Chronic Diseases and Injuries in Canada

Volume 33 · Number 1 · December 2012

Assessing the reach of nicotine replacement therapy as a preventive public health measure

S. J. Bondy, PhD (1, 2); L. M. Diemert, MSc (2); J. C. Victor, MSc (2, 3); P. W. McDonald, PhD (2, 4); J. E. Cohen, PhD (1, 5)

https://doi.org/10.24095/hpcdp.33.1.03

This article has been peer reviewed.

Author references:

1. Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
2. Ontario Tobacco Research Unit, University of Toronto, Toronto, Ontario, Canada
3. Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada
4. School of Public Health and Health Systems, University of Waterloo, Waterloo, Ontario, Canada
5. Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States

Correspondence: Susan Bondy, Dalla Lana School of Public Health, 6th Floor, 155 College Street, Toronto, ON M5T 3M7; Tel.: 416-978-0141; Fax: 416-978-8299;

Email: Sue.Bondy@utoronto.ca

Abstract

Introduction: Access to Nicotine Replacement Therapy (NRT) is a key public health intervention to reduce smoking. We assessed prevalence and correlates of use of NRT in Ontario, where NRT is available without prescription.

Methods: Participants were a representative sample of 2262 adult smokers in the Ontario Tobacco Survey cohort. Prospectively measured use of NRT over a 6-month period was reported in relation to smoking behaviour and history, attempts to quit, receipt of other supports for cessation supports and attitudes toward NRT.

Results: Overall, 11% of smokers used NRT over the six-month follow-up period.

Prevalence was 25% among the 27% of smokers matching clinical guidelines that recommend NRT as a therapeutic option, and low among smokers not trying to quit.

Conclusion: With increasing accessibility of NRT, further surveillance and research are warranted to determine the impact of the reach and benefits of NRT, considering both the general and targeted smoking populations.

Keywords: smoking cessation, nicotine, evidence-based medicine, population surveillance

Introduction

In trials, nicotine replacement therapy (NRT) nearly doubles the likelihood of smoking cessation,^{Endnote 1–3} and so has the potential to reduce the disease burden from tobacco.^{Endnote 4} Ensuring access to NRT is a required public health intervention for all nations, including Canada, that have signed the World Health Organization Framework Convention on Tobacco Control.^{Endnote 5,Endnote 6} Several jurisdictions (e.g. Canada, United States, United Kingdom, Australia and much of Europe) have made NRT available over the counter (OTC) without prescription, while others propose to do the same.

Several authors have stated that measures to make NRT more available have increased its use,^{Endnote 7,Endnote 8} while others argue it is still underutilized.^{Endnote 9–11} However, few reports have described uptake of NRT at population levels where these have been made available OTC.^{Endnote 12–14} The cost of NRT in Canada has been described both as a serious barrier^{Endnote 15} and a contribution to inequality in access to effective cessation services.^{Endnote 16} New publicly funded programs are being considered and enacted to increase access and use of this treatment.^{Endnote 17} The effectiveness of making NRT readily accessible should be evaluated with quantitative surveillance data on the size of the ideal target population as well as the proportion of the population reached by the intervention.^{Endnote 18} These data have not been available in Canada.

This report addresses a gap in knowledge about the size of the population of smokers representing unmet need for increased use of NRT in Ontario. There is some controversy about whether all, or only specific, smokers should be encouraged to use NRT, and if medication is over-promoted to smokers who do not need it to quit.^{Endnote 19} Therefore, we report on prevalence of NRT use in all smokers and those matching de jure guidelines applied in programs providing publicly funded NRT in Ontario^{Endnote 20} and elsewhere^{Endnote 1,Endnote 21} to quantify reach of this preventive measure in smokers representing targeted and not targeted users. Targeting criteria used are drawn from evidence-based reviews,^{Endnote 22} including Cochrane reports ^{Endnote 1,Endnote 2} and meta-analyses.^{Endnote 23,Endnote 24} These have concluded that there is strong evidence of the benefit of NRT for smokers who are both nicotine dependent (largely defined as consuming more than 10 to 15 cigarettes per day) and motivated to quit smoking.^{Endnote 1,Endnote 2} It is also recommended as a best practice that NRT users receive behavioural counselling, to achieve the additive effects of both interventions.^{Endnote 1,Endnote 2,Endnote 22} Authors who advocate that NRT is suited to all smokers without restrictions^{Endnote 8,Endnote 11,Endnote 25} argue that NRT may be effective without clinical help and that the number of cigarettes smoked per day may not correlate with the presence or severity of withdrawal symptoms targeted by the medication or the perceived need for the medication.^{Endnote 11,Endnote 24–33} Others have suggested there may be increased use of NRT for reasons other than quitting (e.g. to postpone quitting or to cut down but continue smoking), and they have indicated a need to monitor such potential trends.^{Endnote 34–38}

