Many people who are exposed to second-hand cigarette smoke on a day-to-day basis do not realize it, according to newly published research by physicians at the Icahn School of Medicine at Mount Sinai. Yet exposure to this carcinogen carries an increased risk for heart disease and lung cancer, and mortality by an average of three years, exceeding even that of former smokers who are not exposed.
These were among the findings reported by Raja M. Flores, MD, and Emanuela Taioli, MD, PhD, in a study that appeared in the October issue of Carcinogenesis.
“Second-hand smoke is a lot more pervasive and more deadly than people think,” says Dr. Flores, Ames Professor of Cardiothoracic Surgery, and Chairman of the Department of Thoracic Surgery at the Mount Sinai Health System. “But we found that people are being exposed to second-hand smoke who don’t even know it.”
The researchers were surprised by their own findings, says Dr. Taioli, Director of the Institute for Translational Epidemiology, and Professor of Population Health Science and Policy, and Thoracic Surgery.
Dr. Taioli says the original plan was to show that government policies have largely been successful in protecting people from second-hand smoke. “We wanted to show that if you don’t smoke and you’re not exposed to second-hand smoke, you would be risk-free,” she says. “But we actually showed something we didn’t expect, that we still have a lot of work to do in improving our public health policies.”
They also found that currently used questionnaires capture only a fraction of people who are actually exposed to second-hand smoke, thereby underestimating its overall economic toll.
The researchers mined government databases to produce their study. They used data from the National Health and Nutrition Examination Survey (NHANES) that was gathered between 1999 to 2010 and collected from self-reported nonsmokers over the age of 20. Cotinine—a chemical produced by nicotine that lasts for up to 20 hours in a person’s urine, saliva, or blood—was measured at the time the subjects were recruited. Dr. Taioli then linked the NHANES data with the National Death Index over the same time period.
By extrapolating further, Drs. Taioli and Flores connected their findings with data from the U.S. Centers for Disease Control and Prevention that showed second-hand smoke exposure is unequally distributed in the population, with children, non-Hispanic blacks, persons living in poverty, and people who rent their housing being disproportionately affected.
“Where is their exposure coming from?” asks Dr. Flores. “This is a public health issue. Our next steps will be to really
focus on where people are getting exposed and what we can do to stop it.”
Dr. Taioli points out that the study supports stricter legislation on smoke-free areas in public housing, as well as increased education in minority communities about the deleterious effects of second-hand smoke in cars, homes, and other places where families gather. Dr. Flores says early screenings for heart disease and lung cancer may also help to catch diseases before they have a chance to progress.
“This study shows that nonsmokers who are exposed to second-hand smoke have a significant increase in premature death,” says Philip J. Landrigan, MD, MSc, Dean for Global Health and Professor of Preventive Medicine, and Pediatrics, at the Icahn School of Medicine at Mount Sinai. “There are obvious implications for people who live and work in environments where they are exposed to second-hand smoke and have no power to prevent exposure.”