Shifting towards healthier transport: carrots or sticks? Systematic review and meta-analysis of population-level interventions.

BACKGROUND: Promoting active travel can be beneficial for both health and the environment. However, evidence about the most effective strategies is inconsistent. We aimed to compare the effectiveness of interventions with positive (ie, carrot), negative (ie, stick), or a combination of strategies on changing population-level travel behaviour. We also aimed to identify which intervention functions, or mechanisms of how interventions seek to alter behaviour (eg, by addressing safety or accessibility), affect transport outcomes. METHODS: For this systematic review and meta-analysis, we searched eight online databases for studies published before March 28, 2022: Web of Science, MEDLINE, Scopus, Applied Social Sciences Index and Abstracts, Global Health, PsycINFO, CINAHL, and Transport Research International Documentation. We did not restrict searches by language or publication date. We included controlled before-and-after studies of population-level interventions and travel behaviours (ie, driving, public transport, walking, and cycling) from adults in the general population. We categorised interventions according to their function. Depending on whether gains or losses due to intervention function could occur, we classified interventions as carrot (eg, new bike-share programmes), stick (eg, congestion charging), or combined carrot-and-stick interventions (eg, pedestrianising areas by use of reallocated parking space). We used harvest plots to summarise the findings and guide narrative synthesis. Where possible, we converted outcomes into standardised mean differences and did random-effects meta-analyses. FINDINGS: From 38 916 records screened, 102 reports describing 121 interventions met the inclusion criteria. 79 interventions were carrots, 22 were carrot-and-sticks, and 20 were sticks. Results for carrot interventions were less consistent than for stick or combined interventions. Findings from the meta-analysis (64 reports describing 67 interventions) agreed with those in the narrative synthesis; although effects were statistically non-significant, for driving outcomes, interventions with stick strategies (standardised mean difference [SMD] -0·17, 95% CI -0·36 to 0·02) and combined carrot-and-stick strategies (-0·13, -0·47 to 0·20) had point estimates of greater magnitude than those for interventions with carrot strategies (-0·10, -0·23 to 0·03). Likewise, for active travel outcomes, combined carrot-and-stick strategies had a higher point estimate (0·33, -0·01 to 0·68) compared with carrot interventions (0·08, -0·05 to 0·21). Functions thought to change behaviour using financial means were effective at decreasing driving behaviour, whereas those improving access, safety, and space were effective for increasing active travel outcomes. INTERPRETATION: This Article found that, although transport interventions with only positive strategies are more commonly evaluated, interventions that combine both positive and negative strategies might be more effective at encouraging alternatives to driving at the population level. Further research is needed for interventions involving a stick strategy, which remain less widely implemented or well studied than those with only carrot strategies. FUNDING: Medical Research Council, Cambridge Trust.

Impacts of new cycle infrastructure on cycling levels in two French cities: an interrupted time series analysis.

BACKGROUND: Cities globally have started to make substantial investment in more sustainable forms of transportation. We aimed to evaluate whether the construction of new cycling infrastructure in Paris and Lyon, France, affected population cycling activity along new or improved routes. METHODS: Routinely collected cycle count data from January 2014 to March 2020 were acquired for the cities of Paris and Lyon. Improvements were identified at 15 locations with 6 months of pre- and post-intervention data. Comparison streets were chosen within Paris or Lyon for which pre-intervention trends in cycling were similar to those at intervention sites. Controlled interrupted time series analyses and autocorrelation were performed adjusting for seasonality. Random-effects meta-analysis combined results across streets within each city and overall. RESULTS: On average, cycling counts/day increased on both intervention and control streets in Paris and Lyon. In general, results of the ITS analysis indicated no significant change in the level or trend as a result of the improvements in either city. Meta-analysis suggested that intervention streets in Paris had a larger positive pooled effect size for level change (218 cycle counts, 95% CI -189, 626, I2 = 0%) compared to Lyon (34, 95% CI -65, 133, I2 = 14%); however, confidence intervals for both cities were wide and included no effect. CONCLUSIONS: The findings suggest that improving or constructing new cycle lanes may be necessary but not sufficient to induce significant changes in cycling levels. There is a need to understand how context, intervention design and other complementary interventions can improve the effectiveness of new cycling infrastructure.

Associations of Exposure to Perfluoroalkyl Substances With Thyroid Hormone Concentrations and Birth Size.

