Built environment and changes in blood pressure in middle aged and older adults

Few studies have examined interaction effects between person and environment, especially for cardiovascular disease (CVD) risk. The purpose of this study was to examine built environment characteristics and resident health behaviors as they relate to change in blood pressure, an important component of CVD.

Participants (N=1145, aged 50-75 at baseline) were recruited from 120 neighborhoods in Portland, Oregon. Using a longitudinal design, we assessed changes in participants' systolic and diastolic blood pressure from baseline to 1-year follow-up (2006-2007 to 2007-2008). Independent variables included baseline neighborhood-level measures of GIS-constructed neighborhood walkability and density of fast-food restaurants, and resident-level measures of meeting physical activity recommendations and eating fruits and vegetables.

There was a small but significant resident-level increase in both systolic and diastolic blood pressure (P<0.001) over the 1-year observation period. A similar trend was also observed at the neighborhood level (P<0.001). Significant differences in change in blood pressure, by neighborhood walkability, were observed, with decreases in systolic and diastolic blood pressure for those living in high walkable neighborhoods (P<0.001). Neighborhoods of low walkability but with a high density of fast-food outlets and residents making visits to fast-food restaurants were significantly associated with increases in blood pressure measures over time. The negative effect of fast-food restaurants on blood pressure was diminished among high-walkable neighborhoods, with benefits observed among residents meeting guidelines for physical activity and eating fruits and vegetables.

Neighborhoods with high walkability may ameliorate the risk of hypertension at the community level and promotion of neighborhood walkability could play a significant role in improving population health and reducing CVD risk.