The National Heart, Lung, and Blood Institute has awarded Scott C. Brown, Ph.D., research associate professor, and Jose Szapocznik, Ph.D., professor and chair emeritus, both in the Department of Public Health Sciences, a $2.27 million grant that will support a three-year, multi-disciplinary study of neighborhood greenness and metabolic syndrome among Hispanics.
The study is an ancillary study of the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), which is the most comprehensive study to date covering epidemiological health and disease trends in the large and growing Hispanics/Latinos minority group.
Hispanics and Latinos — the largest minority group in the United States — are at a relatively high risk for metabolic syndrome, which includes high blood pressure, high blood sugar, increased waist circumference and abnormal cholesterol levels. The syndrome increases a person’s risk for heart attack and stroke. Neighborhood greenness, also known as vegetative presence, is a novel and understudied protective factor for the syndrome that has not yet been systematically studied across Hispanic heritage groups.
“The study will assess cumulative greenness exposure, such as tree canopy, for each participant’s neighborhood using high-resolution satellite imagery over a six-year period, and relate the greenness information to each participant’s waist circumference — which is a measure of central adiposity — as well as four other metabolic syndrome indicators, including blood pressure, triglycerides, low HDL cholesterol and fasting glucose,” Dr. Brown said.
Building on the HCHS/SOL study, the new research will be the first to prospectively and longitudinally investigate the impact of neighborhood cumulative greenness exposure on metabolic syndrome indicators within and across Hispanic ethnic subgroups.
Dr. Brown and Dr. Szapocznik will work with a group of interdisciplinary experts, including Joanna Lombard, M.Arch., professor in UM’s School of Architecture, and Neil Schneiderman, Ph.D., professor in the Department of Psychology and Miami site PI for the larger HCHS/SOL study, as well as experts from the University of North Carolina, San Diego State University and the University of California at San Diego.
To conduct the study, the research team will use a sample of 8,000 participants from the Miami and San Diego HCHS/SOL sites, which are two U.S. areas with significant Hispanic/Latino populations. They will investigate the impact of natural experiment in greening on metabolic syndrome in both cities, as both communities are undergoing significant greening interventions.
“Given that both Miami and San Diego are undergoing tree-planting interventions, this study provides an opportunity to evaluate the impact of these interventions on metabolic syndrome indicators,” Dr. Szapocznik said.
The exposure to neighborhood greenness will be assessed to reflect moves and changes in the environment. To determine differences in the relationship of cumulative greenness to metabolic syndrome, multi-group analyses by indicators such as sex, site and the three larger Hispanic subgroups of Cubans, Mexicans and Central/South Americans, will also be conducted.
Biological pathways that will be examined include the relationship of greenness to changes in waist circumference, which may in turn impact the four other metabolic syndrome indicators.
Planned post-hoc analyses will examine changes in greenness, such as in tree-planting, in relation to risk for metabolic syndrome, diabetes, hypertension and hyperlipidemia, as well as possible roles of physical activity and social support as pathways in the relationship of greenness to biomarkers, which include insulin resistance and inflammation.
“Although recent research, including our own, suggests that higher levels of greenness such as tree canopy and parks may be associated with better health outcomes, the current study hopes to identify the specific behavioral and biological mechanisms through which greenness may lead to enhanced health, which may be important for interventions,” Dr. Brown said.
Researchers said the findings from this study may improve the understanding of greenness’ health impacts among Hispanics/Latinos, a growing and understudied population at risk for metabolic syndrome, diabetes and hypertension.
Should findings reveal that neighborhood greenness impacts risk for developing metabolic syndrome, policymakers may recognize the health benefits in supporting green infrastructure to reduce odds of the syndrome, diabetes, hypertension and cardiovascular disease among Hispanics.