What are the health benefits of active travel? A systematic review of trials and cohort studies

Impact of Distance on Mode of Active Commuting in Chilean Children and Adolescents

Active commuting could contribute to increasing physical activity. The objective of this study was to characterise patterns of active commuting to and from schools in children and adolescents in Chile. A total of 453 Chilean children and adolescents aged between 10 and 18 years were included in this study. Data regarding modes of commuting and commuting distance was collected using a validated questionnaire. Commuting mode was classified as active commuting (walking and/or cycling) or non-active commuting (car, motorcycle and/or bus). Commuting distance expressed in kilometres was categorised into six subgroups (0 to 0.5, 0.6 to 1, 1.1 to 2, 2.1 to 3, 3.1 to 5 and >5 km). Car commuting was the main mode for children (to school 64.9%; from school 51.2%) and adolescents (to school 50.2%; from school 24.7%). Whereas public bus commuting was the main transport used by adolescents to return from school. Only 11.0% and 24.8% of children and adolescents, respectively, walk to school. The proportion of children and adolescents who engage in active commuting was lower in those covering longer distances compared to a short distance. Adolescents walked to and from school more frequently than children. These findings show that non-active commuting was the most common mode of transport and that journey distances may influence commuting modes in children and adolescents.

Perceived public transport infrastructure modifies the association between public transport use and mental health: Multilevel analyses from the United Kingdom

AIMS

Investments to promote public transport utilisation are being championed to achieve sustainable development, but the potential co-benefits for mental health are comparatively under-researched. We hypothesised that frequent users of public transport would be more likely to have better mental health (possibly due to increased levels of physical activity), but among the more frequent users, less favourable perceptions of public transport infrastructure (PPTI) could have a negative influence on mental health.

METHODS

Multilevel linear and logistic regressions were fitted on 30,214 participants in the UK Household Longitudinal Study with lagged PPTI and confounder measures at baseline and indicators of active travel and mental health (General Health Questionnaire (GHQ), SF-12 Mental Component Scale (MCS) and the Warwick Edinburgh Mental Well Being Scale (WEMWBS)) at follow-up.

RESULTS

Compared to participants expressing poor PPTI, those who felt it was excellent were 1.29 (95%CI 1.15, 1.45) times more likely to be frequent users of public transport and 1.53 (95%CI 1.33, 1.76) times more likely to choose to walk or cycle journeys of less than two to three miles. Frequent use of public transport was found to be consistently associated with better mental health for GHQ caseness (OR 0.85, 95%CI 0.79, 0.91), GHQ score (coefficient -0.28, 95%CI -0.41, -0.16), MCS (coefficient 0.45, 95%CI 0.23, 0.66), and WEMWBS (coefficient 0.30, 95%CI 0.19, 0.40). Among frequent users of public transport, participants expressing poor PPTI were 1.46 (95%CI 1.11, 1.93) times more likely to report poorer mental health according to the GHQ caseness indicator, compared to frequent users that regarded PPTI as excellent. Similar results were observed for the other indicators of mental health.

CONCLUSIONS

These findings indicate that while the provision of public transport infrastructure is a necessary pre-condition for stimulating population increases in physical activity, PPTI improvements needs to be prioritised to leverage the full mental health-related co-benefits of active travel.

Interactions of psychosocial factors with built environments in explaining adolescents' active transportation

The present study examined independent and interacting associations of psychosocial and neighborhood built environment variables with adolescents' reported active transportation. Moderating effects of adolescent sex were explored. Mixed-effects regression models were conducted on data from the Teen Environment and Neighborhood observational study (N=928) in the Seattle, WA and Baltimore regions 2009-2011. Frequency index of active transportation to neighborhood destinations (dependent variable) and 7 psychosocial measures were reported by adolescents. Built environment measures included home walkability and count of nearby parks and recreation facilities using GIS procedures and streetscape quality from environmental audits. Results indicated all 3 environmental variables and 3 psychosocial variables (self-efficacy, social support from peers, and enjoyment of physical activity) had significant positive main effects with active transportation (Ps<0.05). Three of 21 two-way interactions were significant in explaining active transportation (Ps<0.1): self-efficacy×GIS-based walkability index, barriers to activity in neighborhood×MAPS streetscape scores, and self-efficacy×GIS-based counts of parks and recreation facilities. In each two-way interaction the highest active transportation was found among adolescents with the combination of activity-supportive built environment and positive psychosocial characteristics. Three-way interactions with sex indicated similar associations for girls and boys, with one exception. Results provided modest support for the ecological model principle of interactions across levels, highlight the importance of both built environment and psychosocial factors in shaping adolescents' active transportation, demonstrated the possibility of sex-specific findings, and suggested strategies for improving adolescents' active transportation may be most effective when targeting multiple levels of influence.

The relationship between bicycle commuting and perceived stress: a cross-sectional study

INTRODUCTION

Active commuting - walking and bicycling for travel to and/or from work or educational addresses - may facilitate daily, routine physical activity. Several studies have investigated the relationship between active commuting and commuting stress; however, there are no studies examining the relationship between solely bicycle commuting and perceived stress, or studies that account for environmental determinants of bicycle commuting and stress. The current study evaluated the relationship between bicycle commuting, among working or studying adults in a dense urban setting, and perceived stress.

METHODS

A cross-sectional study was performed with 788 adults who regularly travelled to work or study locations (excluding those who only commuted on foot) in Barcelona, Spain. Participants responded to a comprehensive telephone survey concerning their travel behaviour from June 2011 through to May 2012. Participants were categorised as either bicycle commuters or non-bicycle commuters, and (based on the Perceived Stress Scale, PSS-4) as either stressed or non-stressed. Multivariate Poisson regression with robust variance models of stress status based on exposures with bicycle commuting were estimated and adjusted for potential confounders.

RESULTS

Bicycle commuters had significantly lower risk of being stressed than non-bicycle commuters (Relative Risk; RR (95% CI)=0.73 (0.60 to 0.89), p=0.001). Bicycle commuters who bicycled 4 days per week (RR (95% CI)=0.42 (0.24 to 0.73), p=0.002) and those who bicycled 5 or more days per week (RR (95% CI)=0.57 (0.42 to 0.77), p<0.001) had lower risk of being stressed than those who bicycled less than 4 days. This relationship remained statistically significant after adjusting for individual and environmental confounders and when using different cut-offs of perceived stress.

CONCLUSIONS

Stress reduction may be an important consequence of routine bicycle use and should be considered by decision makers as another potential benefit of its promotion.

Associations of commuting to school and work with demographic variables and with weight status in eight European countries: The ENERGY-cross sectional study

This study aims to assess the prevalence of different modes of commuting to school and work for 10-12year-olds and their parents; to assess the associations with demographic variables (country, sex, parental education and ethnicity) and with weight status in eight European countries. As part of the ENERGY project a cross-sectional survey was conducted in 2010 in which modes of commuting and socio-demographic variables for children (N=7903) and one of their parents (n=6455) were measured by questionnaires. Children's weight and height were objectively measured; parents self-reported their weight and height. Logistic multilevel regression analyses assessed the associations between mode of commuting and overweight. Differences between countries and differences in mode of commuting according to demographic variables were tested using χ²-test and Marascuilo's Post-hoc analysis. There were marked differences between countries, especially regarding cycling to school, which was common in The Netherlands and Norway and rare in Greece and Spain. Demographic variables were associated with mode of commuting in children and parents. Mode of commuting was not associated with being overweight in children, after adjustment for demographic variables. Bicycling to work, but not other modes of commuting, was significantly inversely associated with being overweight among parents (OR=0.74 (95%CI 0.57-0.97)). Interventions targeting active commuting may promote cycling, and should take into account the differences regarding demographic variables.

Analyzing the impact of public transit usage on obesity

The objective of this paper is to estimate the impact of county-level public transit usage on obesity prevalence in the United States and assess the potential for public transit usage as an intervention for obesity. This study adopts an instrumental regression approach to implicitly control for potential selection bias due to possible differences in commuting preferences among obese and non-obese populations. United States health data from the 2009 Behavioral Risk Factor Surveillance System and transportation data from the 2009 National Household Travel Survey are aggregated and matched at the county level. County-level public transit accessibility and vehicle ownership rates are chosen as instrumental variables to implicitly control for unobservable commuting preferences. The results of this instrumental regression analysis suggest that a one percent increase in county population usage of public transit is associated with a 0.221 percent decrease in county population obesity prevalence at the α=0.01 statistical significance level, when commuting preferences, amount of non-travel physical activity, education level, health resource, and distribution of income are fixed. Hence, this study provides empirical support for the effectiveness of encouraging public transit usage as an intervention strategy for obesity.

Longitudinal associations between built environment characteristics and changes in active commuting

Background

Few studies have assessed the predictors of changes in commuting. This study investigated the associations between physical environmental characteristics and changes in active commuting.

