 RESEARCH AND PRACTICE 
`
`Factors Associated With Successful Smoking Cessation
`in the United States, 2000
`
`| Chung-won Lee, PhD, MA, and Jennifer Kahende, PhD
`
`Cigarette smoking is the leading cause of pre-
`ventable death in the United States. Each
`year, it kills more than 440 000 Americans,1
`and about 8.6 million people in the United
`States have illnesses attributable to smoking.2
`In addition, direct medical costs related to
`smoking total about $ 75 billion annually.1
`The adverse health effects of cigarette smok-
`ing and the benefits of quitting are well docu-
`mented and widely known to the general
`public.3–6 Even so, as of 2003, some 45.4
`million US adults (21.6%) were current
`smokers.7
`In 2003, the Centers for Disease Control
`and Prevention (CDC) found from self-reports
`that 41% of current smokers (20.2 million)
`had tried to quit smoking for 1 or more days
`within the previous 12 months.7 Many smok-
`ers who try to quit cite a desire to improve
`their health as the main reason.8,9 Unfortu-
`nately, most smokers are not successful in
`quitting, primarily because they are addicted
`to nicotine.10–14 Motivation and readiness to
`quit are predictors of successful quitting, but
`dependence on nicotine has been found to
`be a stronger predictor.13
`Numerous studies have addressed factors
`associated with making a quit attempt or with
`successful smoking cessation. Past studies have
`examined such demographic factors as gen-
`der, age, marital status, income, and education
`to assess whether they differed between smok-
`ers who tried to quit and those who did not
`try, as well as between successful and unsuc-
`cessful quitters.5,12,13,15–17 For example, Derby
`et al.18 found that for women, successful
`smoking cessation was associated with not liv-
`ing with a smoker; for men, it was correlated
`with increased age. Hymowitz et al.19 found
`that being older, male, and having higher in-
`come predicted cessation, as did 2 behavioral
`variables—smoking fewer cigarettes and hav-
`ing previous quit attempts. Hatziandreu et al.10
`found that greater educational attainment was
`positively associated with trying to quit and
`
`Objectives. Each year, nearly 2 in 5 cigarette smokers try to quit, but fewer than
`10% succeed. Taking a multifaceted approach to examine the predictors of suc-
`cessfully quitting smoking, we identified factors associated with successful quitting
`so that cessation programs could be tailored to those at highest risk for relapse.
`Methods. Using data from the 2000 National Health Interview Survey, we em-
`ployed multiple regression analysis to compare demographic, behavioral, and en-
`vironmental characteristics of current smokers who tried unsuccessfully to quit
`in the previous 12 months with characteristics of those able to quit for at least 7
`to 24 months before the survey.
`Results. Successful quitters were more likely than those unable to quit to have rules
`against smoking in their homes, less likely to have switched to light cigarettes for
`health concerns, and more likely to be aged 35 years or older, married or living with
`a partner, and non-Hispanic White, and to have at least a college education.
`Conclusions. Programs promoting smoking cessation might benefit by in-
`volving family or other household members to encourage smoke-free homes.
`(Am J Public Health. 2007;97:1503–1509. doi:10.2105/AJPH.2005.083527)
`
`that people aged 17 to 24 years and those
`aged 65 or older tried to quit more fre-
`quently. In addition, Wilcox et al.20 found
`that people with higher income and educa-
`tional levels were more likely to reattempt
`quitting after a relapse. Similarly, Borland et
`al.21 found that having higher education was
`a predictor of successfully quitting, but they
`found that having previous quit attempts was
`a predictor of relapse to smoking.
`The environment in which an addictive
`behavior such as smoking occurs is a signifi-
`cant factor in determining whether or not
`that behavior is maintained.22 Several studies
`found that being in daily contact with other
`smokers reduced the likelihood of success in
`quitting.23–25 Similarly, Senore et al.26 and
`Gourlay et al.27 found that the likelihood of
`success in quitting was lower among smokers
`who lived with other smokers than among
`those who did not. Farkas et al.28 found that
`bans in both the workplace and in the home
`were significant predictors of successful quit-
`ting. Correspondingly, Woodruff et al.29
`found a lower prevalence of smoking among
`workers employed in jobs with smoke-free
`policies. Other studies have found that bans
`on smoking in the workplace increase
`
`cessation and promote reduction in cigarette
`consumption.30–32
`With regard to quit-related behaviors and
`methods of quitting, past studies have been
`inconsistent. Some found that switching to
`low-tar cigarettes helped smokers to quit,33–35
`but a large, prospective, population-based
`study36 found that this practice was not asso-
`ciated with the number of quit attempts.
