Environmental factors that contribute to higher heart disease rates

Cardiovascular disease (CVD) is the leading cause of death in the US. Identifying the underlying causes of CVD requires a close look at the role of social determinants of health (SDOH) in associated risk.

While SDOH present a vast number of variables for researchers to parse in ongoing studies, current research suggests a strong connection between heart disease and environmental factors, which create barriers to cardiovascular health.

The role of ‘greenness’ in heart health

A cross-sectional study published by the Journal of the American Heart Association looked at the effects of greenness on 249,405 Medicare beneficiaries, age 65 and older. Each participant lived in Miami-Dade County, FL, between 2010-2011. Researchers used descriptive analyses to identify links between greenness in neighborhoods and rates of heart disease in those who lived there.

After incorporating sociodemographics and adjusting for genetic risk factors, the results showed a significantly decreased risk of three types of heart disease in participants exposed to greater levels of greenery. These participants were 25% less likely to develop acute myocardial infarction (AMI), 20% less likely to develop ischemic heart disease (IHD), and 16% less likely to develop heart failure (HF). Participants living in green areas also showed a decreased risk of all cardiovascular diseases.

Confirming previous theories regarding the relationship between greenery and heart health, the authors of the JAHA study suggest that green spaces promote physical and social activity in senior populations. The strategic addition of greenness in neighborhoods could help senior populations prevent risk of CVD.

Congenital heart disease in infants

While exposure to greenery may be linked to rates of heart disease, congenital heart disease (CHD) is associated with a number of other environmental factors. 

Congenital heart disease, which refers to abnormally structured heart and vessels, is diagnosed in 1.35 million infants globally per year. According to a systematic review published by Frontiers in Cardiovascular Medicine, 165 meta-analyses of 41 studies showed that air pollutants, including sulfur dioxide and carbon monoxide, increase the risk of CHD in infants.

On top of that, maternal fever, obesity, and exposure to drugs, antidepressants, and alcohol during pregnancy posed a higher risk of CHD in infants. Paternal advanced age, smoking, and alcohol use may also be associated with infants who bear a CHD diagnosis.

Zip codes, community, and coronary heart disease

The prevalence of coronary heart disease in the US is directly related to patients’ neighborhoods. A 2020 article published in Circulation looks at data from the REGARDS (Reasons for Geographic and Racial Differences in Stroke) study. Researchers found links between zip codes, access to community, and coronary heart disease rates.

The result showed that participants who lived in zip codes associated with high rates of poverty were more likely to suffer fatal incidents of coronary heart disease. Such areas were also associated with lack of public health infrastructure and health insurance, compounding the risk.

Zip codes tied to poverty also highlighted a lack of community care among participants. Patients were more likely to experience fatal coronary heart disease if they experienced social isolation, or went at least one month without familial or community interaction. Social isolation, which occurred more often for participants in zip codes with high poverty, was associated with poorer health outcomes overall.

Exercise in urban environments

Zip codes lacking public health infrastructure require land use modifications to better serve populations at high risk of CVD. Environmental barriers can unfortunately make choosing an active lifestyle—which is known to improve cardiovascular health—difficult for patients in less-leafy areas. To combat heart disease in high-risk populations, the American Heart Association suggests implementing community environmental changes to create access to exercise opportunities.

According to an article published by the JAHA, land use and environmental design conducive to physical activity in cities must involve pedestrian and cycling transportation systems. For example, creating convenient, activity-friendly routes for bicyclists and pedestrians could promote an active lifestyle and also offer physical protections from automobiles. Children and young adults could benefit from access to secured walking and biking routes to schools, paving the way for cardiovascular health while maintaining personal safety. 

Proximity to parks, recreational facilities, and neighborhood destinations are also high on the priority list. The authors of the article emphasized the importance of access to such systems. 

“Intervention approaches must be designed to enhance opportunities for active transportation, leisure-time physical activity, or both,” the authors wrote. “Active transportation encompasses all human-powered means of travel to reach a destination such as walking, bicycling, or wheelchair rolling.”

Sources

1. Jilani MH, Javed Z, Yahya T, et al. Social determinants of health and cardiovascular disease: current state and future directions towards healthcare equity. Current Atherosclerosis Reports. 2021;23(9):55.

2. Omura JD, Carlson SA, Brown DR, et al. Built environment approaches to increase physical activity: a science advisory from the american heart association. Circulation. 2020;142(11):e160-e166.

3. Safford MM, Reshetnyak E, Sterling MR, et al. Number of social determinants of health and fatal and nonfatal incident coronary heart disease in the regards study. Circulation. 2021;143(3):244-253.

4. US EPA O. Basic information about the built environment. United States Environmental Protection Agency. 2022.

5. Wang K, Lombard J, Rundek T, et al. Relationship of neighborhood greenness to heart disease in 249 405 us medicare beneficiaries. Journal of the American Heart Association. 2019;8(6):e010258.

6. Zhang TN, Wu QJ, Liu YS, et al. Environmental risk factors and congenital heart disease: an umbrella review of 165 systematic reviews and meta-analyses with more than 120 million participants. Frontiers in Cardiovascular Medicine. 2021;0.