Methods

Adults from the population-based European Prospective Investigation into Cancer (EPIC)-Norfolk cohort self-reported commuting patterns in 2000 and 2007. Active commuters were defined as those who reported ‘always’ or ‘usually’ walking or cycling to work. Environmental attributes around the home and route were assessed using Geographical Information Systems. Associations between potential environmental predictors and uptake and maintenance of active commuting were modelled using logistic regression, adjusting for age, sex and BMI.

Results

Of the 2757 participants (62% female, median baseline age: 52, IQR: 50–56 years), most were passive commuters at baseline (76%, n = 2099) and did not change their usual commute mode over 7 years (82%, n = 2277). In multivariable regression models, participants living further from work were less likely to take up active commuting and those living in neighbourhoods with more streetlights were more likely to take up active commuting (both p < 0.05). Findings for maintenance were similar: participants living further from work (over 10 km, OR: 0.06; 95% CI: 0.25 to 0.13) and had a main or secondary road on route were more likely to maintain their active commuting (OR: 0.52; 95% CI: 0.28 to 0.98). Those living in neighbourhoods with greater density of employment locations were less likely to maintain their active commuting.

Conclusions

Co-locating residential and employment centres as well as redesigning urban areas to improve safety for pedestrians and cyclists may encourage active commuting. Future evaluative studies should seek to assess the effects of redesigning the built environment on active commuting and physical activity.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4396-3) contains supplementary material, which is available to authorized users.

Obesity-related health impacts of fuel excise taxation- an evidence review and cost-effectiveness study

BACKGROUND

Reducing automobile dependence and improving rates of active transport may reduce the impact of obesogenic environments, thereby decreasing population prevalence of obesity and other diseases where physical inactivity is a risk factor. Increasing the relative cost of driving by an increase in fuel taxation may therefore be a promising public health intervention for obesity prevention.

METHODS

A scoping review of the evidence for obesity or physical activity effect of changes in fuel price or taxation was undertaken. Potential health benefits of an increase in fuel excise taxation in Australia were quantified using Markov modelling to simulate obesity, injury and physical activity related health impacts of a fuel excise taxation intervention for the 2010 Australian population. Health adjusted life years (HALYs) gained and healthcare cost savings from diseases averted were estimated. Incremental cost-effectiveness ratios (ICERs) were reported and results were tested through sensitivity analysis.

RESULTS

Limited evidence on the effect of policies such as fuel taxation on health-related behaviours currently exists. Only three studies were identified reporting associations between fuel price or taxation and obesity, whilst nine studies reported associations specifically with physical activity, walking or cycling. Estimates of the cross price elasticity of demand for public transport with respect to fuel price vary, with limited consensus within the literature on a probable range for the Australian context. Cost-effectiveness modelling of a AUD0.10 per litre increase in fuel excise taxation using a conservative estimate of cross price elasticity for public transport suggests that the intervention would be cost-effective from a limited societal perspective (237 HALYs gained, AUD2.6 M in healthcare cost savings), measured against a comparator of no additional increase in fuel excise. Under "best case" assumptions, the intervention would be more cost-effective (3181 HALYs gained, AUD34.2 M in healthcare cost savings).

CONCLUSIONS

Exploratory analysis suggests that an intervention to increase fuel excise taxation may deliver obesity and physical activity related benefits. Whilst such an intervention has significant potential for cost-effectiveness, potential equity and acceptability impacts would need to be minimised. A better understanding of the effectiveness and cost-effectiveness of a range of transport interventions is required in order to achieve more physically active transport environments.

Physical activity when riding an electric assisted bicycle

Background

The objectives of the present study were to compare time spent cycling, exercise intensity, and time spent in moderate- (MPA) and vigorous intensity physical activity (VPA) when cycling on an E-bike and a conventional bicycle on two “cycling-to-work” routes with differences in topography, defined as a hilly and a flat route.

Methods

Eight adults (23–54 years, two women) cycled outdoors on a conventional bicycle and an E-bike, on a flat (8.2 km) and a hilly (7.1 km) route, resulting in 32 journeys. Duration, elevation, and oxygen consumption were recorded using a portable oxygen analyser with GPS. A maximal cardiorespiratory fitness test was performed on a cycle ergometer. Resting metabolic rate was obtained by indirect calorimetry with a canopy hood.

Results

The participants spent less time (median (IQR)) cycling on the E-bike compared with the conventional bicycle, on both the hilly (18.8 (4.9) vs. 26.3 (6.4) minutes) and the flat (20.0 (2.9) vs. 23.8 (1.8) minutes) routes. Lower exercise intensity was observed with the E-bike compared with the conventional bicycle, both on the hilly (50 (18) vs. 60 (22) % of maximal oxygen uptake) and the flat (52 (19) vs. 55 (12) % of maximal oxygen uptake) routes. In both cycling modes, most time was spent in MVPA (92–99%). However, fewer minutes were spent in MVPA with the E-bike than the conventional bicycle, for both the hilly (26% lower) and the flat (17% lower) routes. Cycling on the E-bike also resulted in 35 and 15% fewer minutes in vigorous intensity, respectively on the hilly and flat routes.

Conclusion

Cycling on the E-bike resulted in lower trip duration and exercise intensity, compared with the conventional bicycle. However, most of the time was spent in MVPA. This suggests that changing the commuting mode from car to E-bike will significantly increase levels of physical activity while commuting.

Prevalence of active transportation among adults in Latin America and the Caribbean: a systematic review of population-based studies

OBJECTIVE

To describe the prevalence of "active" (self-propelled, human-powered) transportation in the Latin America and Caribbean (LAC) region over the past decade.

METHODS

MEDLINE, Excerpta Medica (Embase), SportDiscus, Lilacs, MediCarib, Web of Science, OVID, CINAHL, Scopus, Google Scholar, National Transportation Library, and TRIS/TRID were searched for articles on active transportation published between January 2003 and December 2014 with (at least) a title and abstract in English, Portuguese, or Spanish. Research was included in the study if the two reviewing authors agreed it 1) was conducted in an adult sample (≥ 18 years old), 2) was designed to be representative of any LAC area, and 3) reported at least one measure of active transportation. Reference lists of included papers and retrieved reviews were also checked. A total of 129 key informants (87 scientific experts and 42 government authorities) were contacted to identify additional candidate publications. Two other authors extracted the data independently.

RESULTS

A total of 10 459 unique records were found; the full texts of 143 were reviewed; and a total of 45 studies were included in the study, yielding estimates for 72 LAC settings, most of which were in Argentina, Brazil, and Colombia. No eligible studies were found for the years 2003-2004, resulting in a 10-year study time frame. Estimates were available for walking, cycling, or the combination of both, with a high degree of heterogeneity (heterogeneity index (I2) ≥ 99%). The median prevalence of active transportation (combining walking and cycling) was 12.0%, ranging from 5.1% (in Palmas, Brazil) to 58.9% (in Rio Claro, Brazil). Men cycled more than women in all regions for which information was available. The opposite was true for walking.

CONCLUSIONS

Prevalence of active transportation in LAC varied widely, with great heterogeneity and uneven distribution of studies across countries, indicating the need for efforts to build comprehensive surveillance systems with standardized, timely, and detailed estimates of active transportation in order to support policy planning and evaluation.

Active transport and obesity prevention - A transportation sector obesity impact scoping review and assessment for Melbourne, Australia

Given the alarming prevalence of obesity worldwide and the need for interventions to halt the growing epidemic, more evidence on the role and impact of transport interventions for obesity prevention is required. This study conducts a scoping review of the current evidence of association between modes of transport (motor vehicle, walking, cycling and public transport) and obesity-related outcomes. Eleven reviews and thirty-three primary studies exploring associations between transport behaviours and obesity were identified. Cohort simulation Markov modelling was used to estimate the effects of body mass index (BMI) change on health outcomes and health care costs of diseases causally related to obesity in the Melbourne, Australia population. Results suggest that evidence for an obesity effect of transport behaviours is inconclusive (29% of published studies reported expected associations, 33% mixed associations), and any potential BMI effect is likely to be relatively small. Hypothetical scenario analyses suggest that active transport interventions may contribute small but significant obesity-related health benefits across populations (approximately 65 health adjusted life years gained per year). Therefore active transport interventions that are low cost and targeted to those most amenable to modal switch are the most likely to be effective and cost-effective from an obesity prevention perspective. The uncertain but potentially significant opportunity for health benefits warrants the collection of more and better quality evidence to fully understand the potential relationships between transport behaviours and obesity. Such evidence would contribute to the obesity prevention dialogue and inform policy across the transportation, health and environmental sectors.

What Is Driving Obesity? A Review on the Connections Between Obesity and Motorized Transportation

PURPOSE OF REVIEW

Traveling by automobile rather than walking or cycling can encourage obesity by eliminating physical activity. As national obesity rates in the USA have reached 37.9% in 2014, understanding the connections between obesity and transportation choices can help policymakers in the public health community propose effective obesity interventions at the national level.

