Researchers Try to Separate Smoking Fact From Fiction : Health: Effects of secondhand exposure are being studied. But there is a collision of politics and science.
The big brown building, a short walk off a country road in this scenic college town, looks more like a barn than a high-tech university laboratory. Inside, a rare and curious contraption is engaged in a habit that the surgeon general warns is bad for your health.
This is Kent Pinkerton’s creation: the UC Davis smoking machine.
As an associate professor of anatomy at Davis, Pinkerton is interested in how the lungs work. His specialty has landed him at the crossroads of politics and medicine. In his lab at the university’s Institute of Toxicology and Environmental Health, Pinkerton and his colleagues hope their unusual smoking machine will inject hard science into the roiling national debate over the dangers of secondhand smoke.
How, they are eager to know, are the cells and tissues of the lungs altered by exposure to secondhand smoke? Are infants born smaller when they are exposed in the womb? Does secondhand smoke induce changes in the nasal passageways that lead to asthma? Is there a precise dose--for lack of a better term--at which it becomes dangerous? If so, where does the threshold lie?
At a time when “Secondhand Smoke Kills” billboards are popping up across California, and the government has classified secondhand smoke as a human carcinogen, nonsmokers worry that the slightest whiff of smoke could wreak havoc on their lungs and hearts. Cigarette companies are waging a counterattack, insisting that it is little more than a nuisance.
The truth, which independent scientists say is somewhere in between, may emerge from the smoking machine.
Scientific truths about secondhand smoke are not easy to come by. Studies are difficult and expensive to conduct, and funding is limited. Moreover, ethical considerations prevent researchers from subjecting humans to cigarette smoke, at least not for days on end. Nor can they ask people to smoke for the sake of science.
Hence the busy Davis smoking machine.
Five days a week, six hours a day, the machine is at work, blowing smoke at guinea pigs and hamsters, whose body parts will later be dissected in an effort to identify biological reactions that may be similar in humans. The device--one of just two large-scale smoking machines in the nation outside of those owned by tobacco companies--smokes more precisely than any person ever could, and therein lies its value.
There are no Marlboros, Camels or Virginia Slims here. Rather, the smoking machine’s brand of choice is one few people have heard of--the 1R4F. These low-tar and nicotine research cigarettes, each manufactured from the same tobacco blend, are produced by the University of Kentucky. They were rolled in 1983 and kept in a deep freeze until being shipped to Davis, where they are conditioned for up to 48 hours at 70% humidity before being smoked.
Every 10 minutes, a steel piston fires another 1R4F into a revolving cylinder. A small metal coil, the sort used to heat an ordinary blow-dryer, lights the cigarette with a tiny red glow. As ashes begin to emerge, two others are in various stages of being smoked. The whole mechanism is encased in a plexiglass box that is yellow with smoke residue. Through a series of pipes, the box is connected to chambers where the animals are kept.
With every puff, the cylinder clicks another revolution and a red light flashes. Each cigarette--there are never more than three burning at any time--is smoked in precisely the same fashion: one puff a minute, each puff lasting two seconds, eight puffs in all. To create each puff, a vacuum draws in 35 milliliters of air--no more, no less.
There is, Pinkerton says, an important reason for all this precision.
Soft-spoken and lanky, the scientist is a master of understatement, never going out on a limb. “If we are going to understand the mechanisms (by which secondhand smoke injures people),” he says, “we need to have well-controlled conditions.”
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The Davis studies have been under way for three years--a short span in science, when research often lasts for decades. The university scientists are particularly interested in the effects of secondhand smoke on young children; studies show infants and toddlers--who may suffer from bronchitis, asthma and other respiratory diseases when exposed to secondhand smoke in the home--are its primary victims.
Among the Davis findings: Toxicologist Peter Witschi has shown that pregnant rats exposed to secondhand smoke gave birth to pups that weighed 6% less than those born to other rats--not a dramatic reduction, but one that experts say is significant. Dr. Jesse Joad, a pediatrician, has demonstrated that newborn rats exposed to secondhand smoke in the womb and after birth test positive for asthma. Pinkerton has found that the lungs of newborn rats develop more slowly when exposed to secondhand smoke.
As part of the experiments, Joad is investigating how nerve fibers in the lungs of guinea pigs are harmed by exposure to secondhand smoke; the damage prevents the lungs from fending off other pollutants. Witschi is trying to determine whether a particularly strong carcinogen called NNK produces lung tumors in hamsters exposed to secondhand smoke, as it does in animals that breathe direct smoke.
