@article{ref1,
title="Quasi-causal associations of physical activity and neighborhood walkability with body mass index: A twin study",
journal="Preventive medicine",
year="2014",
author="Duncan, Glen E. and Cash, Stephanie Whisnant and Horn, Erin E. and Turkheimer, Eric",
volume="70",
number="",
pages="90-95",
abstract="OBJECTIVE: Physical activity, neighborhood walkability, and body mass index (BMI, kg/m(2)) associations were tested using quasi-experimental twin methods. We hypothesized that physical activity and walkability were independently associated with BMI within twin pairs, controlling for genetic and environmental background shared between them. <br><br>METHODS: Data were from 6,376 (64% female; 58% identical) same-sex pairs, University of Washington Twin Registry, 2008-2013. Neighborhood walking, moderate-to-vigorous physical activity (MVPA), and BMI were self-reported. Residential address was used to calculate walkability. Phenotypic (non-genetically informed) and biometric (genetically informed) regression was employed, controlling for age, sex, and race. <br><br>RESULTS: Walking and MVPA were associated with BMI in phenotypic analyses; associations were attenuated but significant in biometric analyses (Ps<0.05). Walkability was not associated with BMI, however, was associated with walking (but not MVPA) in both phenotypic and biometric analyses (Ps<0.05), with no attenuation accounting for shared genetic and environmental background. <br><br>CONCLUSIONS: The association between activity and BMI is largely due to shared genetic and environmental factors, but a significant causal relationship remains accounting for shared background. Although walkability is not associated with BMI, it is associated with neighborhood walking (but not MVPA) accounting for shared background, suggesting a causal relationship between them.<p /> <p>Language: en</p>",
language="en",
issn="0091-7435",
doi="10.1016/j.ypmed.2014.11.024",
url="http://dx.doi.org/10.1016/j.ypmed.2014.11.024"
}