`Giovino et al.35 found that the consumption
`of low-tar cigarettes was associated with de-
`creased quit rates. From the California To-
`bacco Survey, Farkas37 found that “fading”
`in smoking (i.e., reducing consumption) in-
`creased the probability of cessation. In the
`same survey, it was also observed that heavy
`smokers (those who smoked more than 15
`cigarettes a day) were less successful at quit-
`ting in the preceding 18 months than light
`smokers.37,38 Cinciripini et al.39 compared 2
`cessation methods—gradual reduction in ciga-
`rette consumption and “cold turkey”—and
`found that groups that gradually increased
`the time interval between cigarettes were
`more successful at quitting than groups that
`did not. McGovern and Lando40 found that
`switching brands to reduce nicotine consump-
`tion increased the probability of cessation.
`
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`the US civilian noninstitutionalized popula-
`tion that began in 1957. In 2000, data were
`collected through computer-aided face-to-
`face interviews conducted at respondents’
`homes. The NHIS collects a multitude of in-
`formation on health-related behaviors, such
`as cigarette smoking, physical activity, and al-
`cohol use, in addition to demographic charac-
`teristics. In 2000, approximately 100 620
`people from 38 633 sampled households
`participated in the survey,50 including
`32 374 adults (aged 18 years and older). Our
`analysis was limited to adults who answered
`questions on tobacco.
`In 2000, a special cancer control module
`was added to the NHIS that included in-
`depth questions on current and former smok-
`ers’ cessation-related behaviors. In the main
`part of the survey, questions measured re-
`spondents’ smoking status (current, former, or
`never smoker), history of smoking, amount
`of cigarette use, and among current smokers,
`whether they had tried to quit during the past
`year. The cancer control module contained
`detailed questions on tobacco use and cessa-
`tion, including age at which smoking started,
`use of low-tar and low-nicotine cigarettes,
`quitting methods used among former smok-
`ers, whether current smokers had attempted
`to quit during the past year, and lifetime
`number of quit attempts. The 2000 NHIS
`data were therefore used for this study de-
`spite the fact that there are more recent NHIS
`data sets available.
`
`Measures
`Dependent variable. We compared recent
`successful quitters (who had quit 7–24
`months earlier and had not relapsed) with
`current smokers who had a recent failed quit
`attempt (past 12 months). The successful
`quitters had responded “yes” to the question,
`“Have you smoked at least 100 cigarettes in
`your entire life?”; “not at all” to the question,
`“Do you now smoke cigarettes every day,
`some days or not at all?”; and “7–24 months”
`to the question, “How long has it been since
`you quit smoking cigarettes?” Since smokers
`who quit 1 to 6 months earlier are at high
`risk of relapse, we did not include them as re-
`cent successful quitters; some studies have
`shown that about 65% to 75% would relapse
`within a year.42,51,52
`
`Current smokers who had a recent failed
`quit attempt answered “yes” to the question,
`“Have you smoked at least 100 cigarettes in
`your entire life?”; “every day” or “some days”
`to the question, “Do you now smoke ciga-
`rettes every day, some days or not at all?”;
`and “yes” to the question, “During the past
`12 months, have you stopped smoking for
`more than one day because you were trying
`to quit smoking?”
`The screening process used to select re-
`cent successful quitters and current smokers
`with a recent failed quit attempt is illustrated
`in Figure 1.
`Independent variables. Demographic charac-
`teristics included age, gender, education, mar-
`ital status, and race/ethnicity. Age was cate-
`gorized as 18–24, 25–34, 35–44, 45–54,
`55–64, or 65 years or older. Educational
`status was divided into less than high school
`graduate, high school diploma or GED (gen-
`eral equivalency diploma), some college or
`associate degree, and college degree or
`higher. Marital status was dichotomized into
`(1) married or living with partner and
`(2) never married or divorced, separated, or
`widowed. Racial/ethnic categories were non-
`Hispanic White, non-Hispanic Black, His-
`panic, and other.
