Environmental Exposures and Cardiovascular Death, with Gregory Weiss, MD

Gregory Weiss, MD

Much talk is made of climate change and increasing environmental dangers with rising temperatures, increasing pollution, and population explosions around the world. The age-old question of nature versus nurture continues to vex researchers and clinicians alike.

We know very well that both our genetic predisposition and the environment we are exposed to play crucial roles in our health, fitness, and ultimately our demise. Studies show that in 2019, environmental factors were associated with approximately 11.3 million deaths including 5.1 million from cardiovascular disease (CVD).²

Michael Hadley, MD, and colleagues at the Icahn School of Medicine at Mount Sinai feel strongly that understanding the relationships between environmental risk factors and health is a critical step towards designing targeted policies and programs to reduce the burden of attributable disease.¹ While many studies have looked at individual environmental risk factors for disease, the authors sought to develop a spatial environmental model accounting for independent associations between multiple environmental factors and mortality across different socioeconomic populations.

Utilizing data from the Golestan Cohort Study in Iran, Hadley’s group enrolled over 50,000 individuals compiling mortality data along with spatial environmental factors available from public databases including: ambient air pollution, household fuel use and ventilation, socioeconomic environment, proximity to traffic, distance to coronary intervention centers, population density, nighttime light exposure, and land use.¹

The resulting data collected was illuminating to say the least. The authors showed that populations exposed to high levels of outdoor air pollution were 17 percent more likely to die from CVD and 20 percent more likely to die from any cause when compared to those not exposed to high levels of air pollution.¹ Subjects who were exposed to indoor combustion of any kind of biomaterial without proper ventilation were 23% more likely to die from any cause and 36% more likely to die from heart disease.¹

Those burning kerosene without ventilation were 19 percent more likely to die from CVD and 9 percent more likely to die from any cause.¹ Those in close proximity to small and large roadways realized a 13% increase in risk for any cause mortality.¹ With regards to healthcare access, for every six miles subjects lived away from a heart catheterization center the risk of dying from heart disease went up by 2% and all-cause mortality by 1%.¹ Finally, no significant relationship was found between socioeconomic status, population density, nighttime light, and land usage and an increased risk for death.¹

“This study advances our understanding of which environmental factors may be most detrimental to cardiovascular health,” Hadley said.

The most powerful contribution of this study comes in the revelation that the total burden of heart disease attributed to indoor and outdoor pollution is equivalent to that attributed to smoking tobacco.¹ For perspective, cigarette smoking is the number one modifiable risk factor for cardiovascular disease worldwide.³ The authors of this study suggest that these data can be used to target specific populations based on exposure for interventions tailored to those specific exposures.

“Our work demonstrates how publicly available data can be used to create risk maps for individual communities, even in rural, low-income settings,” Hadley stated. “Eventually, we expect health systems to use similar approaches to create environmental risk maps for the communities they serve. The data can empower physicians to estimate environmental risks posted to their patients and offer individualized recommendations to mitigate risk.”

The information is out there. Data on pollution, air quality, water quality, and distance to critical access hospitals is a matter of public record. Clinicians can use this data to recommend wearing masks for pollution or ventilation improvement when utilizing indoor fuel for heat. There is a reason local weather stations report air quality and smog levels in their daily reports. Our job as clinicians is to make these data available to our patients in real time. Recommending our patients, especially those with preexisting conditions, avoid exposure based on their specific circumstances and location may significantly extend their lives and improve their quality of living.

References:

1. Hadley MB, Nalini M, Adhikari S, Szymonifka J, Etemadi A, Kamangar F, et al. (2022) Spatial environmental factors predict cardiovascular and all-cause mortality: Results of the SPACE study. PLoS ONE 17(6): e0269650. https://doi.org/10.1371/journal.pone.0269650
2. Murray CJ, Aravkin AY, Zheng P, Abbafati C, Abbas KM, Abbasi-Kangevari M, et al. Global burden of 87 risk factors in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019. The Lancet. 2020; 396(10258):1223–49. https://doi.org/10.1016/S0140-6736 (20)30752-2 PMID: 33069327
3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8006904/