Unique miRNome and transcriptome profiles underlie microvascular heterogeneity in mouse kidney.

Endothelial cells in blood vessels in the kidney exert different functions depending on the (micro)vascular bed they are located in. The present study aimed to investigate microRNA and mRNA transcription patterns that underlie these differences. We zoomed in on microvascular compartments in the mouse renal cortex by laser microdissecting the microvessels prior to small RNA- and RNA-sequencing analyses. By these means, we characterized microRNA and mRNA transcription profiles of arterioles, glomeruli, peritubular capillaries, and postcapillary venules. Quantitative RT-PCR, in situ hybridization, and immunohistochemistry were used to validate sequencing results. Unique microRNA and mRNA transcription profiles were found in all microvascular compartments, with dedicated marker microRNAs and mRNAs showing enriched transcription in a single microvascular compartment. In situ hybridization validated the localization of microRNAs mmu-miR-140-3p in arterioles, mmu-miR-322-3p in glomeruli, and mmu-miR-451a in postcapillary venules. Immunohistochemical staining showed that von Willebrand factor protein was mainly expressed in arterioles and postcapillary venules, whereas GABRB1 expression was enriched in glomeruli, and IGF1 was enriched in postcapillary venules. More than 550 compartment-specific microRNA-mRNA interaction pairs were identified that carry functional implications for microvascular behavior. In conclusion, our study identified unique microRNA and mRNA transcription patterns in microvascular compartments of the mouse kidney cortex that underlie microvascular heterogeneity. These patterns provide important molecular information for future studies into differential microvascular engagement in health and disease.NEW & NOTEWORTHY Renal endothelial cells display a high level of heterogeneity depending on the (micro)vascular bed they reside in. The molecular basis contributing to these differences is poorly understood yet of high importance to increase understanding of microvascular engagement in the kidney in health and disease. This report describes m(icro)RNA expression profiles of microvascular beds in the mouse renal cortex and uncovers microvascular compartment-specific m(icro)RNAs and miRNA-mRNA pairs, thereby revealing important molecular mechanisms underlying renal microvascular heterogeneity.

Changes in Individual and Social Environmental Characteristics in Relation to Changes in Physical Activity: a Longitudinal Study from Primary to Secondary School.

PURPOSE: Physical activity (PA) strongly decreases when children make the transition from primary to secondary school. The study aimed to investigate how individual and social environmental factors toward PA changed when children (11-12 years) made the transition from primary to secondary school (13-14 years) and how changes in these factors were related to changes in different PA domains. METHODS: In total, 321 children (48.9 % girls) and one of their parents both filled out a questionnaire concerning individual (i.e., attitude, self-efficacy, perceived benefits, and barriers of PA) and social environmental factors related to PA (parental support, friend's co-participation, parental trust in child's ability to be physically active, and social norm) in the last grade of primary school and 2 years later. Children wore an activity monitor for 7 days and self-reported different domains of PA. RESULTS: Most individual and social factors became less positive toward PA after the transition to secondary school. Among girls, a more positive attitude and an increase in self-efficacy were related to an increase in average daily steps and sports during leisure, respectively. Among boys, a decrease in perceived barriers (lack of time and parental reported lack of transportation to sport activities) was related to a decrease in average daily steps. An increase in parental support and a decrease in the parental perceived barrier of not liking sports were related to an increase in sports during leisure. CONCLUSIONS: The prevention of adverse changes in individual and social factors toward physical activity may lead to a smaller decrease or an increase in physical activity.

Parental perceived neighborhood attributes: associations with active transport and physical activity among 10-12 year old children and the mediating role of independent mobility.

