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Identification of Adolescent Tobacco Users in a Pediatric Practice
Irwin Benuck, MD;
Samuel S. Gidding, MD;
Helen J. Binns, MD, MPH
Arch Pediatr Adolesc Med. 2001;155:32-35.
ABSTRACT
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Context Though prevention of adolescent tobacco use is a major public health
goal, there is little information on the ability of pediatricians to identify
adolescents experimenting with tobacco and regular tobacco users.
Objectives To pilot use of a short questionnaire and analysis of urinary cotinine
level to identify adolescent smokers in a pediatric practice, and to determine
characteristics of tobacco users.
Setting Suburban pediatric practice.
Method Consecutive high school students completed a short questionnaire and
urine cotinine assessment. Three groups were defined: smokers (urine cotinine
level >100 ng/mL), experimenters (smoked within the last year; urine continine
level  100 ng/mL), and nonsmokers. Logistic regression was used to examine
characteristics of experimenters.
Results One hundred twenty-four adolescents were enrolled throughout 3 months:
83 nonsmokers (67%), 28 experimenters (23%), and 13 smokers (10%). The questionnaire
alone identified 92% of regular smokers. Smoking frequency increased by grade
level. Smoking initiation occurred with peers. Compared with nonsmokers, smokers
and experimenters were more likely to be older and have a majority of friends
who smoked. Smokers were more likely to have a family member who smoked. A
majority of smokers and experimenters had tried to quit and understood the
adverse health effects of tobacco use.
Conclusions Adolescent smokers and experimenters were identified using a brief questionnaire.
This method will allow pediatricians the opportunity to identify at-risk adolescents
before they become regular smokers. Further studies at primary care offices
are needed to examine identification of adolescents at highest risk and examine
methods to initiate smoking cessation before addiction is established.
INTRODUCTION
DURING THE last decade, the prevalence of tobacco use by teenagers has
increased. This has occurred despite the proliferation of educational programs
and heightened media attention concerning adverse health effects of tobacco
use.1, 2 During this same period,
adult tobacco use has declined. Several factors have been associated with
teen smoking.3, 4, 5
These include peer pressure, exposure to tobacco advertisements and promotions,
and having a parent or other family member who smokes.4, 6
Teenagers who smoke are more likely than those who do not to exhibit poor
school performance and to not accept health concerns about the harmful effects
of tobacco.4
Although many organizations and individuals have stressed the importance
of incorporating antismoking and smoking cessation counseling into pediatric
practice, there is a paucity of information on this topic.3, 7, 8
Recommendations for how to obtain information on tobacco use from teenagers
during office visits do not exist. There are no studies on whether biomarkers
of tobacco exposure are helpful in confirming reported exposure. This study
piloted a method for pediatricians to characterize tobacco use among adolescents
(9th-12th grades) at health maintenance visits. We used a self-completed survey
to assess tobacco use, and urine cotinine level to validate the self-report.
Further, this study characterized 3 groups of teenagers: habitual users (regular
smokers), experimenters, and nonusers. Successful stratification would allow
targeted intervention strategies.
SUBJECTS AND METHODS
High school students aged 14 through 18 years visiting for health maintenance
were sequentially recruited during a 3-month period in the summer at a suburban
pediatric practice. After a routine physical examination by one author (I.B.),
participants completed a 26-item questionnaire pertaining to tobacco use and
attitudes. A urine specimen was also collected for cotinine analysis to validate
questionnaire responses. Only students accompanied by parents and with parental
consent were enrolled. Data were obtained anonymously from students and with
the parent's knowledge that they would not receive study results. The study
was approved by a local institutional review board.
DATA INSTRUMENT
The questionnaire was developed specifically for this study and included
items on demographics, tobacco use (onset, how often, circumstances of smoking,
smoking habits of friends and family), attitudes about smoking and its health
effects, and physical activity. Those who had ever smoked were asked to characterize
their smoking: why, how, and with whom they began smoking; whether they had
ever tried to quit smoking; and if their parents knew they smoked, and if
so, how their parents found out. Those who tried to quit smoking were asked
if they were successful at quitting and what methods they used to try to quit.
To assess attitudes and beliefs about smoking, Likert scale responses (5-point
scale; strongly disagree = 1, strongly agree = 5) were requested to 3 statements:
"Smoking will shorten my life," "Smoking is fun," and "Smoking is an adult
activity."
Key questions from the survey are displayed in Figure 1. The complete survey is available on request from the authors.
Test-retest was not conducted.
Urine samples were refrigerated and then shipped to a commercial laboratory
for cotinine assessment (capillary gas chromatography technique; Agilent Corp,
Little Falls, Del). The minimum value of cotinine detection was 10 ng/mL.
