By: Dr. Mika Moran and Dr. Usama Bilal
SALURBAL Project

Spanish translation here
Portuguese translation here

Greenspaces can benefit health in many ways and play an essential role in healthy urban planning. By supporting physical activity, greenspaces can help prevent lifestyle-related chronic health conditions, such as cardiovascular diseases and related risk factors like obesity and diabetes. Greenspaces also contribute to psychological restoration and stress reduction, which may help reduce violence and crime. Greenspaces help mitigate environmental hazards such as air pollution and heat, indirectly reducing the risk for related health conditions.  

Despite their multiple health benefits, urban green spaces are often concentrated in affluent areas, leaving low-income communities with limited access. Such unequal distribution of greenspace can further exacerbate socioeconomic inequalities in health outcomes such as well-being, physical activity, and obesity.

unequal distribution of greenspace in Mexico City
source: Unequal Scenes

But what if greenspaces could be leveraged to reduce health inequalities? This question is driving research to explore the equigenesis hypothesis of greenspace.  

Growing evidence supports the connections between greenspaces and narrower inequalities in mental well-being, depression, and all-cause and circulatory disease mortality. Greenspace has also been linked to reduced racial disparities in COVID-19 infections. However, most of these findings are from high-income countries.

To address this research gap, a recent SALURBAL study examined the equigenesis hypothesis in Latin America for the first time. This research examined associations between greenness and education inequalities in life expectancy and cause-specific mortality.

The new SALURBAL study looked at three causes of death: communicable, maternal, neonatal and nutritional deaths; cardiovascular deaths; and violent deaths. Researchers examined death records from 2012-2016 for 671 sub-cities located within 28 cities across 9 Latin American countries.

The study results confirm that there are substantial socioeconomic health inequalities in the region, and that higher levels of education were associated with higher life-expectancy and lower cause-specific mortality. However, greenspace seemed to affect the connections between educational attainment and different causes of death in different ways.

For example, among men, each 1-unit increase in education was associated with a 16% decrease in violence-related mortality in the least green areas, but only an 8% decrease in the greenest areas.

These results support of the equigenesis hypothesis by showing that greener areas had smaller education inequalities in violence-related mortality. However, the findings related to other causes of death and to life expectancy question the equigenesis hypothesis by showing wider education inequalities in these outcomes in greener areas.

For example, among women, each 1-unit increase in education was associated with only a 1% reduction in cardiovascular deaths in the least green areas, but with a 6% decrease in greenest areas. These results therefore link greenness with greater socioeconomic inequalities in cardiovascular death in women.

Although mixed, these findings indicate that greenspaces play an important role in in shaping urban health inequalities. We know that there are wide socioeconomic inequalities in Latin American cities, and that existing greenspaces are both sparse and unequally distributed.  Future greening policies need to make a concerted effort to ensure that unequal access to green spaces does not exacerbate existing health inequalities. Researchers and decision-makers can start by engaging local populations in planning processes, to ensure that policies and interventions consider and respond to the historical, socioeconomic, and cultural characteristics and dynamics of each urban context.