Context Adults aged 18 to 24 years, many of whom are in college, represent the
youngest legal targets for tobacco industry marketing. Cigarette smoking has
been described among college students, but little is known about noncigarette
tobacco use by college students or cigar use by adults of any age.
Objectives To assess the prevalence of all forms of tobacco use (cigarettes, cigars,
pipes, and smokeless tobacco) among US college students and to identify student-
and college-level factors associated with use of each product.
Design The Harvard College Alcohol Survey, a self-administered survey conducted
in 1999.
Setting One hundred nineteen nationally representative US 4-year colleges.
Subjects A total of 14,138 randomly selected students (60% response rate).
Main Outcome Measures Self-report of current (in the past 30 days), past-year, and lifetime
use of cigarettes, cigars, pipes, smokeless tobacco, and all tobacco products.
Results Nearly half (45.7%) of respondents had used a tobacco product in the
past year and one third (32.9%) currently used tobacco. Cigarettes accounted
for most of the tobacco use (28.5% current prevalence), but cigar use was
also substantial (37.1% lifetime prevalence, 23.0% past-year prevalence, and
8.5% current prevalence) and combinations of the 2 were common. Total tobacco
use was higher in men than in women (37.9% vs 29.7%; P<.001),
despite nearly identical current cigarette smoking rates between the sexes
(28.5% for women vs 28.4% for men), because of greater use of cigars (current
prevalence, 15.7% vs 3.9%; P<.001) and smokeless
tobacco (current prevalence, 8.7% vs 0.4%; P<.001)
by men. Tobacco use was significantly higher among white students (P<.001), users of other substances (alcohol and marijuana) (P<.001), and students whose priorities were social rather
than educational or athletic (P<.05). Among students
who had used both cigars and cigarettes, only 8.9% smoked cigars at an earlier
age than they had smoked cigarettes.
Conclusion Our study indicates that tobacco use is common among college students
and is not limited to cigarettes. College appears to be a time when many students
are trying a range of tobacco products and are in danger of developing lifelong
nicotine dependence. National efforts to monitor and reduce tobacco use of
all types should expand to focus on college students and other young adults.
Tobacco use is increasing among young Americans. Cigarette smoking rates
among adolescents increased by 32% between 1991 and 1997.1,2
Cigarette smoking by young adults (18-24 years) increased by 16% between 1995
and 1997, presumably reflecting the aging of the adolescent cohort.2 Young adults, who represent the youngest legal targets
of tobacco industry marketing, may also be initiating tobacco use in larger
numbers. If this trend continues, it threatens to reverse the decline in smoking
prevalence among US adults that has occurred during the past half century.3
The smoking behavior of college students is a useful index of tobacco
use among young adults. More than one third of adults aged 18 to 24 years
attend college, and one quarter attend a 4-year college.4
US colleges and universities enroll more than 12 million students5 and are a potential site for interventions to discourage
tobacco use. Between 1993 and 1997, cigarette smoking prevalence increased
28% among US college students.6 Whether this
trend is continuing needs to be determined.
There is also reason to suspect that college students use a broader
range of tobacco products than cigarettes, although this has not been assessed.7 Cigar smoking is a particular concern.8
Following a sharp increase in promotional activities by manufacturers, cigar
consumption in the United States increased by 50% between 1993 and 1998, reversing
a 30-year decline.9,10 The rise
in cigar sales presumably corresponds to an increase in cigar smoking prevalence,
but this is uncertain because recent data on the prevalence of cigar use are
limited and not based on national samples.11,12
Data from California suggest that cigar use is increasing most rapidly among
young adults, who had the lowest rates of cigar use before 1990.9,11
Cigar smoking rates are higher among individuals with more education and higher
incomes, a pattern opposite to that observed for cigarette smoking.2,11 High rates of cigar use were reported
by adolescents in high school surveys conducted between 1996 and 1999.1,13-15 These
adolescents may continue to smoke cigars as they enter young adulthood. These
lines of evidence suggest that the prevalence of cigar smoking may be especially
high in college students. As young adults in the process of furthering their
education, college students appear to fit the demographic profile of new cigar
smokers.
Consequently, total tobacco use by young adults may be considerably
higher than has been detected by previous analyses limited to cigarettes.6 Little is known about the full spectrum of tobacco
use among the college population or about risk factors for the use of different
tobacco products.8 This information is essential
to guide the development of interventions. This article reports the prevalence
and patterns of use of all tobacco products among respondents to the 1999
Harvard College Alcohol Survey, a large nationally representative sample of
US college students.