BACKGROUND: During the last decades, the use of active travel modes declined in all age groups. Childhood is a critical time to establish lifelong healthy patterns. To develop effective interventions in this age group, insight in the correlates of health behaviors and the possible mediating factors is necessary. Among children, the role of parents may not be overlooked. Therefore, this study aimed to examine the associations of parental perceptions of neighborhood environmental attributes with active transport and total physical activity in 10-12 year old Belgian boys and girls. Furthermore, this study examined the potential mediating effect of independent mobility on these associations. METHODS: In the present study, 736 10-12 year old children and their parents from 44 elementary schools in Flanders, Belgium, participated. The children were asked to wear an activity monitor and to fill in a survey questioning demographic factors and the Flemish Physical Activity Questionnaire. The parents filled in a survey concerning demographic factors, the child's level of independent mobility and environmental perceptions (Neighborhood Environmental Walkability Scale). RESULTS: Overall, boys reported more active transport when parents perceived more land use mix diversity, shorter distances to school, good land use mix access, higher residential density and less pleasing neighborhood aesthetics. Higher total physical activity levels were reported when parents perceived shorter distances to school and availability of walking/cycling infrastructure. None of the associations was mediated by independent mobility in boys. Girls reported more active transport when parents perceived higher residential density, more land use mix diversity, shorter distances to school, good land use mix access, available walking/cycling infrastructure and convenient recreational facilities. Girls reported higher total physical activity levels when parents perceived high residential density, good land use mix access, well-maintained and high quality walking/cycling infrastructures and more traffic safety. Independent mobility was found to be an important mediator of these associations in girls. CONCLUSIONS: Neighborhood environmental interventions to increase children's active transport and physical activity can be effective when combined with awareness raising programs for parents. Furthermore, among girls encouraging independent mobility may contribute to behavior change.

Changes in physical activity during the transition from primary to secondary school in Belgian children: what is the role of the school environment?

BACKGROUND: Key life periods have been associated with changes in physical activity (PA). This study investigated (1) how PA changes when primary school children transfer to secondary school, (2) if school environmental characteristics differ between primary and secondary schools and (3) if changes in school environmental characteristics can predict changes in PA in Belgian schoolchildren. Moderating effects of gender and the baseline level of PA were investigated for the first and third research question. METHODS: In total, 736 children (10-13 years) of the last year of primary school participated in the first phase of this longitudinal study. Two years later, 502 of these children (68.2%) agreed to participate in the second phase. Accelerometers, pedometers and the Flemish Physical Activity Questionnaire were used to measure PA. School environmental characteristics were reported by the school principals. Cross-classified regression models were conducted to analyze the data. RESULTS: Self-reported active transport to school and accelerometer weekday moderate to vigorous PA (MVPA) increased after the transition to secondary school while self-reported extracurricular PA and total PA decreased. Pedometer weekday step counts decreased, but this decrease was only apparent among those who achieved the PA guidelines in primary school.Secondary schools scored higher on the school environmental characteristics: provision of sports and PA during lunch break, active schoolyards and playgrounds and health education policy but lower on sports and PA after-school than primary schools. Changes in the school environmental characteristics: active commuting to school, active schoolyards and playgrounds and health education policy resulted in changes in self-reported extracurricular PA, total PA , pedometer/accelerometer determined step counts and accelerometer determined MVPA. Moderating effects were found for baseline PA and gender. CONCLUSION: PA changed after the transition to secondary school. In general, secondary schools seem more likely to foster strategies to promote PA during school hours than primary schools who seem more likely to foster strategies to promote PA after school. Changes in school environmental characteristics may contribute to changes in PA. Thus, if confirmed in future studies, efforts are needed to implement these components in schools as early as possible to positively affect the change in PA.

Does the perception of neighborhood built environmental attributes influence active transport in adolescents?

BACKGROUND: Among Belgian adolescents active transport (AT) is a common physical activity (PA) behavior. Preliminary evidence suggests that AT can be an important opportunity for increasing adolescents' daily PA levels. To inform interventions, predictors of this PA behavior need to be further explored. Therefore, in the perspective of the ecological models this study aimed (a) to investigate the relationship between the perception of neighborhood built environmental attributes and adolescents' AT and (b) to explore the contribution of the perception of neighborhood built environmental attributes beyond psychosocial factors. METHODS: For the purpose of this study, data from the Belgian Environmental Physical Activity Study in Youth (BEPAS-Y), performed between 2008 and 2009, was used. The final study population consisted of 637 adolescents aged 13-15 years. The participants completed a survey measuring demographic and psychosocial factors, the Flemish Physical Activity Questionnaire and the Dutch version of the Neighborhood Environmental Walkability Scale. RESULTS: A set of stepwise linear regression analyses with backward elimination revealed that a shorter distance to school, perceiving neighborhoods to have connected streets, a lower degree of land use mix diversity, less infrastructure for walking and a lower quality of the infrastructure for walking are associated with more min/day AT to and from school (p all <0.05). Furthermore, marginally significant associations (p < 0.10) were found between residential density and safety from crime and AT to and from school. No relationship between the perception of the neighborhood built environmental attributes and walking for transport during leisure time and cycling for transport during leisure time was found. CONCLUSIONS: The substantial contribution of the perception of neighbourhood built environmental attributes to AT found in Belgian adults, could not totally be confirmed by this study for Belgian adolescents. Among Belgian adolescents, the contribution of neighborhood environmental perceptions to explain the variance in AT seems to be dependent of the purpose of AT. Further research is needed to explore this relationship in specific subgroups and to overcome some of the limitations this study had to contend with.

