Associations of leisure-time sitting in cars with neighborhood walkability

Background: Too much sitting, including time spent sitting in cars, is associated with poor health outcomes. Identifying the built-environment attributes that may reduce vehicular sitting time can inform future initiatives linking the public health, urban design, and transportation sectors. Methods: Data collected in 2003–2004 from adult residents (n = 2521) of Adelaide, Australia were used. Logistic regression analyses examined associations of prolonged time spent sitting in cars during leisure time (30 min/day or more) with neighborhood walkability and its components (dwelling density; intersection density; land use mix; net retail area ratio). Results: Lower overall walkability was significantly associated with a higher odds (OR = 1.43, 95% CI: 1.21–1.70) of spending prolonged time in cars. For analyses with walkability components, lower net retail area ratio, lower residential density, and lower intersection density were significantly associated with prolonged sitting in cars. Conclusion: This study found that residents of high walkable neighborhoods tended to spend less time sitting in cars. In particular, higher net retail area ratio, an indicator of tightly spaced commercial areas, was strongly associated with less time in cars. Policy and planning initiatives to reduce car use require further evidence, particularly on the influence of neighborhood retail areas.