The Harvard College Alcohol Study surveyed randomly selected, cross-sectional
samples of students in a nationally representative sample of 4-year, US colleges
in 1993, 1997, and 1999. Details of the method and sampling procedures are
published elsewhere.16,17 In 1999,
128 (91%) of the original 140 colleges that participated in the 1993 study
were resurveyed. Participating colleges were sent guidelines for drawing a
random sample of undergraduates from their total enrollment of full-time students.
A sample of 225 was selected from each college. Nine (7%) of the 128 schools
were dropped from analyses because of low response rates (less than 40% of
eligible students responding). The final sample was 119 colleges. Cigarette
and cigar use rates did not differ significantly between these 119 colleges
and the total sample of 128 colleges, indicating that omission of the 9 schools
had no effect on the major variable under study. The 119 colleges are located
in 39 states (24% in the Northeast, 29% in the South, 29% in the North Central,
and 18% in the West). Seventy-one percent are located in urban or suburban
settings, and 29% are in small town or rural settings. More than two thirds
are public institutions. Forty-four percent have more than 10,000 students,
23% have 5001 to 10,000 students, and 34% have less than 5000 students. Fifteen
percent have a religious affiliation. Five percent enroll only women.
Questionnaires were mailed to 23,751 students at the 119 schools in
February 1999. Three separate mailings were sent: a questionnaire, a reminder
postcard, and a second questionnaire. Responses were anonymous. Cash awards
were used to encourage students to respond. Sixty percent of students (n =
14,138) returned questionnaires. Response rates varied between 40% and 83%
among the 119 colleges. To explore the potential for bias due to student nonresponse,
a short form of the questionnaire that included a smoking question was mailed
to a sample of students who did not return the 1999 questionnaire. Past 30-day
cigarette smoking rates did not differ significantly between respondents to
the short survey and respondents to the entire student survey (25% vs 28%, P = .17). The correlations between individual colleges'
response rates and their 30-day cigar and cigarette prevalence were 0.04 (P = .68) and 0.01 (P = .11), respectively,
indicating little chance for bias on this basis.
Sixty-one percent of the respondents were female compared with 53% of
the full-time undergraduate population of the 119 participating schools.18 Respondents' ethnicity (76% non-Hispanic white, 7%
Hispanic, 6% black, and 8% Asian) closely resembles that of all students at
the 119 schools (76% white, 7% Hispanic, and 5% black).18
Eighty-five percent of respondents were 18- to 24-year-olds; 23% were freshmen,
22% sophomores, 25% juniors, 22% seniors, and 8% fifth-year or postgraduate
students. Respondents' age distribution closely matches that of students at
all 4-year colleges.19
The questionnaire assessed demographic and background characteristics;
tobacco, alcohol, and other substance use; satisfaction with education; and
students' interests and lifestyle choices.16,17
To assess tobacco use, respondents were asked if they had smoked a cigarette,
cigar, or pipe or used smokeless tobacco. For each, response options were
"never used," "used, but not in the past 12 months," "used, but not in the
past 30 days," or "used in the past 30 days." Also assessed were the number
of days in the past 30 days in which a student had smoked cigarettes and cigars
and the age at which they first smoked these products.
For each tobacco product, all students who reported any use were considered
to be ever (lifetime) users. Current users were students who used the product
in the past 30 days. Past-year users reported having used the product in the
past year. Total tobacco use included cigarettes, cigars, smokeless tobacco,
and pipes. Binge drinking was defined as drinking 5 or more drinks in a row
for men and 4 or more drinks in a row for women during the previous 2 weeks.20 Current marijuana users were students who had smoked
marijuana in the past 30 days. Other illicit drug use was not included in
the analysis, because current use rates were very low.
Statistical analyses were carried out using SAS statistical software
(SAS Institute Inc, Cary, NC). Univariate analyses identified student-level
and college-level characteristics associated with current cigar, cigarette,
smokeless tobacco, and total tobacco use. Sociodemographic factors included
age, sex, ethnicity, year in school, marital status, and highest parental
educational attainment (a proxy for socioeconomic status). Other student-level
variables included current marijuana use, binge drinking, grade point average,
a single-item measure of satisfaction with education, an item assessing the
importance to a student of participating in 9 activities (eg, athletics, academic
work, fraternity or sorority life, parties, and religion), and an item measuring
the number of hours per week a student spent on 8 activities (eg, playing
intercollegiate sports, studying, socializing with friends). College-level
factors included geographic location (West, South, North Central, and Northeast),
campus location (rural or small town vs urban or suburban), size of enrollment
(<5000, 5000-10,000, or >10,000), public vs private status, religious affiliation,
coeducational vs all-female, competitiveness for admission (based on percentage
of applicants accepted), commuter vs noncommuter school, and survey response
rate.
