Nicotine & Tobacco Research, 2015, 882–885 doi:10.1093/ntr/ntu224 Brief report Advance Access publication October 30, 2014
Brief report
Time to First Use Among Daily Smokers and Smokeless Tobacco Users Brad Rodu DDS1,2, Nantaporn Plurphanswat PhD2, Karl Fagerström PhD3
Corresponding Author: Brad Rodu, DDS, University of Louisville, 505 South Hancock Street, Louisville, KY 40202, USA. Telephone: 502-852-7793; Fax: 502-852-7979; E-mail: [email protected]
Abstract Introduction: Time to the first cigarette after waking up in the morning is the most validated measure of dependence among smokers, and its complement is also a good indicator of dependence for smokeless tobacco (ST) users. However, no studies have directly compared these measures. Methods: We used a multivariate logistic regression model to compare the time to first use (TTFU) of cigarettes and ST among white men 18+ years of age who were daily users in the 2003 Tobacco Use Supplement of the Current Population Survey. Smokers were classified as light (1–14 cigarettes per day [cpd]), moderate (15–24 cpd), and heavy (25+ cpd) and ST users were classified as former smokers or exclusive users. Results: There was no difference in TTFU within 5 min between light smokers and exclusive ST users (Odds ratio [OR] = 1.3, CI = 0.95–1.7), but the latter were less likely to use tobacco within 30 min (OR = 0.75, CI = 0.62–0.89). ST former smokers were more likely than light smokers to have a TTFU within 5 min (OR = 1.5, CI = 1.1–2.0) but not within 30 min. Moderate and heavy smokers had significantly higher odds of TTFU within both time points than light smokers. Conclusion: Compared to light smokers, the likelihood of TTFU within 5 min was similar among exclusive ST users and was slightly higher among ST former smokers, offering some support for the Fagerström-Eissenberg hypothesis that the dependence level of cigarettes is higher than that of ST.
Introduction Cigarette smoking is the dominant form of tobacco use in the United States, and it has been the subject of most of the research related to dependence. The Fagerström Tolerance Questionnaire was created in 19781 and was revised in 1991 as the Fagerström Test for Nicotine Dependence (FTND)2 with input from the Heaviness of Smoking Index,3 which recalibrated categories of time to first cigarette (TTFC) to ≤5, 6–30, 31–60 and 61+ min after waking. This classification was significantly correlated with levels of carbon monoxide and cotinine, two readily measured biomarkers of smoking. The scale was renamed by its eponymous author in 2012 as the Fagerström Test for Cigarette Dependence to emphasize its specificity for smoking.4 Fagerström scales have also been adapted for smokeless tobacco (ST) use.5–7
Fagerström and Eissenberg proposed that there is a continuum of dependence among tobacco and nicotine products.8 They observed that the cessation rate for the placebo arm of randomized clinical trials for smoking is about 10% (range 9.8%–11.2%), while the same rate for smokeless tobacco trials is about twice as large (range 19.1%–33.0%). They concluded that cigarettes are the most dependence-producing product and that ST was intermediate, based on the observation that “quitting cigarette smoking is more difficult than quitting ST.” Fagerström and Eissenberg suggested that the level of dependence associated with each tobacco/nicotine product is optimally assessed by a specific instrument, but they acknowledge that this could make product comparisons difficult. However, there is one Fagerström scale item that is virtually identical for both cigarettes and ST:
© The Author 2014. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: [email protected].
882
Downloaded from http://ntr.oxfordjournals.org/ at Nanyang Technological University on November 14, 2015
Department of Medicine, School of Medicine, University of Louisville, Louisville, KY; 2James Graham Brown Cancer Center, University of Louisville, Louisville, KY; 3Smoker’s Information Centre, Fagerström Consulting, Vaxholm, Sweden
1
Nicotine & Tobacco Research, 2015, Vol. 17, No. 7 time to first use (TTFU). For smoking, TTFC has been suggested to be the best predictor of dependence9 and was recently found to be strongly correlated with abstinence and time to relapse among smokers enrolled in cessation trials and in nationally representative samples of smokers from four countries.10 TTFU also correlates with salivary5,7 and serum6 cotinine levels among ST users. The purpose of this study is to compare TTFU among daily cigarette smokers and daily ST users.
