Like so many ripples in a pond, the circumstances that influence how we live our lives are easy to overlook, and harder still to rediscover once they’ve faded into the background.

But the authors of a new study in the American Journal Of Preventative Medicine claim that they’re done just that. Poring over the detailed records of more than 1,800 residents living in Dallas, Texas, the authors believe they’ve stumbled across a strong link between our zip codes and weight scales. They found that people who moved to a poorer neighborhood gained more weight than those who either stayed put or moved to a better or similar neighborhood.

The researchers used data from the Dallas Heart Study (DHS), a multiethnic population-based analysis attempting to identify the biological risk factors behind cardiovascular disease by periodically interviewing and recording information about its participants. This allowed them to effectively see snapshots of the same population as they grew older, looking specifically at two different time periods, 2000 to 2002 and 2007 to 2009. Between the seven years, nearly half of their sample had moved, with one-third of movers having migrated to a poorer neighborhood, defined as having a higher score on their Neighborhood Deprivation Index (NDI). Factors that influenced the NDI score included the percentage of unemployment, households requiring public assistance, and car ownership found within the neighborhood.

After controlling for variables like age, income, and physical activity, the authors found a significant association of weight gain to a higher NDI score, with every one point increase in NDI amounting to a weight gain of an extra pound and a half. Notably, this neighborhood effect was cumulative. "For those who moved to higher-deprivation neighborhoods, the impact of NDI change on weight gain increased with duration of neighborhood residence," the authors wrote. It was only after four years of having moved to a more deprived neighborhood that weight was noticeably influenced, the authors explained.

While it’s been known for some time that the quality of a neighborhood can predict trends in health, including weight, the authors note that their study is among the few to take a sustained, naturalistic look at the connection between weight and poor home environment, and the first to find a specific effect from the length of residence. Other research has taken to coining these environments “obesogenic”, for their propensity to predict higher rates of obesity among its residents.

Without being able to observe changes in diet over time, the authors could only hazard educated guesses as to the reasons for their results.They explain that previous research has found that those living in poorer areas have increased levels of stress, as well as an inability to reliably purchase fruits and vegetables, both of which have been tied to weight gain. Further research of neighborhoods actively undergoing rapid growth or decline might be able to provide more clarification, they add.

Ultimately, the authors hope that their research can better highlight and combat the disparities seen in poorer neighborhoods. By finding those ripples in the pond as they happen, we might be able to provide better lives for everyone, rich or poor.

Source: Powell-Wiley T, Cooper-McCann R, Ayers C, et al. Change in Neighborhood Socioeconomic Status and Weight Gain. American Journal of Preventative Medicine. 2015