- Email: [email protected]
Effects of partner smoking status and gender on long term abstinence rates of patients receiving smoking cessation treatment
Addictive Behaviors 32 (2007) 128 – 136
Effects of partner smoking status and gender on long term abstinence rates of patients receiving smoking cessation treatment Paula Mancho´n Walsh *, Paloma Carrillo, Gemma Flores, Cristina Masuet, Sergio Morchon, Josep Maria Ramon Unidad de Deshabituacio´n Taba´quica, Servicio de Medicina Preventiva, c/ Feixa Llarga, s/n, 08907 L’Hospitalet de Llobregat, Barcelona, Spain
Abstract Aims: To assess the effect of partner smoking status on the success of a cessation program. Design: Prospective cohort. Setting: Smoking Cessation Unit in Hospital of Bellvitge (Hospitalet de Llobregat, Barcelona). Participants: A total of 1516 smokers of 10 or more cigarettes who started a smoking cessation program between January 1995 and December 2001 were included. Measurements: All patients gave information about smoking history and smoking partner status. Abstinence was determined by carbon monoxide exhaled. Findings: Significant differences were found in the abstinence rates at 12 months by smoking partner status: abstinence was achieved by 28.3% of patients with smoking partner, and by 46.5% of patients without smoking partner ( p b 0.001). Subjects whose partner was smoking at the beginning of the program appear to be more likely to relapse than subjects without smoking partners ( p b 0.001) and this is more pronounced in women than in men. However no significant gender differences were found in any group of smoking partner status. Conclusions: Having a smoking partner is a determinant of relapse 1year after the beginning of the cessation program. Interacting not just with the smoker, but also with his or her partner, could neutralize interpersonal influences making smokers more accessible to behavioural and pharmacological techniques. D 2006 Elsevier Ltd. All rights reserved. Keywords: Smoking; Smoking cessation; Gender; Partner; Spouses
* Corresponding author. 46 Chisholm Street, Darlinghurst, 2010 NSW, Australia. Fax: +61 93 260 78 49. E-mail address: [email protected] (P.M. Walsh). 0306-4603/$ - see front matter D 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.addbeh.2006.03.027
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1. Introduction Smoking is the most important preventable cause of morbidity and mortality in many developed countries (Ezzati & Lopez, 2003). It is a proven risk factor for a variety of health problems and involves also those exposed to environmental tobacco smoke. Smoking has a multifactorial dependence: physical, psychological and social. The interaction between nicotine addiction, sociodemographic characteristics and behaviour factors is relevant to predict the success of smoking cessation (Kottke, Battista, & DeFriese, 1988). It has been estimated that less than 50% of all smokers will quit permanently (Skaar et al., 1997). This shows the need to increase our understanding of the process of stop smoking. Therefore, the present study of determinants of cessation through a cessation program is relevant. A substantial body of evidence indicates that social support predicts the success of cessation attempts (Chandola, Head, & Bartley, 2004; Gourlay, Forbes, Marriner, Pethica, & McNeil, 1994; Park, Tudiver, Schultz, & Campbell, 2004). Furthermore, Chandola et al. (2004) and also Park et al. (2004) have recently reported that the presence of other smokers in the household is a negative predictor for smoking cessation. The relevance of the presence or absence of a partner in the smoking cessation was studied by Senore et al. (1998) who suggested that smokers, married or living common-law, were significantly more likely to quit than those who were single, divorced or widowed. However no clear conclusions have emerged about the influence of partner’s characteristics in quitting, especially the influence of partner’s smoking status. A retrospective cohorts study assessing the effect of partner smoking behaviour was carried out by Monden, De Graaf, & Kraaykamp (2003) indicating that the presence of a nonsmoking partner increases the likelihood of quitting. The aim of the study was to assess the effect of partners smoking status on the success of a cessation program.