Evidence for the effectiveness of NRT obtained OTC also remains weaker than for clinical settings. This will depend on who uses it and how it is used, which makes patterns of NRT use important to monitor.^{Endnote 39}

Methods

Study population and design

We conducted our research in Ontario, Canada, a province with a comprehensive Tobacco Control Strategy. Throughout the study period, NRT patch and gum forms were readily available OTC at pharmacies, grocery stores and convenience stores. No other forms of NRT (e.g. inhaler, lozenge) were licensed for use, and NRT products were licensed for use in immediate cessation (i.e. not to be used while still smoking or quitting gradually). Most OTC products were paid for privately^{Endnote 40} and not covered in universal drug benefits.

Data were from the Ontario Tobacco Survey, a population-representative telephone survey and panel study of adult smokers^{Endnote 41,Endnote 42} recruited from July 2005 through June 2007 (for whom NRT attitude questions were included in the interview). Of 2681 smokers at baseline (daily or occasional smokers who had smoked within 30 days and 100 or more cigarettes in their lifetime), 2262 had complete baseline and first six-month follow-up data (84.4% retention). Approximately 12% of the sample were studied during a time when they could have been eligible for a free, government-funded NRT distribution program.^{Endnote 20}

The University of Toronto and the University of Waterloo provided ethical approval to conduct and use the data from the Ontario Tobacco Survey.

Study variables

Respondents were asked at baseline if they had ever or never previously used NRT. At the six-month interview, respondents were asked if they had used either the nicotine patch, gum or inhaler in the preceding six months ''to quit or reduce smoking.'' We defined six-month period prevalence of NRT use as any use of NRT during follow-up, regardless of history.

A number of smokers' characteristics were considered as predictors of NRT use. These included factors known to be associated with quit attempts and measures derived to reflect practice guidelines around NRT (intention to quit; indications of nicotine dependence assessed through consumption level, typically 10 or more cigarettes; and receipt of behavioural supports for cessation). Six-month intention to quit smoking was obtained at baseline by asking, ''Are you planning to quit smoking within the next month, within the next six months, sometime in the future, beyond six months, or are you not planning to quit?'' Endnote 43,Endnote 44 A second derived covariate classified smokers as intending to quit if they intended to do so at baseline or reported having made a serious attempt to quit during the six-month follow-up. We calculated baseline consumption, time to first cigarette after wakingEndnote 45 and Heaviness of Smoking Index.Endnote 46 Respondents were also asked if they considered themselves ''very,'' ''somewhat'' or ''not at all'' addicted to cigarettes.Endnote 47 Derived variables were also created for combinations of indications for NRT (defined as above).

Respondents' confidence in their ability to quit was measured in four levels from ''not at all'' through ''very confident'' that they would succeed if they decided to quit completely in the next six months. Reports of having made a serious attempt to quit smoking, having received physician advice to quit smoking and using specific behavioural supports for cessation were obtained at baseline and follow-up. Attitudes toward pharmaceutical smoking cessation aids were determined at baseline from agreement with the following statements: ''stop-smoking medications make it easier to quit than trying to quit on your own''; ''the cost of stop-smoking medications makes it difficult to use them''; ''stop-smoking medications are hard to get''; and ''the risk of side effects from stop-smoking medications concerns you.'' The demographic characteristics considered were age, sex, education and rural residence.Endnote 48 Rural residence was considered as a potential indicator of relatively poorer access to NRT (due to any of the following: limited access to primary care providers who might recommend pharmacotherapy; larger distances to pharmacies that carry the product; or greater cost of the product in more remote locations).

Analyses

Use of NRT was reported in bivariate analyses and multivariable models relating NRT use to smoker demographics, baseline attitudes and smoking characteristics and to behaviours related to smoking cessation.

We obtained prevalence ratios for NRT use in relation to covariates using log-binomial regression models including all smokers. We restricted this to smokers who reported making a quit attempt during the six-month follow-up period. Regression diagnostics included assessment for non-linearity and multi-colinearity. All descriptive and multivariable analyses used sampling weights for the Ontario Tobacco Survey smoker cohort, which were calculated to produce estimates representative of the underlying population of Ontario adult recent smokers at baseline.^{Endnote 41} Variance estimates took the sampling design into account and were obtained using the Taylor series expansion methods in Stata version 11 (StataCorp LP, College Station, TX, United States).^{Endnote 49}

Results

Table 1 presents the characteristics of 2262 respondents with complete six-month follow-up data, along with six-month prevalence of NRT use by smoker characteristics, predictors of cessation and attitudes toward NRT. Similarity of the sample to the underlying population is reported elsewhere.^{Endnote 41,Endnote 42} In this cohort 64% smoked 10 or more cigarettes per day at baseline, and 52% reported smoking within 30 minutes of waking. Most respondents (83%) had previously tried to quit, and 47% had previously used NRT. In our sample, 40% reported an intention to quit smoking at baseline, which is somewhat lower than estimates from other sources for the same population (55%–59%,^{Endnote 50,Endnote 51} although with different measures of intention^{Endnote 52}).