Methods
883 The second was another binary variable equal to one if a respondent smoked his first cigarette or used ST within 30 min after waking up. We conducted a separate regression analysis of TTFU as a continuous variable. Relevant demographic variables included age (18–24, 25–44, 45–64 and 65+ years), highest educational attainment (up to high school diploma and more than high school), marital status (married and unmarried, which included divorced/separated, widowed, never married), and family income ($0–$34,999, $35,000–$74,999, and $75,000+). We also included the region of residence (North, Midwest, South, and West).
Data Source and Sample
Measures Variables In this study, current smokers were defined as those who had smoked at least 100 cigarettes in their lifetime and smoked every day at the time of the survey. Former smokers had smoked at least 100 cigarettes in their lifetime but did not smoke at the time of the survey. Current ST users were defined as those who used chewing tobacco or snuff every day; they were classified into two groups; former smokers or exclusive ST users. Smokers and ST users were separately asked the following questions. “How soon after you wake up do you typically smoke your first cigarette of the day?” and “How soon after you wake up do you typically first use [ST]?” Responses had been coded in the survey dataset as two variables, number and unit (minutes, hours), which we transformed into a single variable, minutes. We classified answers as TTFU ≤5, 6–30, 31–60 and >60 min.2 Because all of our subjects were daily users, we assumed that the unit variable had been miscoded for the small number (n = 15) with TTFU ≥ 24 hr, and we changed the unit measurement for these subjects to minutes. For cigarette consumption, the number of cigarettes smoked per day was classified as light (1–14), moderate (15–24), and heavy (25+). ST users were not asked any questions regarding consumption. We excluded some-day smokers and some-day ST users because the latter were not asked about TTFU. Dual users were not included because some smokers who were also ST users were not asked the TTFU question for ST use. For regression analyses we constructed two dependent variables. The first was a binary variable equal to one if a respondent smoked his first cigarette or used ST within the first 5 min after waking up.
Analysis Descriptive analysis was conducted to compare TTFU among smokers, ST former smokers, and exclusive ST users. We used a multivariate logistic regression model to obtain the odd ratios (ORs) for associations between tobacco use behavior and TTFU within 5 min (model 1) and TTFU within 30 min (model 2). In a separate analysis we used a linear regression model to examine TTFU as a continuous variable with respect to tobacco use. All analyses were unweighted because we specifically focused on only white men, and estimates are adjusted for all other variables in the models.
Results The final sample consisted of 10,478 cigarette smokers; the proportions of light, moderate and heavy smokers were 25%, 52%, and 23% respectively. There were 1,176 ST users; 38% were former smokers and the rest were exclusive users. Supplementary Table 1 lists the demographic characteristics of light, moderate and heavy smokers, ST former smokers and exclusive ST users. The latter were the youngest group (average age 39.9 years); heavy smokers and ST former smokers were the oldest (47.2 and 48.0 years respectively). Light smokers were the least likely to be married (47%), while ST former smokers were the most likely (71%). Two-thirds of all heavy smokers, ST former smokers and exclusive ST users were in the South or the Midwest. Figure 1 shows the distribution of TTFU among smokers and ST users. The proportion of men with TTFU within 5 min was not different among light smokers (9%) exclusive ST users (10%) and ST former smokers (12%); all were significantly lower than among moderate (22%) and heavy smokers (47%). Twenty-nine percent of exclusive ST users had a TTFU within 30 min, compared with 69% of moderate smokers and 89% of heavy smokers. Compared to light smokers, the odds of TTFU within 5 min was not significantly different among exclusive ST users (OR = 1.28, 95% CI = 0.97–1.68) but was slightly higher among ST former smokers (OR = 1.46, 95% CI = 1.06–2.02) (Table 1). Moderate and heavy smokers were more likely to have a TTFU within 5 min (OR = 3.09, 95% CI = 2.65–3.60 and OR = 9.09, 95% CI = 7.72–10.71, respectively). Results were similar for TTFU within 30 min, except that the OR for exclusive ST users, compared with light smokers, was significantly lower (OR = 0.74, 95% CI = 0.62–0.89). Other factors associated with modestly lower ORs were being married and having higher family income. Factors associated with modestly higher ORs include older age (for TTFU within 30 min) and less education. The mean values for TTFU for tobacco use categories are in Supplementary Table 1. The large standard deviations reflect the large range of values. The median for light smokers and both groups
Downloaded from http://ntr.oxfordjournals.org/ at Nanyang Technological University on November 14, 2015
We used data from the Tobacco Use Supplement of the Current Population Survey (TUS-CPS), sponsored by the National Cancer Institute and the Centers for Disease Control and Prevention in February, June, and November 2003.11 The basic CPS is conducted monthly to study unemployment and labor force participation. The TUS is a supplement that contains information regarding tobacco use behaviors. All household members age 15 years and older who completed the core CPS were eligible for the TUS. The 2003 TUS-CPS survey was administered to 249,620 people in the civilian, non-institutionalized U.S. population; it included both self-respondents, who were eligible to complete the entire survey, and proxy-respondents, who provided answers for all eligible household members and completed only selected questions. We excluded proxyrespondents because they did not have detailed information on tobacco use and self-respondents with missing demographic or tobacco use variables. The sampling frame for our analysis was white men age 18+ years because the prevalence of ST use among men of other race/ethnicity and among women was too low to provide reliable information.12
Nicotine & Tobacco Research, 2015, Vol. 17, No. 7
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Table 1. Odds Ratios for TTFUa Within 5 Min and Within 30 Min According to Tobacco Use and Other Characteristics Within 5 min Odds ratio (95% CI)
p value
Odds ratio (95% CI)
p value
(1)
(2)
(3)
(4)
3.09 (2.65, 3.60) 9.09 (7.72, 10.71) 1.46 (1.06, 2.02) 1.28 (0.97, 1.68)
.000 .000 .022 .085
3.88 (3.51, 4.28) 12.28 (10.57, 14.27) 1.06 (0.86, 1.30) 0.74 (0.62, 0.89)
.000 .000 .613 .001
1.01 (0.85, 1.19) 1.04 (0.87, 1.23) 0.90 (0.72, 1.13) 1.34 (1.21, 1.48) 0.90 (0.82, 0.99)
.946 .682 .360 .000 .036
1.39 (1.20, 1.60) 1.67 (1.44, 1.94) 1.69 (1.39, 2.05) 1.28 (1.17, 1.40) 0.89 (0.81, 0.97)
.000 .000 .000 .000 .010
0.80 (0.72, 0.89) 0.59 (0.50, 0.69) 0.80 (0.68, 0.95)
.000 .000 .010
0.88 (0.80, 0.98) 0.72 (0.63, 0.82) 0.90 (0.77, 1.04)
.015 .000 .159
0.97 (0.85, 1.11) 1.08 (0.95, 1.24) 0.99 (0.86, 1.15) 11,654
.653 .251 .921
1.05 (0.93, 1.19) 1.04 (0.92, 1.18) 0.97 (0.85, 1.10) 11,654
.441 .520 .616
Note. Exponentiated coefficients: ref. = reference group; ST = smokeless tobacco; TTFU = time to first use. a Adjusted for all other variables in the model.
Figure 1. Distribution (%) of daily smokers and smokeless tobacco (ST) users according to TTFU (minutes).
Downloaded from http://ntr.oxfordjournals.org/ at Nanyang Technological University on November 14, 2015
Tobacco use: ref. light smoker Moderate smoker Heavy smoker ST user former smoker Exclusive ST user Age (years): ref. 18–24 25–44 45–64 65+ ≤ High school Married Family income: ref.