`Behavioral characteristics included age
`when respondent started smoking regularly,
`whether respondent ever switched to low-tar
`or low-nicotine products to reduce health
`risk, and lifetime quit attempts. The question
`“How old were you when you first started to
`smoke fairly regularly?” was asked of both
`former and current smokers. On the basis of
`the distribution of the age at which respon-
`dents first smoked cigarettes regularly, we
`created 3 categories: younger than 15, 15 to
`18, and 19 years and older. For lifetime quit
`attempts, former smokers were asked, “In
`your whole life, including the last time, how
`many times did you stop smoking for one
`day or longer because you were trying to quit
`smoking?” Current smokers were asked, “In
`your whole life, how many times have you
`stopped smoking for one day or longer be-
`cause you were trying to quit smoking?” On the
`basis of the distribution of responses to these
`questions, the number of lifetime quit at-
`tempts was categorized as 1, 2, 3 to 5, and
`6 or more.
`
`Gilpin and Pierce found that people often
`do not accurately remember past quit at-
`tempts other than the most recent one.41
`A cross-sectional study of lung health by Mur-
`ray et al.42 found that the number of quit
`attempts had a negative impact on smoking
`abstinence for men but no relationship to ab-
`stinence among women. Raw et al.43 reported
`that it took smokers 3 to 4 quit attempts be-
`fore they could quit completely. The US Pub-
`lic Health Service (PHS) Clinical Practice
`Guideline states that both having social sup-
`port during quit attempts and a longer time
`before the first cigarette of the day increase
`the likelihood of quitting, because a shorter
`time before the first cigarette signals a higher
`level of addiction.44
`Most past studies of factors affecting quit
`attempts and their outcomes have been lim-
`ited to specific populations or have addressed
`individual demographic or environmental
`characteristics. Recognizing the dynamic na-
`ture of smoking behavior, Horn,45 Prochaska
`et al.,46–48 and DiClemente et al.49 found that
`change in smoking behavior followed a series
`of stages, with each stage individually influ-
`enced by different factors. In addition, a few
`studies have examined several aspects of
`smokers’ characteristics to determine the pre-
`dictors of making quit attempts or successful
`smoking cessation, but almost none of them
`have taken a holistic approach where smok-
`ers’ demographic, behavioral, and environ-
`mental characteristics and the methods used
`to quit are examined together.
`In this study, using a representative sample
`of the US population, we identified statisti-
`cally significant predictors of successful smok-
`ing cessation. To do so, we compared the ap-
`proaches to smoking cessation of people who
`recently succeeded in quitting with those of
`current smokers who attempted but failed to
`quit in the previous year. Identifying predic-
`tors for successful quitting will help to target
`smoking cessation programs and interventions
`in the United States.
`
`METHODS
`
`Study Population
`We used data from the 2000 National
`Health Interview Survey (NHIS), a large,
`population-based, cross-sectional survey of
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`SAS version 8.2 (SAS Institute Inc, Cary, NC)
`and SUDAAN version 8.0 (Research Triangle
`Institute, Research Triangle Park, NC) were
`used for all analyses. We conducted a prelimi-
`nary descriptive analysis to examine the distri-
`butions of demographic, behavioral, environ-
`mental, and quitting method variables, and
`then we carried out a multivariate logistic re-
`gression analysis to identify statistically signifi-
`cant factors of successful smoking cessation.
`
`RESULTS
`
`Study Population
`For the 2000 NHIS, the overall adult re-
`sponse rate was 72.1%. Among the 32 374
`adults who completed the survey, 7421 were
`current smokers, 6995 former smokers, and
`17 657 never smokers (smoking status was
`unknown for 301). Of the 7421 current
`smokers, 3218 (43.4%) had attempted to
`quit for longer than 1 day during the previ-
`ous 12 months. Among former smokers, 363
`reported quitting 7 to 12 months before the
`survey and 409 had quit 13 to 24 months
`earlier. The 430 people who had quit 1 to 6
`months earlier were not included because, as
`mentioned earlier, they are at high risk of
`relapse. Thus, among current and former
`smokers who had attempted to quit during
`the previous 12 months (n = 4011), 363, or
`9.1%, sustained their abstinence for at least
`7 to 12months.