BACKGROUND: Adequate thyroid function during pregnancy is essential for optimal fetal growth. Gestational exposure to perfluoroalkyl substances (PFAS) can negatively affect birth size and disrupt maternal and neonatal thyroid function, although the interrelationship is unclear. OBJECTIVE: We aimed to quantify the associations between maternal serum-PFAS concentrations and birth weight, birth length, and cranial circumference. We also aimed to estimate associations between PFAS and thyroid hormone (TH) concentrations, thereby elucidating whether THs potentially mediate the associations between PFAS concentrations and birth size. METHODS: We studied a population-based prospective cohort of 172 mother-singleton pairs from the Faroe Islands. Twelve PFAS were measured in maternal serum obtained at 34 weeks of gestation. THs were measured in maternal and cord serum. Associations between PFAS concentrations and birth size and TH concentrations were estimated using multivariable linear regressions. Sex-stratified analyses along with a mediation analysis were performed to estimate potential mediating effects of THs in the association between PFAS and birth outcomes. RESULTS: Several PFASs were negatively associated with birth weight, length, and head circumference, and a general positive association between maternal serum-PFASs and cord serum-thyroid-stimulating hormone (TSH; also known as thyrotropin) was found. For instance, a doubling in perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) was associated with a 53% (95% CI, 18%-99%) and 40% (95% CI, 8%-81%) increases in TSH concentrations, respectively. There was little evidence of sexually dimorphic associations. Overall, THs were not found to mediate associations between PFASs and birth size. CONCLUSION: In this study, several PFASs were negatively associated with birth size and increased THs; however, this did not explain lower birth weight among children exposed to PFAS.

Physical Activity Levels and New Public Transit: A Systematic Review and Meta-analysis.

CONTEXT: Physical inactivity is a public health concern as it contributes to the rising burden of noncommunicable diseases. Introducing new public transportation options, such as extending or building new light rail or bus rapid transit stations, could encourage commuters to walk to and from public transit stops, thus increasing their physical activity levels. Despite previous research generally finding positive associations between public transit usage and physical activity levels, few have summarized the association between introducing new public transportation options and different intensities of physical activity. This study aimed to systematically review the current evidence and perform a meta-analysis on this association. EVIDENCE ACQUISITION: Ten databases were systematically searched for studies published between 1997 and 2017. To ensure comparability, study outcomes were converted to MET hours/week. A random effects meta-analysis and sensitivity analysis were then conducted. EVIDENCE SYNTHESIS: Nine studies were identified to be included in the systematic review, of which five were eligible for meta-analysis. Pooled results suggest that building new public transit options is associated with a statistically significant increase in light to moderate physical activity levels by 1.76 MET hours/week (95% CI=0.19, 3.32, p=0.03). This is equivalent to increasing walking and other light to moderate physical activity by about 30 minutes per week, relative to baseline. No significant effect was found for the moderate to vigorous physical activity outcome. CONCLUSIONS: Results show new public transit options can substantially contribute to increasing low- to moderate-intensity exercise levels, which has the potential to improve health on a population scale.

Epigenetic activation of MGAT3 and corresponding bisecting GlcNAc shortens the survival of cancer patients.

Bisecting GlcNAc on N-glycoproteins is described in E-cadherin-, EGF-, Wnt- and integrin- cancer-associated signaling pathways. However, the mechanisms regulating bisecting GlcNAc expression are not clear. Bisecting GlcNAc is attached to N-glycans through beta 1-4 N-acetylglucosaminyl transferase III (MGAT3), which is encoded by two exons flanked by high-density CpG islands. Despite a recently described correlation of MGAT3 and bisecting GlcNAc in ovarian cancer cells, it remains unknown whether DNA methylation is causative for the presence of bisecting GlcNAc. Here, we narrow down the regulatory genomic region and show that reconstitution of MGAT3 expression with 5-Aza coincides with reduced DNA methylation at the MGAT3 transcription start site. The presence of bisecting GlcNAc on released N-glycans was detected by mass spectrometry (LC-ESI-qTOF-MS/MS) in serous ovarian cancer cells upon DNA methyltransferase inhibition. The regulatory impact of DNA methylation on MGAT3 was further evaluated in 18 TCGA cancer types (n = 6118 samples) and the results indicate an improved overall survival in patients with reduced MGAT3 expression, thereby identifying long-term survivors of high-grade serous ovarian cancers (HGSOC). Epigenetic activation of MGAT3 was also confirmed in basal-like breast cancers sharing similar molecular and genetic features with HGSOC. These results provide novel insights into the epigenetic regulation of MGAT3/bisecting GlcNAc and demonstrate the importance of N-glycosylation in cancer progression.