Green Spaces, Land Cover, Street Trees and Hypertension in the Megacity of São Paulo.

Tiana C L Moreira,Thais Mauad,Paulo A Lotufo,Itamar De Souza Santos,Demóstenes F Silva Filho,Isabela Bensenor,Jefferson L Polizel

doi:10.3390/ijerph17030725

Abstract

Proximity to green spaces has been shown to be beneficial to several cardiovascular outcomes in urban spaces. Few studies, however, have analyzed the relationship between these outcomes and green space or land cover uses in low–medium income megacities, where the consequences of rapid and inordinate urbanization impose several health hazards. This study used a subgroup of the dataset from The Brazilian Longitudinal Study of Adult Health ELSA-BRASIL (n = 3418) to identify the correlation between the medical diagnosis of hypertension and green spaces in the megacity of São Paulo. Land cover classification was performed based on the random forest algorithm using geometrically corrected aerial photography (orthophoto). Three different indicators of exposure to green spaces were used: number of street trees, land cover and number of parks within 1 km. We used logistic regression models to obtain the association of the metrics exposure and health outcomes. The number of street trees in the regional governments (OR = 0.937 and number of parks within 1 km (OR = 0.876) were inversely associated with a diagnosis of hypertension. Sixty-three percent of the population had no parks within 1 km of their residence. Our data indicate the need to encourage large-scale street tree planting and increase the number of qualified parks in megacities.

Highlights

The rapid concentration of populations in large urban agglomerations has produced megacities, i.e., cities with more than 10 million inhabitants
We considered the sum of tree canopies and grass as green space and the sum of the different types of roof as constructed areas
The risk factors for cardiovascular diseases considered in ELSA-BRASIL were smoking habits, Body mass index (BMI), physical activity, excessive drinking, hypertension, diabetes, dyslipidemia and salt consumption for the study population (n = 3418)

Summary

Introduction

The rapid concentration of populations in large urban agglomerations has produced megacities, i.e., cities with more than 10 million inhabitants. A range of potential health hazards are present in megacities, especially in the developing world: traffic-related air pollution, substandard housing, urban violence, vector-borne diseases, inadequate sanitation, and insufficient or contaminated drinking water, among others [1]. São Paulo city, the 10th most populated megacity in the world, has more than 11 million habitants [2] and its metropolitan area is home to 21 million individuals. The abovementioned adverse impacts on the health of a megacity can be mitigated by the availability of green spaces, which can offer different ecosystem services (ESSs) and create beneficial health effects. The ESSs associated with green spaces fall into different categories: provisioning (e.g., food, water, fuel and wood); regulating (e.g., regulation of temperature, water, disease); cultural. Public Health 2020, 17, 725; doi:10.3390/ijerph17030725 www.mdpi.com/journal/ijerph

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