RECENT FINDINGS

Following from foundational studies examining associations between the built environment and leisure walking, recent studies consider a diverse set of transportation choices regarding mode (e.g., automobile, walking, public transit) and purpose (e.g., commuting, leisure), along with studies on the effectiveness of several transportation-related interventions for obesity. The reviewed studies point toward potential interventions for obesity; there is emerging evidence that commuting by public transit may be one such intervention. Moreover, new data-gathering tools such as global positioning systems, geographic information systems, and accelerometers may alleviate statistical obstacles in conducting future studies.

From sedentary to active school commute: Multi-level factors associated with travel mode shifts

Previous research has examined personal, social, and environmental correlates of active commuting to school, but most were cross-sectional and mode choice studies. This exploratory case study utilized a retrospective natural experiment opportunity, where a group of students transferred to a new school, and therefore experienced changes in their home-to-school travel environments. It examined whether such changes led to mode shifts from sedentary (car or school bus) to active (walking and bicycling) and what factors were associated with those shifts. Retrospective parental survey data (n=165, response rate=46%) were collected in 2011 from a new elementary school that opened in 2010 in Austin, Texas. The survey asked about the child's school travel mode and parental perceptions of home-to-school travel environments before and after the transfer, as well as personal and social factors. Multivariate logistic regressions were used to predict the odds of shifting from sedentary to active modes, using personal, social, and physical environmental variables. Sixty-eight (41.2%) respondents reported a sedentary-to-active mode shift for school commuting. Such shifts were associated with changes in school travel environments (e.g., shorter travel distance, improved safety, and decreased availability of bike lanes/paths) and relevant programs/services (e.g., increase in walking-promotion programs, and decrease in school bus service due to shortened distances). Targeting the current sedentary mode users is important to bring health benefits through increased physical activity and environmental benefits from reduced automobile use. Sedentary-to-active mode shifts may be encouraged by providing walking-promotion programs and by reducing travel distances and safety threats en route to school.

A comprehensive scoring system to measure healthy community design in land use plans and regulations

Comprehensive land use plans and their corresponding regulations play a role in determining the nature of the built environment and community design, which are factors that influence population health and health disparities. To determine the level in which a plan addresses healthy living and active design, there is a need for a systematic, reliable and valid method of analyzing and scoring health-related content in plans and regulations. This paper describes the development and validation of a scoring tool designed to measure the strength and comprehensiveness of health-related content found in land use plans and the corresponding regulations. The measures are scored based on the presence of a specific item and the specificity and action-orientation of language. To establish reliability and validity, 42 land use plans and regulations from across the United States were scored January-April 2016. Results of the psychometric analysis indicate the scorecard is a reliable scoring tool for land use plans and regulations related to healthy living and active design. Intraclass correlation coefficients (ICC) scores showed strong inter-rater reliability for total strength and comprehensiveness. ICC scores for total implementation scores showed acceptable consistency among scorers. Cronbach's alpha values for all focus areas were acceptable. Strong content validity was measured through a committee vetting process. The development of this tool has far-reaching implications, bringing standardization of measurement to the field of land use plan assessment, and paving the way for systematic inclusion of health-related design principles, policies, and requirements in land use plans and their corresponding regulations.

Patterns and correlates of physical activity in adolescents in Dhaka city, Bangladesh

OBJECTIVES

Despite the widely acknowledged public health importance of physical activity (PA), few studies have examined levels of PA in Bangladesh. The purpose of this study was to investigate the patterns and correlates of PA in adolescents in Bangladesh.

STUDY DESIGN

Cross-sectional survey.

METHODS

A total of 798 students, aged 13-17 years; 48% girls, from eight purposively selected secondary schools in Dhaka city, Bangladesh completed a self-administered questionnaire including the 3-Day PA Recall. Parents completed a separate questionnaire to provide household/family-level data. Multilevel generalized linear modelling was used to identify the correlates of PA for boys and girls.

RESULTS

Two-thirds (66%) of the adolescents met the recommendations of 60 min/day of moderate to vigorous PA (MVPA) daily, with more boys than girls (76% and 55%, respectively). The most common activities reported were walking for travel (42%), cricket (33%) and household chores (30%). Multivariable modelling showed that girls' PA was positively associated with mother's education level, walking to school, involvement in school sports and having home sports equipment. Boys' PA was positively associated with mother's employment, having home sports equipment, having a playground at school and walking to school.

CONCLUSIONS

One third of adolescents in Bangladesh were insufficiently active with girls less active than boys. Walking to school and access to sports facilities including playgrounds and home equipment may be important to promote activity among Bangladeshi adolescents, with special attention to the girls.

Socioeconomic and regional differences in active transportation in Brazil

OBJECTIVE

To present national estimates regarding walking or cycling for commuting in Brazil and in 10 metropolitan regions.

METHODS

By using data from the Health section of 2008’s Pesquisa Nacional por Amostra de Domicílio (Brazil’s National Household Sample Survey), we estimated how often employed people walk or cycle to work, disaggregating our results by sex, age range, education level, household monthly income per capita, urban or rural address, metropolitan regions, and macro-regions in Brazil. Furthermore, we estimated the distribution of this same frequency according to quintiles of household monthly income per capita in each metropolitan region of the country.

RESULTS

A third of the employed men and women walk or cycle from home to work in Brazil. For both sexes, this share decreases as income and education levels rise, and it is higher among younger individuals, especially among those living in rural areas and in the Northeast region of the country. Depending on the metropolitan region, the practice of active transportation is two to five times more frequent among low-income individuals than among high-income individuals.

CONCLUSIONS

Walking or cycling to work in Brazil is most frequent among low-income individuals and the ones living in less economically developed areas. Active transportation evaluation in Brazil provides important information for public health and urban mobility policy-making

Associations of specific types of sports and exercise with all-cause and cardiovascular-disease mortality: a cohort study of 80 306 British adults

BACKGROUND/AIM

Evidence for the long-term health effects of specific sport disciplines is scarce. Therefore, we examined the associations of six different types of sport/exercise with all-cause and cardiovascular disease (CVD) mortality risk in a large pooled Scottish and English population-based cohort.

METHODS

Cox proportional hazards regression was used to investigate the associations between each exposure and all-cause and CVD mortality with adjustment for potential confounders in 80 306 individuals (54% women; mean±SD age: 52±14 years).

RESULTS

Significant reductions in all-cause mortality were observed for participation in cycling (HR=0.85, 95% CI 0.76 to 0.95), swimming (HR=0.72, 95% CI 0.65 to 0.80), racquet sports (HR=0.53, 95% CI 0.40 to 0.69) and aerobics (HR=0.73, 95% CI 0.63 to 0.85). No significant associations were found for participation in football and running. A significant reduction in CVD mortality was observed for participation in swimming (HR=0.59, 95% CI 0.46 to 0.75), racquet sports (HR=0.44, 95% CI 0.24 to 0.83) and aerobics (HR=0.64, 95% CI 0.45 to 0.92), but there were no significant associations for cycling, running and football. Variable dose-response patterns between the exposure and the outcomes were found across the sport disciplines.

CONCLUSIONS

These findings demonstrate that participation in specific sports may have significant benefits for public health. Future research should aim to further strengthen the sport-specific epidemiological evidence base and understanding of how to promote greater sports participation.

Direct observations of active school transportation and stroller use in kindergarten children

Little is known about kindergarten students' active school transportation (AST) and stroller/wagon use as sedentary travel devices. The primary objective of this cross-sectional study was to determine the prevalence of kindergarten children arriving to school by active and sedentary modes, including strollers, in Toronto elementary schools and compare to students in kindergarten to grade 6 (K–6). The secondary objective was to examine factors associated with AST in kindergarten and K–6 students. School travel mode was counted using direct observations at elementary schools in the City of Toronto in 2015. Two samples were observed: 1) Kindergarten sample: a random sample of schools with separate kindergarten entrances (n = 26 schools, 1069 children); 2) Kindergarten to grade 6 sample: observations were conducted at arrival locations at 50% of eligible elementary schools for students of all ages (n = 88 schools, 17,224 children). Proportions arriving by different travel modes were compared using Chi-square analysis. Negative binomial regression was conducted to examine the association between school characteristics and AST. AST was lower in the kindergarten compared to the K–6 sample (60% versus 74%, χ² = 91.37, p < 0.001). The predominant sedentary mode for kindergarten students was by vehicle (38%), with < 2% using strollers/wagons. Recent immigrant status was related to higher AST in kindergarten students; higher social disadvantage, crossing guards, school population and collision rates were related to higher AST in the K–6 sample. Factors influencing AST in young students require further investigation to influence the development of healthy active lifestyles at an early age.

•

Observational counts of school transportation mode and stroller use was conducted.

•

Active school transportation (AST) was less in kindergarten versus all age students.

•

< 2% of kindergarten students use strollers for transportation to school.

•

School proportion of recent immigrants was related to AST in kindergarten students.

•

Higher social disadvantage was most strongly related to AST in all age students.

