Alexandra Molloy
When Henry Wechsler pores over the smoking trends from the last few rounds of the Harvard School of Public Health College Alcohol Study (CAS), he is troubled. The 1990s has marked a banner decade for the tobacco industry with regard to the college student population, a group heretofore virtually immune to its influence, and has left Wechsler, principal investigator of CAS, with a bad taste in his mouth. “When a group that’s been resistant to tobacco increases its smoking rate dramatically, there’s reason to sound an alarm,” he notes. Despite a dramatic reduction in smoking in the United States overall, it’s become all too clear that tobacco remains stubbornly popular among adolescents and young adults, in whom nearly all smoking behaviors take their initial stranglehold. From 1993 to 1997, Wechsler and his CAS colleagues watched the prevalence of smoking rise 28 percent, with increases across all kinds of colleges and all student subgroups, to hold steady at a ten-year high today. The trend, combined with an approximately 32 percent decade-long rise in high school smoking, threatens to slow or even reverse the decline seen in adult use since 1965.
Although concerned with all kinds of substance use by young people, Wechsler did not start CAS with smoking at the forefront of his mind. Since its inception in 1993, the now-famous national study has primarily focused on the use--and abuse--of alcohol by college students and was first to coin the oft-used phrase "binge drinking." But the CAS surveys did always ask about behaviors around other substances including tobacco, and researchers were startled when they began to look at the responses about smoking. "What’s interesting,"says Nancy Rigotti, internist and director of the Tobacco Research and Treatment Center at Massachusetts General Hospital and associate professor of health and social behavior at the School, who joined Wechsler several years ago to help analyze the smoking data from CAS, "is Henry just happened to be asking the right questions at the right time to document this increase in tobacco use among young adults, which was a population researchers and policymakers had not been thinking about."
Instead, the population most on the public’s and policymakers' minds during the '80s and '90s was children under 18, primarily because it was an age group everyone could rally around. "Nobody, including the tobacco industry, could say publicly that they wanted kids to smoke," recalls Rigotti, who worked at the Kennedy School of Government on smoking policy at the time. "So the idea of stopping kids from smoking became something like motherhood and apple pie--there was nobody against it." The result: on the one hand, an abundance of well-documented research on smoking in children and, on the other, a disregard for the young-adult smokers they were to become.
The abundance of college smokers uncovered by CAS in the last decade was probably the result of a cohort effect, as the boom of "baby" smokers in the '80s grew up and went off to college--or, as many in the tobacco control industry quip, as "the Joe Camel generation matriculated." Many kids who picked up the habit as children brought their addiction in tow. Those teens who avoided the practice thus far were subjected to a volatile combination of exposure and experimentation, plunged into living situations close to smokers and removed from parental influences. It is this juxtaposition of adolescent and adult, smoker and non-smoker, that makes the college population so appealing to the CAS researchers, who hope to gain insights into both the behaviors of childhood and adulthood by closely examining the transitional stage between the two. “Some college smokers are still not addicted," notes Wechsler. "Many of them smoke small amounts. Many of them are experimenting with it. Many are trying to give it up. So this is a time period of change, and it's important to try and intervene."
But why intervene at all? What's the harm in a little youthful diversion or exploration? For one, nicotine addiction seems to play a more significant role in youth smoking than ever thought. Most teenage smokers, when asked, say they will give up the habit five years hence; but the results of CAS and other surveys indicate unequivocally that this has not been the case, and at least half of young people who take up smoking continue to use tobacco as adults. In general, the long-term health consequences can be devastating--cancer, heart attack, stroke, emphysema--but the aftereffects may be even worse the earlier you start. Taking up the practice early in life has been associated with a variety of afflictions in adulthood including generalized anxiety disorder, chronic obstructive pulmonary disease, depression, even gum disease. A 1996 Harvard School of Public Health study showed that cigarette smoking actually slowed the growth of lung function in adolescents, particularly girls.
Of course, the most obvious detriment to starting young is it allows the chronic diseases typically associated with smoking to strike all the more quickly. If current trends persist, about 500 million people alive today will eventually be dead from tobacco--half of them in middle age, losing 20 to 25 productive years of life. Of these chronic diseases, lung cancer reigns king; smokers in the U.S. are 20 times more likely to die of lung cancer in middle age than nonsmokers. David Christiani may now know why.
Christiani, professor of occupational medicine and epidemiology at the School, heads a large multidisciplinary program looking into the genetic susceptibility to lung cancer. In a recently published study, he and his colleagues found that smokers who begin in adolescence are at particular risk of irreversible genetic damage that may lead to lung cancer--even if they eventually stop smoking. Examining the healthy lung tissue of former smokers with lung cancer, the researchers found an inverse relation between age at smoking initiation and the concentrations of DNA adducts, long-lasting aggregates of tobacco carcinogens and genetic material believed to be the precursors to tumor formation. The reason for this persistent DNA damage may be that young smokers are less able to remove adducts through DNA repair or cell turnover than older smokers; alternatively, young smokers may remove adducts just fine but are more susceptible to adduct formation and thus accumulate more in the end. Whatever the explanation, the results reinforce the notion that smoking irreparably damages your health, and the earlier you start, the greater that damage will be.
But getting that notion across to young people is easier said than done. "These are chronic diseases we're talking about," says Christiani, "and, by definition, you have to be thinking more about your future than your present. That’s a very hard struggle with young people. They think 40 or 50 is so over the hill, it seems ridiculous to them to worry. But all of us who are middle aged and never smoked are now very happy. Believe it or not, you're still very young at 40, and that’s the age group where we're seeing many lung cancer patients now."
A unique way of conveying the more immediate health consequences of smoking to young people may be an inadvertent outcome of Christiani's recent work. His study found that DNA adduct levels in certain blood cells correlate nicely with the adduct levels measured in lung tissue, which means assessing DNA damage--and predicting lung cancer risk--can be accomplished with a simple blood test in an outwardly healthy individual rather than an invasive biopsy of lung tissue. "This is a great advance," notes Christiani, "because you could go to high schools or colleges, take blood samples, and say, look, you are already showing damage in your blood, tissues, and DNA from smoking. Maybe that would help provide them appropriate feedback for quitting."
Christiani emphasizes that this synergy between bench science and behavioral research will be essential to successfully curbing the smoking epidemic. His group aims to follow up its recent research by looking at age and gender with regard to various gene polymorphisms; they have found evidence that an individual’s genetic makeup can influence smoking--lung cancer risk and that the effect seems to be much stronger in young people and women--two groups, he notes, that are the target of the most intense tobacco marketing today. Wechsler and Rigotti, too, are moving beyond pure prevalence analysis to include more survey questions on policy-related issues in CAS and to pursue major system-wide interventions like smoke-free dorms. "So now we’re getting into the business of how to change things as well as looking at what’s happening,” says Rigotti. "It’s hard not to try and make things better."When it comes to tobacco and youth, making things better is sure to be a long and arduous journey. "The point is one shouldn’t get disheartened,"declares Wechsler. "There are many ways that we can intervene and help young people avoid smoking. And we should try all of them."
Harvard Public Health Review Winter 2002/text version
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