2. Methods We undertook a prospective study of 1516 smokers of 10 or more cigarettes per day who were attended at the specialised Smoking Cessation Unit (SCU) of the Hospital de Bellvitge (L’Hospitalet de Llobregat, Barcelona, Spain), a University Teaching Hospital in the metropolitan area of Barcelona, between January 1995 and December 2001 and followed-up until May 2003. We excluded patients who had psychiatric history. This unit receives patients from the medical and surgical departments of the hospital, and from Primary Health Centres in the surrounding area. During this period, 2123 smokers visited the unit and received treatment for smoking cessation (70.0% with nicotine patches for nicotine replacement therapy (NRT), 13.5% with nicotine gums for NRT, 6.3% patches plus gums for NRT, 5.3% anxiolytics, 3.6% antidepressants (mainly bupropion, from the year 2000 onwards) and 0.6% antidepressants plus some type of NRT). The treatment was determined in relation to the subject’s characteristics and on the basis of cognitive-behavioural counseling and pharmacological therapy. Details of the cohort of smokers and measurements have been published (Morchon, Blasco, Rovira, Arias, & Ramon, 2001). During the first visit we collected sociodemographic and anthropometric information, medical history (presence of diabetes, cardiovascular diseases, chronic obstructive pulmonary disease and cancer) and data from smoking history including: onset age, current and past consumption (in cigarettes per day),
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type and brand of cigarettes smoked, number of prior attempts to quit, level of nicotine dependence by Fagerstro¨m Test (Fagerstro¨m & Scneider, 1989). The abstinence was confirmed during the visits with the measurement of carbon monoxide (CO) concentrations in exhaled air. Partner was defined as spousal equivalent residing with the patient. Smoking status of the partner was also collected in the first visit. Smoking partner was defined as smoking daily at the beginning of the program. Subjects with non-smoking partner were those who were singles and those whose partners did not smoke. Once treatment was initiated, follow-up visits were arranged every 15 days during the first 2 months and then at intervals of 3, 6, 9 and 12 months. The process of cessation was assessed in every visit (presence of withdrawal symptoms, relapse, adverse effects of pharmacological therapy and exhaled CO). In order to analyse long term abstinence and relapse we designed a telephone administered follow-up questionnaire. Between February and May 2003, smokers studied were interviewed by trained staff. The questionnaire included information on current smoking status and, in case of relapse, the date (month and year) when they started smoking again. Additional information on educational level and occupation was collected in the telephone survey, as well as information on passive smoking exposure and the opinion on current smoking regulations. Nonrespondents were excluded from the analyses. The outcome variable was the likelihood of relapse. We considered abstinence of smoking if expired CO b 6ppm. Participants were considered to relapse if they declared, after quitting smoking, to be daily or occasional smokers. Since follow-up was done by telephone, no biological measurement of long-term abstinence was possible. The time of relapse was calculated as the number of months from the date of quitting smoking to the date of the follow-up interview. Those patients who relapsed immediately after the intervention (n = 370) were assigned a 1-day time of follow-up. One independent variable was social class. Since no complete information on this variable was available from the initial visit, we used the information from the follow-up questionnaire. To derive the social class, we collected the information on occupation using the adaptation of the British General Classification proposed by the Spanish Societe of Epidemiology and Family and Community Medicine (Grupo de trabajo de la Sociedad Espan˜ola de Epidemiologı´a, de la Sociedad Espan˜ola de Medicina Familiar y Comunitaria, 2000). For both men and women, social class was assigned based on main own occupation, and in the case of retired or non-occupied persons, the last occupation was used. The social class of students and housewives was assigned based on the current or more recent occupation of the head of the household. Due to small numbers, we grouped classes as following: I–II, III and IV–V.
3. Statistical analysis Means and standard deviations were used to examine continuous variables, and stratified by sex, and were compared using Student Test. Chi square test was used to compare quit rates at 6, 12 and 24months by presence of smoking partner and by sex. Kaplan-Meyer method and the Log-Rank test were used to estimate cumulative abstinence (probability of continuing abstinent and 95% confidence intervals, CI) at 6, 12 and 24months by presence of smoking partner status.
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Table 1 Consumption and cessation characteristics by sex and smoking partner status Men
Women
Smoking partner Non smoking P* (n = 195) partner (n = 698)
Smoking partner Non smoking P* P** (n = 236) partner (n = 381)
Age 42.32 F 9.22 Initiation age 15.43 F 3,18 Number of cigarettes 33.22 F 13.66 smoked daily before cessation program Fagerstro¨m Test 7.57 F 2.18 Number of previous 1.86 F 1.44 quit attempts
48.95 F 12.02 15.91 F 4.53 30.26 F 14.26
7.76 F 2.05 2.53 F 2.77
b 0.001 39.19 F 9.61 NS 17.34 F 4.72 b 0.05 28.80 F 11.18
NS NS
7.48 F 2.26 2.63 F 0.32
Smoking partner
40.72 F 10.00 18.03 F 6.09 28.45 F 12.26
7.62 F 2.15 2.29 F 2.32
NS b 0.001 NS b 0.001 NS b 0.001
NS NS
NS NS
NS: not significant. * Statistical significance of comparison between smoking partner group and nonsmoking partner group using Student’s t-test. ** Statistical significance of comparison between men and women using Student’s t-test.
The relative risk (estimated as hazard rate ratios, HR) and 95% CI of relapse at the end of follow up was assessed with a multivariate Cox regression model, after checking the proportionality of the hazards during follow-up. Since there are well-recognised gender-based differentials in the dynamics of smoking in this population, all analyses were performed separately for men and women (Borras, Fernandez, Schiaffino, Borrell, & La Vecchia, 2000; Garcia et al., 2004). All statistical tests were 2-tailed and values of p b 0.05 were considered significant.
4. Results There were 1516 subjects, 59.0% were men (n = 895) and 41.0% women (n = 621). Mean age was 44.5 years (SD: 11.6 years). Men with a smoking partner smoked more at day ( p = 0.01) and were younger at the beginning of the cessation therapy than men without smoking partner ( p b 0.001) (Table 1). No significant differences were observed in smoking onset age, level of nicotine dependence or in the number of previous quit attempts.
