PURPOSE: Physical inactivity and obesity continue to be challenging public health issues. There is growing evidence that the built environment is related to participation in physical activity and obesity. Cohort studies provide an opportunity to study these relationships in large samples of individuals living in a wide range of settings. In this study we examined associations between the perceived neighborhood environment and walking and body mass index (BMI) in a cohort of U.S. women.
METHODS: The Nurses' Health Study II is a longitudinal study initiated in 1989 with over 100,000 nurses from 14 states. The 2005 survey included four binary (yes/no) questions on the perceived neighborhood environment: 1) presence of sidewalks, 2) availability of shops and other destinations within easy walking distance of home, 3) free or low cost recreation facilities, and 4) perceived safety of walking at night. Women reported their weekly duration of walking for exercise or walking to work during the past year and were classified based on obtaining ≥ 150 min/wk. BMI was calculated with self-reported height and weight. Multiple logistic and linear regression were used to examine associations between the environmental variables and walking and BMI, respectively, controlling for age and other potential confounders.
RESULTS: Data were analyzed on 82,108 women (mean age = 50.5 ± 4.6 y). Thirty-five percent walked ≥ 150 min/wk; the mean BMI = 27.3 ± 6.4. Forty-eight percent of women reported sidewalks in their neighborhood, 25.2% reported shops and other destinations, 64.4% reported free or low cost recreation facilities, and 5.9% reported it was unsafe to walk at night. Presence of sidewalks (odds ratio (OR) = 1.17; 95% confidence interval (CI): 1.14, 1.21), destinations (OR = 1.34; 95% CI: 1.29, 1.38), and recreation facilities (OR = 1.28; 95% CI: 1.24, 1.32) were positively associated with walking. The perception that it was unsafe to walk at night was negatively associated with walking (OR = 0.86; 95% CI: 0.80, 0.92). All four environmental variables were significantly associated with BMI (p < 0.0001).
CONCLUSIONS: Among a large sample of women, perceived environmental factors were associated with walking at least 150 min/wk and lower BMI. The findings are consistent with and contribute to the growing evidence-base on the built environment.