Brief report
Time to First Use Among Daily Smokers and Smokeless Tobacco Users Brad Rodu DDS1,2, Nantaporn Plurphanswat PhD2, Karl Fagerström PhD3
Corresponding Author: Brad Rodu, DDS, University of Louisville, 505 South Hancock Street, Louisville, KY 40202, USA. Telephone: 502-852-7793; Fax: 502-852-7979; E-mail: [email protected]
Abstract Introduction: Time to the first cigarette after waking up in the morning is the most validated measure of dependence among smokers, and its complement is also a good indicator of dependence for smokeless tobacco (ST) users. However, no studies have directly compared these measures. Methods: We used a multivariate logistic regression model to compare the time to first use (TTFU) of cigarettes and ST among white men 18+ years of age who were daily users in the 2003 Tobacco Use Supplement of the Current Population Survey. Smokers were classified as light (1–14 cigarettes per day [cpd]), moderate (15–24 cpd), and heavy (25+ cpd) and ST users were classified as former smokers or exclusive users. Results: There was no difference in TTFU within 5 min between light smokers and exclusive ST users (Odds ratio [OR] = 1.3, CI = 0.95–1.7), but the latter were less likely to use tobacco within 30 min (OR = 0.75, CI = 0.62–0.89). ST former smokers were more likely than light smokers to have a TTFU within 5 min (OR = 1.5, CI = 1.1–2.0) but not within 30 min. Moderate and heavy smokers had significantly higher odds of TTFU within both time points than light smokers. Conclusion: Compared to light smokers, the likelihood of TTFU within 5 min was similar among exclusive ST users and was slightly higher among ST former smokers, offering some support for the Fagerström-Eissenberg hypothesis that the dependence level of cigarettes is higher than that of ST.
Introduction Cigarette smoking is the dominant form of tobacco use in the United States, and it has been the subject of most of the research related to dependence. The Fagerström Tolerance Questionnaire was created in 19781 and was revised in 1991 as the Fagerström Test for Nicotine Dependence (FTND)2 with input from the Heaviness of Smoking Index,3 which recalibrated categories of time to first cigarette (TTFC) to ≤5, 6–30, 31–60 and 61+ min after waking. This classification was significantly correlated with levels of carbon monoxide and cotinine, two readily measured biomarkers of smoking. The scale was renamed by its eponymous author in 2012 as the Fagerström Test for Cigarette Dependence to emphasize its specificity for smoking.4 Fagerström scales have also been adapted for smokeless tobacco (ST) use.5–7
Fagerström and Eissenberg proposed that there is a continuum of dependence among tobacco and nicotine products.8 They observed that the cessation rate for the placebo arm of randomized clinical trials for smoking is about 10% (range 9.8%–11.2%), while the same rate for smokeless tobacco trials is about twice as large (range 19.1%–33.0%). They concluded that cigarettes are the most dependence-producing product and that ST was intermediate, based on the observation that “quitting cigarette smoking is more difficult than quitting ST.” Fagerström and Eissenberg suggested that the level of dependence associated with each tobacco/nicotine product is optimally assessed by a specific instrument, but they acknowledge that this could make product comparisons difficult. However, there is one Fagerström scale item that is virtually identical for both cigarettes and ST:
© The Author 2014. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: [email protected].
882
Downloaded from http://ntr.oxfordjournals.org/ at Nanyang Technological University on November 14, 2015
Department of Medicine, School of Medicine, University of Louisville, Louisville, KY; 2James Graham Brown Cancer Center, University of Louisville, Louisville, KY; 3Smoker’s Information Centre, Fagerström Consulting, Vaxholm, Sweden
1
Nicotine & Tobacco Research, 2015, Vol. 17, No. 7 time to first use (TTFU). For smoking, TTFC has been suggested to be the best predictor of dependence9 and was recently found to be strongly correlated with abstinence and time to relapse among smokers enrolled in cessation trials and in nationally representative samples of smokers from four countries.10 TTFU also correlates with salivary5,7 and serum6 cotinine levels among ST users. The purpose of this study is to compare TTFU among daily cigarette smokers and daily ST users.