Table 2 Comparison of 6, 12 and 24 months abstinence rate by gender and smoking partner status Abstinence time in months
Smoking partner Men n (%)a
Women n (%)a
Men n (%)a
Women n (%)a
6 12 24
74 (39.4) 58 (30.8) 42 (26.3)
82 (35.3) 61 (26.3) 46 (20.6)
351 (50.9) 319 (46.2) 277 (43.8)
199 (53.3) 175 (46.9) 155 (43.9)
a
No smoking partner
P* b 0.05 b 0.05 b 0.05
Cumulative abstinence using Kaplan-Meyer method. * Statistic significance of comparison between abstinent group and non abstinent group by smoking partner status using ChiSquare Test.
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Table 3 Relapse Relative Risk Men
No smoking partner Smoking partner Nicotine dependence (Fagerstro¨m) Social class I, II Social class III Social class IV, V
Women
Crude HR (CI 95%)
Adjusted HR (CI 95%)
Crude HR (CI 95%)
Adjusted HR (CI 95%)
1 1.46 1.03 1 0.98 1.29
1 1.48 1.03 1 0.99 1.32
1 1.66 1.05 1 1.28 1.56
1 1.63 1.05 1 1.31 1.45
(1.21–1.77) (0.99–1.08) (0.76–1.27) (1.03–1.63)
(1.21–1.80) (0.99–1.08) (0.76–1.29) (1.04–1.69)
(1.36–2.01) (1.00–1.09) (0.98–1.66) (1.21–1.99)
(1.33–1.99) (1.00–1.09) (1.00–1.72) (1.12–1.88)
Hazard ratio of relapse estimated by a Cox model, adjusted per: age, nicotine dependence and social class.
In contrast, no significant differences were found in any of the variables between women who had a smoking partner and women who did not (Table 1). We found significant gender differences in the current age ( p b 0.001), smoking initiation age ( p b 0.001) and the number of cigarettes per day ( p b 0.001) among the smoking partner group. No significant gender differences were found in 6th, 12th and 24thmonth abstinence rates in any group of partner smoking status (Table 2). In contrast to subjects with a smoking partner, among those who did not have smoking partner, women had the higher abstinence rate. To the same extent, we noted 1,0
Continuous abstinence
,8
,6
,4
,2
0,0 0
3
6
9
12
15
18
21
24
time in months Non smoking partner Smoking partner
Fig. 1. Abstinence time in men (n = 893) by smoking partner status.
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1,0
continuous abstinence
,8
,6
,4
,2
0,0 0
2
4
6
8
10
12
14
16
18
20
22
24
time in months Non smoking partner Smoking partner
Fig. 2. Abstinence time in women (n = 617) by smoking partner status.
that the difference of abstinence rate between those who had smoking partner and those who did not was higher among women than among men. At the 6th, 12th and 24thmonth, significant differences were observed by smoking partner status with lower proportion of abstinents among those who had smoking partner. The results of the multivariate Cox regression model are reported in Table 3 and show the likelihood of relapse as a function to exposure to smoking partner, adjusted by age, nicotine dependence and social class. Subjects whose partner was smoking at the beginning of the program appear to be more likely to relapse than subjects without smoking partner ( p b 0.001) and this in a more pronounced way in women than in men. We also observed significant differences (logrank test p b 0.001) in the abstinence curves comparing by partner smoking status (Figs. 1 and 2). Abstinence curves appear to decrease faster among the smoking partner group than among the other being this decline more pronounced in the first 3months, thereafter they take similar trajectories. This rate difference seems larger in abstinence curves of women than in men’s.