Cycling in São Paulo, Brazil (1997-2012): Correlates, time trends and health consequences

The purpose of the study was to describe cyclists and cycling trips, and to explore correlates, time trends and health consequences of cycling in São Paulo, Brazil from 1997 to 2012. Cross-sectional analysis using repeated São Paulo Household Travel Surveys (HTS). At all time periods cycling was a minority travel mode in São Paulo (1174 people with cycling trips out of 214,719 people). Poisson regressions for individual correlates were estimated using the entire 2012 HTS sample. Men were six times more likely to cycle than women. We found rates of bicycle use rising over time among the richest quartile but total cycling rates dropped from 1997 to 2012 due to decreasing rates among the poor. Harms from air pollution would negate benefits from physical activity through cycling only at 1997 air pollution levels and at very high cycling levels (≥ 9 h of cycling per day). Exposure-based road injury risk decreased between 2007 and 2012, from 0.76 to 0.56 cyclist deaths per 1000 person-hours travelled. Policies to reduce spatial segregation, measures to tackle air pollution, improvements in dedicated cycling infrastructure, and integrating the bicycle with the public transport system in neighborhoods of all income levels could make cycling safer and prevent more individuals from abandoning the cycling mode in São Paulo.

•

Cycling rates increased between 1997 and 2007 but decreased in 2012.

•

Cycling decreased in the 25% poorest and increased in the 25% richest people.

•

Strong gender and age inequalities were observed, favouring men and young people.

•

In current air pollution levels, benefits from cycling outweigh harms in the city.

•

Exposure-based road injury risk decreased between 1997 and 2012.

Assessment of sedentary behaviors and transport-related activities by questionnaire: a validation study

Background

Comprehensive assessment of sedentary behavior (SB) and physical activity (PA), including transport-related activities (TRA), is required to design innovative PA promotion strategies. There are few validated instruments that simultaneously assess the different components of human movement according to their context of practice (e.g. work, transport, leisure). We examined test-retest reliability and validity of the Sedentary, Transportation and Activity Questionnaire (STAQ), a newly developed questionnaire dedicated to assessing context-specific SB, TRA and PA.

Methods

Ninety six subjects (51 women) kept a contextualized activity-logbook and wore a hip accelerometer (Actigraph GT3X + ^TM) for a 7-day or 14-day period, at the end of which they completed the STAQ. Activity-energy expenditure was measured in a subgroup of 45 subjects using the double labeled water (DLW) method. Test-retest reliability was assessed using intra-class-coefficients (ICC) in a subgroup of 32 subjects who filled the questionnaire twice one month apart. Accelerometry was annotated using the logbook to obtain total and context-specific objective estimates of SB. Spearman correlations, Bland-Altman plots and ICC were used to analyze validity with logbook, accelerometry and DLW data validity criteria.

Results

Test-retest reliability was fair for total sitting time (ICC = 0.52), good to excellent for work sitting time (ICC = 0.71), transport-related walking (ICC = 0.61) and car use (ICC = 0.67), and leisure screen-related SB (ICC = 0.64-0.79), but poor for total sitting time during leisure and transport-related contexts. For validity, compared to accelerometry, significant correlations were found for STAQ estimates of total (r = 0.54) and context-specific sitting times with stronger correlations for work sitting time (r = 0.88), and screen times (TV/DVD viewing: r = 0.46; other screens: r = 0.42) than for transport (r = 0.35) or leisure-related sitting-times (r = 0.19). Compared to contextualized logbook, STAQ estimates of TRA was higher for car (r = 0.65) than for active transport (r = 0.41). The questionnaire generally overestimated work- and leisure-related SB and sitting times, while it underestimated total and transport-related sitting times.

Conclusions

The STAQ showed acceptable reliability and a good ranking validity for assessment of context-specific SB and TRA. This instrument appears as a useful tool to study SB, TRA and PA in context in adults.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-016-3412-3) contains supplementary material, which is available to authorized users.

Which Socio-Ecological Factors Associate with a Switch to or Maintenance of Active and Passive Transport during the Transition from Primary to Secondary School?

Objectives

The aim was to investigate which individual, psychosocial and physical neighborhood environmental factors associate with children’s switch to or maintenance of active/passive transport to school and to leisure time destinations during the transition from primary to secondary school.

Methods

Children (n = 313) filled out a questionnaire in the last year of primary school and 2 years later to assess socio-demographic characteristics and self-reported transport. One of their parents completed a questionnaire to assess parental perceptions of psychosocial and physical neighborhood environmental factors.

Results

The increase of the home-school distance was significantly associated with children’s switch to or maintenance of passive transport to school compared to a switch to (OR = 0.81; p = 0.03) and maintenance (OR = 0.87; p = 0.03) of active transport to school. Low SES was associated with children’s switch to active transport to school compared to maintenance of active transport (OR = 3.67; p = 0.07). For transport to leisure time destinations, other factors such as parental perceived neighborhood safety from traffic and crime (OR = 2.78; p = 0.004), a positive social norm (OR = 1.49; p = 0.08), positive attitudes (OR = 1.39; p = 0.08) (i.e. more benefits, less barriers) towards their children’s physical activity and poor walking/cycling facilities in the neighborhood (OR = 0.70; p = 0.06) were associated with children’s maintenance of active transport to leisure time destinations compared to a switch to or maintenance of passive transport.

Conclusions

This longitudinal study can give directions for interventions promoting children’s active transport during the transition to secondary school. It is necessary to promote different possibilities at primary school for children to use active transport when going to secondary school. Walking/cycling a part of the home-school trip can be a possible solution for children who will be living at non-feasible distances from secondary school. Providing safe neighborhoods, combined with programs for parents stimulating a positive social norm and positive attitudes towards physical activity during primary school, can be effective.

Is there such a thing as sustainable physical activity?

There is a global need to diminish climate gas emissions, and a simultaneous call for enhanced levels of physical activity. Increased physical activity entails reduced risk for overweight and chronic diseases, as well as a potential to reduce transport's major contribution to global CO₂ emissions. However, increased physical activity level also implies increased energy expenditure. Therefore, we aim to introduce the concept of sustainable physical activity, and to suggest certain physical activity habits due to their potentially sustainable properties. Worldwide, a third of adults and four fifths of adolescents ought to be more physically active in order to comply with current physical activity recommendations. Yet, considering upcoming resource challenges, types of physical activity should be taken into account. Active transportation represents carbon-friendly means of transportation as well as an opportunity for enhanced physical activity. Physical activity conducted in the local community is likely to favor sustainability through less use of fossil fuel, as it makes transportation redundant. Moreover, going "back to basic", using less equipment and appliances for everyday tasks could contribute toward energy balance through increased physical activity, and could decrease resource use. Finally, balancing food intake and energy expenditure would require less food production with accompanying energy savings.

Transportation Planning and Quality of Life: Where Do They Intersect?

Policy makers and researchers are increasingly recognizing the connections between public health and transportation, but health improvements are typically framed from a physical health perspective rather than considering broader quality of life (QOL) impacts. Currently, there is a limited understanding of the ways in which transportation and QOL intersect, and little is known about how metropolitan planning organizations (MPOs) in the United States are addressing QOL outcomes. This study addressed these gaps by developing a conceptual framework holistically linking transportation to QOL. The proposed framework identified four transportation-related QOL dimensions-physical, mental, social, and economic well-being-which are predominantly influenced by three components of the transportation system: mobility/accessibility, the built environment, and vehicle traffic. This framework then formed the basis for a content analysis of 148 long-range transportation plans in the United States to evaluate the extent to which QOL is being considered in the planning process. The results of the analysis and a follow-up examination of 13 plans revealed that MPOs are inconsistently addressing QOL. Plans primarily targeted QOL enhancement from the perspective of physical well-being, while mental and social well-being were rarely considered. Policy recommendations were provided to more comprehensively integrate QOL into the transportation planning process.

Active Traveling and Its Associations with Self-Rated Health, BMI and Physical Activity: A Comparative Study in the Adult Swedish Population

Active traveling to a daily occupation means that an individual uses an active way of traveling between two destinations. Active travel to work or other daily occupations offers a convenient way to increase physical activity levels which is known to have positive effects on several health outcomes. Frequently used concepts in city planning and regional planning today are to create environments for active commuting and active living. Even then, little research has focused on traveling modes and subjective health outcomes such as self-rated health (SRH). This study aimed to explore and investigate associations between travel mode and health-related outcomes, such as self-rated health (SRH), body mass index (BMI) and overall physical activity, in an adult population in Sweden. A cross-sectional study was conducted in a randomly selected population-based sample (n = 1786, age 45-75 years); the respondents completed a questionnaire about their regular travel mode, demographics, lifestyle, BMI and SRH. Chi-square tests and logistic regressions found that inactive traveling was associated with poor SRH, a greater risk of obesity or being overweight and overall physical inactivity. In addition, lifestyle factors, such as choice of food and smoking habits, were associated with SRH, BMI and overall physical activity.