 

Between baseline and the first six-month follow-up, 11% reported using NRT (see Table 1). Overall, 26% reported making a serious quit attempt and just 2% of all smokers in the sample were first-time users of NRT in this six-month period. There was no detectable difference in NRT use among the 12% of respondents whose time on study coincided with a free NRT give-away program in Ontario (data not shown).

Table 1 also shows the prevalence of NRT use by smoker characteristics. Use was significantly higher among respondents who intended to quit altogether (using various measures), who made serious attempts to quit, and who had received behavioural or professional supports for cessation. NRT use was also positively associated with baseline cigarette consumption, lifetime number of quit attempts, prior use of NRT, perceived addiction, confidence in ability to quit and attitudes toward stop-smoking medications. Age, sex or education were not associated with NRT use; nor was rural/urban residence in our analyses (data not shown).

Among smokers who intended to quit altogether (either a prior intention to quit at baseline or a reported serious attempt during the follow-up period) and a baseline consumption of 10 or more cigarettes per day (the 27% of smokers meeting explicit practice guidelines), 25% used NRT. The highest prevalence of NRT use observed by subgroup, at 31%, was among smokers who exactly met the most conservative eligibility criteria and also reported past or recent receipt of behavioural support (Table 1).

Table 2 shows the characteristics and responses of the 301 individuals who used NRT in the six-month follow-up window. The large majority of NRT users had a history of quit attempts at the baseline interview (91%), expressed an intention to quit (as baseline intention to quit [61%] or attempt in follow-up [72%]), had used NRT at or before the baseline interview (80%) and reported themselves to be ''very addicted'' (77%). NRT users tended to believe stop-smoking medications made it easier to quit (84%) and that they were readily available (88%), but also that the cost made it difficult to use them (58%).

Table 3 shows the results of simultaneously adjusted log-binomial regression models predicting use of NRT during six-month follow-up among all smokers and among only those who reported attempting to quit during the same follow-up window. Demographic characteristics including age and education were not associated with NRT use after adjustment for smoking behaviour and history.

Among all smokers, history of quit attempts at baseline was unrelated to NRT use. However, respondents were over 6 times more likely to use NRT if they reported a serious attempt to quit smoking over the same six-month follow-up period; they were also more likely to use NRT if they had previously used it. Both a lifetime history of physician advice or behavioural supports for cessation and reported receipt of advice or support during the same follow-up window were statistically significant predictors of NRT use in the fully adjusted model. Consumption-based smoking behaviour measures at baseline (number of cigarettes per day and time to first cigarette) and confidence in ability to quit were not statistically significant after adjustment for history of quitting behaviour.

When the analysis of predictors of NRT use was restricted to smokers who made a serious attempt to quit in the six-month time frame, history of support for cessation was positively associated with NRT use. However, after adjustment for this, behavioural support reported during the same reference period was not related to NRT use. (Additional models, not shown, indicate substitution effect where either past or sametime period history of behavioural supports were positively associated with NRT use, and the two were correlated.) Unlike the associations found among all smokers, among those who made a quit attempt higher number of cigarettes per day at baseline was positively associated with reported use of NRT in the next six months, but not previous quit attempts. A ''don't know'' response to the attitude item about price of NRT was negatively correlated with use. Conversely a ''don't know'' response to the question on ease of access was positively associated with use (p = .048 for the contrast).

 

Discussion

In Ontario, 30% of those making a quit attempt used NRT. This is lower than that found in a study by Reid and Hammond^{Endnote 53} that showed that a fairly stable 50% of smokers making quit attempts over two years used medication. Our study is the first to consider which smokers should be using NRT, based on evidence-based guidelines for NRT effectiveness. Of the 27% of smokers who met guidelines for use in our analysis, just under 25% used NRT. This leaves roughly 20% of all Ontario smokers as, arguably, an ''ideal'' but unreached target population.