`The distribution of the study sample by de-
`mographic, behavioral, and environmental
`characteristics, as well as the quitting methods
`used the last time respondents either success-
`fully quit or attempted but failed to quit, are
`shown in Table 1.
`Among current smokers who had at-
`tempted to quit but failed, about two thirds
`(66%) were aged 44 years or younger, 75%
`were non-Hispanic White, 60% were married
`or living with a partner, and 58% had a high
`school education or less. Seventy percent had
`attempted to quit smoking at least 3 times,
`69% started to smoke regularly at age 18 or
`younger, and almost two thirds (65%) re-
`ported that others at home smoked.
`Among recent successful quitters, 60% were
`aged 35 or younger, 81% were non-Hispanic
`White, 68% were married or living with a
`partner, and 48% had only a high school
`
`FIGURE 1—Survey screening process used to select recent successful quitters and current
`smokers with a recent failed quit attempt: National Health Interview Survey, 2000.
`
`For environmental variables, we examined
`the presence of (1) smoking in the workplace,
`(2) a no-smoking policy at work, and (3)
`smoking in the home. Respondents were
`asked, “As far as you know, has anyone
`smoked in your work area in the last week?”
`The survey also asked, “Does your employer
`have an official policy that restricts smoking
`in any way?” To incorporate respondents who
`were not currently employed, the variable for
`those 2 questions was categorized as yes, no,
`and not employed. For the home environ-
`ment, the survey asked, “During the past
`week, how many days did anyone smoke ciga-
`rettes, cigars, or pipes anywhere inside your
`home?” Respondents were grouped into less
`than 1 day per week/rarely/none and 1–7
`days per week.
`For quitting methods, the NHIS asked for-
`mer smokers, “When you stopped smoking
`completely, which of these methods did you
`use?” It then listed the following methods:
`stopping all at once, gradually decreasing the
`number of cigarettes smoked, following in-
`structions in a pamphlet or book, one-on-one
`
`counseling, stop-smoking clinic or program,
`nicotine patch, nicotine-containing gum, nico-
`tine nasal spray, nicotine inhaler, medication
`(Zyban, bupropion, or Wellbutrin), switched
`to chewing tobacco or snuff, and any other
`method. For current smokers, the response
`options were the same but the question was
`worded, “The last time you stopped smoking,
`which of these methods did you use?” Re-
`spondents were asked to select all of the quit-
`ting methods they used the last time. On the
`basis of the sample needed to achieve stable
`estimates, only 3 methods could be exam-
`ined in the analysis: stopped all at once, grad-
`ually decreased the number of cigarettes
`smoked, and use of a nicotine patch or gum.
`
`Statistical Analysis
`Analyses were performed to identify which
`demographic, behavioral, and environmental
`characteristics and which quitting methods
`were associated with successful cessation.