Write, draw, show, and tell: a child-centred dual methodology to explore perceptions of out-of-school physical activity

BACKGROUND

Research to increase children's physical activity and inform intervention design has, to date, largely underrepresented children's voices. Further, research has been limited to singular qualitative methods that overlook children's varied linguistic ability and interaction preference. The aim of this study was to use a novel combination of qualitative techniques to explore children's current views, experiences and perceptions of out-of-school physical activity as well as offering formative opinion about future intervention design.

METHODS

Write, draw, show and tell (WDST) groups were conducted with 35 children aged 10-11 years from 7 primary schools. Data were analysed through a deductive and inductive process, firstly using the Youth Physical Activity Promotion Model as a thematic framework, and then inductively to enable emergent themes to be further explored. Pen profiles were constructed representing key emergent themes.

RESULTS

The WDST combination of qualitative techniques generated complimentary interconnected data which both confirmed and uncovered new insights into factors relevant to children's out-of-school physical activity. Physical activity was most frequently associated with organised sports. Fun, enjoyment, competence, and physical activity provision were all important predictors of children's out-of-school physical activity. Paradoxically, parents served as both significant enablers (i.e. encouragement) and barriers (i.e. restricting participation) to physical activity participation. Some of these key findings would have otherwise remained hidden when compared to more traditional singular methods based approaches.

CONCLUSIONS

Parents are in a unique position to promote health promoting behaviours serving as role models, physical activity gatekeepers and choice architects. Given the strong socialising effect parents have on children's physical activity, family-based physical activity intervention may offer a promising alternative compared to traditional school-based approaches. Parents' qualitative input is important to supplement children's voices and inform future family-based intervention design. The WDST method developed here is an inclusive, interactive and child-centred methodology which facilitates the exploration of a wide range of topics and enhances data credibility.

Longitudinal associations of active commuting with wellbeing and sickness absence

OBJECTIVE

Our aim was to explore longitudinal associations of active commuting (cycling to work and walking to work) with physical wellbeing (PCS-8), mental wellbeing (MCS-8) and sickness absence.

METHOD

We used data from the Commuting and Health in Cambridge study (2009 to 2012; n=801) to test associations between: a) maintenance of cycling (or walking) to work over a one year period and indices of wellbeing at the end of that one year period; and b) associations between change in cycling (or walking) to work and change in indices of wellbeing. Linear regression was used for testing associations with PCS-8 and MCS-8, and negative binomial regression for sickness absence.

RESULTS

After adjusting for sociodemographic variables, physical activity and physical limitation, those who maintained cycle commuting reported lower sickness absence (0.46, 95% CI: 0.14-0.80; equivalent to one less day per year) and higher MCS-8 scores (1.50, 0.10-2.10) than those who did not cycle to work. The association for sickness absence persisted after adjustment for baseline sickness absence. No significant associations were observed for PCS-8. Associations between change in cycle commuting and change in indices of wellbeing were not significant. No significant associations were observed for walking.

CONCLUSIONS

This work provides some evidence of the value of cycle commuting in improving or maintaining the health and wellbeing of adults of working age. This may be important in engaging employers in the promotion of active travel and communicating the benefits of active travel to employees.

Change in active transportation and weight gain in pregnancy

BACKGROUND

Pregnancy is characterised by large weight gain over a short period, and often a notable change in mode of transportation. This makes pregnancy suitable for examining the plausible, but in the scientific literature still unclear, association between active transportation and weight gain. We hypothesize that women continuing an active mode of transportation to work or school from pre- to early pregnancy will have a lower gestational weight gain (GWG) than those who change to a less active mode of transportation.

METHODS

We analysed prospective data from the Norwegian Fit for Delivery (NFFD) trial. Between September 2009 and February 2013 606 women were consecutively enrolled in median gestational week 16 (range; 8-20). Of 219 women who used an active mode of transportation (biking, walking, public transportation) pre-pregnancy, 66 (30%) converted to a less active mode in early pregnancy ("active-less active" group), and 153 (70%) continued with active transportation ("active-active" group). Pre-pregnancy weight was self-reported. Weight at gestational (GA) weeks 16, 30, 36, and at term delivery was objectively measured. Weight gain was compared between the two groups. Linear mixed effects analysis of the repeated weight measures was performed including the group*time interaction.

RESULTS

A significant overall group effect was observed for the four time points together ("active-active" group: 77.3 kg vs. "active-less active" group: 78.8 kg, p = 0.008). The interaction term group*time was significant indicating different weight gain throughout pregnancy for the two groups; the mean differences between the groups were 0.7 kg at week 16, 1.4 kg at week 30, 2.1 kg at week 36, and 2.2 kg at term delivery, respectively.

CONCLUSION

The findings indicate that active transportation is one possible approach to prevent excessive weight gain in pregnancy.

Health impacts of the Cambridgeshire Guided Busway: a natural experimental study

Background

Improving transport infrastructure to support walking and cycling on the journey to and from work – active commuting – could help to promote physical activity and improve population health.

Aims

To assess whether or not investment in new high-quality transport infrastructure was associated with an increase in active commuting; wider health impacts of changes in travel behaviour; determinants of the use and uptake of active commuting; and how changes in travel behaviour were distributed in the population and related to the wider social context.

Design

The Commuting and Health in Cambridge study, comprising a quasi-experimental cohort study combined with both nested and supplementary in-depth quantitative and qualitative studies.

Setting

Cambridgeshire, UK.

Participants

A cohort of 1143 adults living within 30 km of Cambridge, working in the city and recruited in 2009; and a separate sample of 1710 users intercepted on the Cambridgeshire Guided Busway in 2012.

Intervention

The Cambridgeshire Guided Busway, comprising a new bus network using 22 km of guideway (segregated bus track) accompanied by a traffic-free path for pedestrians and cyclists, opened in 2011.

Main outcome measure

Change in time spent in active commuting from 2009 to 2012, using a self-reported measure validated using georeferenced combined heart rate and movement sensor data.

Methods

A delay from 2009 to 2011 in completing the intervention entailed some changes to the original design and attrition of the cohort. A period of methodological and observational research on active commuting preceded the evaluation, which was based on a quasi-experimental cohort analysis together with the intercept and qualitative data. A graded measure of each participant’s exposure to the intervention, based on the proximity of the busway to his or her home, served as the basis for controlled comparisons.

Results

Commuting practices were complex and shaped by various changeable social and environmental factors. Walking and cycling were often incorporated into longer commuting journeys made predominantly by car or public transport. In multivariable multinomial regression analyses, exposure to the intervention was associated with a greater likelihood of a large increase in the proportion of commuting trips involving any active travel [adjusted relative risk ratio (RRR) 1.80, 95% confidence interval (CI) 1.27 to 2.55], of a large decrease in the proportion of trips made entirely by car (RRR 2.09, 95% CI 1.35 to 3.21), and of an increase in weekly cycle commuting time (RRR 1.34, 95% CI 1.03 to 1.76). There was a mixed pattern of effects at the individual level, with the intervention providing a more supportive environment for active commuting for some and not for others. There was some evidence that the effect was most pronounced among those who reported no active commuting at baseline, and observational evidence suggesting a relationship between active commuting, greater overall physical activity, and improved well-being and weight status.

Conclusions

These findings provide new empirical support and direction for reconfiguring transport systems to improve population health and reduce health inequalities. They should be combined with evidence from research evaluating related environmental changes in other settings, preferably using longer periods of observation and controlled comparisons, to support more generalisable causal inference.

Funding

The National Institute for Health Research Public Health Research programme.

Tourism Experiences and Self-Rated Health Among Older Adults in China

OBJECTIVE

To investigate factors associated with tourism experiences, and the association between tourism experiences and subsequent self-rated health.

METHOD

Multilevel logistic regression models and four waves of panel data from a large nationally representative survey of older adults in China were employed.

RESULTS

Those who had a tourism experience tended to be younger, men, urban residents, have a higher socioeconomic status (SES), and frequently participate in leisure activities and exercise. However, controlling for SES, women were more likely than men to have a tourism experience. Notably, tourism was negatively associated with poor self-rated health and the association was robust to adjustments for a wide range of confounders.

DISCUSSION

The net beneficial impact of tourism on self-rated health may operate through several mechanisms such as improvements in tourists' cognitive functioning, healthy lifestyles, self-esteen, family and social relations, and psychological and spirtual well-being. Tourism participation is an effective way to promote healthy aging.

Getting England to be more physically active: are the Public Health Responsibility Deal's physical activity pledges the answer?

BACKGROUND

The Public Health Responsibility Deal (RD) in England is a public-private partnership involving voluntary pledges between government, industry, and other organisations to improve public health by addressing alcohol, food, health at work, and physical activity. This paper analyses the RD physical activity (PA) pledges in terms of the evidence of their potential effectiveness, and the likelihood that they have motivated actions among organisations that would not otherwise have taken place.

METHODS

We systematically reviewed evidence of the effectiveness of interventions proposed in four PA pledges of the RD, namely, those on physical activity in the community; physical activity guidelines; active travel; and physical activity in the workplace. We then analysed publically available data on RD signatory organisations' plans and progress towards achieving the physical activity pledges, and assessed the extent to which activities among organisations could be attributed to the RD.

