Examining the association between self-reported and accelerometer derived physical activity and the immediate built environment in older women: Results from the healthy women study

Participation in regular physical activity has been shown to be positively associated with favorable mental and physical health for older individuals, yet women aged 65 years and older are the least likely population group by age and gender to be regularly active. This study examined the relationship between GIS-based measures of the built environment and physical activity among a population of older women. Body mass index (BMI) was investigated as a potential effect modifier of the association between physical activity and the immediate built environment in older women.^ The immediate (a half mile radius) built environment was characterized for each participant\u27s residence using five GIS-based variables: population density, green space, connectivity (streets intersection density), neighborhood destinations such as fitness centers, grocery stores and pharmacies, and changes in elevation (or slope). Observational physical activity data were collected from 141 women aged 68 to 77 years via self-report and accelerometer, as part of the Healthy Women Study long-term follow-up visit. Associations among the set of built environment features and physical activity estimates were computed, and multivariable regressions were developed to adjust for individual-level covariates.^ The features of the built environment that were associated with physical activity varied by intensity of physical activity and by method of physical activity data collection. The strength of these associations was consistently modified by BMI category, where the BMI category of BMI ≥25 kg/m 2 was generally more significantly correlated with built environment features. Self-reported leisure-time physical activity was inversely correlated with changing elevations (slope) within the half mile radius (p\u3c0.05) for the entire sample, and highly significantly inversely correlated (p\u3c0.001) among overweight participants (BMI≥25 kg/m2). Sedentary time, as measured by accelerometry, was associated with connectivity for all participants (p\u3c0.06). Among participants with BMI≥25 kg/m 2, green space, fitness centers and pharmacies were also significantly correlated with reported leisure time physical activity (p\u3c0.05, p\u3c0.001 and p\u3c0.01, respectively), and the number of fitness centers was inversely associated with sedentary time (p\u3c0.05).^ In summary, the results of the current study demonstrate that built environment is associated with reported physical activity and sedentary time among older women, as assessed through survey instrument and accelerometer. Self-reported physical activity was associated with more features of the immediate physical environment among women with a BMI ≥25 kg/m2 compared to women with a normal BMI. This work suggests that elevation change (slope) is a potential barrier to physical activity in this population, and underscores the need for further investigation of how BMI moderates the relationship of built environment and physical activity among older women.