Few such studies have been done before. “This is very beginning stuff,” Joad said, adding: “The kind of testing that we are going to do absolutely could never be done on children.”
Tobacco industry critics contend that the research is a waste of time.
Chris Coggins, a toxicologist for cigarette maker R.J. Reynolds, says he has done his own animal research on rats and found no biological changes in the heart, lungs or respiratory system. The only damage documented in the study--which appeared last year in the journal Inhalation Toxicology--occurred in the tip of the rats’ noses, Coggins said, and was “completely reversible” when they were no longer exposed to the smoke.
Tobacco industry consultant Gio Batta Gori, also a toxicologist, calls the Davis studies irrelevant. Humans, Gori argues, have the “intrinsic capacity” to clear their bodies of low-level pollutants, including secondhand smoke.
“You can manipulate the experiments any way you want and come up with some results,” Gori complained of the research at Davis and other animal studies. “You can choose a strain (of animal) that is susceptible, and you can use doses that are beyond the capacity of the animals to clear.”
Witschi says the doses can be manipulated--and must be--if scientists are to learn at what levels secondhand smoke becomes dangerous.
The animals in the Davis experiments are generally exposed at 1,000 micrograms of smoke particles per cubic meter of air--levels that the researchers say are high, but can be found in typical smoking environments, such as bars. However, some studies--including Witschi’s NNK research--employ levels as high as 4,000 micrograms, concentrations that he acknowledges are much higher than those found in the real world.
These concentrations are a matter of great dispute. Coggins, the Reynolds toxicologist, maintains that real-world concentrations average only 35 micrograms per cubic meter in smoking homes. In bars, he says, concentrations would run only as high as 100 micrograms per cubic meter. His rat studies employed exposures of 100 micrograms, 1,000 micrograms and 10,000 micrograms--and found no effects even at the highest dose, he said.
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On such minutiae hang the answers to crucial questions about secondhand smoke’s health effects.
According to the U.S. Centers for Disease Control and Prevention, as well as health advocacy groups, 53,000 people die each year from exposure to secondhand smoke. This figure is based on epidemiology studies, which examine patterns of illness but do not prove cause and effect.
The studies implicate secondhand smoke in lung cancer and other cancers, heart disease, sudden infant death syndrome, bronchitis, pneumonia and asthma, especially in children.
The U.S. Environmental Protection Agency, relying on the lung cancer epidemiology, has declared secondhand smoke a Group A human carcinogen--a classification that puts it in the same category as radon and asbestos. But tobacco industry officials say the EPA’s research is flawed because people overestimate the amount of smoke they have been exposed to, or lie about their smoking habits.
The animal research may settle this debate by showing what epidemiology cannot: precisely how secondhand smoke wreaks its havoc, and exactly how much exposure is dangerous.
Experts say it is not safe to assume that passive smoking affects people in the same way as active smoking. This is for two reasons: Those exposed to secondhand smoke get a smaller dose--inhaling about 1% of the toxins that smokers absorb. At the same time, however, secondhand smoke is much dirtier, partly because it does not go through a cigarette filter, said Stanton Glantz, a UC-San Francisco researcher.
In the business of tobacco research, what smokers inhale is known as “mainstream smoke.” What comes off the burning end of the cigarette is “sidestream smoke.” Secondhand smoke--also known as environmental tobacco smoke--is made up mostly of sidestream smoke, but also includes what the smoker exhales.
Sidestream smoke is a complex blend of more than 4,000 chemicals--including carbon monoxide, formaldehyde, ammonia, nicotine, zinc, nickel and arsenic. In the air, it is an elusive target; some chemicals evaporate, some condense, some attach to the lining of the lungs when inhaled while others do not.
The EPA has found that five known human carcinogens and nine probable carcinogens are emitted at higher levels in sidestream smoke than in mainstream smoke. Other toxic elements--including carbon monoxide, ammonia, nicotine and acetone--are more concentrated insidestream than mainstream smoke. NNK, the carcinogen Witschi is studying, is one to four times stronger in sidestream smoke than in mainstream smoke.
This is not to suggest, experts say, that exposure to secondhand smoke is more dangerous than active smoking--it is not. But, with the exception of tobacco industry scientists, researchers who are trying to assess the danger of secondhand smoke are finding that exposure clearly has biological effects.
