Publications

Social networks can influence physical activity, but little is known about how best to engineer online and in-person social networks to increase activity. The purpose of this study was to conduct a randomized trial based on the Social Networks for Activity Promotion model to assess the incremental contributions of different procedures for building social networks on objectively measured outcomes. Physically inactive adults (n = 308, age, 50.3 (SD = 8.3) years, 38.3 % male, 83.4 % overweight/obese) were randomized to one of three groups. The Promotion group evaluated the effects of weekly emailed tips emphasizing social network interactions for walking (e.g., encouragement, informational support); the Activity group evaluated the incremental effect of adding an evidence-based online fitness walking intervention to the weekly tips; and the Social Networks group evaluated the additional incremental effect of providing access to an online networking site for walking as well as prompting walking/activity across diverse settings. The primary outcome was mean change in accelerometer-measured moderate-to-vigorous physical activity (MVPA), assessed at 3 and 9 months from baseline. Participants increased their MVPA by 21.0 min/week, 95 % CI [5.9, 36.1], p = .005, at 3 months, and this change was sustained at 9 months, with no between-group differences. Although the structure of procedures for targeting social networks varied across intervention groups, the functional effect of these procedures on physical activity was similar. Future research should evaluate if more powerful reinforcers improve the effects of social network interventions. The trial was registered with the ClinicalTrials.gov (NCT01142804).

Ecological models of health behaviour are an important conceptual framework to address the multiple correlates of obesity. Several single-country studies previously examined the relationship between the built environment and obesity in adults, but results are very diverse. An important reason for these mixed results is the limited variability in built environments in these single-country studies. Therefore, the aim of this study was to examine associations between perceived neighbourhood built environmental attributes and BMI/weight status in a multi-country study including 12 environmentally and culturally diverse countries.A multi-site cross-sectional study was conducted in 17 cities (study sites) across 12 countries (Australia, Belgium, Brazil, China, Colombia, Czech Republic, Denmark, Mexico, New Zealand, Spain, the UK and USA). Participants (n = 14222, 18-66 years) self-reported perceived neighbourhood environmental attributes. Height and weight were self-reported in eight countries, and measured in person in four countries.Three environmental attributes were associated with BMI or weight status in pooled data from 12 countries. Safety from traffic was the most robust correlate, suggesting that creating safe routes for walking/cycling by reducing the speed and volume of traffic might have a positive impact upon weight status/BMI across various geographical locations. Close proximity to several local destinations was associated with BMI across all countries, suggesting compact neighbourhoods with more places to walk related to lower BMI. Safety from crime showed a curvilinear relationship with BMI, with especially poor crime safety being related to higher BMI.Environmental interventions involving these three attributes appear to have international relevance and focusing on these might have implications for tackling overweight/obesity.

Prions induce highly typical histopathological changes including cell death, spongiosis and activation of glia, yet the molecular pathways leading to neurodegeneration remain elusive. Following prion infection, enhanced nuclear factor- κ B (NF- κ B) activity in the brain parallels the first pathological changes. The NF- κ B pathway is essential for proliferation, regulation of apoptosis and immune responses involving induction of inflammation. The I κ B kinase (IKK) signalosome is crucial for NF- κ B signalling, consisting of the catalytic IKK α /IKK β subunits and the regulatory IKK γ subunit. This study investigated the impact of NF- κ B signalling on prion disease in mouse models with a central nervous system (CNS)-restricted elimination of IKK β or IKK γ in nearly all neuroectodermal cells, including neurons, astrocytes and oligodendrocytes, and in mice containing a non-phosphorylatable IKK α subunit ( IKKα AA/AA ). In contrast to previously published data, the observed results showed no evidence supporting the hypothesis that impaired NF- κ B signalling in the CNS impacts on prion pathogenesis.

Results of a Multi-level Intervention to Prevent and Control Childhood Obesity among Latino Children: The Aventuras Para Niños Study

Background: Assessment of park characteristics that may support physical activity (PA) can guide the design of more activity-supportive parks. Direct-observation measures are seldom used due to time and resource restraints. Methods: The authors developed shortened versions of the original Environmental Assessment of Public Recreation Spaces (EAPRS) tool and tested their construct validity by comparing scores from 40 parks in San Diego, CA to observe park use and PA. Results: PA elements were positively associated with park use and park PA across all versions, with the highest correlations for trails (.45 for use and .51 for PA using EAPRS-Original; .57 use and .62 PA using Abbreviated; and .38 use and .43 PA using Mini). Presence of amenities, using Abbreviated and Mini versions, was correlated with park use (.71, .64) and PA (.67, .59). The overall park quality score using Abbreviated and Mini had similar correlations (adjusted for park size) with park use (.74, .72) and PA (.72, .70) as EAPRS-Original (.71 use and .73 PA). Conclusion: In all 3 versions, EAPRS overall park scores were strongly related to observed park use and PA. Shorter versions of EAPRS make it more feasible to use park observations in research and practice.

DNA methylation may be a component of a multilevel control mechanism that regulates eukaryotic gene expression. We used synthetic oligonucleotides to investigate the effect of cytosine methylation on the binding of the transcription factor Sp1 to its target sequence (a G + C-rich sequence known as a "GC box"). Concatemers of double-stranded 14-mers containing a GC box successfully competed with the human metallothionein IIA promoter for binding to Sp1 in DNase I protection experiments. The presence of 5-methylcytosine in the CpG sequence of the GC box did not influence Sp1 binding. The result was confirmed using double-stranded 20-mers containing 16 base pairs of complementary sequence. Electrophoretic gel retardation analysis of annealed 28-mers containing a GC box incubated with an Sp1-containing HeLa cell nuclear extract demonstrated the formation of DNA-protein complexes; formation of these complexes was not inhibited when an oligomer without a GC box was used as a competitor. Once again, the presence of a 5-methylcytosine residue in the GC box did not influence the binding of the protein to DNA. The results therefore preclude a direct effect of cytosine methylation on Sp1-DNA interactions.

Land use mix reflects the availability of diverse destinations providing opportunities for active transportation. Online mapping platforms (e.g. Google Maps) show promise for measuring neighborhood features due to their ease of use and accessibility. The purpose of this study was to evaluate the validity and reliability of an online version of the Microscale Audit of Pedestrian Streetscapes (MAPS) tool by comparing Google׳s Aerial View (AV), Street View (SV), and a composite of the two views (Composite) to in-person field audits. Raters evaluated residential routes and commercial clusters (n=120) using the online MAPS tool in low and high walkability and socioeconomic status (SES) neighborhoods of two U.S. regions. Thirty land uses were evaluated for each route and cluster. Concurrent validity between field and online audits was examined using percent agreement and weighted kappa statistics (κ) for individual items and intra-class correlation coefficients (ICCs) for item subscales. Reliability was examined using ICCs. Most field-to-online land use item comparisons showed moderate to perfect agreement (κ=0.41–0.88). SV (10 out of 19 comparisons) outperformed AV (7 out of 19) and Composite (9 out of 19) compared to field audits. Subscale comparisons were fair to almost perfect (ICC 0.27-0.89). AV (7 out of 10 subscales) outperformed SV compared to field audits. Reliability between AV and SV was substantial to perfect (ICC 0.61-1.00) for most items (15 out of 21 eligible items) and substantial to almost perfect (ICC 0.61-0.96) for 9 of the 10 subscales. Online approaches did not differ after stratifying routes by SES. Audits using online MAPS were an acceptable alternative to evaluating land uses in the field. The Street View method is recommended based on better performance with individual land uses and equal performance in high and low socioeconomic status neighborhoods.