Objectively measured sedentary time and physical activity time across the lifespan: a cross-sectional study in four age groups.

BACKGROUND: From a health perspective it is suggested to promote a positive balance between time spent in light intensity physical activity (LIPA) and sedentary behaviour (SB) (i.e. spending more time in LIPA than time spent in SB). However, no studies have reported prevalence rates of the LIPA-SB balance yet. The aim of this study was to objectively investigate the time spent in SB, in LIPA and moderate-to-vigorous intensity physical activity (MVPA) in four Belgian age groups and to explore which proportion of the population had a favorable balance between LIPA and SB and combined this with recommended amount of MVPA. METHODS: Accelerometer data from 7 cross-sectional studies (N=2083) in four age groups (preschoolers, primary schoolchildren, secondary schoolchildren and adults) were aggregated. Differences in SB and PA between age groups and between men and women were determined by two-way MANCOVA. LIPA-SB balance was calculated and participants were categorized into one of four groups: (1) positive LIPA-SB balance (LIPA> SB) & sufficient MVPA (2) negative LIPA-SB balance & sufficient MVPA (3) positive LIPA-SB balance & insufficient MVPA (4) negative LIPA-SB balance & insufficient MVPA. RESULTS: For the total sample, 55% of the waking time was spent in SB, 39% in LIPA and 6% in MVPA. Differences in SB between age groups was dependent from gender (p<0.001). Further, a positive LIPA-SB balance was assessed in 18% of the total sample and only 10% combined this positive balance with recommended amount of MVPA. Secondary schoolgirls were most at risk, with only 1% of the sample combining a positive LIPA-SB balance with sufficient MVPA. Another risk group was the large proportion (43%) of adult men who combined sufficient MVPA with a negative LIPA-SB balance. CONCLUSION: A high proportion of the Belgian population is at risk if taking into account both SB and PA levels. Secondary schoolgirls have the unhealthiest SB and PA profile and are therefore an important target group for interventions both increasing MVPA and decreasing SB. In men more attention should be given in promoting a positive LIPA-SB balance independently from their compliance with the MVPA guidelines.

Active living neighborhoods: is neighborhood walkability a key element for Belgian adolescents?

BACKGROUND: In adult research, neighborhood walkability has been acknowledged as an important construct among the built environmental correlates of physical activity. Research into this association has only recently been extended to adolescents and the current empirical evidence is not consistent. This study investigated whether neighborhood walkability and neighborhood socioeconomic status (SES) are associated with physical activity among Belgian adolescents and whether the association between neighborhood walkability and physical activity is moderated by neighborhood SES and gender. METHODS: In Ghent (Belgium), 32 neighborhoods were selected based on GIS-based walkability and SES derived from census data. In total, 637 adolescents (aged 13-15 year, 49.6% male) participated in the study. Physical activity was assessed using accelerometers and the Flemish Physical Activity Questionnaire. To analyze the associations between neighborhood walkability, neighborhood SES and individual physical activity, multivariate multi-level regression analyses were conducted. RESULTS: Only in low-SES neighborhoods, neighborhood walkability was positively associated with accelerometer-based moderate to vigorous physical activity and the average activity level expressed in counts/minute. For active transport to and from school, cycling for transport during leisure time and sport during leisure time no association with neighborhood walkability nor, with neighborhood SES was found. For walking for transport during leisure time a negative association with neighborhood SES was found. Gender did not moderate the associations of neighborhood walkability and SES with adolescent physical activity. CONCLUSIONS: Neighborhood walkability was related to accelerometer-based physical activity only among adolescent boys and girls living in low-SES neighborhoods. The relation of built environment to adolescent physical activity may depend on the context.