Student-level and college-level factors that were significantly associated
with cigar, cigarette, smokeless tobacco, and total tobacco use in the univariate
analysis (P<.001) were included in multiple logistic
regression models. Separate models were built for cigar, cigarette, smokeless
tobacco, and total tobacco use. Current use was the outcome variable for all
models. All multivariate models included sex, ethnicity, year in school, marital
status, and highest parental educational attainment. Two-way interaction terms
of these factors with sex were included in the initial model, and those with
statistical significance were retained in the final model. Year in school
was used in place of age to examine the effect of duration of exposure to
the college environment. Results do not differ when age is substituted in
the models. Adjusted odds ratios (ORs) with 95% confidence intervals are reported.
The final logistic regression model was fitted by the Generalized Estimating
Equations approach,21,22 with
the independent working correlation, to make more robust inference using clustered
outcomes due to our sampling scheme. Odds ratios obtained from the Generalized
Estimating Equations method were almost identical with those from ordinary
logistic regression, whereas the SEs of ORs associated with the college characteristics
were slightly larger. The Generalized Estimating Equations–based results
are reported herein.
Prevalence of Tobacco Use
More than 60% of college students have tried a tobacco product, nearly
half used tobacco in the past year, and one third used tobacco in the past
month (Table 1). Cigarettes account
for most of the tobacco use. More than half of college students (53.4%) have
smoked a cigarette, 38.1% did so in the past year, and 28.5% were current
(past 30-day) cigarette smokers. Among current smokers, 32.0% smoke less than
1 cigarette per day, 43.6% smoke 1 to 10 cigarettes per day, and only 12.8%
smoke 1 or more pack per day. Current, past-year, and lifetime cigarette smoking
rates in this college sample did not change between 1997 and 1999.6
Total tobacco use is higher among men than women (Table 1). More than half of men (53.0%) and 41.3% of women have
used tobacco in the past year, whereas 37.9% of men and 29.7% of women are
current tobacco users. The sex difference in total tobacco use is entirely
attributable to a higher prevalence of noncigarette tobacco use among men,
because men and women have nearly identical cigarette smoking rates.
Cigar smoking accounts for the largest share of noncigarette tobacco
use (Table 1). More than one third
of college students have ever smoked a cigar, including more than half of
the men and one quarter of the women. Nearly 1 in 4 college students smoked
a cigar in the past year, and 8.5% smoked a cigar in the past month. Most
cigar use is occasional: less than 1% of current (past 30-day) cigar users
smoked daily, and 89.7% smoked a cigar on fewer than 5 of the past 30 days.
Smokeless tobacco use is much less prevalent than cigarette or cigar smoking.
Pipe smoking is rare.
The use of cigarettes, smokeless tobacco, and all products combined
is more common in non-Hispanic whites than in Hispanics, blacks, or Asians
(Table 2). In contrast, the prevalence
of cigar use is similar in whites and blacks (9.2% vs 8.1%) but lower in Hispanics
and Asians. Cigar smoking is actually more prevalent among black women than
white women (6.8% vs 4.0%, P = .003), whereas a reverse
relationship exists for men (10.9% vs 17.2%, P =
.008). This finding should be interpreted with caution because results for
blacks are based on a small sample and need confirmation.
Combinations of Tobacco Products
Most college students who have used tobacco used more than 1 product.
Among tobacco users, 51.3% used more than 1 tobacco product in the past year
(36.3% used 2 tobacco products, 14.4% used 3 products, and 0.6% used all 4
products). The most frequent combinations were cigarettes and cigars (19.7%),
cigarettes and pipes (12.0%), and cigarettes, cigars, and smokeless tobacco
(6%). In contrast, 77.5% of current tobacco use was restricted to a single
product. Among current users, the most frequent combination was cigars and
cigarettes.
Men used multiple tobacco products more often than women; 58.2% of men
vs 27.5% of women had used more than 1 tobacco product in the past year (P<.001), whereas 37.1% of men but only 10.6% of women
had used more than 1 tobacco product in the past month (P<.001). The combination of cigarettes and cigars accounts for nearly
all multiple tobacco product use in women and is by far the most frequent
combination among men.