`Sampling weights were used to account for
`the NHIS design and to achieve estimates for
`the US adult population. Statistical packages
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`TABLE 1—Selected Characteristics of US Adults, by Smoking Cessation Status: National
`Health Interview Survey, 2000
`
`Characteristic
`
`Attempted but Failed
`to Quit in Past Year, %
`
`Successfully Quit
`for 7–24 Months, %
`
`Demographic
`
`Age, y
`18–24
`25–34
`35–44
`45–54
`55–64
`≥ 65
`Gender
`Man
`Woman
`Race/ethnicity
`Non-Hispanic White
`Non-Hispanic Black
`Hispanic
`Other
`Marital status
`Married or living with a partner
`Never married, divorced, separated, or widowed
`Education
`Less than high school
`High school graduate or GED
`Some college or associate degree
`College graduate or higher
`
`Lifetime quit attempts
`1
`2
`3–5
`≥ 6
`Age first smoked regularly, y
`≤ 14
`15–18
`≥ 19
`Ever switched to low-tar/low-nicotine products
`
`No-smoking policy at work
`Others smoke at work
`Others smoke at home
`
`Stopped at once or cold turkey
`Gradually decreased no. of cigarettes
`Nicotine patch or gum
`
`19.1
`21.7
`25.4
`18.6
`9.6
`5.6
`
`51.3
`48.7
`
`75.4
`12.1
`8.0
`4.5
`
`60.2
`39.8
`
`20.9
`36.6
`30.7
`11.8
`
`14.3
`15.9
`35.3
`34.6
`
`20.8
`47.7
`31.5
`52.5
`
`39.9
`11.8
`65.1
`
`72.1
`10.5
`16.2
`
`Behavioral
`
`Environmental factors
`
`Quitting methods used
`
`16.3
`22.5
`20.7
`15.4
`13.4
`11.6
`
`50.0
`50.0
`
`80.5
`7.5
`7.7
`4.3
`
`67.9
`32.1
`
`18.1
`30.0
`30.2
`21.7
`
`37.6
`16.5
`26.9
`19.0
`
`23.6
`50.3
`26.1
`41.9
`
`45.2
`8.8
`15.8
`
`75.7
`8.6
`12.4
`
`Note. GED = general equivalency diploma. Percentages given for Environmental Factors and Quitting Methods used were those
`persons who replied “yes” to the question posed.
`
`education or less. Almost half (46%) had tried
`to quit 3 or more times, 74% had started to
`smoke regularly at age 18 or younger, and
`16% reported that others at home smoked.
`
`Multivariate Analysis
`The odds ratios (with 95% confidence
`intervals) for successful cessation are shown
`by type of characteristic in Table 2. All 4
`
`demographic characteristics were significantly
`associated with cessation. The odds of suc-
`cessful quitting increased with age. People
`with a college education or more were 1.83
`times as likely to be successful quitters as
`those with less than a high school education.
`People who were married or living with a
`partner and non-Hispanic Whites were also
`more likely to succeed in quitting.
`Regarding smoking-related behaviors, try-
`ing numerous times to quit and switching to
`low-tar or low-nicotine cigarettes for health
`reasons reduced the likelihood of successful
`cessation. With respect to environmental fac-
`tors, people who had a smoke-free home were
`10 times as likely to be successful quitters as
`those who lived in a home where smoking
`took place. For workers, having a no-smoking
`policy at work doubled the likelihood of suc-
`cessful cessation. A person’s gender, the pres-
`ence of smokers at work, going “cold turkey,”
`gradually decreasing the number of cigarettes,
`and using nicotine replacement therapy did
`not significantly predict cessation.
`
`DISCUSSION
`
`We used a large population-based sample
`of US adults to examine multiple factors that
`might be associated with successful smoking
`cessation. By contrast, most earlier studies
`have examined quit attempts among popula-
`tion subgroups (such as pregnant women,
`working populations, or specific communi-
`ties),18,19,21,53–55 the impact of individual inter-
`ventions,28,36,42 or the influence of specific
`population or environmental characteris-
`tics.28,51,55 To better guide smokers who wish
`to quit, we must understand the underlying
`dynamics of the quitting process with respect
`not only to smokers’ demographic and behav-
`ioral characteristics but also their living and
`working environments. The significant gap
`between the proportion of current and for-
`mer smokers who had tried to quit during
`the previous year (43%) and those who actu-
`ally quit for 7 or more months (9%) by itself
`reflects the reality that intentions alone are
`not enough.
