Background and Purpose
Many built environment factors have been related to physical activity and walking behavior (Bauman et al., 2012), microscale features that affect people’s experience of the environment have been less studied. The Microscale Audit of Pedestrian Streetscapes (MAPS) tool was designed to measure features such as street design, transit stops, sidewalk qualities, street crossing amenities, social features and aesthetics.

Objectives
To examine associations of a wide range of microscale environmental attributes, using a reliable instrument and systematic scoring system (Millstein et al., 2013), with multiple physical activity measures, in four age groups.  The present study fills additional gaps by studying three regions of the US, presenting findings with and without adjustments for macro-level neighborhood walkability, and assessing individual microscale attributes and cumulative scores.  Microscale characteristics were expected to be significantly associated primarily with walking for transportation, and the cumulative scores were expected to be stronger correlates of walking for transport than any individual characteristic.

Methods
Objective microscale environmental data were collected as part of three studies examining the relation of neighborhood design to physical activity, nutrition behaviors, and weight status in children, adolescents, adults, and older adults.  These studies were conducted in urban and suburban neighborhoods in Seattle/King County, WA, San Diego, CA, and the Baltimore, MD-Washington, DC regions.  Neighborhoods were selected to vary on macro-environment features and median income, so present analyses represented a wide range of neighborhood built environment and sociodemographic characteristics.  Participants (n=3677) represented four age groups (children, adolescents, adults and older adults).  MAPS audits were conducted along a 0.25 mile route from participant homes toward the nearest non-residential destination (i.e., shops or services, a park, or a school).  A comprehensive scoring system (Millstein et al., 2013) was used to construct subscales and overall summary scores for each section of MAPS: route, intersections, segments, and cul-de-sacs.  Walking/biking for transportation and leisure/neighborhood physical activity were measured with age-appropriate surveys (ActiveWhere, GPAQ, CHAMPS).  Objective physical activity was measured with accelerometers.  Mixed linear regression analyses were performed to assess the effect of MAPS scores on multiple physical activity outcomes for each age group, adjusting for all covariates as fixed effects and participant clustering in census block groups as a random effect.  All models were run with and without adjusting for macro-level GIS-defined walkability (high/low).

Results
There were many significant associations across all age groups after adjusting for macro-level walkability (51.2%, 22.1% and 15.7% of MAPS scores were significantly associated with walking/biking for transport, leisure/neighborhood physical activity, and objectively-measured MVPA, respectively).  Destinations and land use, streetscape, segment, and intersection variables were mainly related to transport walking/biking. Aesthetic variables were related to leisure/neighborhood physical activity.  The overall summary score was related to total MVPA in children and older adults.  Cul-de-sacs were related to neighborhood physical activity in children and adolescents.  In general, the strongest associations were seen with the MAPS summary scores.

Conclusions
The value of using observational measures of streetscapes was demonstrated by many findings that MAPS variables significantly explained physical activity among four age groups, adjusting for macro-level walkability.  The pattern of findings suggests that many modifiable built environment attributes are related to physical activity.  Environment-physical activity associations were specific to domain, consistent with hypotheses and previous research. The present study provides substantial evidence that microscale features independently explain physical activity, especially active transportation, adjusting for walkability. The importance of these findings is that microscale features like sidewalk quality, street crossing aids, and aesthetic variables are feasible and affordable to change.  Given that the strongest associations were with MAPS summary scores, physical activity behavior is more likely to be influenced by the cumulative impact of numerous environmental attributes than by a few critical variables.

Implications for Practice and Policy
Present findings provide strong evidence that microscale environment attributes are related to physical activity patterns across age groups, and these associations are independent of macro-level walkability.  The pattern of findings is consistent with an interpretation that the cumulative effect of numerous attributes is the likely mechanism of effect.  Using instruments like MAPS can help identify built environment changes that can be achieved at a reasonable cost and in a feasible time frame with a likelihood of improving physical activity.

References

1. Bauman, A.E., Reis, R.S., Sallis, J.F., Wells, J.C., Loos, R.J.F., & Martin, B.W. on behalf of the Lancet Physical Activity Series Working Group. (2012). Correlates of physical activity: Why are some people physically active and others not? The Lancet, 380, 258-271.
2. Millstein, R.A., Cain, K.L., Sallis, J.F., Conway, T.L., Geremia, C., Frank, L.D., Chapman, J., Van Dyck, D., Dipzinski, L., Kerr, J., Glanz, K., Saelens, B.E. (2013). Development, scoring, and reliability of the Microscale Audit of Pedestrian Streetscapes (MAPS). BMC Public Health, 13, 403.

Support / Funding Source
NIH grants RO1 ES014240, RO1 HL083454, and RO1 HL077141.