5. Discussion The results of the study show that having a smoking partner makes smoking cessation difficult. Before the cessation program started, men who did not have a smoking partner smoked less cigarettes than men whose partner was smoking hence this lower cigarettes consumption could make quitting
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easier (Freund, D’Agostino, Belanger, Kannel, & Stokes, 1992; Hymowitz et al., 1997). These differences in tobacco consumption could be explained differently in the group of men who do not have a smoking partner. Having a nonsmoking partner could be a positive influence even before the beginning of the cessation program. On the other hand, single men would not have negative influence from a smoking partner. In contrast, no differences in women tobacco consumption between groups of smoking status partner were observed. Among those who had a smoking partner, although no significant differences were found in the abstinence rate, men showed a longer and higher tobacco exposition than women because of their higher daily cigarette consumption, younger initiation age and later cessation. In fact, men present the highest morbidity and mortality from smoking-related diseases (Bobak, 2003; Prescott et al., 1998). One year after the beginning of the cessation program it appeared that almost half of women without smoking partner continued abstinent compared to a quarter of women with smoking partner. With a less pronounced difference than women, men having a smoking partner were also less likely to be abstinent than men without a smoking partner. Gender differences in the efficacy of nicotine replacement therapies (NRT) were examined in a meta-analytical review indicating that giving NRT in conjunction with high-intensity non pharmacological support was more important for women than for men (Cepeda-Benito, Reynoso, & Erath, 2004). NRT and low support were efficacious for women at only short-term follow-up, and men benefited from NRT at all follow-up regardless of the intensity of the adjunct support. In fact women generally appear to be less nicotine-dependent than men. Furthermore, sex differences in nicotine versus non-nicotine reinforcement as determinants of tobacco smoking were studied by Perkins, Jacobs, Sanders, & Caggiula (2002). The authors noted than whereas men smoke mostly to experience the direct psychoactive effects of nicotine, women seek other types of reinforcement from smoking like olfactory-taste and hand to mouth sensations, expectations that smoking will facilitate social interactions, reduce negative mood and prevent weight gain. All these suggestions would be in line with our findings indicating that having a smoking partner do influence more women than men in smoking cessation. Although our results suggest than women would be more sensitive to their partner smoking status then men, we did not find significant gender differences. Westmaas and Langsam (2005) in their recent study of predictors of cessation among self-quitters didn’t also find gender differences in quit rates but observed different predictors for men and women. Before elaborating further on results, we need to discuss some possible limitations of our study. One of these limitations could come from the heterogenicity of the nonsmoking partner group. This group includes single persons and subjects whose partners do not smoke. Nonsmoking partners can be either neversmokers or former smokers. In their study, cited in the introduction, Monden et al. reported that respondents whose partners were former smokers were almost five times more likely to quit smoking than single respondents and they were twice as likely to quit compared to those living with a never-smoker. So a former smoking partner might stimulate cessation more than a partner who has never smoked. Furthermore we only had information about partner smoking history at the beginning of the therapy. Another limitation would be that since follow-up was done by telephone, no biological measurement of long-term abstinence was possible. In regard to the advantages of our study, the prospective design and the large sample size are notable. Finally, as expected, our results are consistent with those found by Monden et al. and those found by McBride et al. (1998) indicating that having a smoking partner is a determinant of relapse one year after
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the beginning of the cessation program. Otherwise, our findings suggest that the effect of having a smoking partner is more important in the first 3 months of the cessation program in both men and women. An additional evidence about the relevance of social support in smoking cessation is given in this study. Interacting not just with the smoker, but also with his or her partner, could neutralize interpersonal influences making smokers more accessible to behavioural and pharmacological techniques. To increase our understanding of the process of stopping smoking, more research should examine the relevance of smoking status partner as determinant of smoking cessation.
References Bobak, M. (2003). Relative and absolute gender gap in all-cause mortality in Europe and the contribution of smoking. European Journal of Epidemiology, 18, 15 – 18. Borras, J. M., Fernandez, E., Schiaffino, A., Borrell, C., & La Vecchia, C. (2000). Pattern of smoking initiation in Catalonia, Spain, from 1948 to 1992. American Journal of Public Health, 90, 1459 – 1462. Cepeda-Benito, A., Reynoso, J., & Erath, S. (2004). Meta-analysis of the efficacy of nicotine replacement therapy for smoking cessation: Differences between men and women. Journal of Consulting and Clinical Psychology, 72, 712 – 722. Chandola, T., Head, J., & Bartley, M. (2004). Socio-demographic predictors of quitting smoking: How important are household factors? Addiction, 99, 770 – 777. Ezzati, M., & Lopez, A. D. (2003). Estimates of global mortality attributable to smoking in 2000. Lancet, 362, 847 – 852. Fagerstro¨m, K. O., & Scneider, N. (1989). Measuring nicotine dependence: A review of the FTND. Journal of Behavioral Medicine, 12, 159 – 182. Freund, K., D’Agostino, R., Belanger, A., Kannel, W., & Stokes, J. (1992). Predictors of smoking cessation: The Framingham study. American Journal of Epidemiology, 135, 957 – 964. Garcia, M., Schiaffino, A., Twose, J., Borrell, C., Salto, E., & Peris, M., et al. (2004). Smoking cessation in a population-based cohort study. Archivos de Bronchoneumologı´a, 40, 348 – 354. Gourlay, S. G., Forbes, A., Marriner, T., Pethica, D., & McNeil, J. J. (1994). Prospective study of factors predicting outcome of transdermal nicotine treatment in smoking cessation. British Medical Journal, 309, 842 – 846. Grupo de trabajo de la