`We found that having a smoke-free home,
`having a no-smoking policy at work, being
`aged 35 or older, having a college education
`or more, being married or living with a
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`TABLE 2—Odds Ratios With 95% Confidence Intervals Comparing Those Who Successfully
`Quit Smoking With Unsuccessful Quitters: National Health Interview Survey, 2000
`
`Characteristic
`
`Odds Ratio (95% Confidence Interval)
`
`P
`
`Demographic
`
`Age, y
`18–24
`25–34
`35–44
`45–54
`55–64
`≥ 65
`Education
`Less than high school
`High school graduate or GED
`Some college or associate degree
`College graduate or higher
`Marital status
`Married or living with a partner
`Never married, divorced, separated,
`or widowed
`Race/ethnicity
`Non-Hispanic White
`Non-Hispanic Black
`Hispanic
`Other
`
`Lifetime quit attempts
`1
`2
`3–5
`≥ 6
`Ever switched to low-tar/nicotine products
`Yes
`No
`
`Others smoking at home
`Yes
`No
`No-smoking policy at work
`No
`Yes
`
`1.00 (Reference)
`1.32 (0.92, 1.90)
`1.47 (1.02, 2.12)
`1.80 (1.19, 2.71)
`3.58 (2.30, 5.58)
`5.34 (3.47, 8.22)
`
`1.00 (Reference)
`1.02 (0.73, 1.43)
`1.20 (0.87, 1.66)
`1.83 (1.24, 2.69)
`
`1.00 (Reference)
`0.73 (0.58, 0.91)
`
`1.00 (Reference)
`0.67 (0.47, 0.97)
`0.69 (0.49, 0.96)
`0.74 (0.42, 1.28)
`
`1.00 (Reference)
`0.43 (0.31, 0.60)
`0.28 (0.21, 0.37)
`0.19 (0.14, 0.26)
`
`1.00 (Reference)
`1.32 (1.04, 1.66)
`
`Behavioral
`
`Environmental
`
`1.00 (Reference)
`10.47 (8.15, 13.46)
`
`1.00 (Reference)
`2.01 (1.20, 3.37)
`
`.137
`.038
`.005
`< .001
`< .001
`
`.889
`.268
`.002
`
`.005
`
`.032
`.026
`.279
`
`< .001
`< .001
`< .001
`
`.021
`
`< .001
`
`.008
`
`Note. GED = general equivalency diploma. Successful quitters were defined as those who had maintained their quit status for
`7 to 24 months. Unsuccessful quitters were defined as those who had tried to quit for 1 day or more during the past year but
`relasped before 7 months.
`
`partner, being a non-Hispanic White, having
`only 1 lifetime attempt to quit, and not
`switching to low-tar or low-nicotine products
`for health reasons were significantly associ-
`ated with cessation. The significant influence
`of 2 environmental factors (smoke-free home
`
`and no-smoking policy at work) was found in
`several earlier studies. For example, using
`US population-based survey data, Farkas et
`al.28 found that working in a smoke-free
`workplace and living under a partial or total
`home smoking ban were positively associ-
`
`ated with successful cessation. In a multivari-
`ate study that examined predictors of cessa-
`tion, Hymowitz et al.19 identified the absence
`of other smokers in the household as a sig-
`nificant predictor. Finally, Derby et al.,18 Bor-
`land et al.,21 and McMahon and Jason56 iden-
`tified the positive influence of social support
`on sustained cessation after the implementa-
`tion of a smoking ban for workers.
`Similar to our findings, having higher edu-
`cation,21,53,55 being married,18 and older
`age19 have all been identified by others as
`determinants of successful cessation. Data
`on the relationship of gender to cessation
`have been contradictory, with some studies
`finding men more likely to be successful
`quitters19,55,57 and others53,56,58 finding no
`relationship with gender.
`Regarding behavioral characteristics, our
`finding of a negative correlation between mul-
`tiple attempts to quit and successful cessation
`accords well with the findings of Borland et
`al.21 and Murray et al.42 The latter group
`found that male participants who had more
`quit attempts at baseline were less likely to
`sustain cessation over 5 years. On the other
`hand, Hymowitz et al.19 reported that having
`more than 1 previous quit attempt was associ-
`ated with successful cessation. Although Hy-
`land et al.36 found that switching to a low-tar
`cigarette did not alter the likelihood of success-
`ful cessation over a 2-year period, our multi-
`variate analysis found that switching to low-tar
`or low-nicotine products was negatively associ-
`ated with successful cessation. Although a few
`previous studies19,52,54 have identified older
`age of initiation as a significant predictor of
`successful cessation, we found no relationship
`between age at which a person started smok-
`ing and successful cessation.