Cotinine is a metabolite of nicotine and is present in the urine at a concentration
of greater than 100 ng/mL after tobacco use at a frequency of more than 7
cigarettes per day.9 Regular smokers generally
have levels greater than 200 ng/mL, while those heavily exposed to smoke (20-80
h/wk) have a mean urine cotinine level of approximately 30 ng/mL.10 In this study, levels at or above 100 ng/mL were
considered indicative of habitual smokers.
ANALYSES
Participants were stratified into 3 groups according to cotinine results
and questionnaire responses: (1) smoker (urine cotinine level at >100 ng/mL,
regardless of questionnaire responses); (2) experimenter (urine cotinine level
not detectable and reported tobacco use in the past year, or cotinine 100
ng/mL); and (3) nonsmoker (urine cotinine level not detectable and no reported
tobacco use in the past year). Descriptive statistics by smoking group were
calculated for characterization of responses to items of interest on the questionnaire.  2 Tests or t tests, as appropriate, were used
to examine differences between groups. Trends across grade level and smoking
groups were examined using linear-by-linear association (LLA). Using information
provided on average number of cigarettes smoked per day, week, month, or year,
the average number of cigarettes smoked per month was computed. Kruskal-Wallis
1-way analysis of variance (KW) was used to examine differences between groups
for attitudes about smoking. Logistic regression was used to examine characteristics
associated with experimentation with tobacco. Factors associated with tobacco
use were entered into a logistic regression model using a forward stepwise
approach. All interaction terms were examined. The model was tested using
the method of Hosmer and Lemeshow.11 Because
of low sample size, models examining characteristics of smokers are not presented.
Data analyses were performed using SPSS for Windows (Statistical Product and
Service Solutions 10.0; SPSS Inc, Chicago, Ill).
RESULTS
Throughout the 3-month recruitment period, 124 consecutive high school
students enrolled in the study. The subjects were 71% male (mean age, 15.2
years; SD, 1.3 years) and 100% white. There were 83 nonsmokers (67%), 28 experimenters
(23%), and 13 smokers (10%). The range of urine cotinine levels for smokers
was 110 ng/mL to 2000 ng/mL. Two smokers had a cotinine level between 100
ng/mL and 200 ng/mL. Two subjects classified as experimenters had measurable
cotinine levels (49 ng/mL and 98 ng/mL, respectively).
Smoking rates did not differ by sex. Tobacco use significantly increased
by grade (LLA, P<.001). There were 15%, 17%, 29%,
and 37% of subjects in 9th, 10th, 11th, and 12th grades, respectively, who
were experimenters, and 0%, 12%, 14%, and 23%, respectively, who were smokers.
Twelve of 13 subjects classified as smokers reported smoking within
the past week on the questionnaire (ie, sensitivity of the survey to screen
for smokers was 92%). Twenty-nine percent of experimenters reported cigarette
use within the past week, 18% within the past month, and 46% within the past
year. Of the 2 subjects who were classified as experimenters because of measurable
cotinine levels, 1 denied ever smoking, and 1 reported last smoking more than
1 year ago. There was wide variation in the number of cigarettes smoked per
month for both smokers and experimenters (with 13 smokers and 23 experimenters
answering this question). One smoker reported smoking less than 1 cigarette
per month, 6 (46%) reported smoking 9 to 43 cigarettes per month, and the
remaining 6 smokers reported smoking a range of 150 to 600 cigarettes per
month. A majority of experimenters (65%) reported smoking less than 1 cigarette
per month, and the rest reported smoking 2 to 87 cigarettes per month.
The average age at initiation of tobacco use did not significantly differ
between smokers and experimenters (12.5 years vs 13.2 years, respectively; P = .29). Parent and sibling smoking varied significantly
across groups (Table 1). Twenty-seven
percent of nonsmokers, 39% of experimenters, and 85% of smokers reported having
a family member who smoked (LLA, P<.001). However,
according to questionnaire responses, only 62% of smokers' parents (8 of 13)
and 35% of experimenters' parents (7 of 20) knew the subject had smoked. The
first cigarette was almost always taken in the company of siblings or friends
(96% of experimenters and 100% of smokers). Most experimenters (70%) and smokers
(92%) said that one reason they began smoking was because their friends smoked.
There was a graded relationship between smoking status and friends' smoking
behaviors (Table 2).
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Table 1. Characteristics of Nonsmokers, Experimenters, and Smokers*
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Table 2. Logistic Regression Model
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A logistic regression model was developed to compare experimenters with
nonsmokers. Factors considered in analyses are displayed in Table 2. Only grade and friends smoking were significant in the
logistic regression (Table 2).
Variables in the model did not significantly interact.