Sociedad Espan˜ola de Epidemiologı´a, de la Sociedad Espan˜ola de Medicina Familiar y Comunitaria. (2000). Una propuesta de medida de la clase social. Clasificacio´n de las clases sociales segu´n la ocupacio´n. Atencio´n Primaria, 25, 350 – 363. Hymowitz, N., Cummings, K. M., Hyland, A., Lynn, W. R., Pechacek, T., & Hartwell, T. D. (1997). Predictors of smoking cessation in a cohort of adult smokers followed for five years. Tobacco Control, 6, 57 – 62. Kottke, T., Battista, R., & DeFriese, G. (1988). Attributes of successful smoking cessation interventions in medical practice. A meta-analysis of 39 controlled trials. The Journal of the American Medical Association, 259, 2883 – 2889. McBride, C. M., Curry, S. J., Grothaus, L. C., Nelson, J. C., Lando, H., & Pirie, P. L. (1998). Partner smoking status and pregnant smoker’s perceptions of support for and likelihood of smoking cessation. Health Psychology: Official journal of the Division of Health Psychology. American Psychological Association, 17, 63 – 69. Monden, C. W., De Graaf, N. D., & Kraaykamp, G. (2003). How important are parents and partners for smoking cessation in adulthood? An event history analysis. Preventive Medicine, 36, 197 – 203. Morchon, S., Blasco, J. A., Rovira, A., Arias, C. N., & Ramon, J. M. (2001). Efectividad de una intervencio´n de deshabituacio´n taba´quica en pacientes con patologı´a cardiovascular. Revista Espan˜ola de Cardiologı´a, 54, 1271 – 1276. Park, E. W., Tudiver, F., Schultz, J. K., & Campbell, T. (2004). Does enhancing partner support and interaction improve smoking cessation? A meta- analysis. Annals of Family Medicine, 2, 170 – 174. Perkins, K., Jacobs, L., Sanders, M., & Caggiula, A. (2002). Sex differences in the subjective and reinforcing effects of cigarette nicotine dose. Psychopharmacology, 163, 194 – 201.
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Prescott, E., Osler, M., Andersen, P. K., Hein, H. O., Borch-Johsen, K., Lange, P., et al. (1998). Mortality in women and men in relation to smoking. International Journal of Epidemiology, 27, 27 – 32. Senore, C., Battista, R., Shapiro, S., Segnan, N., Ponti, A., Rosso, S., et al. (1998). Predictors of smoking cessation following physicians counseling. Preventive Medicine, 27, 412 – 421. Skaar, K. L., Tsoh, J. Y., McLure, J. B., Cinciripini, P. M., Friedman, K., & Wetter, D. W. (1997). Smoking cessation 1: An overview of research. Behavioral Medicine, 23, 5 – 13. Westmaas, J. L., & Langsam, K. (2005). Unaided smoking cessation and predictors of failure to quit in a community sample: Effects of gender. Addictive Behaviors, 30, 1405 – 1424.
Effects of partner smoking status and gender on long term abstinence rates of patients receiving smoking cessation treatment Paula Mancho´n Walsh *, Paloma Carrillo, Gemma Flores, Cristina Masuet, Sergio Morchon, Josep Maria Ramon Unidad de Deshabituacio´n Taba´quica, Servicio de Medicina Preventiva, c/ Feixa Llarga, s/n, 08907 L’Hospitalet de Llobregat, Barcelona, Spain
Abstract Aims: To assess the effect of partner smoking status on the success of a cessation program. Design: Prospective cohort. Setting: Smoking Cessation Unit in Hospital of Bellvitge (Hospitalet de Llobregat, Barcelona). Participants: A total of 1516 smokers of 10 or more cigarettes who started a smoking cessation program between January 1995 and December 2001 were included. Measurements: All patients gave information about smoking history and smoking partner status. Abstinence was determined by carbon monoxide exhaled. Findings: Significant differences were found in the abstinence rates at 12 months by smoking partner status: abstinence was achieved by 28.3% of patients with smoking partner, and by 46.5% of patients without smoking partner ( p b 0.001). Subjects whose partner was smoking at the beginning of the program appear to be more likely to relapse than subjects without smoking partners ( p b 0.001) and this is more pronounced in women than in men. However no significant gender differences were found in any group of smoking partner status. Conclusions: Having a smoking partner is a determinant of relapse 1year after the beginning of the cessation program. Interacting not just with the smoker, but also with his or her partner, could neutralize interpersonal influences making smokers more accessible to behavioural and pharmacological techniques. D 2006 Elsevier Ltd. All rights reserved. Keywords: Smoking; Smoking cessation; Gender; Partner; Spouses
* Corresponding author. 46 Chisholm Street, Darlinghurst, 2010 NSW, Australia. Fax: +61 93 260 78 49. E-mail address: [email protected] (P.M. Walsh). 0306-4603/$ - see front matter D 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.addbeh.2006.03.027
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1. Introduction Smoking is the most important preventable cause of morbidity and mortality in many developed countries (Ezzati & Lopez, 2003). It is a proven risk factor for a variety of health problems and involves also those exposed to environmental tobacco smoke. Smoking has a multifactorial dependence: physical, psychological and social. The interaction between nicotine addiction, sociodemographic characteristics and behaviour factors is relevant to predict the success of smoking cessation (Kottke, Battista, & DeFriese, 1988). It has been estimated that less than 50% of all smokers will quit permanently (Skaar et al., 1997). This shows the need to increase our understanding of the process of stop smoking. Therefore, the present study of determinants of cessation through a cessation program is relevant. A substantial body of evidence indicates that social support predicts the success of cessation attempts (Chandola, Head, & Bartley, 2004; Gourlay, Forbes, Marriner, Pethica, & McNeil, 1994; Park, Tudiver, Schultz, & Campbell, 2004). Furthermore, Chandola et al. (2004) and also Park et al. (2004) have recently reported that the presence of other smokers in the household is a negative predictor for smoking cessation. The relevance of the presence or absence of a partner in the smoking cessation was studied by Senore et al. (1998) who suggested that smokers, married or living common-law, were significantly more likely to quit than those who were single, divorced or widowed. However no clear conclusions have emerged about the influence of partner’s characteristics in quitting, especially the influence of partner’s smoking status. A retrospective cohorts study assessing the effect of partner smoking behaviour was carried out by Monden, De Graaf, & Kraaykamp (2003) indicating that the presence of a nonsmoking partner increases the likelihood of quitting. The aim of the study was to assess the effect of partners smoking status on the success of a cessation program.
