Huge Drop Seen in Secondhand Smoke Levels
Exposure to environmental tobacco smoke among nonsmokers dropped more than 75% during the last decade, an indication that efforts to curb indoor smoking have been effective, federal health officials announced Wednesday.
“In the 20-plus years that I’ve been doing environmental health, I’ve never seen any measure change” so much in such a short period of time, said Dr. Richard J. Jackson, an official of the Centers for Disease Control and Prevention. “To see this dramatic drop . . . it really is striking.”
But the report also showed that children and teenagers up to age 19, nonsmokers all, had higher measurable levels of cotinine in their systems than adults, meaning “too many people, especially young people, . . . continue to be exposed,” CDC said.
The measurement of cotinine--a byproduct of tobacco that can be detected in blood and urine--came from a landmark report issued by CDC that for the first time revealed Americans’ exposure to 27 chemicals in the environment.
Most of the substances have never been measured in human bodies before, so comparisons cannot be made. But cotinine has--and the overall drop since 1991 prompted Terry Pechacek, of CDC’s office on smoking and health, to conclude that “our nationwide efforts to ensure clean indoor air . . . are working.”
Environmental tobacco smoke has been deemed a carcinogen by the National Institutes of Health toxicology program and is believed responsible for an estimated 3,000 annual cases of lung cancer among nonsmokers. Some studies also have estimated that it accounts for as many as 62,000 deaths from coronary heart disease every year.
The CDC report also showed that levels of lead--another substance that has previously been measured--have decreased.
Lead in children younger than 5--the age at which even small amounts can cause cognitive problems--dropped from 2.7 micrograms per deciliter of blood in 1994 to 2.0 micrograms in 1999. The most dangerous levels are considered to be 10 micrograms or above.
“This is good news,” said Dr. John Balbus, director of the Center for Risk Science and Public Health at George Washington University School of Public Health. Both have been “the subject of massive government efforts to try to get them lowered. These substances did not come down on their own.”
But the results were not all encouraging. Certain populations of children at high risk for lead exposure--for example, those living in homes containing lead-based paint or lead-contaminated dust--”remain a major public health concern,” the agency said.
The report also showed high levels of mercury, which can be toxic to the nervous system of a developing fetus, and higher than expected levels of certain pesticides and phthalates. Phthalates are found in plastics and many common cosmetics.
The findings prompted public health officials and others to call for increased research into the health effects produced by these compounds and a doubling of federal spending from $30 million to $60 million to launch such a research effort.
“It will still not be enough [money], but we regard it as a significant down payment [to] begin to produce data that could establish the connection between these levels of chemicals and . . . human disease,” said Dr. Richard Levinson, associate executive director of the American Public Health Assn.
CDC officials looked for metabolites of seven major phthalates in humans and were surprised to find that two of them--which are produced in much lower commercial quantities than the others--showed up in greater levels than the others.
The two, diethyl phthalate and dibutyl phthalate, were “considerably higher than one would have predicted,” said Jackson, who heads CDC’s National Center for Environmental Health.
Animal studies have linked phthalates to birth defects and the disruption of normal hormone function.
But the Cosmetic, Toiletry and Fragrance Assn., which represents the cosmetics industry, stressed that use of phthalates in cosmetics and personal care products “is supported by an extensive body of scientific research and data that confirm safety,” and have undergone considerable safety reviews by the Food and Drug Administration and others.
“Phthalates are widely used in many everyday products in modern society,” the group said. “Consumers can have confidence in their cosmetics given their oversight by FDA and long history of safe use.”
