CHAPTER 110: ENVIRONMENT AND HEART DISEASE

INTRODUCTION

People in today’s ever more densely populated, tightly interconnected, highly urbanized and warming world are surrounded by a complex array of environmental threats to health that include air pollution, water pollution, toxic chemicals, changing dietary patterns, emerging infectious diseases, the urban built environment, noise, and global climate change. Numerous etiologic associations have been established between environmental exposures and disease, including cardiovascular disease.¹

Pollution is the single most important environmental cause of disease and death.^2,3 The World Health Organization estimates that household air pollution causes 4.3 million deaths annually in persons of all ages^4,5; many of these deaths are due to heart disease and stroke.⁶ Ambient air pollution causes 3.7 million deaths,⁷ and many are due to heart disease and stroke. Polluted drinking water, poor sanitation, and inadequate hygiene cause 842,000 deaths.⁸ Polluted dust and soil at active and abandoned mines, smelters, industrial facilities, and hazardous waste sites kill tens of thousands more.⁹

Toxic chemicals in the environment are significant causes of disease, specifically cardiovascular disease.² Substances known to be cardiotoxic and reviewed in this chapter include air pollution^2,3; metals,⁹ including lead, mercury, arsenic, cobalt, and thallium; halogenated hydrocarbons, including chlorinated, brominated, and fluorinated compounds; organophosphate insecticides; nitrates; and carbon disulfide. Diseases of the heart and cardiovascular system that are linked to toxic chemical exposures in the environment include arrhythmias, hypertension, peripheral vascular injury, cardiomyopathy, acute myocardial infarction (MI), stroke, and sudden death. Toxic chemicals that disrupt endocrine signaling can increase risk for cardiovascular disease by causing elevated lipid levels and increasing risk for obesity, the metabolic syndrome, and diabetes.^10,11

Likelihood is high that, beyond the known cardiotoxic chemicals, there are other chemicals in the modern environment whose toxicity to the heart and cardiovascular system has not yet been recognized.¹² These undiscovered cardiotoxins will be found hidden in plain sight among the more than 80,000 new synthetic chemicals that have been invented in the past half century, that are used widely today in myriad consumer products and that, because of failure of stewardship by the chemical industry and by governments, have never been tested for safety or toxicity.¹² People are widely exposed to these materials, and annual national surveys conducted by the Centers for Disease Control and Prevention find measurable levels of more than 100 untested synthetic chemicals in the bodies of virtually all Americans.¹³

Two additional environmental exposures that increase risk of cardiovascular disease are noise and global climate change. These are discussed in this chapter.

Given the widespread exposure of the American population to multiple environmental chemicals of unexamined toxicity, every physician is advised to obtain a brief history of occupational and environmental exposure from every new patient and to ask more detailed follow-up questions or seek consultation with a specialist in ...