Publications

Introduction Numerous studies have found associations between characteristics of urban environments and risk factors for dementia and cognitive decline, such as physical inactivity and obesity. However, the contribution of urban environments to brain and cognitive health has been seldom examined directly. This cohort study investigates the extent to which and how a wide range of characteristics of urban environments influence brain and cognitive health via lifestyle behaviours in mid-aged and older adults in three cities across three continents. Methods and analysis Participants aged 50–79 years and living in preselected areas stratified by walkability, air pollution and socioeconomic status are being recruited in Melbourne (Australia), Barcelona (Spain) and Hong Kong (China) (n=1800 total; 600 per site). Two assessments taken 24 months apart will capture changes in brain and cognitive health. Cognitive function is gauged with a battery of eight standardised tests. Brain health is assessed using MRI scans in a subset of participants. Information on participants’ visited locations is collected via an interactive web-based mapping application and smartphone geolocation data. Environmental characteristics of visited locations, including the built and natural environments and their by-products (e.g., air pollution), are assessed using geographical information systems, online environmental audits and self-reports. Data on travel and lifestyle behaviours (e.g., physical and social activities) and participants’ characteristics (e.g., sociodemographics) are collected using objective and/or self-report measures. Ethics and dissemination The study has been approved by the Human Research Ethics Committee of the Australian Catholic University, the Institutional Review Board of the University of Hong Kong and the Parc de Salut Mar Clinical Research Ethics Committee of the Government of Catalonia. Results will be communicated through standard scientific channels. Methods will be made freely available via a study-dedicated website. Trial registration number ACTRN12619000817145.

Background Active commuting to school can be a meaningful contributor to overall physical activity in children. To inform better micro-level urban design near schools that can support active commuting to school, there is a need for measures that capture these elements. This paper describes the adaptation of an observational instrument for use in assessing micro-scale environments around urban elementary schools in the United States. Methods The Micro-scale Audit of Pedestrian Streetscapes for Safe Routes to School (MAPS-SRTS) was developed from existing audit instruments not designed for school travel environments and modifications for the MAPS-SRTS instrument include the structure of the audit tool sections, the content, the observation route, and addition of new subscales. Subscales were analyzed for inter-rater reliability in a sample of 36 schools in Austin, TX. To assess reliability for each subscale, one-way random effects single-measure intraclass correlation coefficients (ICC) were used. Results Compared to the 30 original subscales, the adapted MAPS-SRTS included 26 (86.6%) subscales with revised scoring algorithms. Most MAPS-SRTS subscales had acceptable inter-rater reliability, with an ICC of 0.97 for the revised audit tool. Conclusions The MAPS-SRTS audit tool is a reliable instrument for measuring the school travel environment for research and evaluation purposes, such as assessing human-scale determinants of active commuting to school behavior and documenting built environment changes from infrastructure interventions.

The extracellular signals which regulate the myogenic program are transduced to the nucleus by mitogen-activated protein kinases (MAPKs). We have investigated the role of two MAPKs, p38 and extracellular signal-regulated kinase (ERK), whose activities undergo significant changes during muscle differentiation. p38 is rapidly activated in myocytes induced to differentiate. This activation differs from those triggered by stress and cytokines, because it is not linked to Jun-N-terminal kinase stimulation and is maintained during the whole process of myotube formation. Moreover, p38 activation is independent of a parallel promyogenic pathway stimulated by insulin-like growth factor 1. Inhibition of p38 prevents the differentiation program in myogenic cell lines and human primary myocytes. Conversely, deliberate activation of endogenous p38 stimulates muscle differentiation even in the presence of antimyogenic cues. Much evidence indicates that p38 is an activator of MyoD: (i) p38 kinase activity is required for the expression of MyoD-responsive genes, (ii) enforced induction of p38 stimulates the transcriptional activity of a Gal4-MyoD fusion protein and allows efficient activation of chromatin-integrated reporters by MyoD, and (iii) MyoD-dependent myogenic conversion is reduced in mouse embryonic fibroblasts derived from p38alpha(-/-) embryos. Activation of p38 also enhances the transcriptional activities of myocyte enhancer binding factor 2A (MEF2A) and MEF2C by direct phosphorylation. With MEF2C, selective phosphorylation of one residue (Thr293) is a tissue-specific activating signal in differentiating myocytes. Finally, ERK shows a biphasic activation profile, with peaks of activity in undifferentiated myoblasts and postmitotic myotubes. Importantly, activation of ERK is inhibitory toward myogenic transcription in myoblasts but contributes to the activation of myogenic transcription and regulates postmitotic responses (i.e., hypertrophic growth) in myotubes.

Purpose: The study aims were to determine: (a) how class structure varies by dance type, (b) how moderate-to-vigorous physical activity (MVPA) and sedentary behavior vary by dance class segments, and (c) how class structure relates to total MVPA in dance classes. Method: Participants were 291 boys and girls ages 5 to 18 years old enrolled in 58 dance classes at 21 dance studios in Southern California. MVPA and sedentary behavior were assessed with accelerometry, with data aggregated to 15-s epochs. Percent and minutes of MVPA and sedentary behavior during dance class segments and percent of class time and minutes spent in each segment were calculated using Freedson age-specific cut points. Differences in MVPA (Freedson 3 Metabolic Equivalents of Tasks age-specific cut points) and sedentary behavior ( < 100 counts/min) were examined using mixed-effects linear regression. Results: The length of each class segment was fairly consistent across dance types, with the exception that in ballet, more time was spent in technique as compared with private jazz/hip-hop classes and Latin-flamenco and less time was spent in routine/practice as compared with Latin-salsa/ballet folklorico. Segment type accounted for 17% of the variance in the proportion of the segment spent in MVPA. The proportion of the segment in MVPA was higher for routine/practice (44.2%) than for technique (34.7%). The proportion of the segment in sedentary behavior was lowest for routine/practice (22.8%). Conclusion: The structure of dance lessons can impact youths' physical activity. Working with instructors to increase time in routine/practice during dance classes could contribute to physical activity promotion in youth.

