World Trade Center (WTC) CHEST

Overview

This project will evaluate the effects of World Trade Center (WTC) exposure in WTC responders 10-13 years following the events of 9/11. Prior studies have described persistent pulmonary function abnormalities in a significant portion of responders. The investigators study seeks to examine the relationship between pulmonary function abnormalities and other markers of chronic cardiopulmonary disease and further elucidate the pathophysiologic effects of exposure to inhaled particulate matter (PM) on 9/11. This study will provide critical information regarding risk of exposure to PM, risk factors for disease and potential for improvements in diagnosis and treatment.

Serious illness and injury following the September 11, 2001 (9/11) attacks on the World Trade Center (WTC) affects thousands of responders who worked on the WTC rescue and recovery effort. During this time, these individuals sustained exposure to a vast array of environmental toxins and physical hazards. The population of survivors presents a unique opportunity to rigorously examine the effects of inhaled particulate matter on risk of persistent pulmonary and chronic cardiopulmonary disease. Original reports of 9,500 WTC responders examined between July 2002 and April 2004, noted abnormal pulmonary function results in one-third of participants. Further studies of this population have demonstrated persistent changes in pulmonary function tests 9 years after exposure (2010 Annual Report on 9/11 Health). Numerous complex interactions between pulmonary and cardiovascular systems exist. In fact, at the molecular level, evidence supports an integral role for reactive oxygen species (ROS)-dependent pathways in the instigation of pulmonary oxidative stress, systemic pro-inflammatory responses, vascular dysfunction and atherosclerosis. Studies in animals have shown that inhalation of particles can lead to weakening of the heart muscle. In addition, patients who have developed pulmonary disease from inhalation of particulate matter may develop increased pressures in the pulmonary arteries, as well as dysfunction of the right ventricle of the heart. Finally, patients who have suffered blockage of the coronary arteries may exhibit abnormalities in the heart function that may be detected by an echocardiogram. Preliminary work by our group revealed echocardiographic evidence of cardiac abnormalities in a subset of 1190 WTC responders. Diastolic dysfunction, or impaired ventricular relaxation, is known to accompany aging and is associated with hypertensive heart disease. In our analysis of subjects \< 50 years of age, BMI \< 30, and lacking a diagnosis of hypertension, the investigators found a prevalence of diastolic dysfunction of 47%. Importantly, when the population was narrowed to exclude former or current smokers, and those with LV abnormalities, 12% had abnormalities of RV diastolic function. The investigators propose to analyze the relationship between pulmonary function abnormalities and evidence of diastolic dysfunction. Persuasive data implicates obstructive sleep apnea (OSA) in the development of hypertension, arrhythmias, vascular dysfunction and cardiac disease. Webber et al demonstrated an increased prevalence of obstructive sleep apnea (OSA) among firefighters exposed to the WTC disaster, and our group has demonstrated a similar prevalence of screen positive for OSA among 2500 law enforcement officers present at Ground Zero. The relationship between OSA and risk of cardiac disease involves similar pathophysiologic pathways including inflammation and impaired vascular reactivity. In addition to the traditional risk factors for cardiovascular disease (CVD), studies have indicated that exposure to inhalation of particulate matter (PM) contribute to CV morbidity and mortality. The 2010 American Heart Association Scientific Statement on Particulate Matter Air Pollution and Cardiovascular Disease provided compelling evidence of increased risk due to air pollution. Although the exact mechanisms by which PM cause these toxic effects are not adequately understood, and it is likely that different mechanisms are responsible for acute and chronic effects. In addition, PM consists of many different components, and different components may affect CVD by different mechanisms, such as electrophysiologic changes, inflammation, coagulation, endothelial cell function effects and atherosclerosis. In summary, thousands of WTC responders sustained exposure to thousands of tons of coarse and fine PM, cement dust, glass fibers, asbestos, lead, hydrochloric acid, polychlorinated biphenyls, organochlorine pesticides, and polychlorinated dioxins and furans. It is unknown to what extent the exposure to PM modified risk of developing atherosclerotic disease, in addition to the pulmonary effects and effects on cardiac function.