people with and without cars, all living within 400 metres of the proposed route of the new motorway. We elicited their views and experiences of the local urban environment and the likely impact of the new motorway using a topic guide based on seven key environmental constructs (aesthetics, green space, convenience of routes, access to amenities, traffic, road danger and personal danger) reflecting an overall ecological model of walking and cycling.

Results

Traffic was widely perceived to be heavy despite a low local level of car ownership. Few people cycled, and cycling on the roads was widely perceived to be dangerous for both adults and children. Views about the likely impacts of the new motorway on traffic congestion, pollution and the pleasantness of the local environment were polarised. A new motorway has potential to cause inequitable psychological or physical severance of routes to local amenities, and people may not necessarily use local walking routes or destinations such as parks and shops if these are considered undesirable, unsafe or 'not for us'. Public transport may have the potential to promote or discourage active travel in different socioeconomic contexts.

Conclusions

Altering the urban landscape may influence walking and cycling in ways that vary between individuals, may be inequitable, and may not be predictable from quantitative data alone. A more applied ecological behavioural model may be required to capture these effects.

Public health evaluation in the twenty-first century: time to see the wood as well as the trees

This paper argues that concepts, methodologies and practices within public health need further development if they are to be sufficient to allow us to develop, undertake and evaluate interventions in the twenty-first century. The public health profession, and the disciplines that contribute to it, maintains the historical focus upon detailed micro analysis (individual and health sector) and not broader macro analysis (societal and system). This brief paper suggests why this is and outlines three challenges it poses: specifying and evaluating outcomes; specifying and understanding complex causal pathways in social interventions and the development of multisector evaluation, to meet information demands from multiple stakeholders. While there is general agreement that public health evaluation needs development, this paper argues that the focus needs to be more upon a broader evaluative space than is currently practiced. There is a need to move beyond primary and secondary health-related effects upon individuals, and focus more on evaluation of the wider range and distribution of direct and indirect effects upon individuals, communities and populations. That is, those involved in public health evaluation need to step back and first consider the wood before focusing in on specific trees.

Congestion road tax and physical activity

BACKGROUND

Large-scale policy and environmental changes, such as congestion road taxes, may be a way to promote active transportation.

PURPOSE

This study aimed to examine the potential effect of a congestion road tax on physical activity.

METHODS

Baseline data were collected during October-November 2003, follow-up data in May 2006, and analysis was performed in September 2008. The short self-administered version of the International Physical Activity Questionnaire was used to assess physical activity. Data from those with access to motorized vehicles in the Stockholm region (n=165), where the tax was in place, were compared with those from the Göteborg/Malmö regions (n=138). Within each region before and during the road tax implementation, the data were analyzed for differences in time spent at different intensity levels of physical activity, in addition to sitting, as well as for changes in reported time in overall (weighted) physical activity.

RESULTS

There were no significant differences in the magnitude of the changes of the intensity levels of physical activity, weighted overall physical activity, or sitting, between Stockholm and Göteborg/Malmö. Among those exposed to the congestion road tax and with access to motorized vehicles, an increase in moderate physical activity (p=0.036); overall physical activity (p=0.015); and a reduction in time spent sitting (p=0.009) was observed. No differences were observed among those unexposed.

CONCLUSIONS

The results from this study on the influence of a congestion road tax on levels of physical activity, though inconclusive, suggest that policy changes such as a congestion road tax might promote improvements in physical activity levels in individuals with motorized vehicles.

Assessing the unintended health impacts of road transport policies and interventions: translating research evidence for use in policy and practice

Background

Transport and its links to health and health inequalities suggest that it is important to assess both the direct and unintended indirect health and related impacts of transport initiatives and policies. Health Impact Assessment (HIA) provides a framework to assess the possible health impacts of interventions such as transport. Policymakers and practitioners need access to well conducted research syntheses if research evidence is to be used to inform these assessments. The predictive validity of HIA depends heavily on the use and careful interpretation of supporting empirical evidence. Reviewing and digesting the vast volume and diversity of evidence in a field such as transport is likely to be beyond the scope of most HIAs. Collaborations between HIA practitioners and specialist reviewers to develop syntheses of best available evidence applied specifically to HIA could promote the use of evidence in practice.

Methods

Best available research evidence was synthesised using the principles of systematic review. The synthesis was developed to reflect the needs of HIA practitioners and policymakers.

Results

Aside from injury reduction measures, there is very little empirical data on the impact of road transport interventions. The possibility of impacts on a diverse range of outcomes and differential impacts across groups, make it difficult to assess overall benefit and harm. In addition, multiple mediating factors in the pathways between transport and hypothesised health impacts further complicate prospective assessment of impacts. Informed by the synthesis, a framework of questions was developed to help HIA practitioners identify the key questions which need to be considered in transport HIA.

Conclusion

Principles of systematic review are valuable in producing syntheses of best available evidence for use in HIA practice. Assessment of the health impacts of transport interventions is characterised by much uncertainty, competing values, and differential or conflicting impacts for different population groups at a local or wider level. These are issues pertinent to the value of HIA generally. While uncertainty needs explicit acknowledgement in HIA, there is still scope for best available evidence to inform the development of healthy public policy.

