Background: Very few experimental studies exist describing the effect of changes to the built environment and opportunities for physical activity (PA). We examined the impact of an urban trail created on a frozen waterway on visitor counts and PA levels. Methods: We studied a natural experiment in Winnipeg, Manitoba, Canada that included 374,204 and 237,362 trail users during the 2017/2018 and 2018/2019 winter seasons. The intervention was a 10 km frozen waterway trail lasting 8–10 weeks. The comparator conditions were the time periods immediately before and after the intervention when ~10 kms of land-based trails were accessible to the public. A convenience sample of 466 participants provided directly measured PA while on the frozen waterway. Results: Most trail users were 35 years or older (73%), Caucasian (77%), and had an annual household income >$50,000 (61%). Mean daily trail network visits increased ~four-fold when the frozen waterway was open (median and interquartile range (IQR) = 710 (239–1839) vs. 2897 (1360–5583) visits/day, p < 0.001), compared with when it was closed. Users achieved medians of 3852 steps (IQR: 2574–5496 steps) and 23 min (IQR: 13–37 min) of moderate to vigorous intensity PA (MVPA) per visit, while 37% of users achieved ≥30 min of MVPA. Conclusion: A winter-specific urban trail network on a frozen waterway substantially increased visits to an existing urban trail network and was associated with a meaningful dose of MVPA. Walking on water could nudge populations living in cold climates towards more activity during winter months.

IntroductionAspects of the built environment that support physical activity are associated with better population health outcomes. Few experimental data exist to support these observations. This protocol describes the study of the creation of urban trials on cardiovascular disease (CVD)-related morbidity and mortality in a large urban centre.Methods and analysisBetween 2008 and 2010, the city of Winnipeg, Canada, built four, paved, multiuse (eg, cycling, walking and running), two-lane trails that are 5–8 km long and span ~60 neighbourhoods. Linking a population-based health data with census and environmental data, we will perform an interrupted time series analysis to assess the impact of this natural experiment on CVD-related morbidity and mortality among individuals 30–65 years of age residing within 400–1200 m of the trail. The primary outcome of interest is a composite measure of incident major adverse CVD events (ie, CVD-related mortality, ischaemic heart disease, stroke and congestive heart failure). The secondary outcome of interest is a composite measure of incident CVD-related risk factors (ie, diabetes, hypertension and dyslipidaemia). Outcomes will be assessed quarterly in the 10 years before the intervention and 5 years following the intervention, with a 4-year interruption. We will adjust analyses for differences in age, sex, ethnicity, immigration status, income, gentrification and other aspects of the built environment (ie, greenspace, fitness/recreation centres and walkability). We will also assess trail use and trail user profiles using field data collection methods.Ethics and disseminationEthical approvals for the study have been granted by the Health Research Ethics Board at the University of Manitoba and the Health Information Privacy Committee within the Winnipeg Regional Health Authority. We have adopted an integrated knowledge translation approach. Information will be disseminated with public and government partners.Trial registration numberNCT04057417.

Objective To determine if expansion of multi-use physical activity trails in an urban centre is associated with reduced rates of cardiovascular disease (CVD). Methods This was a natural experiment with a difference in differences analysis using administrative health records and trail-based cycling data in Winnipeg, Canada. Prior to the intervention, each year, 314,595 (IQR: 309,044 to 319,860) persons over 30 years without CVD were in the comparison group and 37,901 residents (IQR: 37,213 to 38,488) were in the intervention group. Following the intervention, each year, 303,853 (IQR: 302,843 to 304,465) persons were in the comparison group and 35,778 (IQR: 35,551 to 36,053) in the intervention group. The natural experiment was the construction of four multi-use trails, 4-7 km in length, between 2010 and 2012. Intervention and comparison areas were based on buffers of 400 m, 800 m and 1200 m from a new multi-use trail. Bicycle counts were obtained from electromagnetic counters embedded in the trail. The primary outcome was a composite of incident CVD events: CVD-related mortality, ischemic heart disease, cerebrovascular events and congestive heart failure. The secondary outcome was a composite of incident CVD risk factors: hypertension, diabetes and dyslipidemia. Results Between 2014 and 2018, 1,681,125 cyclists were recorded on the trails, which varied ~ 2.0-fold across the four trails (2358 vs 4264 counts/week in summer months). Between 2000 and 2018, there were 82,632 CVD events and 201,058 CVD risk events. In propensity score matched Poisson regression models, the incident rate ratio (IRR) was 1.06 (95% CI: 0.90 to 1.24) for CVD events and 0.95 (95%CI: 0.88 to 1.02) for CVD risk factors for areas within 400 m of a trail, relative to comparison areas. Sensitivity analyses indicated this effect was greatest among households adjacent to the trail with highest cycling counts (IRR = 0.85; 95% CI: 0.75 to 0.96). Conclusions The addition of multi-use trails was not associated with differences in CVD events or CVD risk factors, however the differences in CVD risk may depend on the level of trail use. Trial registration Trial registration number: NCT04057417.

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Introduction: There is little experimental evidence of the impact of multi-use recreational trails that support physical activity on cardiovascular disease (CVD). Hypothesis: Neighbourhoods that added multi-use trails would experience a greater decline in CVD events and risk factors compared to neighbourhoods that did not. Methods: We used a difference in differences design to study the addition of four multi-use trails 4-7km in length on CVD-related outcomes using administrative health, census and built environment data available for all citizens 30 years of age and older from Winnipeg, Canada. A 400m buffer stratified intervention and comparison neighbourhoods. Bicycle counts were recorded via electromagnetic counters for 5 years on all trails. The primary and secondary outcomes were composite measures of incident CVD events (mortality, ischemic heart disease, cerebrovascular disease and congestive heart failure) and CVD risk factors (hypertension, diabetes and dyslipidemia) and assessed quarterly for 10 years prior to and 6 years following the intervention. Intervention and comparison areas were propensity score matched, using scores regressed from baseline measures of age, sex, socioeconomic indicators, and built environment attributes that support physical activity. Results: Between 2012 and 2018, 1,429,588 cyclists were recorded on the trails and cycling use varied ~2.0-fold across the trails. Between 2000 and 2018, there were 82,632 CVD events and 201,058 CVD risk events. During the 18-year natural experiment CVD event rates and risk factors declined ~33% in both comparison and intervention neighbourhoods. In propensity score matched regression models, the incident rate ratio was 1.06 (95% CI: 0.90 to 1.24) for CVD events and 0.92 (95% CI: 0.84 to 1.02) for CVD risk factors. Sensitivity analyses revealed greater effect sizes with increasing trail use (incident rate ratios for highest vs lowest cycling counts = 0.85; 95% CI: 0.75 to 0.96 vs 1.08; 95% CI: 0.92 to 1.27). Conclusions: The addition of recreational multi-use trails was not associated with changes in overall CVD events or risk factors in adjacent neighbourhoods, compared to distant neighbourhoods, however, the effects on CVD risk factors may be influenced by trail use.