Noncigarette tobacco use occurs more often in combination with cigarette
use than in isolation. Among current cigar smokers, 33.4% smoked only cigars,
whereas 61.4% smoked both cigars and cigarettes. Of current smokeless tobacco
users, 30.6% used only smokeless tobacco, whereas 62.3% also smoked cigarettes.
The median age of first cigarette use was 14 years for both sexes. The
median age of first cigar use was 17 years for men and 18 years for women.
However, 26.8% of cigar smokers (33.3% of women and 21.9% of men) had their
first cigar at 19 years or older, when they were presumably in college. Among
5262 respondents who had ever used both cigars and cigarettes, 63.8% had smoked
a cigarette at a younger age than they had smoked a cigar, 27.3% had started
both at the same age, and only 8.9% had used cigars at a younger age than
cigarettes.
Correlates of Tobacco Use
Table 3 displays the multivariate
analyses examining student-level and college-level sociodemographic factors
associated with current use of all tobacco products. Table 4 displays the result of a similar analysis focused on student
behaviors and lifestyles. Total tobacco use is significantly (P<.05) linked with sex, ethnicity, marital status, other substance
use, high-risk behaviors, and certain college lifestyles. Male and white students
are more likely to use tobacco than female and nonwhite students (Table 3).
Students who use tobacco are
also more likely to smoke marijuana, binge drink, have more sexual partners,
have lower grades, rate parties as important, and spend more time socializing
with friends (Table 4). Tobacco
users are less likely than nonusers to rate athletics or religion as important
and to be satisfied with their education. Total tobacco use is not related
to parental educational attainment. The only college-level factor associated
with tobacco use is geographic location. Tobacco use is lower in western colleges
(Table 3). Except for sex, these
same factors are also independently associated with current cigarette smoking.
Cigar smokers differ from cigarette smokers in several ways. Men are
far more likely than women to smoke cigars. Blacks are as likely to smoke
cigars as are whites. Like cigarette smoking, current cigar use is associated
with the use of other tobacco products and other substances (alcohol and marijuana)
and is more common among students who express strong interest in parties.
Unlike cigarettes, cigars are also more often used by students who rate fraternities
and sororities and attending sporting events as important.
Smokeless tobacco use also has distinctive features. It has the strongest
association with male sex and white race of all tobacco products. Unlike cigarettes,
it is just as common in the West as in other areas, and there is a trend toward
greater use by students enrolled in colleges in rural areas or small towns.
Unlike cigarettes, smokeless tobacco use is more common among intercollegiate
athletes.
This study contains several new findings. It demonstrates that tobacco
use among college students is more prevalent than previously appreciated,
because tobacco use is not limited to cigarettes. Cigar smoking is substantial,
and smokeless tobacco (and, rarely, pipes) are also used. Most tobacco users
use more than 1 tobacco product, with cigars and cigarettes being the most
common combination. Because men are more likely than women to use noncigarette
tobacco products, overall tobacco use rates are higher in men than women,
despite identical rates of cigarette smoking. Whether the gap between the
sexes in noncigarette tobacco product use will follow the pattern of cigarettes
and narrow in the future deserves to be monitored. In the meantime, these
data indicate that assessments limited to cigarette smoking will underestimate
the level of tobacco use in the college population, especially among men.
This study also reports some good news. Cigarette use by college students,
which increased dramatically between 1993 and 1997,6
stabilized between 1997 and 1999. Our previous work suggested college is a
time of considerable flux in cigarette smoking.6
This article extends that work to show that college students are experimenting
with the full range of tobacco products and that this is occurring across
all types of colleges. College students who use tobacco share many characteristics.
They are more likely to be white, single, and experimenting with other risky
behaviors, such as binge drinking, using marijuana, and having more sexual
partners. Tobacco use also appears to be part of a college lifestyle that
values social life over educational achievement, athletic participation, or
religion. A similar pattern was observed in an analysis of predictors of cigarette
use in the 1993 version of this survey.23 Although
many of the same characteristics identify students who are likely to use any
tobacco product, this article demonstrates that there are distinctive patterns
of cigar and smokeless tobacco use that distinguish their users from cigarette
smokers.
Cigar smoking in the United States was primarily a behavior of older
men until the early 1990s.9 Few young adults
and few women smoked cigars. Our data demonstrate how much this pattern has
changed. Cigar use is now common among college students. Although it remains
much more common among men than women, an unprecedented number of female college
students now smoke cigars. Cigar use patterns had other unique features. First,
cigar use by freshmen and sophomores exceeds that of juniors and seniors.
