Infrastructure, policy and regulatory interventions to increase physical activity to prevent cardiovascular diseases and diabetes: a systematic review.

BACKGROUND: Noncommunicable diseases are major contributors to morbidity and mortality worldwide. Modifying the risk factors for these conditions, such as physical inactivity, is thus essential. Addressing the context or circumstances in which physical activity occurs may promote physical activity at a population level. We assessed the effects of infrastructure, policy or regulatory interventions for increasing physical activity. METHODS: We searched PubMed, Embase and clinicaltrials.gov to identify randomised controlled trials (RCTs), controlled before-after (CBAs) studies, and interrupted time series (ITS) studies assessing population-level infrastructure or policy and regulatory interventions to increase physical activity. We were interested in the effects of these interventions on physical activity, body weight and related measures, blood pressure, and CVD and type 2 diabetes morbidity and mortality, and on other secondary outcomes. Screening and data extraction was done in duplicate, with risk of bias was using an adapted Cochrane risk of bias tool. Due to high levels of heterogeneity, we synthesised the evidence based on effect direction. RESULTS: We included 33 studies, mostly conducted in high-income countries. Of these, 13 assessed infrastructure changes to green or other spaces to promote physical activity and 18 infrastructure changes to promote active transport. The effects of identified interventions on physical activity, body weight and blood pressure varied across studies (very low certainty evidence); thus, we remain very uncertain about the effects of these interventions. Two studies assessed the effects of policy and regulatory interventions; one provided free access to physical activity facilities and showed that it may have beneficial effects on physical activity (low certainty evidence). The other provided free bus travel for youth, with intervention effects varying across studies (very low certainty evidence). CONCLUSIONS: Evidence from 33 studies assessing infrastructure, policy and regulatory interventions for increasing physical activity showed varying results. The certainty of the evidence was mostly very low, due to study designs included and inconsistent findings between studies. Despite this drawback, the evidence indicates that providing access to physical activity facilities may be beneficial; however this finding is based on only one study. Implementation of these interventions requires full consideration of contextual factors, especially in low resource settings. TRIAL REGISTRATION: PROSPERO 2018 CRD42018093429.