RESULTS

Where combined with environmental approaches, interventions such as mass media campaigns to communicate the benefits of physical activity, active travel in children and adults, and workplace-related interventions could in principle be effective, if fully implemented. However, most activities proposed by each PA pledge involved providing information or enabling choice, which has limited effectiveness. Moreover, it was difficult to establish the extent of implementation of pledges within organisations, given that progress reports were mostly unavailable, and, where provided, it was difficult to ascertain their relevance to the RD pledges. Finally, 15 % of interventions listed in organisations' delivery plans were judged to be the result of participation in the RD, meaning that most actions taken by organisations were likely already under way, regardless of the RD.

CONCLUSIONS

Irrespective of the nature of a public health policy to encourage physical activity, targets need to be evidence-based, well-defined, measurable and encourage organisations to go beyond business as usual. RD physical activity targets do not adequately fulfill these criteria.

Theorising and testing environmental pathways to behaviour change: natural experimental study of the perception and use of new infrastructure to promote walking and cycling in local communities

OBJECTIVE

Some studies have assessed the effectiveness of environmental interventions to promote physical activity, but few have examined how such interventions work. We investigated the environmental mechanisms linking an infrastructural intervention with behaviour change.

DESIGN

Natural experimental study.

SETTING

Three UK municipalities (Southampton, Cardiff and Kenilworth).

PARTICIPANTS

Adults living within 5 km of new walking and cycling infrastructure.

INTERVENTION

Construction or improvement of walking and cycling routes. Exposure to the intervention was defined in terms of residential proximity.

OUTCOME MEASURES

Questionnaires at baseline and 2-year follow-up assessed perceptions of the supportiveness of the environment, use of the new infrastructure, and walking and cycling behaviours. Analysis proceeded via factor analysis of perceptions of the physical environment (step 1) and regression analysis to identify plausible pathways involving physical and social environmental mediators and refine the intervention theory (step 2) to a final path analysis to test the model (step 3).

RESULTS

Participants who lived near and used the new routes reported improvements in their perceptions of provision and safety. However, path analysis (step 3, n=967) showed that the effects of the intervention on changes in time spent walking and cycling were largely (90%) explained by a simple causal pathway involving use of the new routes, and other pathways involving changes in environmental cognitions explained only a small proportion of the effect.

CONCLUSIONS

Physical improvement of the environment itself was the key to the effectiveness of the intervention, and seeking to change people's perceptions may be of limited value. Studies of how interventions lead to population behaviour change should complement those concerned with estimating their effects in supporting valid causal inference.

Changes in mode of travel to work: a natural experimental study of new transport infrastructure

BACKGROUND

New transport infrastructure may promote a shift towards active travel, thereby improving population health. The purpose of this study was to determine the effect of a major transport infrastructure project on commuters' mode of travel, trip frequency and distance travelled to work.

METHODS

Quasi-experimental analysis nested within a cohort study of 470 adults working in Cambridge, UK. The intervention consisted of the opening of a guided busway with a path for walking and cycling in 2011. Exposure to the intervention was defined as the negative of the square root of the shortest distance from home to busway. The outcome measures were changes in commute mode share and number of commute trips - both based on a seven-day travel-to-work record collected before (2009) and after (2012) the intervention - and change in objective commute distance. The mode share outcomes were changes in the proportions of trips (i) involving any active travel, (ii) involving any public transport, and (iii) made entirely by car. Separate multinomial regression models were estimated adjusting for commute and sociodemographic characteristics, residential settlement size and life events.

RESULTS

Proximity to the busway predicted an increased likelihood of a large (>30 %) increase in the share of commute trips involving any active travel (relative risk ratio [RRR] 1.80, 95 % CI 1.27, 2.55) and a large decrease in the share of trips made entirely by car (RRR 2.09, 95 % CI 1.35, 3.21), as well as a lower likelihood of a small (<30 %) reduction in the share of trips involving any active travel (RRR 0.47, 95 % CI 0.28, 0.81). It was not associated with changes in the share of commute trips involving any public transport, the number of commute trips, or commute distance.

CONCLUSIONS

The new infrastructure promoted an increase in the share of commuting trips involving active travel and a decrease in the share made entirely by car. Further analysis will show the extent to which the changes in commute mode share were translated into an increase in time spent in active commuting and consequent health gain.

Walking for Transportation: What do U.S. Adults Think is a Reasonable Distance and Time?

BACKGROUND

Less than one-third of U.S. adults walk for transportation. Public health strategies to increase transportation walking would benefit from knowing what adults think is a reasonable distance to walk. Our purpose was to determine 1) what adults think is a reasonable distance and amount of time to walk and 2) whether there were differences in minutes spent transportation walking by what adults think is reasonable.

METHODS

Analyses used a cross-sectional nationwide adult sample (n = 3653) participating in the 2010 Summer ConsumerStyles mail survey.

RESULTS

Most adults (> 90%) think transportation walking is reasonable. However, less than half (43%) think walking a mile or more or for 20 minutes or more is reasonable. What adults think is reasonable is similar across most demographic subgroups, except for older adults (≥ 65 years) who think shorter distances and times are reasonable. Trend analysis that adjust for demographic characteristics indicates adults who think longer distances and times are reasonable walk more.

CONCLUSIONS

Walking for short distances is acceptable to most U.S. adults. Public health programs designed to encourage longer distance trips may wish to improve supports for transportation walking to make walking longer distances seem easier and more acceptable to most U.S. adults.

Associations between active travel and weight, blood pressure and diabetes in six middle income countries: a cross-sectional study in older adults

BACKGROUND

There is little published data on the potential health benefits of active travel in low and middle-income countries. This is despite increasing levels of adiposity being linked to increases in physical inactivity and non-communicable diseases. This study will examine: (1) socio-demographic correlates of using active travel (walking or cycling for transport) among older adults in six populous middle-income countries (2) whether use of active travel is associated with adiposity, systolic blood pressure and self-reported diabetes in these countries.

METHODS

Data are from the WHO Study on Global Ageing and Adult Health (SAGE) of China, India, Mexico, Ghana, Russia and South Africa with a total sample size of 40,477. Correlates of active travel (≥150 min/week) were examined using logistic regression. Logistic and linear regression analyses were used to examine health related outcomes according to three groups of active travel use per week.

RESULTS

46.4% of the sample undertook ≥150 min of active travel per week (range South Africa: 21.9% Ghana: 57.8%). In pooled analyses those in wealthier households were less likely to meet this level of active travel (Adjusted Risk Ratio (ARR) 0.77, 95% Confidence Intervals 0.67; 0.88 wealthiest fifth vs. poorest). Older people and women were also less likely to use active travel for ≥150 min per week (ARR 0.71, 0.62; 0.80 those aged 70+ years vs. 18-29 years old, ARR 0.82, 0.74; 0.91 women vs. men). In pooled fully adjusted analyses, high use of active travel was associated with lower risk of overweight (ARR 0.71, 0.59; 0.86), high waist-to-hip ratio (ARR 0.71, 0.61; 0.84) and lower BMI (-0.54 kg/m(2), -0.98;- 0.11). Moderate (31-209 min/week) and high use (≥210 min/week) of active travel was associated with lower waist circumference (-1.52 cm (-2.40; -0.65) and -2.16 cm (3.07; -1.26)), and lower systolic blood pressure (-1.63 mm/Hg (-3.19; -0.06) and -2.33 mm/Hg (-3.98; -0.69)).

CONCLUSIONS

In middle-income countries use of active travel for ≥150 min per week is more common in lower socio-economic groups and appears to confer similar health benefits to those identified in high-income settings. Efforts to increase active travel levels should be integral to strategies to maintain healthy weight and reduce disease burden in these settings.

Impact of changes in mode of travel to work on changes in body mass index: evidence from the British Household Panel Survey

Background

Active commuting is associated with various health benefits, but little is known about its causal relationship with body mass index (BMI).

Methods

We used cohort data from three consecutive annual waves of the British Household Panel Survey, a longitudinal study of nationally representative households, in 2004/2005 (n=15 791), 2005/2006 and 2006/2007. Participants selected for the analyses (n=4056) reported their usual main mode of travel to work at each time point. Self-reported height and weight were used to derive BMI at baseline and after 2 years. Multivariable linear regression analyses were used to assess associations between switching to and from active modes of travel (over 1 and 2 years) and change in BMI (over 2 years) and to assess dose–response relationships.

Results

After adjustment for socioeconomic and health-related covariates, the first analysis (n=3269) showed that switching from private motor transport to active travel or public transport (n=179) was associated with a significant reduction in BMI compared with continued private motor vehicle use (n=3090; −0.32 kg/m², 95% CI −0.60 to −0.05). Larger adjusted effect sizes were associated with switching to active travel (n=109; −0.45 kg/m², −0.78 to −0.11), particularly among those who switched within the first year and those with the longest journeys. The second analysis (n=787) showed that switching from active travel or public transport to private motor transport was associated with a significant increase in BMI (0.34 kg/m², 0.05 to 0.64).