The majority of smokers and experimenters had tried to quit smoking
(7 [58%] of 12 smokers; 16 [76%] of 21 experimenters). Three current smokers
and 13 experimenters said that they were successful in quitting smoking. Among
those who tried to quit, 20 (91%) of 22 attempted quitting without help; 2
subjects were aided by school programs. Six (7%) of the 83 nonsmokers admitted
to smoking, but did not fit our definition of experimenter because their last
cigarette use was more than 1 year ago.
Ever trying other forms of tobacco (pipes, cigars, smokeless tobacco)
was more commonly reported among smokers and experimenters than among nonsmokers
(69% smokers, 46% experimenters, and 11% nonsmokers; P<.001).
The majority of teenagers who had tried other forms of tobacco had tried cigars
(26 [84%] of 31); pipe and smokeless tobacco use were less frequent (pipes,
13%; smokeless tobacco, 29%).
Most subjects disagreed with the statement, "Smoking is an adult activity."
Sixty-two percent of smokers, 57% of experimenters, and 38% of nonsmokers
disagreed or strongly disagreed with this statement. This did not significantly
differ between groups (KW, P = .06). Ninety-six percent
of nonsmokers disagreed or strongly disagreed with the statement "Smoking
is fun," while this was true for only 46% of smokers and 57% of experimenters
(median response [range]: smokers, 3 [1-5]; experimenters, 2 [1-4]; nonsmokers,
1 [1-3]; KW, P<.001). Most subjects strongly agreed
with the statement "Smoking will shorten my life," (strongly agree: smokers,
46%; experimenters, 54%; nonsmokers, 74%). This differed significantly between
groups (median result [range]: smokers, 4 [2-5]; experimenters, 5 [1-5]; nonsmokers,
5 [1-5]; KW, P = .02).
Nonsmokers, experimenters, and smokers reported similar rates of participation
on school sports teams (nonsmokers, 64%; experimenters, 64%; smokers, 39%)
and other sports not affiliated with a school (nonsmokers, 48%; experimenters,
44%; smokers, 54%). However, smokers reported a lower frequency of intense
activity ("a physical activity where you work up a sweat"); 58% of nonsmokers,
61% of experimenters, and 15% of smokers reported doing such activities at
least 5 days per week (2, P = .01).
COMMENT
This study has demonstrated the feasibility of routine assessment of
smoking status in a private practice setting. The biomarker for tobacco use
confirmed that adolescent regular smokers were generally truthful in filling
out a questionnaire on smoking habits when assured anonymity. Those we defined
as experimenters either smoked at levels too low to produce detectable urinary
cotinine levels or had low detectable urinary cotinine levels from infrequent
smoking or smoke exposure. Information about tobacco use gleaned in this study
was generally similar to that obtained in national surveys about tobacco use
with regard to the items sampled including age at initiation, risk factors,
and attitudes.1, 2, 4
A short questionnaire taking 3 to 5 minutes to complete and inquiring about
smoking history, smoking habits of family members, and smoking habits of friends
should be sufficient to stratify adolescents with regard to tobacco use. In
particular, 3 to 4 brief questions that ask about smoking frequency, smoking
status of family members, and whether more than half of the patient's friends
smoke are sufficient to identify someone who either smokes or experiments,
or is at high risk. Use of this instrument in an open fashion, so that the
physician can identify and validate responses, is needed.
Perhaps the most important finding in this study is that pediatricians
have the ability to identify adolescents in the experimenter stage, before
nicotine addiction has developed. A questionnaire alone is satisfactory for
this purpose. However, the pediatrician may be misled if he or she bases a
categorization of experimenter vs smoker on number of cigarettes smoked per
day. A biological marker of tobacco use is critical to separate heavier smokers
from experimenters or causal smokers, as some smokers with positive urine
cotinine levels reported few cigarettes smoked per day. Urinary cotinine levels
are subject to dilution effects and measurable levels may be attributable
to secondhand smoke exposure.10, 12
However, because of the strong relationship of smoking with associating with
friends that smoke, a misclassification in the direction of identifying the
teenager as an experimenter or smoker when determining need for intervention
would be prudent.
Many classification systems can be devised to stratify adolescent smokers
into groups ranging from "never smokers" through intermediate groups to regular
smokers.13 Our data suggest that pediatricians
in suburban practice may be able to reliably tell smokers from never smokers
by questionnaire alone. The younger adolescent, or the adolescent who reports
low cigarette use or last cigarette use more than 1 week ago is more likely
to be an experimenter or irregular unaddicted smoker. Biologic measures of
nicotine exposure are useful if the pediatrician plans to consider referral
for intervention based on degree of exposure. Further studies of smoking cessation
in adolescence at all levels of exposure must be conducted before first guidelines
for treatment can be established.