This pattern was not observed for other tobacco products and was contrary
to our expectation that cigar smoking rates would increase with more years
of exposure to college. It suggests that the cigar use is a new phenomenon
entering the college population. College student cigar use may increase in
the future, as the cohort of juniors and seniors progresses through college
and is joined by adolescents in whom cigar use is already high.1,13-15
A second unexpected feature was the higher rate of cigar smoking by black
students. This is in sharp contrast to black students' lower rate of all other
tobacco product use. This preliminary finding needs confirmation in future
work with larger samples. College students who use smokeless tobacco have
their own distinctive features. They are predominantly white men who attend
schools in rural areas, thereby fitting the pattern of smokeless tobacco use
in the broader population.24 Intercollegiate
athletes, in whom cigarette smoking rates are low, are more likely to use
smokeless tobacco, perhaps as a substitute form of nicotine.
Although the prevalence of tobacco use by college students is high,
the intensity of their tobacco use is low. One third of cigarette smokers
and 99% of cigar smokers do not smoke every day. Even this low level of use
is a cause for concern. Low levels of tobacco exposure for many years can
produce substantial morbidity and mortality, as research on passive smoking
shows.25 More important, the intermittent use
of cigars, smokeless tobacco, or cigarettes repeatedly exposes a user to nicotine,
a drug capable of producing physical dependence. Low levels of nicotine exposure
during college might evolve later into nicotine dependence and daily cigarette
smoking. Our data do not suggest that cigars act as a gateway to cigarette
use in college students, since only 9% of cigar and cigarette users smoked
cigars first, but this issue deserves further study. Cigar or smokeless tobacco
use might also contribute to the persistence of tobacco use in former cigarette
smokers and thereby facilitate a return to cigarette smoking. Cigar smoking
among college students may diffuse to other segments of the population, especially
to children or adolescents, because of the effect of peer modeling. The visibility
of tobacco products on campus, even if used intermittently, sends a dangerous
message about the social acceptability of tobacco use. The broad use of tobacco
among a substantial portion of 18- to 24-year-olds could portend a future
increase in overall adult tobacco use.
The results of this study must be viewed within the context of its limitations.
One potential limitation is nonresponse bias. Although the survey response
rate was 60%, the prevalence of cigarette smoking did not differ between respondents
and a sample of nonrespondents, and there was no correlation between smoking
rates and response rates at individual schools. We attempted to control for
potential bias by including college response rate as an independent variable
in multivariate analyses. Students' self-report was our measure of tobacco
use. Biochemical measures have established the validity of relying on self-reported
smoking status in national surveys.26,27
Underreporting of smoking status is probably even less likely in this survey,
which focused on alcohol rather than tobacco.
College students comprise the largest group of Americans aged 18 to
24 years. This is the youngest age group that tobacco manufacturers can legally
target for marketing efforts. The college years are a crucial period in the
development or abandonment of smoking behavior.6
Tobacco use in this group should be monitored closely, and young adults should
be included in all tobacco control efforts.
Colleges offer a potential site for interventions to discourage tobacco
use. These efforts clearly need to broaden beyond cigarettes to address the
use of cigars and smokeless tobacco. Colleges' alcohol and substance use prevention
and treatment programs should address tobacco, because use patterns are so
highly correlated. Data from this study can help colleges target interventions
to the students at greatest risk of using specific tobacco products. These
efforts should be accompanied by environmental and policy changes that discourage
tobacco use and reinforce the message that nonsmoking is the norm. One key
component is to make college buildings, including dormitories and living quarters,
smoke free. This policy protects nonsmokers from passive smoke exposure and
protects all students from the fire hazard of tobacco use in dormitories.
It also limits the visibility and accessibility of tobacco products and may
discourage initiation, help keep occasional smokers from becoming regular
users, and boost the success of smokers who are trying to quit. Reducing tobacco
use of all types among young adults should be a national health priority.
1.Centers for Disease Control and Prevention. Tobacco use among high school students: United States, 1997.
MMWR Morb Mortal Wkly Rep.1998;47:229-233.Google Scholar 2. Cigarette smoking among adults: United States 1997.
MMWR Morb Mortal Wkly Rep.1999;48:993-996.Google Scholar 3. Tobacco use: United States 1900-1999.
