title: GPS-Based Exposure to Greenness and Walkability and Accelerometry-Based Physical Activity.
abstract: Background:Physical inactivity is a risk factor for cancer that may be influenced by environmental factors. Indeed, dense and well-connected built environments and environments with natural vegetation may create opportunities for higher routine physical activity. However, studies have focused primarily on residential environments to define exposure and self-reported methods to estimate physical activity. This study explores the momentary association between minute-level global positioning systems (GPS)-based greenness exposure and time-matched objectively measured physical activity.Methods:Adult women were recruited from sites across the United States. Participants wore a GPS device and accelerometer on the hip for 7 days to assess location and physical activity at minute-level epochs. GPS records were linked to 250 m resolution satellite-based vegetation data and Census Block Group-level U.S. Environmental Protection Agency (EPA) Smart Location Database walkability data. Minute-level generalized additive mixed models were conducted to test for associations between GPS measures and accelerometer count data, accounting for repeated measures within participant and allowing for deviations from linearity using splines.Results:Among 360 adult women (mean age of 55.3 ± 10.2 years), we observed positive nonlinear relationships between physical activity and both greenness and walkability. In exploratory analyses, the relationships between environmental factors and physical activity were strongest among those who were white, had higher incomes, and who were middle-aged.Conclusions:Our results indicate that higher levels of physical activity occurred in areas with higher greenness and higher walkability.Impact:Findings suggest that planning and design policies should focus on these environments to optimize opportunities for physical activity.Cancer Epidemiol Biomarkers Prev; 26(4); 525-32. ©2017 AACRSee all the articles in thisCEBP Focussection, "Geospatial Approaches to Cancer Control and Population Sciences."
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts. pjames@hsph.harvard.edu.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.|Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.
authors.forename: Peter
authors.initials: P
authors.lastname: James
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.|Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.
authors.forename: Jaime E
authors.initials: JE
authors.lastname: Hart
authors.affiliation: Department of Parks, Recreation, and Tourism Management, North Carolina State University, Raleigh, North Carolina.|Center for Geospatial Analytics, North Carolina State University, Raleigh, North Carolina.
authors.forename: J Aaron
authors.initials: JA
authors.lastname: Hipp
authors.affiliation: Division of Gastroenterology, Hepatology and Nutrition, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.|Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Mitchell
authors.affiliation: Department of Family Medicine & Public Health, University of California, San Diego, San Diego, California.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Kerr
authors.affiliation: Urban Form Lab, University of Washington, Seattle, Washington.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Hurvitz
authors.affiliation: Perelman School of Medicine and School of Nursing, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Karen
authors.initials: K
authors.lastname: Glanz
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.|Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.
authors.forename: Francine
authors.initials: F
authors.lastname: Laden
mesh_terms: D061725:Accelerometry / Q000379:methods; D000368:Aged; D015331:Cohort Studies; D015444:Exercise; D005260:Female; D040362:Geographic Information Systems; D006801:Humans; D008875:Middle Aged; D012111:Residence Characteristics; D057566:Self Report