`Several limitations to the present study
`need to be noted. First, because the NHIS is
`a US-based study of civilian, noninstitutional-
`ized people, some groups of interest (e.g., the
`military, those in extended care facilities, the
`homeless, people living abroad) were ex-
`cluded. Second, because we relied on self-
`reports to determine smoking status, smoking
`could be underreported through respondents’
`wish to give a socially desirable response.59,60
`Recent studies, however, have shown that
`self-reports and biochemical measurements of
`serum cotinine concentration (which indicate
`
`August 2007, Vol 97, No. 8 | American Journal of Public Health
`
`Lee and Kahende | Peer Reviewed | Research and Practice | 1507
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`JLI Ex. 2018, Page 5 of 7
`
`

`

` RESEARCH AND PRACTICE 
`
`effective programs will need to involve not
`only smokers who intend to quit but also
`their family members, friends, and col-
`leagues, and at the same time implementing
`smoke-free policies that support cessation.
`
`About the Authors
`At the time of the study, the authors were with the Office on
`Smoking and Health, National Center for Chronic Disease
`Prevention and Health Promotion, Centers for Disease
`Control and Prevention, Atlanta, Ga.
`Requests for reprints should be sent to Chung-won Lee,
`PhD, CDC/Global AIDS Program, HIV Prevention
`Branch, 1600 Clifton Rd, NE, MS E-04 Atlanta, GA
`30333 (e-mail: clee2@cdc.gov).
`This article was accepted July 15, 2006.
`Note. The views expressed in this article are that of the
`authors and do not necessarily reflect the views of the Cen-
`ters for Disease Control and Prevention.
`
`Contributors
`C. Lee originated the study, conducted the data analy-
`sis, and led the writing. J. Kahende assisted with the in-
`terpretation of the findings and the writing and re-
`viewed drafts of the article.
`
`Acknowledgments
`We thank Ralph Caraballo and Anne Malacher for their
`thoughtful comments on the article.
`
`References
`1.
`Centers for Disease Control and Prevention. An-
`nual smoking-attributable mortality, years of potential
`life lost, and economic costs—United States, 1995–1999.
`MMWR Mortal Wkly Rep. 2002;51:300–303.
`2.
`Centers for Disease Control and Prevention.
`Cigarette smoking-attributable morbidity—United
`States, 2000. MMWR Morb Mortal Wkly Rep. 2003;
`52:842–844.
`3.
`The Health Consequences of Smoking: A Report of
`the Surgeon General. Atlanta, Ga: National Center for
`Chronic Disease Prevention and Health Promotion,
`Office on Smoking and Health; 2004.
`4.
`Smoking and Health: Report of the Advisory Com-
`mittee to the Surgeon General of the Public Health Service.
`Washington, DC: Public Health Service, Center for Dis-
`ease Control; 1964. PHS publication 103.
`5.
`The Health Benefits of Smoking Cessation. A Report
`of the Surgeon General. Atlanta, Ga: National Center for
`Chronic Disease Prevention and Health Promotion, Of-
`fice on Smoking and Health; 1990. DHHS publication
`(CDC) 90-8416.
`6. Doll R, Peto R, Wheatley K, Gray R, Sutherland I.
`Mortality in relation to smoking: 40 years’ observation
`on male British doctors. BMJ. 1994;309:901–911.
`7.
`Centers for Disease Control and Prevention. Ciga-
`rette smoking among adults—United States, 2003.
`MMWR Morb Mortal Wkly Rep. 2005;54:509–513.
`8. Gilpin E, Pierce JP, Goodman J, Burns D, Shopland
`D. Reasons smokers give for stopping smoking: do they re-
`late to success in stopping? Tob Control. 1992;1:256–263.
`9.
`Centers for Disease Control and Prevention.
`Smoker’s beliefs about the health benefits of smoking
`
`cessation: 20 US communities. MMWR Morb Mortal
`Wkly Rep. 1990;39:653–656.
`
`10. Hatziandreu EJ, Pierce JP, Lefkopoulou M, et al.
`Quitting smoking in the United States in 1986. J Natl
`Cancer Inst. 1990;82:1402–1406.
`
`11. Killen JD, Fortmann SP, Kraemer HC, Varady A,
`Newman B. Who will relapse? Symptoms of nicotine
`dependence predict long-term relapse after smoking
`cessation. J Consult Clin Psychol. 1992;60:797–801.