Despite the importance of quantitative data on the reach of public health interventions,Endnote 18 few reports have estimated population prevalence of NRT in specific time periods. Population health surveys often lack the precision to quantify NRT conditional on smoking and quit attempts. In 1990, in a sample of Minnesotans with access to NRT through insurance plans with co-payment,Endnote 54 roughly half of those trying to quit used aids, primarily pharmacotherapy; in California between 1999 and 2002, 17% of all smokers used pharmacotherapy in the past year.Endnote 55 In the U.S. in 2003, 32% reported a quit attempt in the past year using medication,Endnote 56 whereas in 2010, 30% of all smokers used medication in the past year.Endnote 57 In the United Kingdom, where NRT is publically funded through the National Health Service, roughly half of smokers used it in recent quit attempts.Endnote 12

Not all smokers feel medications are necessary,Endnote 13,Endnote 14,Endnote 58 and many quit on their own.Endnote 56,Endnote 59 However, Ontario utilization rates may not reflect lack of interest; in 2006, a provincial NRT giveaway attracted 16 000 people in six weeks.Endnote 60 We found no difference in use by education, as anticipated and seen in American data;Endnote 57 however, we did not have access to more direct measures of insurance or ability to pay.Endnote 40

Earlier studies showed that ever users of NRT tend to be more dependent or smoke more cigarettes.Endnote 7,Endnote 45,Endnote 54,Endnote 61–63 In our study, number of cigarettes smoked did not predict NRT use, which contrasts with several retrospective studies;Endnote 7,Endnote 54 however, cigarette consumption was associated with NRT use among smokers trying to quit, as elsewhere.Endnote 12 Among all smokers, lower consumption may follow from efforts to cut down.Endnote 64 American guidelines on NRT cite a minimum number of cigarettes primarily because of a lack of clinical trials data for people who smoke less.Endnote 1–3 Australian practice guidelines, in contrast, state that NRT should be offered with evidence of dependence.Endnote 65 We found that over 90% of respondents who smoked fewer than 10 cigarettes at baseline and who used NRT perceived themselves to be very or somewhat addicted.

Intending or actually trying to quit were significantly associated with NRT use, which was consistent with findings from California.^{Endnote 63} Just 3% of Ontarians who neither intended nor tried to quit used NRT. This does not suggest widespread use of NRT with no intention to quit, as has been suggested as a negative consequence of NRT availability.^{Endnote 34–38,Endnote 66,Endnote 67} However, we asked about NRT use ''to quit or reduce smoking'' (to exclude use of services for a different health reason) and may not have captured all NRT use, for example, by people who planned only to reduce, but not discontinue, smoking. Intention to quit may also change or be unreliably measured.^{Endnote 68} We addressed this by considering intention with and without subsequent attempts to quit.

In our study, smokers who received non-pharmaceutical support were more likely to use NRT, whereas previous studies report mixed findings. NRT users rarely used behavioural supports in Minnesota,^{Endnote 54} whereas in California^{Endnote 7} and Australia^{Endnote 62} NRT users were more likely to use behavioural supports. Ontario data may reflect consistency of advice from professionals and packaging to use behavioural supports. However, as in most studies,^{Endnote 69} we have no information on the intensity or quality of the supports received. Our study, like others,^{Endnote 45,Endnote 61} found that past use of NRT was associated with prospective use, but some use may have started before the baseline interview and continued into follow-up. Not surprisingly, smokers with positive attitudes towards NRT were more likely to use these medications.^{Endnote 62,Endnote 70–72}

Our analysis used data to 2008, after which time NRT manufacturers were permitted to advertise NRT for use while cutting down to quit. Future studies should ask about NRT for use only to cut down or only when one cannot smoke.^{Endnote 63,Endnote 66,Endnote 67,Endnote 73} Our study will provide baseline data to evaluate the impact of these changes and recent initiatives to publicly fund NRT.

Conclusion

Widely available NRT is a recommended population-based measure to reduce tobacco-related health burden. In this population, where NRT was available over the counter and use of supplemental behavioural supports advocated, most smokers trying to quit were not using NRT. Approximately 20% of Ontario smokers were an ''ideal'' but unreached target population for NRT use. Ontario has recently implemented new initiatives to increase the accessibility of NRT. As such, further surveillance and research are warranted to determine the impact of the reach and benefits of NRT, considering both the general and targeted smoking populations.

Acknowledgements

Support for this research was provided by the Ontario Tobacco Research Unit, which receives funding from the Ontario Ministry of Health Promotion and Sport, and the University of Toronto Dalla Lana School of Public Health.

The authors have no conflicts of interest. None of the authors work or have worked in any capacity with, or received remuneration from, the manufacturers or sellers of tobacco products or nicotine replacement therapy products. The lead author was an investigator on The Stop Smoking for Ontario Patients study funded by the Ontario Ministry of Health and Long-Term Care and which received support in kind from manufacturers of nicotine replacement therapy products without intellectual restriction.

References