Criterion distances and environmental correlates of active commuting to school in children.

BACKGROUND: Active commuting to school can contribute to daily physical activity levels in children. Insight into the determinants of active commuting is needed, to promote such behavior in children living within a feasible commuting distance from school. This study determined feasible distances for walking and cycling to school (criterion distances) in 11- to 12-year-old Belgian children. For children living within these criterion distances from school, the correlation between parental perceptions of the environment, the number of motorized vehicles per family and the commuting mode (active/passive) to school was investigated. METHODS: Parents (n = 696) were contacted through 44 randomly selected classes of the final year (sixth grade) in elementary schools in East- and West-Flanders. Parental environmental perceptions were obtained using the parent version of Neighborhood Environment Walkability Scale for Youth (NEWS-Y). Information about active commuting to school was obtained using a self-reported questionnaire for parents. Distances from the children's home to school were objectively measured with Routenet online route planner. Criterion distances were set at the distance in which at least 85% of the active commuters lived. After the determination of these criterion distances, multilevel analyses were conducted to determine correlates of active commuting to school within these distances. RESULTS: Almost sixty percent (59.3%) of the total sample commuted actively to school. Criterion distances were set at 1.5 kilometers for walking and 3.0 kilometers for cycling. In the range of 2.01 - 2.50 kilometers household distance from school, the number of passive commuters exceeded the number of active commuters. For children who were living less than 3.0 kilometers away from school, only perceived accessibility by the parents was positively associated with active commuting to school. Within the group of active commuters, a longer distance to school was associated with more cycling to school compared to walking to school. CONCLUSIONS: Household distance from school is an important correlate of transport mode to school in children. Interventions to promote active commuting in 11-12 year olds should be focusing on children who are living within the criterion distance of 3.0 kilometers from school by improving the accessibility en route from children's home to school.

Measuring physical activity using accelerometry in 13-15-year-old adolescents: the importance of including non-wear activities.

OBJECTIVE: The present study aimed to examine the impact of non-wear activities registered in diaries when using accelerometers to assess physical activity (PA) in young adolescents. DESIGN: Data arise from a large-scale cross-sectional study on PA. PA was objectively assessed using Actigraph™ accelerometers (Actigraph MTI, Manufacturing Technology Inc., Pensacola, FL, USA) during seven consecutive days. Non-wear time activity diaries were provided to register the activities for which the accelerometer was removed. After correction to deal with over-reporting, the registered minutes of PA were used to replace periods of non-wear time measured by the accelerometer. SETTING: Between October 2008 and May 2009 adolescents were recruited by home visits in Ghent (Belgium). SUBJECTS: Young adolescents (n 513; 48·6% boys) aged 13 to 15 years. RESULTS: Of the total sample, 49·9% registered at least one activity of moderate to vigorous intensity in the non-wear time activity diary. More adolescents registered an activity performed on a weekday than on a weekend day and the registered mean number of minutes of moderate to vigorous PA were higher on weekend days. Repeated-measures (M)ANOVA tests revealed a significant difference between the mean minutes with and without non-wear activities for all PA intensities, regardless of adolescents' socio-economic status or gender. More adolescents achieved the PA recommendations after inclusion of the non-wear activities irrespective of accelerometer thresholds used. CONCLUSIONS: The collection of information regarding non-wear time by non-wear time activity diaries when using accelerometers in 13-15-year-old adolescents can lead to different PA outcomes at the individual level and therefore can improve the ability to accurately measure PA.

The use of accelerometry in adolescents and its implementation with non-wear time activity diaries in free-living conditions.

