In this age of precision medicine — a focus on tailored therapies and interventions instead of a one-size-fits-all approach to patient care and public health — attention will need to be placed on physical environment as well as social factors and lifestyle to help improve health outcomes. New evidence from a National Institutes of Health (NIH) study shows that one area where this approach is realizing promising opportunities is the obesity epidemic.
NIH researcher, Tiffany M. Powell-Wiley, MD, MPH, and her colleagues have uncovered an important link between weight and neighborhood socioeconomic deprivation — a validated measure of socioeconomic disadvantage. In their study, published in the American Journal of Preventive Medicine (April 2015, online version), they found that an increase in neighborhood deprivation appears to be directly associated with an increase in weight. In short, revitalizing a neighborhood could help reduce the rate of obesity in that area.
“This finding identifies neighborhood deprivation as more than just a quality-of-life or cosmetic issue; it is an important public health issue as well, that must be taken into account in efforts to improve community health,” said Powell-Wiley of the Cardiovascular and Pulmonary Branch of NIH’s National Heart, Lung, and Blood Institute.
Powell-Wiley’s research focuses on breaking down barriers that lead to racial, ethnic, regional, and socioeconomic disparities linked to obesity and obesity-related cardiovascular disease prevalence, treatment, and prevention. “The environmental and social contributions to obesity and obesity-related disorders cannot be overlooked if effective prevention and treatment strategies are to be designed,” she said.
In this latest investigation, an increase in neighborhood socioeconomic deprivation was defined as moving to an area with a higher neighborhood deprivation index (NDI) score — a measure of socioeconomic disadvantage. The higher the NDI score, the greater was the degree of deprivation in the neighborhood. This value was determined by using 21 variables from the 2000 U.S. census, such as the unemployment rate and percentage of households on public assistance. Powell-Wiley compared individuals who moved to more deprived areas with those who moved to less deprived areas.
The researchers found that people who moved to more deprived areas gained substantially more weight than people who moved to less deprived areas. They also found that the amount of influence the NDI increase had on weight gain was greater for those who lived in the new area for a longer period of time. The study participants’ perceptions of their neighborhood and physical environments did not have an effect on the results.
Powell-Wiley and colleagues used data from the Dallas Heart Study (a population-based cohort in Dallas County, Texas) to study a multiethnic group of 1,835 individuals aged 18 to 65 years. They used data from 2000 to 2002 and 7-year follow-up studies performed between 2007 and 2009. Each study participant was linked to a Dallas County census block group (a contiguous geographical area defined by the Census Bureau) and an NDI score was calculated for each of these block groups.
The researchers controlled for such factors as age, income, smoking, and physical activity. Powell-Wiley explained that the deprivation exposure appears to have an impact on weight-gain risk by way of either changes in non-physical activity-related behaviors (e.g., diet) or changes in biochemical pathways triggered by exposure to the greater socioeconomic deprivation, or both.
She and her colleagues concluded that increases in neighborhood deprivation appear linked to increases in weight and that this relationship is strengthened by longer exposure to the new level of socioeconomic depression. “Our finding that the individuals who moved to more challenged areas gained excess weight highlights the adverse effect that an increase in neighborhood deprivation can have on weight gain,” Powell-Wiley said. “This is further evidence that the socioeconomic status of a community’s environment can be a major contributing factor to obesity prevalence in that area.”
This research is part of Powell-Wiley’s larger scope of investigations focused on obesity and obesity-related health disparities. In previous work, she used data from the Dallas Heart Study to investigate the relationship between the prevalence of obesity and social determinants of the condition, including access to care and cultural perceptions of weight. In addition, working with 20 churches with predominantly African-American members in the Dallas County area, she helped conduct a study that involved church members holding monthly educational events on cardiovascular disease risk factor management.
Powell-Wiley and her colleagues found that, compared to age- and sex-matched African Americans in Dallas County, the church-based population that was recruited for the intervention had a higher prevalence of obesity and downstream obesity-related cardiovascular risk factors. This was despite the fact that they reported greater physical activity. Based on these findings, she concluded that a church-based, behavioral change intervention may be effective if it provides specific tools for physical activity that promotes improved cardiovascular health. She noted, however, that it is not yet fully clear what types of tools may help in increasing physical activity in a church-based intervention.
Currently, she is working to develop a community-based behavioral change intervention in Washington, D.C., specifically addressing key social risk factors of obesity. She is targeting three wards with the most resource-limited neighborhoods and where obesity and cardiovascular disease are most prevalent compared with other, more affluent wards in the District. As she did in Texas, she is working with church leaders who will help promote and implement the initiative.
Capitalizing on the comfort most people have with mobile devices today, Powell-Wiley has incorporated the use of wearable physical activity monitors and smartphone applications to better understand her study participants’ physical activity levels. Her research team is currently finalizing a health-and-needs assessment to test the effectiveness of using the monitors and smartphone apps in the faith-based communities of the at-risk wards. She explained that this assessment is the first step in developing a community-based pilot intervention to promote behavioral change, particularly an increase in physical activity.
“Obesity is one of the most critical public health concerns today,” Powell-Wiley said. “We have to reverse the trend toward increases in excess weight, which we have seen now for several decades across the population. My hope is that, through these and other studies, we will find ways to help reverse obesity and, whenever possible, prevent it from occurring in the first place.”
Dr. Tiffany Powell-Wiley's Lab Website: http://www.nhlbi.nih.gov/research/intramural/researchers/pi/powell-wiley-tiffany
NHLBI Obesity Research: http://www.nhlbi.nih.gov/research/resources/obesity/