Developing and evaluating complex interventions: the new Medical Research Council guidance

Evaluating complex interventions is complicated. The Medical Research Council's evaluation framework (2000) brought welcome clarity to the task. Now the council has updated its guidance

Personal and environmental correlates of active travel and physical activity in a deprived urban population

Background

Environmental characteristics may be associated with patterns of physical activity in general or with particular types of physical activity such as active travel (walking or cycling for transport). However, most studies in this field have been conducted in North America and Australia, and hypotheses about putative correlates should be tested in a wider range of sociospatial contexts. We therefore examined the contribution of putative personal and environmental correlates of active travel and overall physical activity in deprived urban neighbourhoods in Glasgow, Scotland as part of the baseline for a longitudinal study of the effects of opening a new urban motorway (freeway).

Methods

We conducted a postal survey of a random sample of residents (n = 1322), collecting data on socioeconomic status, perceptions of the local environment, travel behaviour, physical activity and general health and wellbeing using a new 14-item neighbourhood rating scale, a travel diary, the short form of the International Physical Activity Questionnaire (IPAQ) and the SF-8. We analysed the correlates of active travel and overall physical activity using multivariate logistic regression, first building models using personal (individual and household) explanatory variables and then adding environmental variables.

Results

Active travel was associated with being younger, living in owner-occupied accommodation, not having to travel a long distance to work and not having access to a car, whereas overall physical activity was associated with living in social rented accommodation and not being overweight. After adjusting for personal characteristics, neither perceptions of the local environment nor the objective proximity of respondents' homes to motorway or major road infrastructure explained much of the variance in active travel or overall physical activity, although we did identify a significant positive association between active travel and perceived proximity to shops.

Conclusion

Apart from access to local amenities, environmental characteristics may have limited influence on active travel in deprived urban populations characterised by a low level of car ownership, in which people may have less capacity for making discretionary travel choices than the populations studied in most published research on the environmental correlates of physical activity.

Perceived characteristics of the environment associated with active travel: development and testing of a new scale

Background

Environmental characteristics may be associated with patterns of physical activity. However, the development of instruments to measure perceived characteristics of the local environment is still at a comparatively early stage, and published instruments are not necessarily suitable for application in all settings. We therefore developed and established the test-retest reliability of a new scale for use in a study of the correlates of active travel and overall physical activity in deprived urban neighbourhoods in Glasgow, Scotland.

Methods

We developed and piloted a 14-item scale based on seven constructs identified from the literature (aesthetics, green space, access to amenities, convenience of routes, traffic, road safety and personal safety). We administered the scale to all participants in a random postal survey (n = 1322) and readministered the scale to a subset of original respondents (n = 125) six months later. We used principal components analysis and Varimax rotation to identify three principal components (factors) and derived summary scores for subscales based on these factors. We examined the internal consistency of these subscales using Cronbach's alpha and examined the test-retest reliability of the individual items, the subscale summary scores and an overall summary neighbourhood score using a combination of correlation coefficients and Cohen's kappa with and without weighting.

Results

Public transport and proximity to shops were the items most likely to be rated positively, whereas traffic volume, traffic noise and road safety for cyclists were most likely to be rated negatively. Three principal components – 'safe and pleasant surroundings', 'low traffic' and 'convenience for walking' – together explained 45% of the total variance. The test-retest reliability of individual items was comparable with that of items in other published scales (intraclass correlation coefficients (ICCs) 0.34–0.70; weighted Cohen's kappa 0.24–0.59). The overall summary neighbourhood score had acceptable internal consistency (Cronbach's alpha 0.72) and test-retest reliability (ICC 0.73).

Conclusion

This new scale contributes to the development of a growing set of tools for investigating the role of perceived environmental characteristics in explaining or mediating patterns of active travel and physical activity.

Public transit, obesity, and medical costs: assessing the magnitudes

OBJECTIVE

This paper assesses the potential benefits of increased walking and reduced obesity associated with taking public transit in terms of dollars of medical costs saved and disability avoided.

METHODS

I conduct a new analysis of a nationally representative U.S. transportation survey to gauge the net increase in walking associated with public transit usage. I translate minutes spent walking into energy expenditures and reductions in obesity prevalence, estimating the present value of costs and disability that may be avoided.

RESULTS

Taking public transit is associated with walking 8.3 more minutes per day on average, or an additional 25.7-39.0 kcal. Hill et al. [Hill, J.O., Wyatt, H.R., Reed, G.W., Peters, J.C., 2003. Obesity and the environment: Where do we go from here? Science 299 (5608), 853-855] estimate that an increase in net expenditure of 100 kcal/day can stop the increase in obesity in 90% of the population. Additional walking associated with public transit could save $5500 per person in present value by reducing obesity-related medical costs. Savings in quality-adjusted life years could be even higher.

CONCLUSIONS

While no silver bullet, walking associated with public transit can have a substantial impact on obesity, costs, and well-being. Further research is warranted on the net impact of transit usage on all behaviors, including caloric intake and other types of exercise, and on whether policies can promote transit usage at acceptable cost.

Encouraging children and adolescents to be more active

Well evaluated complex interventions are still needed