The joint effects of family risk of obesity and neighborhood environment on obesity among women.

Obesity is a significant health problem in the United States that has encouraged a search for modifiable risk factors, such as walkable neighborhood designs. Prior research has shown linkages between a family history of obesity (i.e., due to either genetic or non-genetic factors) and an individual's risk of elevated body mass index (BMI). Yet, we know little about the possible interactions between neighborhood walkability and family susceptibility to unhealthy BMI in predicting individual BMI. This paper addresses this important research gap using a sample of 9918 women, derived from vital and administrative data in the Utah Population Database. We use a novel indicator of familial risk (a summary measure of siblings' BMI) and a neighborhood walkability score to capture familial susceptibility and environmental exposures, respectively. The analysis focuses on distinct risk combinations of familial susceptibility and neighborhood walkability. Compared with the "best" combination of lean family BMI history and more walkable neighborhoods, women in all of the other three family weight history/neighborhood categories show greater risks of obesity. Our results also indicate that the neighborhood environment has a strong association with individual obesity among women with higher family risk of obesity but that the association between neighborhood environment and individual obesity is even stronger for women with a lower family risk of obesity.