At the University of Maryland, Dr. Rebecca Bascom has performed some of the few studies on humans. After exposing medical students to high concentrations of secondhand smoke for 15 minutes, she found that some experienced itchy eyes and nasal congestion, but that the reaction was not a classic allergic one--meaning standard allergy medicines would not help people who are sensitive to cigarette smoke.
At New York University Medical Center, which maintains the only other large university-based smoking machine in the nation, researcher Arthur Penn is trying to figure out how secondhand smoke affects the hearts of young children exposed to smoke in their homes.
Penn and his colleagues exposed young chickens to very heavy concentrations of sidestream smoke--he used five cigarettes smoked at once--and found significantly larger plaques in their arteries than in a group of control chickens. Over time, these plaques can build up to include deposits of fat and cholesterol, which cause heart disease. Some of the plaque lesions were so big they could be seen without a microscope. All the chickens were on a low-cholesterol diet, he said.
In a subsequent experiment, Penn ratcheted down the exposure level, this time subjecting the chickens to the smoke of just one cigarette--about the same concentration as in a smoky bar. He found that even then, the chickens developed significant plaques, leading him to conclude that the same may happen in children of smokers. At UC-San Francisco, Glantz has conducted similar studies on rabbits with similar results.
“These results,” Penn said, “clearly indicate there are real, long-term effects on the cardiovascular system due to involuntary exposure to cigarette smoke, and our recent studies show that it is at levels you could find in many public venues.”
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Such research, however, does not occur in a vacuum. Politics swirls around these scientists in the same way that secondhand smoke swirls around the animals they study. Penn, Pinkerton and the others are always on guard about what they say, knowing that any statements might be used by one side or the other in the emotional debate over restricting smoking.
The collision of politics and science troubles Pinkerton, for he is not a political man. His sole interest, he says, is science. Understanding how secondhand smoke affects the lungs--particularly in young children--will help him better understand how all kinds of pollutants alter the respiratory system.
“I know it’s a very emotional issue,” he said. “It’s one of those things where we could relieve the consciences of a lot of (parents who smoke) or we could make them feel more guilty than ever.”
And then there are the constant battles for funding. The tobacco industry, through its Center for Indoor Air Research, finances a good portion of research. Pinkerton and Penn have taken tobacco dollars, and have no qualms about it, saying they have never felt interference in their methods or what they publish. But Penn learned an interesting lesson recently: After his low-level exposure chicken studies came up with damning conclusions, the Center for Indoor Air Research told him it would not fund subsequent work.
He is now hunting around for a new grant. “We’ll be happy to take money from almost anybody,” he said, “with no strings attached.”
Pinkerton relies on a grant from Proposition 99, the anti-smoking initiative adopted by California voters in 1988. But that money, too, may run out; in a move that is angering many scientists, Gov. Pete Wilson wants to redirect the research dollars to medical care. The money comes from the same pool that pays for a massive education campaign about the dangers of tobacco, including the ubiquitous secondhand smoke billboards.
Pinkerton says he doesn’t think much about who foots the bill or what their agenda might be.
“We don’t want to be driven by trying to come up with proof for legislative ideas,” he said. “I know that may sound contrary to what our sponsors want, but . . . if that is our only objective to doing research, then I think we are not doing justice to science, and to our whole creative process of trying to understand how things in life work.”
In the Air
Secondhand smoke accounts for 85% of all indoor air pollution, according to researcher James Repace. Pollution is measured in micrograms of “respirable particulates”--breathable particles--per cubic meter of air. The federal standard for clean air is 50 micrograms per cubic meter. Although the tobacco industry disputes his work, Repace’s measurements show that smoky indoor air is more polluted than a busy highway.
Library of Congress:
Washington, D.C.
Reading room
No smokers
Microgram count: 30
McDonald’s restaurant:
Bowie, Md.
One or two smokers
Microgram count: 109
Bowling alley:
Bowie, Md.
14 smokers
Microgram count: 202
Bingo game:
Large church hall
Many smokers
Microgram count: 1,140
Bagel bakery:
Yonkers, N.Y.
No smokers
Microgram count: 25
Interstate 295:
Washington, D.C.
Rush hour
Microgram count: 40
Knights of Columbus dance:
Crofton, Md.
40 smokers
Microgram count: 697
Small conference room:
Controlled experiment
Four chain smokers
Microgram count: 1,947