2. Methods We undertook a prospective study of 1516 smokers of 10 or more cigarettes per day who were attended at the specialised Smoking Cessation Unit (SCU) of the Hospital de Bellvitge (L’Hospitalet de Llobregat, Barcelona, Spain), a University Teaching Hospital in the metropolitan area of Barcelona, between January 1995 and December 2001 and followed-up until May 2003. We excluded patients who had psychiatric history. This unit receives patients from the medical and surgical departments of the hospital, and from Primary Health Centres in the surrounding area. During this period, 2123 smokers visited the unit and received treatment for smoking cessation (70.0% with nicotine patches for nicotine replacement therapy (NRT), 13.5% with nicotine gums for NRT, 6.3% patches plus gums for NRT, 5.3% anxiolytics, 3.6% antidepressants (mainly bupropion, from the year 2000 onwards) and 0.6% antidepressants plus some type of NRT). The treatment was determined in relation to the subject’s characteristics and on the basis of cognitive-behavioural counseling and pharmacological therapy. Details of the cohort of smokers and measurements have been published (Morchon, Blasco, Rovira, Arias, & Ramon, 2001). During the first visit we collected sociodemographic and anthropometric information, medical history (presence of diabetes, cardiovascular diseases, chronic obstructive pulmonary disease and cancer) and data from smoking history including: onset age, current and past consumption (in cigarettes per day),
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type and brand of cigarettes smoked, number of prior attempts to quit, level of nicotine dependence by Fagerstro¨m Test (Fagerstro¨m & Scneider, 1989). The abstinence was confirmed during the visits with the measurement of carbon monoxide (CO) concentrations in exhaled air. Partner was defined as spousal equivalent residing with the patient. Smoking status of the partner was also collected in the first visit. Smoking partner was defined as smoking daily at the beginning of the program. Subjects with non-smoking partner were those who were singles and those whose partners did not smoke. Once treatment was initiated, follow-up visits were arranged every 15 days during the first 2 months and then at intervals of 3, 6, 9 and 12 months. The process of cessation was assessed in every visit (presence of withdrawal symptoms, relapse, adverse effects of pharmacological therapy and exhaled CO). In order to analyse long term abstinence and relapse we designed a telephone administered follow-up questionnaire. Between February and May 2003, smokers studied were interviewed by trained staff. The questionnaire included information on current smoking status and, in case of relapse, the date (month and year) when they started smoking again. Additional information on educational level and occupation was collected in the telephone survey, as well as information on passive smoking exposure and the opinion on current smoking regulations. Nonrespondents were excluded from the analyses. The outcome variable was the likelihood of relapse. We considered abstinence of smoking if expired CO b 6ppm. Participants were considered to relapse if they declared, after quitting smoking, to be daily or occasional smokers. Since follow-up was done by telephone, no biological measurement of long-term abstinence was possible. The time of relapse was calculated as the number of months from the date of quitting smoking to the date of the follow-up interview. Those patients who relapsed immediately after the intervention (n = 370) were assigned a 1-day time of follow-up. One independent variable was social class. Since no complete information on this variable was available from the initial visit, we used the information from the follow-up questionnaire. To derive the social class, we collected the information on occupation using the adaptation of the British General Classification proposed by the Spanish Societe of Epidemiology and Family and Community Medicine (Grupo de trabajo de la Sociedad Espan˜ola de Epidemiologı´a, de la Sociedad Espan˜ola de Medicina Familiar y Comunitaria, 2000). For both men and women, social class was assigned based on main own occupation, and in the case of retired or non-occupied persons, the last occupation was used. The social class of students and housewives was assigned based on the current or more recent occupation of the head of the household. Due to small numbers, we grouped classes as following: I–II, III and IV–V.
