Residential tree canopy and allostatic load in US adults: a population-based cross-sectional study

Area of Science:

• Environmental Health
• Public Health
• Epidemiology

Background:

• Neighborhood characteristics, such as residential greenery, are increasingly recognized as modifiable targets for reducing stress and chronic disease.
• Few studies have explored how the impact of greenery on allostatic load varies across different demographic groups.
• Allostatic load is a measure of the cumulative wear and tear on the body from chronic stress.

Purpose of the Study:

• To investigate the relationship between residential tree canopy and allostatic load in a national sample of US adults.
• To determine if this relationship differs by race/ethnicity or socioeconomic status (SES).
• To examine the potential mediating role of physical activity in this association.

Main Methods:

• Cross-sectional analysis of 40,307 US adults from the National Health and Nutrition Examination Survey (NHANES).
• Residential tree canopy was assessed, and allostatic load was calculated.
• Stratified analyses were conducted by race/ethnicity and SES, with mediation analysis for physical activity.

Main Results:

• Greater residential tree canopy was associated with lower allostatic load.
• Physical activity mediated this association: more tree canopy led to more physical activity, which in turn lowered allostatic load.
• Significant inverse associations were observed for non-Hispanic White and Hispanic individuals, and those with higher SES.

Conclusions:

• Urban design interventions focusing on increasing residential greenery may improve health in specific demographic groups.
• The lack of detected association in non-Hispanic Black and low SES individuals suggests potential unmeasured stressors.
• Findings highlight the complex interplay between environment, behavior, and health outcomes across diverse populations.