The aim of this study was to evaluate the use of a non-wearing time activity diary (hereafter non-wear activity diary) when using accelerometry in adolescents to provide insight into their physical activity levels. In total, 213 Belgian adolescents (89 boys, 124 girls) were eligible for this study. Adolescents wore an accelerometer for seven consecutive days and kept a non-wear activity diary. On the last day, they completed the International Physical Activity Questionnaire for Adolescents. The differences between the accelerometer data with and without use of the non-wear activity diary were significant for all physical activity intensities according to the Wilcoxon signed rank test. Bland-Altman plots showed that with more time spent in any physical activity intensity, the difference between including and not including the non-wear activity diary increased. The correlation coefficient between the International Physical Activity Questionnaire for Adolescents and the accelerometer data increased when the non-wear activity diary was included. Differences in the percentage of adolescents reaching the physical activity recommendations between the accelerometer data only and the accelerometer with the non-wear activity diary were significant. We conclude that if the non-wear activity diary data are not included, some adolescents could be misclassified as not being physically active according to the physical activity recommendations. It is therefore recommended to use a non-wear activity diary for gaining insight into the physical activity levels of individuals.

Interventions for promoting physical activity among European teenagers: a systematic review.

BACKGROUND: Although physical activity is considered to yield substantial health benefits, the level of physical activity among European teenagers is not sufficient. Adolescence is characterized by a decline in physical activity level. Many studies investigated the effectiveness of interventions promoting physical activity among young people, but none dealt with the available evidence specific for Europe. This review was conducted to summarize the effectiveness of interventions to promote physical activity among European teenagers. METHODS: A systematic review was conducted to identify European intervention studies published in the scientific literature since 1995. Four databases were searched, reference lists were scanned and the publication lists of the authors of the retrieved articles were checked. The ANGELO framework was used to categorise the included studies by setting and by intervention components. RESULTS: The literature search identified 20 relevant studies. Fifteen interventions were delivered through the school setting, of which three included a family component and another three a family and community component. One intervention was conducted within a community setting, three were delivered in primary care and one was delivered through the internet. Ten interventions included only an individual component, whereas the other ten used a multi-component approach. None of the interventions included only an environmental component.Main findings of the review were: (1) school-based interventions generally lead to short term improvements in physical activity levels; (2) improvements in physical activity levels by school-based interventions were limited to school related physical activity with no conclusive transfer to leisure time physical activity; (3) including parents appeared to enhance school-based interventions; (4) the support of peers and the influence of direct environmental changes increased the physical activity level of secondary school children; (5) the assumption that a multi-component approach should produce synergistic results can not be confirmed; (6) when interventions aimed to affect more than one health behaviour the intervention appeared to be less effective in favour of physical activity. CONCLUSION: Overall, the current European literature supports the short-term effectiveness of school-based physical activity promotion programmes. The available evidence for the effectiveness in other settings is rather limited and underscores the need for further research.

From Evidence-Based Research to Practice-Based Evidence: Disseminating a Web-Based Computer-Tailored Workplace Sitting Intervention through a Health Promotion Organisation.

Prolonged sitting has been linked to adverse health outcomes; therefore, we developed and examined a web-based, computer-tailored workplace sitting intervention. As we had previously shown good effectiveness, the next stage was to conduct a dissemination study. This study reports on the dissemination efforts of a health promotion organisation, associated costs, reach achieved, and attributes of the website users. The organisation systematically registered all the time and resources invested to promote the intervention. Website usage statistics (reach) and descriptive statistics (website users' attributes) were also assessed. Online strategies (promotion on their homepage; sending e-mails, newsletters, Twitter, Facebook and LinkedIn posts to professional partners) were the main dissemination methods. The total time investment was 25.6 h, which cost approximately 845 EUR in salaries. After sixteen months, 1599 adults had visited the website and 1500 (93.8%) completed the survey to receive personalized sitting advice. This sample was 38.3 ± 11.0 years, mainly female (76.9%), college/university educated (89.0%), highly sedentary (88.5% sat >8 h/day) and intending to change (93.0%) their sitting. Given the small time and money investment, these outcomes are positive and indicate the potential for wide-scale dissemination. However, more efforts are needed to reach men, non-college/university educated employees, and those not intending behavioural change.

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.

Changes in the perceived neighborhood environment in relation to changes in physical activity: A longitudinal study from childhood into adolescence.