3. Statistical analysis Means and standard deviations were used to examine continuous variables, and stratified by sex, and were compared using Student Test. Chi square test was used to compare quit rates at 6, 12 and 24months by presence of smoking partner and by sex. Kaplan-Meyer method and the Log-Rank test were used to estimate cumulative abstinence (probability of continuing abstinent and 95% confidence intervals, CI) at 6, 12 and 24months by presence of smoking partner status.
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Table 1 Consumption and cessation characteristics by sex and smoking partner status Men
Women
Smoking partner Non smoking P* (n = 195) partner (n = 698)
Smoking partner Non smoking P* P** (n = 236) partner (n = 381)
Age 42.32 F 9.22 Initiation age 15.43 F 3,18 Number of cigarettes 33.22 F 13.66 smoked daily before cessation program Fagerstro¨m Test 7.57 F 2.18 Number of previous 1.86 F 1.44 quit attempts
48.95 F 12.02 15.91 F 4.53 30.26 F 14.26
7.76 F 2.05 2.53 F 2.77
b 0.001 39.19 F 9.61 NS 17.34 F 4.72 b 0.05 28.80 F 11.18
NS NS
7.48 F 2.26 2.63 F 0.32
Smoking partner
40.72 F 10.00 18.03 F 6.09 28.45 F 12.26
7.62 F 2.15 2.29 F 2.32
NS b 0.001 NS b 0.001 NS b 0.001
NS NS
NS NS
NS: not significant. * Statistical significance of comparison between smoking partner group and nonsmoking partner group using Student’s t-test. ** Statistical significance of comparison between men and women using Student’s t-test.
The relative risk (estimated as hazard rate ratios, HR) and 95% CI of relapse at the end of follow up was assessed with a multivariate Cox regression model, after checking the proportionality of the hazards during follow-up. Since there are well-recognised gender-based differentials in the dynamics of smoking in this population, all analyses were performed separately for men and women (Borras, Fernandez, Schiaffino, Borrell, & La Vecchia, 2000; Garcia et al., 2004). All statistical tests were 2-tailed and values of p b 0.05 were considered significant.
4. Results There were 1516 subjects, 59.0% were men (n = 895) and 41.0% women (n = 621). Mean age was 44.5 years (SD: 11.6 years). Men with a smoking partner smoked more at day ( p = 0.01) and were younger at the beginning of the cessation therapy than men without smoking partner ( p b 0.001) (Table 1). No significant differences were observed in smoking onset age, level of nicotine dependence or in the number of previous quit attempts.
Table 2 Comparison of 6, 12 and 24 months abstinence rate by gender and smoking partner status Abstinence time in months
Smoking partner Men n (%)a
Women n (%)a
Men n (%)a
Women n (%)a
6 12 24
74 (39.4) 58 (30.8) 42 (26.3)
82 (35.3) 61 (26.3) 46 (20.6)
351 (50.9) 319 (46.2) 277 (43.8)
199 (53.3) 175 (46.9) 155 (43.9)
a
No smoking partner
P* b 0.05 b 0.05 b 0.05
Cumulative abstinence using Kaplan-Meyer method. * Statistic significance of comparison between abstinent group and non abstinent group by smoking partner status using ChiSquare Test.
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Table 3 Relapse Relative Risk Men
No smoking partner Smoking partner Nicotine dependence (Fagerstro¨m) Social class I, II Social class III Social class IV, V
Women
Crude HR (CI 95%)
Adjusted HR (CI 95%)
Crude HR (CI 95%)
Adjusted HR (CI 95%)
1 1.46 1.03 1 0.98 1.29
1 1.48 1.03 1 0.99 1.32
1 1.66 1.05 1 1.28 1.56
1 1.63 1.05 1 1.31 1.45
(1.21–1.77) (0.99–1.08) (0.76–1.27) (1.03–1.63)
(1.21–1.80) (0.99–1.08) (0.76–1.29) (1.04–1.69)
(1.36–2.01) (1.00–1.09) (0.98–1.66) (1.21–1.99)
(1.33–1.99) (1.00–1.09) (1.00–1.72) (1.12–1.88)
Hazard ratio of relapse estimated by a Cox model, adjusted per: age, nicotine dependence and social class.
In contrast, no significant differences were found in any of the variables between women who had a smoking partner and women who did not (Table 1). We found significant gender differences in the current age ( p b 0.001), smoking initiation age ( p b 0.001) and the number of cigarettes per day ( p b 0.001) among the smoking partner group. No significant gender differences were found in 6th, 12th and 24thmonth abstinence rates in any group of partner smoking status (Table 2). In contrast to subjects with a smoking partner, among those who did not have smoking partner, women had the higher abstinence rate. To the same extent, we noted 1,0
Continuous abstinence
,8
,6
,4
,2
0,0 0
3
6
9
12
15
18
21
24
time in months Non smoking partner Smoking partner
Fig. 1. Abstinence time in men (n = 893) by smoking partner status.