Methods
883 The second was another binary variable equal to one if a respondent smoked his first cigarette or used ST within 30 min after waking up. We conducted a separate regression analysis of TTFU as a continuous variable. Relevant demographic variables included age (18–24, 25–44, 45–64 and 65+ years), highest educational attainment (up to high school diploma and more than high school), marital status (married and unmarried, which included divorced/separated, widowed, never married), and family income ($0–$34,999, $35,000–$74,999, and $75,000+). We also included the region of residence (North, Midwest, South, and West).
Data Source and Sample
Measures Variables In this study, current smokers were defined as those who had smoked at least 100 cigarettes in their lifetime and smoked every day at the time of the survey. Former smokers had smoked at least 100 cigarettes in their lifetime but did not smoke at the time of the survey. Current ST users were defined as those who used chewing tobacco or snuff every day; they were classified into two groups; former smokers or exclusive ST users. Smokers and ST users were separately asked the following questions. “How soon after you wake up do you typically smoke your first cigarette of the day?” and “How soon after you wake up do you typically first use [ST]?” Responses had been coded in the survey dataset as two variables, number and unit (minutes, hours), which we transformed into a single variable, minutes. We classified answers as TTFU ≤5, 6–30, 31–60 and >60 min.2 Because all of our subjects were daily users, we assumed that the unit variable had been miscoded for the small number (n = 15) with TTFU ≥ 24 hr, and we changed the unit measurement for these subjects to minutes. For cigarette consumption, the number of cigarettes smoked per day was classified as light (1–14), moderate (15–24), and heavy (25+). ST users were not asked any questions regarding consumption. We excluded some-day smokers and some-day ST users because the latter were not asked about TTFU. Dual users were not included because some smokers who were also ST users were not asked the TTFU question for ST use. For regression analyses we constructed two dependent variables. The first was a binary variable equal to one if a respondent smoked his first cigarette or used ST within the first 5 min after waking up.
Analysis Descriptive analysis was conducted to compare TTFU among smokers, ST former smokers, and exclusive ST users. We used a multivariate logistic regression model to obtain the odd ratios (ORs) for associations between tobacco use behavior and TTFU within 5 min (model 1) and TTFU within 30 min (model 2). In a separate analysis we used a linear regression model to examine TTFU as a continuous variable with respect to tobacco use. All analyses were unweighted because we specifically focused on only white men, and estimates are adjusted for all other variables in the models.
Results The final sample consisted of 10,478 cigarette smokers; the proportions of light, moderate and heavy smokers were 25%, 52%, and 23% respectively. There were 1,176 ST users; 38% were former smokers and the rest were exclusive users. Supplementary Table 1 lists the demographic characteristics of light, moderate and heavy smokers, ST former smokers and exclusive ST users. The latter were the youngest group (average age 39.9 years); heavy smokers and ST former smokers were the oldest (47.2 and 48.0 years respectively). Light smokers were the least likely to be married (47%), while ST former smokers were the most likely (71%). Two-thirds of all heavy smokers, ST former smokers and exclusive ST users were in the South or the Midwest. Figure 1 shows the distribution of TTFU among smokers and ST users. The proportion of men with TTFU within 5 min was not different among light smokers (9%) exclusive ST users (10%) and ST former smokers (12%); all were significantly lower