MMWR Morb Mortal Wkly Rep.1999;48:986-993.Google Scholar 4.US Bureau of the Census. Statistical Abstract of the United States, 1997. 117th ed. Washington, DC: US Dept of Commerce; 1997.
5.National Center for Education Statistics. Digest of Education Statistics, 1996. Washington, DC: US Dept of Education, Office of Educational Research
and Improvement; 1996. NCES publication 96-133.
6.Wechsler H, Rigotti NA, Gledhill-Hoyt J, Lee H. Increased levels of cigarette use among college students: a cause for
national concern.
JAMA.1998;280:1673-1678.Google Scholar 7.Centers for Disease Control and Prevention. Youth risk behavior surveillance: National College Health Risk Behavior
Survey: United States, 1995.
MMWR Morb Mortal Wkly Rep.1997;46:SS-6.Google Scholar 8.Jamner MS. Cigar smoking among college students: prevalence and correlates.
Prev Med.1999;29:187-194.Google Scholar 9.US Department of Health and Human Services. Cigars: Health Effects and Trends. Bethesda, Md: National Cancer Institute; 1998. National Institutes
of Health publication 98-4302. Smoking and Tobacco Control Monograph 9.
10.US Department of Agriculture. Tobacco Situation and Outlook Report. Washington, DC: US Dept of Agriculture, Commodity Economics Division,
Economic Research Service; April 1999.
11.Gilpin EA, Pierce JP. Cigar smoking in California: 1990-96.
Am J Prev Med.1999;16:195-201.Google Scholar 12.Hyland A, Cummings KM, Shopland DR, Lynn WR. Prevalence of cigar use in 22 North American communities: 1989 and
1993.
Am J Public Health.1998;88:1086-1089.Google Scholar 13.Centers for Disease Control and Prevention. Tobacco use among middle and high school students: Florida, 1998 and
1999.
MMWR Morb Mortal Wkly Rep.1999;48:248-253.Google Scholar 14.Centers for Disease Control and Prevention. Cigar smoking among high school students: United States, Massachusetts,
and New York.
MMWR Morb Mortal Wkly Rep.1997;46:433-440.Google Scholar 15.Centers for Disease Control and Prevention. Tobacco use among middle and high school students: United States, 1999.
MMWR Morb Mortal Wkly Rep.2000;49:49-53.Google Scholar 16.Wechsler H, Davenport A, Dowdall G, Moeykens B, Castillo S. Health and behavioral consequences of binge drinking in college.
JAMA.1994;272:1672-1677.Google Scholar 17.Wechsler H, Dowdall GW, Davenport A, Castillo S. Correlates of college student binge drinking.
Am J Public Health.1995;85:921-926.Google Scholar 18.US Department of Education. Digest of Education Statistics. Washington, DC: National Center of Educational Statistics; 1997.
19.US Bureau of the Census. Current Population Reports, P-20-443 and P20-516. Washington, DC: US Bureau of the Census; 1997.
20.Wechsler H, Isaac N. "Binge" drinkers at Massachusetts colleges: prevalence, drinking style,
time trends, and associated problems.
JAMA.1992;267:2929-2931.Google Scholar 21.Liang KY, Zeger SL. Longitudinal data analysis using generalized linear models.
Biometrika.1992;73:12-22.Google Scholar 22.Zeger SL, Liang KY. Models for longitudinal data: a generalized estimating equation approach.
Biometrics.1988;44:1049-1060.Google Scholar 23.Emmons KM, Wechsler H, Dowdall G, Abraham M. Predictors of smoking among US college students.
Am J Public Health.1998;88:104-107.Google Scholar 24.Hatsukami DK, Severson HH. Oral spit tobacco: addiction, prevention and treatment.
Nicotine Tobacco Res.1999;1:21-44.Google Scholar 25.US Department of Health and Human Services. The Health Consequences of Involuntary Smoking: A
Report of the Surgeon General. Washington, DC: US Dept of Health and Human Services; 1986.
26.Caraballo RS, Giovino GA, Pechacek TF, Mowery P. Agreement between self-reports of cigarette smoking and biochemical
measurement of serum nicotine levels. Abstract presented at: Annual Meeting of the Society for Research
on Nicotine and Tobacco; March 28, 1998; New Orleans, La.
27.Frier ME, Bell RM, Ellickson PL. Do Teens Tell the Truth?
The Validity of Self-Reported Tobacco Use by Adolescents. Santa Monica, Calif: RAND; March 1991. N-3291-CHF.