We show that high doses of salicylates reverse hyperglycemia, hyperinsulinemia, and dyslipidemia in obese rodents by sensitizing insulin signaling. Activation or overexpression of the IkappaB kinase beta (IKKbeta) attenuated insulin signaling in cultured cells, whereas IKKbeta inhibition reversed insulin resistance. Thus, IKKbeta, rather than the cyclooxygenases, appears to be the relevant molecular target. Heterozygous deletion (Ikkbeta+/-) protected against the development of insulin resistance during high-fat feeding and in obese Lep(ob/ob) mice. These findings implicate an inflammatory process in the pathogenesis of insulin resistance in obesity and type 2 diabetes mellitus and identify the IKKbeta pathway as a target for insulin sensitization.

Purpose: The purpose of this study was to examine the association between adolescent and parental perceptions of neighborhood safety and adolescents' physical activity in multiple locations and to investigate the moderating effect of sex within this association. Method: This cross-sectional study was conducted with 928 adolescents aged 12 to 16 years old and 1 of their parents. Adolescents and parents reported their perceptions of neighborhood safety (traffic safety, pedestrian safety, crime safety, and stranger danger safety). Adolescents reported how often they were physically active in multiple locations (physical activity in the neighborhood, in parks, and for active transport). Mixed-effects linear regression models were used to investigate these associations while controlling for demographics and the Walkability Index. Results: Parent-perceived crime safety was positively associated with adolescents' physical activity in parks (B = .094, p = .024). Parent-perceived traffic safety was positively associated with adolescents' reported physical activity in the neighborhood (B = .186, p = .014). Adolescents' physical activity for active transport was positively associated with parent-perceived traffic safety (B = .179, p = .001), stranger danger safety (B = .110, p = .013), and crime safety (B = .077, p = .035). There were 2 interactions by sex on the relation between adolescent traffic safety perception and parent pedestrian safety perception in the neighborhood and adolescents' physical activity in parks (i.e., statistically significant only for boys). Conclusions: Parents' perceptions of traffic, stranger danger, and crime safety were all related to adolescents' active transportation. Multiple safety concerns may be motivating parents to restrict adolescent mobility by walking and bicycling.

To examine the association of personal values, the built environment, and auto availability with walking for transportation.Participants were drawn from 11 U.S. metropolitan areas with good transit services.865 adults who had recently made or were contemplating making a residential move.Respondents reported if walking was their primary mode for nine trip purposes. "Personal values" reflected ratings of 15 variables assessing attitudes about urban and environmental attributes, with high reliability (ot = 0.85). Neighborhood form was indicated by a three-item scale. Three binary variables were created to reflect (1) personal values, (2) neighborhood form, and (3) auto availability.The association with walking was reported for each of the three variables, each combination of two variables, and the combination of three variables. An analysis of covariance was applied, and a hierarchic linear regression model was developed.All three variables were associated with walking, and all three variables interacted. The standardized coefficients were 0.23for neighborhood form, 0.21 for autos per person, and 0.18 for personal values.Positive attitudes about urban attributes, living in a supportive neighborhood, and low automobile availability significantly predicted more walking for transportation. A framework for further research is proposed in which a factor representing the role of the automobile is examined explicitly in addition to personal values and urban form.

Purpose To investigate whether adolescents cluster into profiles based on where they accumulate moderate-to-vigorous physical activity (MVPA), if overall MVPA differs across profiles, and if walking to school and participant and neighborhood characteristics explain profile membership. Methods Adolescents (N=528; mean age=14.12±1.44; 50% girls) wore accelerometers and Global Positioning Systems (GPS) trackers for 3.9±1.5 days to assess MVPA minutes in five locations: at home, at school, in home neighborhood, in school neighborhood, and other. Walking to school and participant characteristics were assessed by questionnaire, and neighborhood environment by Geographic Information Systems (GIS). Latent profile analysis (LPA) was used to identify profiles/groups of participants based on accumulation of physical activity across the five locations. Mixed-effects regression tested differences in overall MVPA, walking to school, and other characteristics across profiles. Results Four initial profiles emerged: one Insufficiently Active profile and three Active profiles (Active Around School, Active Home Neighborhood, and Active Other Locations). The Insufficiently Active profile emerging from the first LPA (90% of participants) was further separated into four profiles in a second LPA: Insufficiently Active, and three additional Active profiles (Moderately-Active Around School, Moderately-Active Home Neighborhood, and Active At Home). Those in the six Active profiles had more overall MVPA (41.1–92.7 min/day) than those in the two Insufficiently Active profiles (34.5–38.3 min/day). Variables that differed across profiles included walking to school, sports/athletic ability, and neighborhood walkability. Conclusions Although most participants did not meet the MVPA guideline, the six Active profiles showed the places in which many adolescents were able to achieve the 60-min/day guideline. The home and school neighborhood (partly through walking to school), other locations, and to a lesser extent the home, appeared to be key sources for physical activity that distinguished active from insufficiently active adolescents. Finding the right match between the individual and physical activity source/location may be a promising strategy for increasing active travel and MVPA in adolescents.