`
`12. Venters MH, Kottke TE, Solberg LI, Brekke ML,
`Rooney B. Dependency, social factors, and the smoking
`cessation process: The Doctors Helping Smokers Study.
`Am J Prev Med. 1990;6:185–193.
`
`13. Hymowitz N, Sexton M, Ockene J, Grandits G.
`Baseline factors associated with smoking cessation
`and relapse. MRFIT Research Group. Prev Med. 1991;
`20:590–601.
`
`14. Fagerstrom KO. Measuring degree of physical de-
`pendence to tobacco smoking with reference to individ-
`ualization of treatment. Addict Behav. 1978;3:235–241.
`
`15. Fisher EB, Lichtenstein E, Haire-Joshu D. Multiple
`determinants of tobacco use and cessation. In: Orleans
`CT, Slade J, eds. Nicotine Addiction: Principles and Man-
`agement. New York, NY: Oxford University Press;
`1993:59–88.
`
`16. Berman BA, Gritz ER. Women and smoking: cur-
`rent trend and issues for the 1990s. J Subst Abuse.
`1991;3:221–238.
`
`17. Royce JM, Hymowitz N, Corbett K, Hartwell TD,
`Orlandi MA. Smoking cessation factors among African
`Americans and whites. COMMIT Research Group. Am
`J Public Health. 1993;83:220–226.
`
`18. Derby CA, Laster TM, Vass K, Gonzalez S,
`Carleton RA. Characteristics of smokers who attempt
`to quit and of those who recently succeeded. Am J Prev
`Med. 1994;10:327–334.
`
`19. Hymowitz N, Cummings MK, Hyland A, Lynn WR,
`Pechacek TF, Hartwell TD. Predictors of smoking ces-
`sation in a cohort of adult smokers followed for five
`years. Tob Control. 1997;6(suppl 2):S57–S62.
`
`20. Wilcox NS, Prochaska JO, Velicer WF, DiClemente
`CC. Subject characteristics as predictors of self-change
`in smoking. Addict Behav. 1985;10:407–412.
`
`21. Borland R, Owen N, Hill D, Schofield P. Predicting
`attempts and sustained cessation of smoking after the
`introduction of workplace smoking bans. Health Psy-
`chol. 1991;10:336–342.
`
`22. Orford J. Excessive Appetites: A Psychological View
`of Addictions. Chichester, England: Wiley; 1985.
`
`23. Richmond RL, Kehoe LA, Webster IW. Multivari-
`ate models for predicting abstention following interven-
`tion to stop smoking by general practitioners. Addiction.
`1993;88:1127–1135.
`
`24. Herbert JR, Kristeller J, Ockene JK, et al. Patient
`characteristics and the effect of three physician-delivered
`smoking interventions. Prev Med. 1992;21:557–573.
`
`25. Richmond RL, Austin A, Webster IW. Predicting
`abstainers in a smoking cessation programme adminis-
`tered by general practitioners. Int J Epidemiol. 1988;
`17:530–534.
`
`26. Senore C, Battista RN, Shapiro SH, et al. Predic-
`tors of smoking cessation following physicians’ counsel-
`ing. Prev Med. 1998;27:412–421.
`
`exposure to tobacco smoke) provide similar
`estimates of smoking prevalence in the
`United States.61
`Third, we did not have information on the
`number of cigarettes smoked by former
`smokers. Past studies19,53,55,58,62 have found
`that heavy smokers are less likely than light
`smokers to succeed in quitting. We also could
`not examine the number and duration of
`quitting methods used because the informa-
`tion was unavailable in the data set. The asso-
`ciation between the use of quitting methods
`and cessation outcome may vary depending
`on the number and duration of methods
`used. Although our study did not identify a
`significant impact of nicotine replacement
`therapy on cessation outcome, clinical trials
`have found that the use of such therapy and
`nonnicotine medications such as sustained-
`release Bupropion double long-term absti-
`nence rates.44 Finally, we limited successful
`quitters to those who quit for 7 to 24
`months, but some people will relapse after
`more than 2 years of quitting,42 and thus our
`analysis probably included some people who
`did not quit permanently.
`This study may have several important
`implicati