Conclusions

Interventions to enable commuters to switch from private motor transport to more active modes of travel could contribute to reducing population mean BMI.

International inter-school competition to encourage children to walk to school: a mixed methods feasibility study

BACKGROUND

Active travel to school can be an important contributor to the total physical activity of children but levels have declined and more novel approaches are required to stimulate this as an habitual behaviour. The aim of this mixed methods study was to investigate the feasibility of an international walk to school competition supported by novel swipecard technology to increase children's walking to/from school.

METHODS

Children aged 9-13 years old participated in an international walk to school competition to win points for themselves, their school and their country over a 4-week period. Walks to and from school were recorded using swipecard technology and a bespoke website. For each point earned by participants, 1 pence (£ 0.01) was donated to the charity of the school's choice. The primary outcome was number of walks to/from school objectively recorded using the swipecard tracking system over the intervention period. Other measures included attitudes towards walking collected at baseline and week 4 (post-intervention). A qualitative sub-study involving focus groups with children, parents and teachers provided further insight.

RESULTS

A total of 3817 children (mean age 11.5 ± SD 0.7) from 12 schools in three cities (London and Reading, England and Vancouver, Canada) took part in the intervention, representing a 95% intervention participation rate. Results show a gradual decline in the average number of children walking to and from school over the 4-week period (week 1 mean 29% ± SD2.5; week 2 mean 18% ± SD3.6; week 3 mean 14% ± SD4.0; week 4 mean 12% ± SD1.1). Post intervention, 97% of children felt that walking to school helped them stay healthy, feel happy (81%) and stay alert in class (76%). These results are supported by qualitative findings from children, parents and teachers. Key areas for improvement include the need to incorporate strategies for maintenance of behaviour change into the intervention and also to adopt novel methods of data collection to increase follow-up rates.

CONCLUSIONS

This mixed methods study suggests that an international walk to school competition using innovative technology can be feasibly implemented and offers a novel way of engaging schools and motivating children to walk to school.

The association between access to public transportation and self-reported active commuting

Active commuting provides routine-based regular physical activity which can reduce the risk of chronic diseases. Using public transportation involves some walking or cycling to a transit stop, transfers and a walk to the end location and users of public transportation have been found to accumulate more moderate physical activity than non-users. Understanding how public transportation characteristics are associated with active transportation is thus important from a public health perspective. This study examines the associations between objective measures of access to public transportation and self-reported active commuting. Self-reported time spent either walking or cycling commuting each day and the distance to workplace were obtained for adults aged 16 to 65 in the Danish National Health Survey 2010 (n = 28,928). Access to public transportation measures were computed by combining GIS-based road network distances from home address to public transit stops an integrating their service level. Multilevel logistic regression was used to examine the association between access to public transportation measures and active commuting. Distance to bus stop, density of bus stops, and number of transport modes were all positively associated with being an active commuter and with meeting recommendations of physical activity. No significant association was found between bus services at the nearest stop and active commuting. The results highlight the importance of including detailed measurements of access to public transit in order to identify the characteristics that facilitate the use of public transportation and active commuting.

The relationship between utilitarian walking, utilitarian cycling, and body mass index in a population based cohort study of adults: comparing random intercepts and fixed effects models

OBJECTIVE

To examine associations between utilitarian walking, utilitarian cycling, leisure time physical activity and body mass index (BMI).

METHODS

Participants from the National Population Health Survey (NPHS) of Statistics Canada were interviewed by telephone every two years from 1994 to 2010. Analysis includes data from 6894 living participants aged 18-64years. Fixed effects and random intercepts models examined the association between BMI, utilitarian walking, and utilitarian cycling, controlling for behavioral and sociodemographic factors.

RESULTS

The final adjusted fixed effects models showed no significant relationship between utilitarian walking and BMI. In the unbalanced sample utilitarian cycling for 1 to 5h per week (b=-0.15, 95% CI: -0.28 to -0.02), and more than 5h per week (b=-0.22, 95% CI: -0.44 to 0.00) was significantly associated with BMI over time. In the fully balanced sample utilitarian cycling for 1 to 5h per week (b=-0.12, 95% CI: -0.27 to 0.03), more than 5h per week (b=-0.16, 95% CI: -0.45 to 0.13) was not significantly associated with BMI over time.

CONCLUSION

The results suggest that utilitarian walking is not related to BMI. The relationship between utilitarian cycling and BMI is less clear.

Variations in active transport behavior among different neighborhoods and across adult lifestages

OBJECTIVE

Built environment characteristics are closely related to transport behavior, but observed variations could be due to residents own choice of neighborhood called residential self-selection. The aim of this study was to investigate differences in neighborhood walkability and residential self-selection across life stages in relation to active transport behavior.

METHODS

The IPEN walkability index, which consists of four built environment characteristics, was used to define 16 high and low walkable neighborhoods in Aarhus, Denmark (250.000 inhabitants). Transport behavior was assessed using the IPAQ questionnaire. Life stages were categorized in three groups according to age and parental status. A factor analysis was conducted to investigate patterns of self-selection. Multivariable logistic regression analyses were carried out to evaluate the association between walkability and transport behavior i.e. walking, cycling and motorized transport adjusted for residential self-selection and life stages.

RESULTS

A total of 642 adults aged 20-65 years completed the questionnaire. The highest rated self-selection preference across all groups was a safe and secure neighborhood followed by getting around easily on foot and by bicycle. Three self-selection factors were detected, and varied across the life stages. In the multivariable models high neighborhood walkability was associated with less motorized transport (OR 0.33 95%CI 0.18-0.58), more walking (OR 1.65 95%CI 1.03-2.65) and cycling (OR 1.50 95% CI 1.01-2.23). Self-selection and life stage were also associated with transport behavior, and attenuated the association with walkability.

CONCLUSION

This study supports the hypothesis that some variation in transport behavior can be explained by life stages and self-selection, but the association between living in a more walkable neighborhood and active transport is still significant after adjusting for these factors. Life stage significantly moderated the association between neighborhood walkability and cycling for transport, and household income significantly moderated the association between neighborhood walkability and walking for transport. Getting around easily by bicycle and on foot was the highest rated self-selection factor second only to perceived neighborhood safety.

Systematic review and meta-analysis of reduction in all-cause mortality from walking and cycling and shape of dose response relationship

BACKGROUND AND OBJECTIVE

Walking and cycling have shown beneficial effects on population risk of all-cause mortality (ACM). This paper aims to review the evidence and quantify these effects, adjusted for other physical activity (PA).

DATA SOURCES

We conducted a systematic review to identify relevant studies. Searches were conducted in November 2013 using the following health databases of publications: Embase (OvidSP); Medline (OvidSP); Web of Knowledge; CINAHL; SCOPUS; SPORTDiscus. We also searched reference lists of relevant texts and reviews.

STUDY ELIGIBILITY CRITERIA AND PARTICIPANTS

Eligible studies were prospective cohort design and reporting walking or cycling exposure and mortality as an outcome. Only cohorts of individuals healthy at baseline were considered eligible.

STUDY APPRAISAL AND SYNTHESIS METHODS

Extracted data included study population and location, sample size, population characteristics (age and sex), follow-up in years, walking or cycling exposure, mortality outcome, and adjustment for other co-variables. We used random-effects meta-analyses to investigate the beneficial effects of regular walking and cycling.

RESULTS

Walking (18 results from 14 studies) and cycling (8 results from 7 studies) were shown to reduce the risk of all-cause mortality, adjusted for other PA. For a standardised dose of 11.25 MET.hours per week (or 675 MET.minutes per week), the reduction in risk for ACM was 11% (95% CI = 4 to 17%) for walking and 10% (95% CI = 6 to 13%) for cycling. The estimates for walking are based on 280,000 participants and 2.6 million person-years and for cycling they are based on 187,000 individuals and 2.1 million person-years. The shape of the dose-response relationship was modelled through meta-analysis of pooled relative risks within three exposure intervals. The dose-response analysis showed that walking or cycling had the greatest effect on risk for ACM in the first (lowest) exposure interval.

CONCLUSIONS AND IMPLICATIONS

The analysis shows that walking and cycling have population-level health benefits even after adjustment for other PA. Public health approaches would have the biggest impact if they are able to increase walking and cycling levels in the groups that have the lowest levels of these activities.

REVIEW REGISTRATION

The review protocol was registered with PROSPERO (International database of prospectively registered systematic reviews in health and social care) PROSPERO 2013: CRD42013004266.

Patterns, levels and correlates of self-reported physical activity in urban black Soweto women

BACKGROUND

Urban black South African women have a high prevalence of non-communicable diseases such as obesity and type 2 diabetes. The aim of this study was to assess the physical activity patterns of a cohort of middle-aged urban-dwelling black African women and to determine if physical activity is associated with anthropometric measures and metabolic outcomes in this population.

