Green mobility and obesity risk: A longitudinal analysis in California.

Previous work reports an inverse association between neighborhood greenness and obesity. Limitations of this work, which relies largely on cross-sectional data, include that studies often lack control for unmeasured genetic and sociodemographic factors that may confound associations, and cannot disentangle temporal order between neighborhood greenness and obesity. We move beyond a cross-sectional approach and leverage a longitudinal sibling-linked dataset with health, residential, and demographic information on women with two births in California between 2007 and 2015 (N = 552,929). We used a sibling comparison design to control for unmeasured stable characteristics of women and tested whether a positive change in neighborhood greenness (i.e., "upward green mobility") precedes a reduction in obesity risk. Models also adjusted for baseline obesity risk and time-varying individual- and neighborhood-level socioeconomic factors. As hypothesized, we find that upward green mobility varies inversely with the odds of obesity. Results indicate that small decreases in neighborhood greenness may also show protective associations with obesity risk. Our findings, if replicated, suggest that changing levels (particularly increases) of greenness in the residential environment may combat the rise of obesity.