The aim was to investigate how physical activity and the perceived neighborhood environment in children change when they enter adolescence. Also the relation between changes in the perceived environment and changes in children's physical activity was investigated. In total, 321 children and one of their parents filled out a physical activity questionnaire and the NEWS-Y at two time points (last grade of elementary school and 2 years later). Children also wore an activity monitor. Changes in children's physical activity were dependent on the physical activity domain. Only less than half of children's perceived neighborhood factors changed and about half of the parental perceived neighborhood factors changed. Most of these factors changed towards higher activity friendliness. Changes in the perceived environment were only limitedly related to changes in children's physical activity.

Physical environmental attributes and active transportation in Belgium: what about adults and adolescents living in the same neighborhoods?

PURPOSE: To examine if adults and adolescents living in the same high- and low-walkable neighborhoods have different environmental perceptions and if this is reflected in distinct associations between environmental perceptions and active transportation. DESIGN: Cross-sectional study with observational design. SETTING: In Ghent, 24 neighborhoods were selected, stratified on objectively assessed walkability, and matched on neighborhood income. This resulted in four walkability/income quadrants, each consisting of six neighborhoods. SUBJECTS: Living in the 24 neighborhoods were 1166 adults (20-65 years, 52.1% women) and 477 adolescents (13-15 years, 49.7% girls). MEASURES: All participants completed a sociodemographic questionnaire, the International (adults) or Flemish (adolescents) Physical Activity Questionnaire and the Neighborhood Environmental Walkability Scale. ANALYSIS: Multilevel (two-level: participant-neighborhood) moderated regression models, using MLwiN 2.23. RESULTS: Both adults and adolescents living in objectively high-walkable neighborhoods perceived their environment as more activity friendly than their low-walkable neighborhoods counterparts (11 out of 13 main effects walkability: p < .05). However, perceived residential density (p < .05), land use mix (p < .01), safety for cycling (p < .05), and perceived walkability (p < .001) were associated with active transportation only in adults. CONCLUSION: Different environmental intervention strategies are probably needed to increase active transportation in Belgian adults and adolescents living in the same neighborhoods. In adults, changing objective or perceived environmental characteristics might be effective, whereas in adolescents, the current environmental focus should be changed towards multidimensional research.

Do psychosocial factors moderate the association between neighborhood walkability and adolescents' physical activity?

Ecological models emphasize the interaction between individuals and their environment. Furthermore, they posit that environmental variables influence physical activity (PA) not only directly but also indirectly through their interaction with other factors. This study explored if the association between neighborhood walkability and adolescents' PA is moderated by psychosocial factors using data from the Belgian Environmental PA Study in Youth (BEPAS-Y). BEPAS-Y recruited adolescents from 32 neighborhoods differing in objectively determined neighborhood walkability and income. Between 2008 and 2009, 637 adolescents (13-15 years; 49.4% boys) completed a survey measuring socio-demographic and psychosocial factors and wore an accelerometer for seven days. Multilevel-regression analyses revealed that for adolescents living in low-income neighborhoods, the association between neighborhood walkability and PA is moderated by perceived barriers and perceived benefits toward PA. Neighborhood walkability was positively associated with PA among adolescents, living in low-income neighborhoods, who perceived many barriers and few benefits, while for adolescents who perceived few barriers and many benefits, the PA level was high, irrespective of neighborhood walkability. For adolescents, living in high-income neighborhoods, none of the psychosocial attributes moderated the association between neighborhood walkability and PA. These findings provide some support for the predicted interactions posited by ecological models. Improving neighborhood walkability might increase PA-levels of adolescents living in low-income neighborhoods, with less positive psychosocial profiles, or in other words; those who are most difficult to reach through PA interventions. However, in order to increase PA in large populations, interventions focusing solely on improving neighborhood walkability may not have the desired effect.

Relationship between the physical environment and physical activity in older adults: a systematic review.

Previous reviews on children, adolescents and adults have reported consistent relationships between several physical environmental characteristics and physical activity (PA). This systematic review aims to provide a comprehensive overview of the literature concerning the relationship between the physical environment and PA in older adults. A systematic literature search resulted in the inclusion of 31 articles. Results were inconsistent but most of the studied environmental characteristics were reported not to be related to PA. More studies in different contexts utilizing longitudinal designs, standardized, reliable and validated PA and environmental measurements and investigating possible moderating effects are definitely warranted.