METHODS

Physical activity and sitting time were assessed using the Global Physical Activity Questionnaire (GPAQ) in a cross-sectional study of 977 black African women (mean age 41.0 ± 7.84 years) from the Birth to Twenty study based in Soweto, Johannesburg. Anthropometric outcomes were measured and fasting blood glucose, insulin and lipid profile were analysed to determine metabolic disease risk and prevalence.

RESULTS

Sixty-seven percent of the population were classified as active according to GPAQ criteria, and the domain that contributed most to overall weekly physical activity was walking for travel. Only 45.0% of women participated in leisure time activity. The prevalence of metabolic syndrome in this sample was 40.0%, and the prevalence of overweight and obesity was 29.2% and 48.0%, respectively. Women who reported owning a motor vehicle walked for travel less, and participated in more leisure-time activity (both p < 0.01), while women who owned a television reported significantly lower moderate-vigorous physical activity (MVPA), and walking for travel (both p < 0.01). Sitting time (mins/wk) was not different between the activity groups, but was associated with triglycerides and diastolic blood pressure. Total physical activity was inversely associated with fasting insulin, and physical activity in the work domain was associated with fat free soft tissue mass.

CONCLUSIONS

The findings of this study show that the majority of urban dwelling black South African women are classified as physically active despite a high prevalence of obesity and metabolic disease risk factors. Sitting time had detrimental effects on both triglyceride levels and diastolic blood pressure whilst total physical activity attenuated fasting insulin levels. As walking for travel is a major contributor to physical activity, future research should attempt to determine whether the intensity of this activity plays a role in the prevention of cardiometabolic diseases.

New walking and cycling routes and increased physical activity: one- and 2-year findings from the UK iConnect Study

OBJECTIVES

We evaluated the effects of providing new high-quality, traffic-free routes for walking and cycling on overall levels of walking, cycling, and physical activity.

METHODS

1796 adult residents in 3 UK municipalities completed postal questionnaires at baseline (2010) and 1-year follow-up (2011), after the construction of the new infrastructure. 1465 adults completed questionnaires at baseline and 2-year follow-up (2012). Transport network distance from home to infrastructure defined intervention exposure and provided a basis for controlled comparisons.

RESULTS

Living nearer the infrastructure did not predict changes in activity levels at 1-year follow-up but did predict increases in activity at 2 years relative to those living farther away (15.3 additional minutes/week walking and cycling per km nearer; 12.5 additional minutes/week of total physical activity). The effects were larger among participants with no car.

CONCLUSIONS

These new local routes may mainly have displaced walking or cycling trips in the short term but generated new trips in the longer term, particularly among those unable to access more distant destinations by car. These findings support the potential for walking and cycling infrastructure to promote physical activity.

Views and experiences of behaviour change techniques to encourage walking to work: a qualitative study

Background

High levels of physical inactivity are linked to several chronic diseases including coronary heart disease, type-2 diabetes, obesity, some cancers and poor mental health. Encouraging people to be more active has proven difficult. One way to incorporate physical activity into the daily routine is through the journey to and from work. Although behaviour change techniques (BCTs) are considered valuable in promoting behaviour change, there is very little in the published literature about the views and experiences of those encouraged to use them.

Methods

The Walk to Work study was a feasibility study incorporating an exploratory cluster randomised controlled trial. The 10-week intervention involved training workplace-based Walk to Work promoters (volunteers or nominated by participating employers) to encourage colleagues to increase walking during their daily commute. The intervention used nine specific BCTs: Intention formation, barrier identification, specific goal setting, instruction, general encouragement, self-monitoring of behaviour social support, review of behavioural goals and relapse prevention. Digitally recorded interviews were undertaken with 22 employees, eight of whom were Walk to Work promoters to understand their views and experiences of using these techniques. The Framework method of data management and constant comparison were used to analyse the data and identify key themes.

Results

For each individual BCT, there appeared to be people who found it useful in helping them to increase walking to work and others who did not. Following training, the Walk to Work promoters varied in the extent to which they were able to fulfil their role: additional support and encouragement during the 10-week intervention may be required for the promoters to maintain motivation. Wider contextual (economic climate, unprecedented wet weather) and organisational (workload, car parking facilities) issues were identified that influenced the delivery of, and response to, the intervention.

Conclusions

Walk to work interventions employing BCTs should include sufficient techniques to enable participants to choose a ‘package’ to suit their needs. Additional support at organisational level should also be encouraged, and consideration given to wider contextual factors that impinge on the delivery of, and response to, the intervention.

Trial registration

ISRCTN72882329.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2458-14-868) contains supplementary material, which is available to authorized users.

Associations between active commuting, body fat, and body mass index: population based, cross sectional study in the United Kingdom

OBJECTIVE

To determine if promotion of active modes of travel is an effective strategy for obesity prevention by assessing whether active commuting (walking or cycling for all or part of the journey to work) is independently associated with objectively assessed biological markers of obesity.

DESIGN

Cross sectional study of data from the wave 2 Health Assessment subsample of Understanding Society, the UK Household Longitudinal Study (UKHLS). The exposure of interest, commuting mode, was self reported and categorised as three categories: private transport, public transport, and active transport.

PARTICIPANTS

The analytic samples (7534 for body mass index (BMI) analysis, 7424 for percentage body fat analysis) were drawn from the representative subsample of wave 2 respondents of UKHLS who provided health assessment data (n = 15,777).

MAIN OUTCOME MEASURES

Body mass index (weight (kg)/height (m)(2)); percentage body fat (measured by electrical impedance).

RESULTS

Results from multivariate linear regression analyses suggest that, compared with using private transport, commuting by public or active transport modes was significantly and independently predictive of lower BMI for both men and women. In fully adjusted models, men who commuted via public or active modes had BMI scores 1.10 (95% CI 0.53 to 1.67) and 0.97 (0.40 to 1.55) points lower, respectively, than those who used private transport. Women who commuted via public or active modes had BMI scores 0.72 (0.06 to 1.37) and 0.87 (0.36 to 0.87) points lower, respectively, than those using private transport. Results for percentage body fat were similar in terms of magnitude, significance, and direction of effects.

CONCLUSIONS

Men and women who commuted to work by active and public modes of transport had significantly lower BMI and percentage body fat than their counterparts who used private transport. These associations were not attenuated by adjustment for a range of hypothesised confounding factors.

A cross-sectional study of demographic, environmental and parental barriers to active school travel among children in the United States

Background

Promoting daily routine physical activities, such as active travel to school, may have important health implications. Practitioners and policy makers must understand the variety of factors that influence whether or not a child uses active school travel. Several reviews have identified both inhibitors and promoters of active school travel, but few studies have combined these putative characteristics in one analysis. The purpose of this study is to examine associations between elementary school children’s active school travel and variables hypothesized as correlates (demographics, physical environment, perceived barriers and norms).

Methods

The current project uses the dataset from the National Evaluation of Walk to School (WTS) Project, which includes data from 4^th and 5^th grade children and their parents from 18 schools across the US. Measures included monthly child report of mode of school travel during the previous week (n = 10,809) and perceived barriers and social norms around active school travel by parents (n = 1,007) and children (n = 1,219). Generalized linear mixed models (GLMM) with log-link functions were used to assess bivariate and multivariate associations between hypothesized correlates and frequency of active school travel, assuming random school effect and controlling for the distance to school.

Results

The final model showed that the most relevant significant predictors of active school travel were parent’s perceived barriers, specifically child resistance (Estimate = −0.438, p < 0.0001) and safety and weather (Estimate = −0.0245, p < 0.001), as well as the school’s percentage of Hispanic students (Estimate = 0.0059, p < 0.001), after adjusting for distance and including time within school cluster as a random effect.

Conclusions

Parental concerns may be impacting children’s use of active school travel, and therefore, future interventions to promote active school travel should more actively engage parents and address these concerns. Programs like the Walk to School program, which are organized by the schools and can engage community resources such as public safety officials, could help overcome many of these perceived barriers to active transport.

The contribution of walking to work to adult physical activity levels: a cross sectional study

Objective

To objectively examine the contribution to adult physical activity levels of walking to work.

Methods

Employees (n = 103; 36.3 ± 11.7 years) at 17 workplaces in south-west England, who lived within 2 miles (3.2 km) of their workplace, wore Actigraph accelerometers for seven days during waking hours and carried GPS receivers during the commute to and from work. Physical activity volume (accelerometer counts per minute (cpm)) and intensity (minutes of moderate to vigorous physical activity (MVPA)) were computed overall and during the walk to work.

Results

Total weekday physical activity was 45% higher in participants who walked to work compared to those travelling by car (524.6. ± 170.4 vs 364.6 ± 138.4 cpm) and MVPA almost 60% higher (78.1 ± 24.9 vs 49.8 ± 25.2 minutes per day). No differences were seen in weekend physical activity, and sedentary time did not differ between the groups. Combined accelerometer and GPS data showed that walking to work contributed 47.3% of total weekday MVPA.

Conclusions

Walking to work was associated with overall higher levels of physical activity in young and middle-aged adults. These data provide preliminary evidence to underpin the need for interventions to increase active commuting, specifically walking, in adults.

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.