Community-based smoking cessation programs and programs that have attempted
physician-directed treatment have generally recruited adolescents who smoke
heavily, and these programs have had limited success.7, 8
Thus, the health maintenance visit, which identifies the teenaged smoker in
an early phase of smoking by questionnaire, may provide the window of opportunity
to test cessation interventions before addiction has been established. Of
interest, most teenagers who tried to quit tobacco use did so on their own.
Established smoking cessation programs did not reach them.
This study was conducted in a suburban primary care office setting among
white, privately insured patients. Similar studies should be conducted in
other practice settings to assess the generalizability of these findings and
to develop effective approaches for identification of teenaged smokers across
all ethnic groups and social strata.
Pediatricians have been slow to examine how they might reduce youth
smoking. We could find no pediatric practice-based research on youth smoking
or cessation. Though the primary causes of smoking remain social, and nicotine
addiction is difficult to treat, physicians remain the most trusted carriers
of the antismoking message.3 Because cigarette
smoking begins in early adolescence, the antismoking message should be part
of health maintenance visits beginning at 10 to 11 years of age, particularly
in high-risk situations in which it is known that the patient has family members
who smoke, friends who smoke, or other risk factors. This study has shown
that identifying the young smoker requires use of a simple questionnaire and
that more rigorous identification can be accomplished by simply using a biomarker
for nicotine exposure. Research initiatives directed toward teaching experimenters
to quit might be a way to incorporate pediatricians into the national effort
to stop the rising prevalence of habitual smoking in teenagers.
AUTHOR INFORMATION
Accepted for publication August 22, 2000.
This study was supported in part by the Keeshin Trust, Chicago, Ill.
From the Departments of Pediatrics (Drs Benuck, Gidding, and Binns)
and Preventive Medicine (Dr Gidding), Northwestern University Medical School,
and the Willis J. Potts Children's Heart Center, Children's Memorial Hospital
(Dr Gidding), Chicago, Ill.
Corresponding author: Helen J. Binns, MD, MPH, 2300 Children's Plaza,
Box 208, Chicago, IL 60614 (e-mail: hbinns{at}northwestern.edu).
REFERENCES
| |
1. Centers for Disease Control and Prevention. Tobacco use among high school students—United States, 1997. MMWR Morb Mortal Wkly Rep. 1998;47:229-253.
PUBMED
2. Centers for Disease Control. Trends in smoking initiation among adolescents and young adults—United
States, 1980-1989. MMWR Morb Mortal Wkly Rep. 1995;44:521-525.
PUBMED
3. Perry C, Silvis G. Smoking prevention: behavioral prescriptions for the pediatrician. Pediatrics. 1987;79:790-799.
FREE FULL TEXT
4. US Dept of Health and Human Services. Preventing tobacco use among young people: a report of the Surgeon
General. Washington, DC: US Dept of Health and Human Services; 1994.
5. Gidding SS, Morgan W, Perry C, Isabel-Jones J, Bricker JT. Active and passive tobacco exposure: a serious pediatric health problem.
A statement from the Committee on Atherosclerosis and Hypertension in Children,
Council on Cardiovascular Disease in the Young, American Heart Association. Circulation. 1994;90:2581-2590.
FREE FULL TEXT
6. Evans N, Farkas A, Gilpin E, Berry C, Pierce JP. Influence of tobacco marketing and exposure to smokers on adolescent
susceptibility to smoking. J Nat Cancer Inst. 1995;87:1538-1545.
FREE FULL TEXT
7. Schubiner H, Herrold A, Hurt R. Tobacco cessation and youth: the feasibility of brief office interventions
for adolescents. Prev Med. 1998;27:A47-A54.
8. Smith TA, House RF, Croghan IT, et al. Nicotine patch therapy in adolescent smokers. Pediatrics. 1996;98:659-667.
FREE FULL TEXT
9. Jacob P, Wilson M, Benowitz NL. Improved gas chromatographic method for the determination of nicotine
and cotinine in biologic fluids. J Chromatogr. 1981;222:61-70.
ISI
| PUBMED
10. Wald NJ, Boreham J, Bailey A, Ritchie C, Haddow JE, Knight G. Urinary cotinine as marker of breathing other people's tobacco smoke
[letter]. Lancet. 1984;1:230-231.
FULL TEXT
|
ISI
| PUBMED
11. Hosmer DW, Lemeshow S. Applied Logistic Regression. New York, NY: John Wiley & Sons; 1989:135-175.
12. Benowitz NL. Cotinine as a biomarker of environmental tobacco smoke exposure. Epidemiol Rev. 1996;18:188-204.
FREE FULL TEXT
13. Flay BR, Phil D, Hu FB, Richardson J. Psychosocial predictors of different stages of cigarette smoking among
high school students. Prev Med. 1998;27:A9-A18.
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