than among moderate (22%) and heavy smokers (47%). Twenty-nine percent of exclusive ST users had a TTFU within 30 min, compared with 69% of moderate smokers and 89% of heavy smokers. Compared to light smokers, the odds of TTFU within 5 min was not significantly different among exclusive ST users (OR = 1.28, 95% CI = 0.97–1.68) but was slightly higher among ST former smokers (OR = 1.46, 95% CI = 1.06–2.02) (Table 1). Moderate and heavy smokers were more likely to have a TTFU within 5 min (OR = 3.09, 95% CI = 2.65–3.60 and OR = 9.09, 95% CI = 7.72–10.71, respectively). Results were similar for TTFU within 30 min, except that the OR for exclusive ST users, compared with light smokers, was significantly lower (OR = 0.74, 95% CI = 0.62–0.89). Other factors associated with modestly lower ORs were being married and having higher family income. Factors associated with modestly higher ORs include older age (for TTFU within 30 min) and less education. The mean values for TTFU for tobacco use categories are in Supplementary Table 1. The large standard deviations reflect the large range of values. The median for light smokers and both groups
Downloaded from http://ntr.oxfordjournals.org/ at Nanyang Technological University on November 14, 2015
We used data from the Tobacco Use Supplement of the Current Population Survey (TUS-CPS), sponsored by the National Cancer Institute and the Centers for Disease Control and Prevention in February, June, and November 2003.11 The basic CPS is conducted monthly to study unemployment and labor force participation. The TUS is a supplement that contains information regarding tobacco use behaviors. All household members age 15 years and older who completed the core CPS were eligible for the TUS. The 2003 TUS-CPS survey was administered to 249,620 people in the civilian, non-institutionalized U.S. population; it included both self-respondents, who were eligible to complete the entire survey, and proxy-respondents, who provided answers for all eligible household members and completed only selected questions. We excluded proxyrespondents because they did not have detailed information on tobacco use and self-respondents with missing demographic or tobacco use variables. The sampling frame for our analysis was white men age 18+ years because the prevalence of ST use among men of other race/ethnicity and among women was too low to provide reliable information.12
Nicotine & Tobacco Research, 2015, Vol. 17, No. 7
884
Table 1. Odds Ratios for TTFUa Within 5 Min and Within 30 Min According to Tobacco Use and Other Characteristics Within 5 min Odds ratio (95% CI)
p value
Odds ratio (95% CI)
p value
(1)
(2)
(3)
(4)
3.09 (2.65, 3.60) 9.09 (7.72, 10.71) 1.46 (1.06, 2.02) 1.28 (0.97, 1.68)
.000 .000 .022 .085
3.88 (3.51, 4.28) 12.28 (10.57, 14.27) 1.06 (0.86, 1.30) 0.74 (0.62, 0.89)
.000 .000 .613 .001
1.01 (0.85, 1.19) 1.04 (0.87, 1.23) 0.90 (0.72, 1.13) 1.34 (1.21, 1.48) 0.90 (0.82, 0.99)
.946 .682 .360 .000 .036
1.39 (1.20, 1.60) 1.67 (1.44, 1.94) 1.69 (1.39, 2.05) 1.28 (1.17, 1.40) 0.89 (0.81, 0.97)
.000 .000 .000 .000 .010
0.80 (0.72, 0.89) 0.59 (0.50, 0.69) 0.80 (0.68, 0.95)
.000 .000 .010
0.88 (0.80, 0.98) 0.72 (0.63, 0.82) 0.90 (0.77, 1.04)
.015 .000 .159
0.97 (0.85, 1.11) 1.08 (0.95, 1.24) 0.99 (0.86, 1.15) 11,654
.653 .251 .921
1.05 (0.93, 1.19) 1.04 (0.92, 1.18) 0.97 (0.85, 1.10) 11,654
.441 .520 .616
Note. Exponentiated coefficients: ref. = reference group; ST = smokeless tobacco; TTFU = time to first use. a Adjusted for all other variables in the model.
Figure 1. Distribution (%) of daily smokers and smokeless tobacco (ST) users according to TTFU (minutes).
Downloaded from http://ntr.oxfordjournals.org/ at Nanyang Technological University on November 14, 2015
Tobacco use: ref. light smoker Moderate smoker Heavy smoker ST user former smoker Exclusive ST user Age (years): ref. 18–24 25–44 45–64 65+ ≤ High school Married Family income: ref.
