Longitudinal Impact of Changes in the Residential Built Environment on Physical Activity: Findings from the ENABLE London Study

Background: Studies have found associations between features of the residential built environment and physical activity but these have been mainly cross-sectional. In this paper we explore whether longitudinal changes in environmental exposures are associated with changes in physical activity in adults. Methods: Data from the Examining Neighbourhood Activity in Built Living Environments in London (ENABLE London) study were used. Daily steps at follow-up were regressed on daily steps at baseline, change in built environment exposures and confounding variables using multilevel linear regression to assess if neighbourhood walkability, park proximity and public transport accessibility were associated with changes in accelerometer-derived daily steps. We also explored whether observed effects were moderated by housing tenure as a marker of socio-economic status. Findings: Between baseline and follow-up, participants experienced a 1·4 unit (95%CI 1·2,1·6) increase in neighbourhood walkability; a 270m (95%CI 232,307) decrease in distance to their nearest park; and a 0·7 point (95%CI 0·6,0·9) increase in accessibility to public transport. A 1 s.d. increase in neighbourhood walkability was associated with an increase of 302 (95%CI 110,494) daily steps. A 1 s.d. increase in accessibility to public transport was not associated with any change in steps overall, but was associated with a decrease in daily steps amongst social housing seekers (-295 steps (95%CI -595, 3), and an increase in daily steps for market-rent housing seekers (410 95%CI -191, 1010) (P-value for effect modification=0·03). Interpretation: Targeted changes in the residential built environment may result in increases in physical activity levels. However, the effect of improved accessibility to public transport may not be equitable, showing greater benefit to the more advantaged. Funding Statement: This research is being supported by project grants from the UK National Prevention Research Initiative (MR/J000345/1) and the UK National Institute for Health Research (NIHR; 12/211/69). Diabetes and obesity prevention research at St George’s, University of London is supported by the NIHR Collaboration for Leadership in Applied Health Research and Care, South London. CMN is supported by the Wellcome Trust Institutional Strategic Support Fund (204809/Z/16/Z). BR was supported by a PhD studentship from St George’s, University of London. ARC and ASP are supported by the NIHR Biomedical Research Centre at University Hospitals Bristol National Health Service Foundation Trust and the University of Bristol. AE is funded by the Medical Research Council as part of the Neighbourhoods and Communities Programme (MC_UU_12017–10). BG-C is supported by a National Health and Medical Research Council Principal Research Fellowship (1107672). Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: Full ethical approval was obtained from the relevant Multi-Centre Research Ethics Committee (REC Reference 12/LO/1031). All participants provided written informed consent.