Arq. Bras. Cardiol. 2023; 120(11): e20220844

Association of Income Level and Ischemic Heart Disease: Potential Role of Walkability

Rodrigo Julio Cerci , Miguel Morita Fernandes-Silva, João Vicente Vitola, Juliano Julio Cerci, Carlos Cunha Pereira Neto, Margaret Masukawa, Ana Paula Weller Gracia, Lara Luiza Silvello, Pedro Prado, Murilo Guedes, Adriano Akira Ferreira Hino, Cristina Pellegrino Baena

DOI: 10.36660/abc.20220844

This Original Article is referred by the Short Editorial "Ischemic Heart Disease and Income Level – A Thinking on Social and Structural Determinants".

Abstract

Background

Socioeconomic status has been linked to ischemic heart disease (IHD). High-income neighborhoods may expose individuals to a walking-promoting built environment for daily activities (walkability). Data from the association between income and IHD is lacking in middle-income countries. It is also uncertain whether walkability mediates this association.

Objectives

To investigate whether income is associated with IHD in a middle-income country and whether neighborhood walkability mediates the income-IHD association.

Methods

This cross-sectional study evaluated 44,589 patients referred for myocardial perfusion imaging (SPECT-MPI). Income and walkability were derived from participants’ residential census tract. Walkability quantitative score combined 4 variables: street connectivity, residential density, commercial density, and mixed land use. IHD was defined by abnormal myocardial perfusion during a SPECT-MPI study. We used adjusted mixed effects models to evaluate the association between income level and IHD, and we performed a mediation analysis to measure the percentage of the income-IHD association mediated by walkability. We considered p values below 0.01 as statistically significant.

Results

From 26,415 participants, those living in the lowest-income tertile census tract were more physically inactive (79.1% versus 75.8% versus 72.7%) when compared to higher-income tertile census tracts (p < 0.001). Income was associated with IHD (odds ratio: 0.91 [95% confidence interval: 0.87 to 0.96] for each 1,000.00 international dollars increase in income) for both men and women equally (p for interaction = 0.47). Census tracts with a higher income were associated with better walkability (p < 0.001); however, walkability did not mediate the income-IHD association (percent mediated = −0.3%).

Conclusions

Income was independently associated with higher prevalence of IHD in a middle-income country irrespective of gender. Although walkability was associated with census tract income, it did not mediate the income-IHD association.