Built environment configuration and change in body mass index: the Caerphilly Prospective Study (CaPS).

There exist no long term longitudinal studies assessing BMI trends of older adults in relation to the built environment. We employed cohort data from the Caerphilly Prospective Study (CaPS) to analyze the long term independent associations between a broad set of built environmental factors and change in BMI measured at three time points over a 12-year period. Built environment morphological metrics (morphometrics) used include measures of land use accessibility and space syntax modelled street network accessibility. A multilevel modelling framework was adopted wherein measurement occasions were nested within individuals and individuals were nested within LSOA census areas. BMI was observed to be significantly (p<0.05) associated with a number of built environment factors including mix; density of retail, churches, recreational and leisure services; street network accessibility as well as slope variability. Controlling for socio-demographic and lifestyle factors and for vascular diseases had negligible impact upon the influence of built environmental factors highlighting the importance of urban design and planning in community public health interventions.