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1,0
continuous abstinence
,8
,6
,4
,2
0,0 0
2
4
6
8
10
12
14
16
18
20
22
24
time in months Non smoking partner Smoking partner
Fig. 2. Abstinence time in women (n = 617) by smoking partner status.
that the difference of abstinence rate between those who had smoking partner and those who did not was higher among women than among men. At the 6th, 12th and 24thmonth, significant differences were observed by smoking partner status with lower proportion of abstinents among those who had smoking partner. The results of the multivariate Cox regression model are reported in Table 3 and show the likelihood of relapse as a function to exposure to smoking partner, adjusted by age, nicotine dependence and social class. Subjects whose partner was smoking at the beginning of the program appear to be more likely to relapse than subjects without smoking partner ( p b 0.001) and this in a more pronounced way in women than in men. We also observed significant differences (logrank test p b 0.001) in the abstinence curves comparing by partner smoking status (Figs. 1 and 2). Abstinence curves appear to decrease faster among the smoking partner group than among the other being this decline more pronounced in the first 3months, thereafter they take similar trajectories. This rate difference seems larger in abstinence curves of women than in men’s.
5. Discussion The results of the study show that having a smoking partner makes smoking cessation difficult. Before the cessation program started, men who did not have a smoking partner smoked less cigarettes than men whose partner was smoking hence this lower cigarettes consumption could make quitting
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easier (Freund, D’Agostino, Belanger, Kannel, & Stokes, 1992; Hymowitz et al., 1997). These differences in tobacco consumption could be explained differently in the group of men who do not have a smoking partner. Having a nonsmoking partner could be a positive influence even before the beginning of the cessation program. On the other hand, single men would not have negative influence from a smoking partner. In contrast, no differences in women tobacco consumption between groups of smoking status partner were observed. Among those who had a smoking partner, although no significant differences were found in the abstinence rate, men showed a longer and higher tobacco exposition than women because of their higher daily cigarette consumption, younger initiation age and later cessation. In fact, men present the highest morbidity and mortality from smoking-related diseases (Bobak, 2003; Prescott et al., 1998). One year after the beginning of the cessation program it appeared that almost half of women without smoking partner continued abstinent compared to a quarter of women with smoking partner. With a less pronounced difference than women, men having a smoking partner were also less likely to be abstinent than men without a smoking partner. Gender differences in the efficacy of nicotine replacement therapies (NRT) were examined in a meta-analytical review indicating that giving NRT in conjunction with high-intensity non pharmacological support was more important for women than for men (Cepeda-Benito, Reynoso, & Erath, 2004). NRT and low support were efficacious for women at only short-term follow-up, and men benefited from NRT at all follow-up regardless of the intensity of the adjunct support. In fact women generally appear to be less nicotine-dependent than men. Furthermore, sex differences in nicotine versus non-nicotine reinforcement as determinants of tobacco smoking were studied by Perkins, Jacobs, Sanders, & Caggiula (2002). The authors noted than whereas men smoke mostly to experience the direct psychoactive effects of nicotine, women seek other types of reinforcement from smoking like olfactory-taste and hand to mouth sensations, expectations that smoking will facilitate social interactions, reduce negative mood and prevent weight gain. All these suggestions would be in line with our findings indicating that having a smoking partner do influence more women than men in smoking cessation. Although our results suggest than women would be more sensitive to their partner smoking status then men, we did not find significant gender differences. Westmaas and Langsam (2005) in their recent study of predictors of cessation among self-quitters didn’t also find gender differences in quit rates but observed different predictors for men and women. Before elaborating further on results, we need to discuss some possible limitations of our study. One of these limitations could come from the heterogenicity of the nonsmoking partner group. This group includes single persons and subjects whose partners do not smoke. Nonsmoking partners can be either neversmokers or former smokers. In their study, cited in the introduction, Monden et al. reported that respondents whose partners were former smokers were almost five times more likely to quit smoking than single respondents and they were twice as likely to quit compared to those living with a never-smoker. So a former smoking partner might stimulate cessation more than a partner who has never smoked. Furthermore we only had information about partner smoking history at the beginning of the therapy. Another limitation would be that since follow-up was done by telephone, no biological measurement of long-term abstinence was possible. In regard to the advantages of our study, the prospective design and the large sample size are notable. Finally, as expected, our results are consistent with those found by Monden et al. and those found by McBride et al. (1998) indicating that having a smoking partner is a determinant of relapse one year after
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the beginning of the cessation program. Otherwise, our findings suggest that the effect of having a smoking partner is more important in the first 3 months of the cessation program in both men and women. An additional evidence about the relevance of social support in smoking cessation is given in this study. Interacting not just with the smoker, but also with his or her partner, could neutralize interpersonal influences making smokers more accessible to behavioural and pharmacological techniques. To increase our understanding of the process of stopping smoking, more research should examine the relevance of smoking status partner as determinant of smoking cessation.
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